Giant Cell Arteritis (GCA)

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1. Clinical Overview

Summary

Giant Cell Arteritis (GCA) is the most common form of primary systemic vasculitis in adults. It is a granulomatous Large Vessel Vasculitis predominantly affecting the aorta and its major branches, specifically the extracranial branches of the carotid artery (Temporal, Ophthalmic, Posterior Ciliary).

The Critical Danger: The Ophthalmic Artery supplies the optic nerve. Inflammation here causes Anterior Ischaemic Optic Neuropathy (AION). If untreated, irreversible blindness can occur within hours. The Golden Rule: Suspicion alone is an indication for high-dose steroids. "Time is Vision".

Epidemiology

Incidence and Prevalence:

• Incidence: 15-25 cases per 100,000 population aged > 50 years in Northern Europe. [1,2]
• Age: Strictly > 50 years (diagnostic criterion). Peak incidence 70-80 years. If patient is less than 40, consider Takayasu's arteritis instead.
• Gender: Female preponderance (2-3:1 ratio). [1]
• Geography: Highest incidence in Scandinavia and Northern Europe (particularly individuals of Northern European descent). Much rarer in Asian and African populations. [2]
• Seasonal Variation: Some studies suggest higher incidence in summer months, possibly linked to infectious triggers.

Risk Factors and Associations:

• Genetics: Strong HLA-DRB1*04 association, particularly *0401 and *0404 alleles. [17]
• Ethnicity: Predominantly affects Caucasians of Scandinavian/Northern European ancestry.
• Comorbidity: Strong overlap with Polymyalgia Rheumatica (PMR). [17,18]
  • 40-60% of GCA patients have concurrent PMR symptoms
  • 10-20% of PMR patients develop GCA during disease course
  • "PMR-GCA spectrum disorder" concept gaining acceptance
• Cardiovascular Risk: Increased risk of cardiovascular events (MI, stroke) both during active disease and long-term. [17]
• Infectious Triggers: Controversial association with VZV, parvovirus B19, and Mycoplasma pneumoniae reactivation.

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2. Pathophysiology (The "Wall Attack")

The Anatomy of the Attack

GCA is not just "inflammation"; it is a highly specific T-cell mediated attack on the Internal Elastic Lamina of medium and large arteries.

Step 1: The Trigger (The Unknown Antigen)

• The process starts in the Adventitia (the outer layer of the vessel), not the lumen.
• Dendritic Cells (specifically Tol-Like Receptor positive dendritic cells) residing in the adventitia detect an unknown antigen.
• Theories: Parvovirus B19? Varicella Zoster? A self-antigen in the elastic tissue?
• These dendritic cells become activated and recruit CD4+ T-Cells.

Step 2: The Invasion (Th1 and Th17 Axes)

The T-cells penetrate the vessel wall, differentiating into two distinct lineages:

1. The Th1 Axis (The Granuloma Builder):
   • Secretes Interferon-Gamma (IFN-y).
   • This activates Macrophages to fuse into Giant Cells.
   • These cells release Matrix Metalloproteinases (MMPs) which physically chew up the elastic lamina.
   • Note: This axis is notoriously Steroid-Resistant. This explains why some inflammation persists even on Prednisolone.
2. The Th17 Axis (The Systemic Fire):
   • Secretes IL-17 and IL-6.
   • IL-6 travels to the liver and triggers the acute phase response (High CRP, High Fibrinogen).
   • Note: This axis is Steroid-Sensitive and is also the target of Tocilizumab.

Step 3: The Blockage (Luminal Stenosis)

• The vessel wall does not just get inflamed; it undergoes Remodeling.
• Platelet Derived Growth Factor (PDGF) and VEGF released by macrophages cause Myofibroblasts to migrate to the Intima (inner layer).
• They proliferate, creating a thick layer of "neointima".
• The Result: The lumen (pipe) narrows concentrically. Blood flow drops.
• The Crisis: When the lumen of the Ophthalmic Artery narrows by > 90%, a tiny thrombus precipitates total occlusion -> Stroke of the Eye (AION).

Image: Immunopathology of GCA

Image

Figure 1: The dual Th1/Th17 pathways leading to intimal hyperplasia.

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3. Clinical Features

1. Cranial Symptoms (The "Classic" GCA)

• Headache (60-90%): [3]

  • Often the first symptom and most common presentation.
  • Character: Severe, boring, throbbing, unremitting.
  • Location: Temporal (temples), Occipital (back of head), or diffuse.
  • Quality: Different from patient's usual headaches; new-onset in elderly.
  • Red Flag: A "new headache" in anyone > 50 years requires immediate ESR/CRP check.
  • Pearl: The headache may persist despite normal inflammatory markers in 5-10% of cases (seronegative GCA).

• Scalp Tenderness (Allodynia) (40-70%): [3]

  • The inflamed temporal artery irritates overlying superficial nerves.
  • Patient Quote: "It hurts to brush my hair" or "I can't sleep on that side" or "Combing my hair is painful."
  • Physical finding: Tender, thickened, nodular, or non-pulsatile temporal arteries on palpation.
  • May extend to scalp necrosis in severe cases (rare).

• Jaw Claudication (34-67%): [3]

  • Pathognomonic sign with highest specificity (> 95%) for GCA. [3]
  • Pain in the masseter/temporalis muscles that starts after 1-2 minutes of chewing.
  • Pain intensifies with continued mastication and resolves with rest.
  • Mechanism: Stenosis of the Facial/Maxillary arteries creates "angina of the jaw."
  • Clinical Pearl: Ask specifically: "Do you get pain in your jaw when eating a steak or bagel?"
  • May extend to tongue claudication (pain while talking/eating).

• Tongue/Scalp Necrosis (Rare, less than 1%):

  • Lingual artery occlusion → tongue turns white then black.
  • Medical emergency requiring IV Heparin + high-dose IV steroids + urgent rheumatology consult.
  • May require surgical debridement.

2. Ocular Symptoms (The Emergency - "Time is Vision")

Vision loss occurs in 15-20% of untreated patients and represents a medical emergency. [13,14,15]

• Amaurosis Fugax (Transient Visual Loss) (10-30%): [14,15]

  • Transient monocular blindness lasting seconds to minutes.
  • Classic description: "Curtain coming down over my eye" or "reviewing the troops through a veil."
  • This is a TIA of the retina and indicates impending permanent blindness.
  • Action Required: Immediate IV methylprednisolone 1g STAT. Admit for monitoring.
  • Window to permanent vision loss: Hours to days.

• Diplopia (Double Vision) (6-15%): [14]

  • Caused by ischaemia of the vasa nervorum supplying CN III, IV, or VI.
  • Often precedes blindness (harbinger symptom).
  • May be horizontal or vertical depending on nerve involved.
  • Usually resolves with steroid treatment if caught early.

• AION (Anterior Ischaemic Optic Neuropathy) (5-15%): [13,14,15,16]

  • Sudden, painless, profound loss of vision (usually irreversible).
  • Mechanism: Occlusion of posterior ciliary arteries supplying the optic nerve head.
  • Fundoscopy: Pale, swollen optic disc ("chalky white" or pallid disc swelling).
  • Visual field defect: Typically altitudinal (upper or lower half).
  • Prognosis: Once established, vision rarely returns (less than 10% recovery). Treatment is to save the contralateral eye.
  • Bilaterality Risk: 25-50% risk of fellow eye involvement within days if untreated. [14,15]

• Central Retinal Artery Occlusion (CRAO) (1-3%): [14]

  • Fundoscopy: "Cherry red spot" with pale retina.
  • Differentiate from AION (both can occur in GCA but AION more common).

• Other Ocular Manifestations:

  • Posterior ischaemic optic neuropathy (PION) - rare
  • Choroidal infarction
  • Cotton-wool spots
  • Ocular ischaemic syndrome

3. Systemic Symptoms (The "Occult" GCA / GCA-PMR Overlap)

Up to 40% of patients have NO headache ("Occult GCA" or "Headache-negative GCA"). [1,2] They present with:

• Polymyalgia Rheumatica (PMR) Symptoms (40-60%): [17,18]

  • Bilateral pain and stiffness in shoulder and pelvic girdles.
  • Morning stiffness lasting > 45 minutes (often > 1 hour).
  • Difficulty with activities: raising arms overhead, rising from chair, getting out of bed.
  • Clinical Rule: If a PMR patient develops a new headache → Treat as GCA until proven otherwise.
  • No objective muscle weakness (can eventually force movement through pain).

• Constitutional Symptoms (40-70%): [1,2]

  • Fever: Low-grade to high (up to 39-40°C), often with rigors.
  • Fatigue: Profound, debilitating fatigue disproportionate to other symptoms.
  • Weight Loss: Unintentional weight loss (> 5 kg in weeks).
  • Night Sweats: Drenching, requiring clothing change.
  • Anorexia: Loss of appetite.
  • Can mimic malignancy, infection (TB, endocarditis), or fever of unknown origin (FUO).

• Large Vessel Vasculitis (LVV) (15-80% on imaging): [2,20]

  • Inflammation of the aorta and its major branches (subclavian, axillary, carotid).
  • Limb Claudication: Pain in arms with exertion (hanging washing, carrying shopping).
  • Pulse Deficit: Differing blood pressure between arms (> 10-15 mmHg difference).
  • Vascular Bruits: Audible over subclavian, carotid, or abdominal aorta.
  • Aortic Complications:
    • Aortic aneurysm (thoracic or abdominal) - late complication (years later)
    • Aortic dissection (rare but catastrophic)
    • Aortic regurgitation
  • Screening: Annual chest X-ray or echocardiography for aortic surveillance recommended. [2]

4. Respiratory Symptoms (10-20%)

• Persistent Dry Cough: Due to vasculitis of bronchial arteries or cough receptor sensitization. [1]
• Often misdiagnosed as bronchitis or upper respiratory infection.
• May be the sole presenting symptom in rare cases.

5. Neurological Symptoms (5-15%)

• Stroke/TIA: Carotid or vertebral artery stenosis/occlusion. [20]
• Peripheral Neuropathy: Mononeuritis multiplex (rare).
• Hearing Loss: Auditory artery involvement (rare).
• Cognitive Impairment: Reversible with treatment in some cases.

6. Atypical Presentations (less than 5%)

• Fever of Unknown Origin (FUO): Isolated fever without localizing symptoms. [1]
• Isolated PMR: PMR symptoms without headache (subclinical cranial disease). [18]
• Depression/Confusion: Particularly in elderly patients.
• Cardiac: Myocarditis, pericarditis (very rare).

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4. Diagnosis Strategy

The 2022 ACR/EULAR Classification Criteria for GCA [7,9]

A scoring system (NOT diagnostic criteria but useful framework):

• Age ≥50 years: Mandatory
• Score ≥6 points indicates GCA:
  • New localized headache: +2
  • Temporal artery abnormality on examination (tender, thickened, reduced/absent pulse): +2
  • ESR ≥50 mm/hr OR CRP ≥10 mg/L: +3
  • Halo sign on temporal artery ultrasound: +5
  • TAB positive for GCA: +5

Note: These are classification criteria for research. Clinical diagnosis and treatment initiation should NOT wait for score calculation.

1. Inflammatory Markers

Essential First-Line Tests:

• ESR (Erythrocyte Sedimentation Rate): [1,2,3]

  • Usually markedly elevated (often > 50 mm/hr, frequently > 100 mm/hr).
  • Westergren method is standard.
  • Sensitivity: 76-86% (not 100% - important caveat). [3]
  • May be normal in 4-10% of biopsy-proven GCA ("seronegative GCA"). [3]

• CRP (C-Reactive Protein): [1,2,3]

  • Usually elevated (> 10 mg/L, often > 50 mg/L).
  • More specific than ESR for acute inflammation.
  • Rises and falls faster than ESR (better for monitoring treatment response).
  • Sensitivity: 81-86%. [3]

• Combined ESR and CRP:

  • Negative predictive value > 97% when both normal. [3]
  • However, 4-10% of GCA cases have normal or minimally elevated markers. [3]
  • Clinical suspicion trumps laboratory values.

Other Blood Tests:

• Full Blood Count (FBC):

  • Thrombocytosis (elevated platelets > 400 x10⁹/L): Subtle but specific marker. [3]
  • Normochromic normocytic anaemia (anaemia of chronic disease).
  • Normal white cell count (or mild elevation).

• Liver Function Tests (LFTs):

  • Elevated alkaline phosphatase (ALP) in 30-50% of cases.
  • Mild transaminase elevation possible.

• Other Markers:

  • Hypoalbuminemia (low albumin).
  • Elevated ferritin.
  • Elevated fibrinogen.
  • Normal creatine kinase (CK) - helps distinguish from myositis.

2. Temporal Artery Ultrasound (The New Gold Standard) [6,8]

The "Halo Sign": [6,8]

• A dark (hypoechoic) ring around the artery lumen representing oedema in the thickened, inflamed vessel wall.
• Diagnostic Criteria: Wall thickness > 0.34 mm for common superficial temporal artery; > 0.42 mm for frontal branch. [6]
• Best visualized in longitudinal and transverse views.

Compression Sign: [6]

• The inflamed artery does NOT collapse when compressed with the ultrasound probe (it is a stiff pipe).
• Normal arteries collapse easily.

Advantages: [6]

• Non-invasive: No surgical procedure required.
• Rapid: Results available immediately.
• Repeatable: Can be performed serially.
• Extended Assessment: Can assess facial, occipital, and axillary arteries in same sitting (large vessel involvement).

Performance: [6]

• Sensitivity: 77-87% in expert hands.
• Specificity: 89-96%.
• Operator-dependent: Requires trained sonographer/rheumatologist.
• Temporal Window: Halo sign diminishes rapidly after steroid initiation (usually gone by 2-4 weeks). [8]

Current Guideline Position: [2]

• EULAR/BSR 2020: Temporal artery ultrasound recommended as first-line diagnostic test where expertise available. [2]
• If positive → confirms diagnosis.
• If negative but high clinical suspicion → proceed to biopsy or PET-CT.

3. Temporal Artery Biopsy (TAB) - The Historical Gold Standard [23,24,25]

Indications: [2]

• Ultrasound negative or unavailable AND clinical suspicion remains high.
• Atypical presentations requiring histological confirmation.
• Medicolegal requirement in some jurisdictions.

Technique: [23]

• Remove 1-2 cm segment of superficial temporal artery (frontal branch preferred).
• Performed under local anaesthesia as day-case procedure.
• Mark pulsatile segment preoperatively with Doppler.

Histopathology: [23]

• Classic Findings:

  • Granulomatous inflammation of vessel wall.
  • Multinucleated giant cells (50-75% of cases - NOT required for diagnosis).
  • Fragmentation/destruction of internal elastic lamina.
  • Intimal hyperplasia with luminal narrowing.
  • Mononuclear infiltrate (lymphocytes, macrophages).

• Skip Lesions: [24,25]

  • Inflammation is segmental/patchy along artery length.
  • A short biopsy segment may miss inflamed area.
  • False negative rate: 10-20% (even with adequate length). [24,25]
  • Recommendation: Biopsy ≥1 cm length (ideally 1.5-2 cm). [23,25]

Timing Considerations: [2,25]

• Histological changes persist for 2-4 weeks after steroid initiation. [25]
• NEVER DELAY TREATMENT to arrange biopsy.
• Ideal: Biopsy within 7-10 days of starting steroids (but still diagnostic up to 4 weeks).
• Positive biopsy after steroid treatment still confirms diagnosis.

Sensitivity and Limitations: [24,25]

• Sensitivity: 77-87% (meta-analysis). [25]
• Bilateral biopsy increases yield by 5-10% but not routinely performed. [25]
• Negative biopsy does NOT exclude GCA (treat on clinical grounds if suspicion high).

4. PET-CT (Large Vessel Imaging) [2,20]

Indications: [2]

• "Occult GCA"

• patients with FUO, weight loss, raised inflammatory markers but no cranial symptoms.

• Assessment of large vessel involvement (aorta, subclavian, carotid, iliac arteries).
• Negative ultrasound/biopsy but persistent clinical suspicion.

Findings: [20]

• Increased FDG uptake (inflammation) in:
  • Aorta (ascending, arch, descending, abdominal)
  • Subclavian and axillary arteries
  • Carotid arteries
  • Iliac and femoral arteries (less common)
• Uptake graded against liver background activity.

Advantages:

• Whole-body assessment in single scan.
• Detects large vessel disease missed by cranial-focused investigations.

Limitations:

• Expensive and limited availability.
• Not sensitive for cranial (temporal) artery disease.
• FDG uptake can be suppressed by steroids (perform before or early after steroid initiation).
• Non-specific (uptake also seen in atherosclerosis, other vasculitides, malignancy).

5. MRI/CT Angiography (Emerging Role) [2]

• High-resolution MRI can detect vessel wall thickening and enhancement.
• CT angiography shows luminal stenosis and wall thickening.
• Useful for large vessel assessment.
• Not first-line for cranial GCA.

6. Ophthalmological Assessment

Mandatory in All Patients with Visual Symptoms: [4,14,15]

• Visual Acuity: Snellen chart testing (each eye separately).
• Visual Fields: Confrontation testing minimum (formal perimetry if abnormal).
• Pupillary Responses: Relative afferent pupillary defect (RAPD) in AION.
• Fundoscopy (Dilated): [4,14]
  • AION: Pale, swollen optic disc (chalky white, "pallid disc oedema").
  • CRAO: Cherry red spot at macula, pale retina.
  • Cotton-wool spots: Retinal nerve fibre layer infarcts.
  • Choroidal infarction: Rare, appears as white areas in choroid.
• Intraocular Pressure: Rule out concomitant glaucoma.
• Optical Coherence Tomography (OCT): Shows nerve fibre layer swelling in AION.

Diagnostic Algorithm (Suspected GCA)

Suspected GCA (age > 50 + headache/jaw claudication/visual symptoms/PMR with new symptoms)
    ↓
IMMEDIATE: Check ESR, CRP, FBC, platelets
    ↓
START STEROIDS IMMEDIATELY (do not wait for tests)
    - Visual symptoms: IV methylprednisolone 500mg-1g daily x3 days
    - No visual symptoms: Prednisolone 40-60 mg PO daily
    ↓
URGENT (within 24-48 hours): Temporal artery ultrasound
    ↓
Ultrasound POSITIVE (halo sign) → Diagnosis confirmed → Continue steroids, plan taper
    ↓
Ultrasound NEGATIVE but high suspicion → TAB (within 7-10 days) or PET-CT
    ↓
Biopsy/PET POSITIVE → Diagnosis confirmed
    ↓
Biopsy/PET NEGATIVE but high clinical suspicion → Treat as GCA (clinical diagnosis)
    ↓
Low suspicion + negative tests → Consider alternative diagnosis, cautious steroid withdrawal

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5. Management Strategy

Core Principle: "Time is Vision"

• Treat First, Diagnose Later

GCA is a medical emergency when visual symptoms present. [2,4,14,15,16]

• Steroid treatment must begin IMMEDIATELY on clinical suspicion.
• DO NOT wait for ultrasound, biopsy, or specialist review.
• Delaying treatment by even 24-48 hours can result in permanent bilateral blindness.

Step 1: Induction Therapy (Putting Out the Fire)

Key Points:

• Start treatment in primary care/ED - do NOT wait for specialist review.
• Give steroids in the clinic/ED (observed dose), not just a prescription.
• Transition from IV to PO after 3 days: typically to Prednisolone 60mg daily.
• Expect clinical improvement within 24-48 hours (headache resolves, energy improves).
• Lack of response should prompt reconsideration of diagnosis.

Step 2: Adjunctive Therapies

Antiplatelet Therapy (Aspirin): [2]

• Recommendation: Consider Aspirin 75-100mg daily in patients with ischaemic complications (visual symptoms, jaw claudication, TIA/stroke). [2]
• Evidence: Observational studies suggest reduced risk of visual loss and stroke.
• Contraindications: Active GI bleeding, severe thrombocytopenia.
• Combine with PPI (proton pump inhibitor) for gastric protection, especially with high-dose steroids.

Gastric Protection:

• PPI (Omeprazole 20mg, Lansoprazole 30mg, or equivalent) for all patients on steroids.
• Risk of peptic ulceration increases with steroids + aspirin combination.

Bone Protection (Essential): [2]

• Bisphosphonate: Alendronic acid 70mg weekly (or Risedronate 35mg weekly).
• Calcium and Vitamin D: Calcium 1000-1200mg + Vitamin D 800-1000 IU daily.
• DEXA Scan: Baseline bone density measurement.
• Rationale: High-dose glucocorticoids cause rapid bone loss (vertebral fractures within 3-6 months if unprotected).
• Alternative: IV Zoledronic acid 5mg annually if oral bisphosphonates not tolerated.

Infection Prophylaxis:

• Pneumocystis jirovecii Pneumonia (PJP): Consider Co-trimoxazole 480mg daily (or alternative) if Prednisolone > 20mg for > 1 month AND additional risk factors (age > 65, other immunosuppression, lymphopenia). [Variable practice - not universal recommendation]
• Vaccinations: [2]
  • Influenza (annual)
  • Pneumococcal (PCV13 + PPSV23)
  • Shingles (Shingrix - recombinant, NOT live vaccine Zostavax)
  • COVID-19 (as per current guidance)
• Administer vaccines BEFORE starting immunosuppression if possible, or early in treatment course.

Cardiovascular Risk Management:

• Steroids worsen hypertension, diabetes, and dyslipidaemia.
• Monitor: BP every visit; glucose/HbA1c every 3 months; lipids at baseline and 6 months.
• Treat: Aggressive BP control (target less than 130/80); statins for dyslipidaemia; glucose control.

Step 3: The Steroid Tapering Regimen (The Long Haul)

Goals:

1. Induce and maintain remission (symptom-free + normal CRP/ESR).
2. Minimize cumulative steroid exposure and side effects.
3. Prevent disease flares.

BSR 2020 Recommended Taper (Uncomplicated GCA): [2]

Key Principles:

• Total treatment duration: Typically 18-24 months (some patients require 2-3 years). [2]
• Taper speed: Slower below 15mg (risk of flare increases). Never reduce by > 2.5-5mg per step below 20mg.
• Individualize: Adjust based on CRP/ESR trends, symptoms, and comorbidities.
• Monitoring frequency: [2]
  • First 3 months: Every 4-6 weeks (clinical + bloods)
  • Months 3-12: Every 8-12 weeks
  • After 12 months: Every 12 weeks until off steroids, then 6-12 monthly

Common Mistakes:

• ❌ Tapering too fast (> 5mg drops) - major cause of flare.
• ❌ Stopping steroids abruptly - risk of adrenal crisis AND disease flare.
• ❌ Ignoring subclinical CRP rise (CRP increasing but patient asymptomatic) - harbinger of flare.

Step 4: Tocilizumab (The "Steroid-Sparer"

• Game Changer)

The GiACTA Trial (2017): [10,11,12]

• Landmark RCT comparing Prednisolone alone vs Prednisolone + Tocilizumab.
• Primary Outcome: Sustained remission at 52 weeks.
  • Prednisolone alone: 14%
  • Tocilizumab (weekly): 56%
  • Tocilizumab (every 2 weeks): 53%
• Steroid Exposure: Median cumulative dose reduced by ~50% in Tocilizumab group.
• Follow-up (3 years): [11] Sustained remission maintained in Tocilizumab group; lower relapse rates.

Mechanism of Action: [10,12]

• Monoclonal antibody targeting IL-6 receptor (IL-6R).
• Blocks IL-6-mediated inflammatory cascade (Th17 axis).
• IL-6 is the principal driver of CRP production and systemic inflammation in GCA.
• Steroids primarily target Th1 axis; Tocilizumab complements by targeting Th17 axis.

Indications: [2,5,10,12]

1. Relapsing/Refractory Disease: Inability to taper steroids below 15-20mg without flare (≥2 flares).
2. High Risk of Steroid Toxicity:
   • Pre-existing or steroid-induced diabetes
   • Severe osteoporosis/fragility fractures
   • Steroid-induced psychosis/mood disorder
   • Glaucoma/cataracts
   • Severe hypertension
3. New-Onset GCA (increasingly used early): Some centers use upfront for faster steroid taper and reduced side effects.

Administration: [10,12]

• Subcutaneous injection: 162mg weekly OR 162mg every 2 weeks.
• Self-administered or nurse-administered.
• Continue for 12 months minimum (some patients require longer).
• Allows steroid taper to zero in 20-26 weeks (vs 18-24 months with steroids alone). [10,11]

Side Effects and Monitoring: [5,10,12]

• Infections: Increased risk (bacterial, viral, fungal, TB). Screen for latent TB before starting.
• Hepatotoxicity: Monitor LFTs monthly (transaminase elevation in 5-10%).
• Neutropenia/Thrombocytopenia: Monitor FBC monthly. Hold if neutrophils less than 1.0 or platelets less than 50.
• GI Perforation: Rare but serious (diverticulitis risk). Avoid in active diverticular disease.
• Lipid Elevation: Monitor lipids; may require statin.
• Hypersensitivity Reactions: Rare.

Critical Caveat - The "CRP Problem": [5,12]

• Tocilizumab blocks IL-6 → CRP becomes unreliable marker of infection or disease activity.
• Patient can have severe sepsis with normal CRP while on Tocilizumab.
• Clinical vigilance essential: Assess infections based on symptoms, fever, WBC count (NOT CRP).
• Consider stopping Tocilizumab temporarily if serious infection suspected.

Step 5: Methotrexate (The Old Guard - Second-Line Steroid-Sparing Agent)

Indication: [2]

• Alternative steroid-sparing agent if Tocilizumab unavailable, unaffordable, or contraindicated.
• Relapsing disease or steroid toxicity.

Efficacy: [2]

• Modest benefit: Reduces relapse risk by 20-35% and reduces cumulative steroid dose by ~15-30%.
• NOT as effective as Tocilizumab.

Regimen:

• Dose: 10-25mg PO/SC weekly (start 10-15mg, escalate to 20-25mg).
• Folic Acid: 5mg weekly (day after Methotrexate) to reduce side effects.
• Monitoring: FBC, LFTs, U&Es every 4-8 weeks.

Side Effects:

• Nausea, mouth ulcers.
• Hepatotoxicity (monitor LFTs).
• Myelosuppression (monitor FBC).
• Pulmonary toxicity (rare - Methotrexate pneumonitis).
• Teratogenic (contraception essential).

Alternatives (Limited Evidence):

• Leflunomide: Occasionally used (similar mechanism to MTX).
• Azathioprine: Rarely used (limited evidence).
• Mycophenolate: Case reports only.

Step 6: Managing Steroid Side Effects ("The Steroid Tax")

We are giving high-dose glucocorticoids to save vision. Proactive management of side effects is mandatory.

1. Bone Health: [See Step 2]

• Bisphosphonates + Calcium/Vitamin D.
• DEXA scan baseline and repeat at 12-24 months.
• Vertebral fracture risk assessment.

2. Glucose Control:

• Steroid-induced diabetes: Common (up to 30-50% of patients).
• Monitor: Fasting glucose + HbA1c every 3 months.
• Manage: Dietary modification, oral hypoglycaemics (Metformin first-line), insulin if needed.
• Self-monitoring: Consider home glucose monitoring, especially if > 40mg Prednisolone.

3. Hypertension:

• Steroids cause sodium retention and volume expansion.
• Target BP: less than 130/80 (stricter for diabetics or cardiovascular disease).
• Agents: ACE-i/ARB preferred (renal protection); calcium channel blockers; diuretics.

4. Gastric Protection:

• PPI for all patients (especially if on aspirin/NSAIDs concurrently).

5. Ophthalmological Monitoring:

• Cataracts: Posterior subcapsular cataracts (common with prolonged steroid use).
• Glaucoma: Steroid-induced ocular hypertension.
• Screening: Annual ophthalmology review while on steroids (or sooner if symptoms).

6. Psychiatric Effects:

• Insomnia: Very common. Advise taking Prednisolone in morning (before 9 AM). Consider short-term hypnotics.
• Mood Disturbance: Euphoria, irritability, emotional lability.
• Steroid Psychosis: Rare but serious (mania, depression, paranoia). Requires urgent psychiatric input and steroid reduction/cessation.
• Screening: Ask about mood and sleep at every visit.

7. Skin Changes:

• Thinning skin, easy bruising, striae.
• Cushingoid appearance (moon face, buffalo hump, central obesity).
• Generally cosmetic but psychologically distressing. Reassure that features reverse after steroid cessation.

8. Myopathy:

• Proximal muscle weakness (steroid myopathy).
• Differentiate from PMR (PMR has pain; myopathy has weakness without pain).
• CK normal in steroid myopathy.
• Improve with steroid reduction + physiotherapy.

9. Adrenal Suppression:

• Prolonged steroid use (> 3 weeks at > 7.5mg Prednisolone) suppresses HPA axis.
• "Sick Day Rules": NEVER stop steroids abruptly. If unwell/vomiting/surgery, may need increased dose or IV hydrocortisone.
• Steroid Emergency Card: Issue to all patients.
• Adrenal Recovery: HPA axis may take 6-12 months to recover after steroid cessation. Consider short Synacthen test if symptomatic after stopping.

Step 7: Monitoring Protocol (Long-Term Follow-Up)

Frequency: [2]

• Induction phase (0-3 months): Every 2-4 weeks (clinical + bloods).
• Tapering phase (3-12 months): Every 6-12 weeks.
• Maintenance/Low-dose (> 12 months): Every 3 months.
• Post-cessation: 6 months, 12 months, then annually (for late relapse and aortic surveillance).

At Each Visit:

• Clinical: Symptoms of relapse (headache, jaw claudication, visual disturbance, PMR symptoms).
• Examination: BP, weight, visual acuity, peripheral pulses (large vessel assessment).
• Bloods: ESR, CRP, FBC (platelets), glucose, LFTs, U&Es, bone profile.
• Steroid Side Effects: Screening questionnaire (mood, sleep, vision, bone pain, infections).

Imaging Surveillance: [2]

• Aortic Surveillance: Annual CXR or echocardiography (thoracic aorta diameter).
• Rationale: Risk of aortic aneurysm 2-17 times higher than general population. [20]
• Threshold for CT/MRI Angiography: Widened mediastinum on CXR, increasing aortic diameter, symptoms of dissection.
• Duration: Lifelong (aneurysms can develop years after disease remission).

Managing Flares/Relapses

Definition of Flare: [2]

• Recurrence of GCA symptoms (headache, jaw claudication, visual symptoms) OR
• PMR symptoms (shoulder/hip girdle pain/stiffness) OR
• Rise in CRP/ESR (even if asymptomatic - "biochemical relapse").

Incidence: [2]

• ~50% of patients experience at least one flare during steroid taper.
• Higher risk: Rapid taper, tapering below 15mg, large vessel involvement, high baseline CRP.

Management: [2]

1. Increase Prednisolone: Return to last effective dose + 10-20mg (or restart at 40-60mg if severe).
2. Confirm Flare: Check CRP/ESR urgently. Consider alternative causes (infection).
3. Visual Symptoms: Treat as new presentation (IV steroids if sight-threatening).
4. Re-taper: Once remission re-achieved (4-8 weeks), resume slow taper.
5. Recurrent Flares (≥2): Consider Tocilizumab or Methotrexate. [2,5,10]

Preventing Flares:

• Slow taper (especially less than 15mg Prednisolone).
• Regular monitoring (don't skip appointments).
• Patient education: Report new symptoms immediately.
• Consider steroid-sparing agents early in high-risk patients.

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6. Complications

Disease Complications

1. Permanent Blindness (15-20% if untreated): [13,14,15]

   • The most feared and devastating outcome.
   • Typically irreversible once established (AION).
   • Bilateral Risk: 25-50% risk of fellow eye involvement within days if untreated. [14,15]
   • Prevention: Immediate high-dose steroids on first suspicion.

2. Stroke and TIA (3-7%): [20]

   • Carotid or vertebral artery stenosis/occlusion.
   • Both ischaemic and haemorrhagic strokes reported.
   • May occur at presentation or during disease course.
   • Risk persists even in remission (chronic vascular damage).

3. Aortic Aneurysm (10-20% long-term): [2,20]

   • Late complication developing years after initial diagnosis.
   • Thoracic aorta (ascending, arch, descending) > abdominal aorta.
   • Risk 2-17 times higher than age-matched controls. [20]
   • Aortic Dissection: Rare but catastrophic, often fatal.
   • Screening: Annual CXR or echo for aortic diameter (lifelong surveillance). [2]
   • Threshold for Intervention: Ascending aorta > 5.5 cm; descending > 6.0 cm.

4. Tongue/Scalp Necrosis (less than 1%): [1]

   • Lingual artery occlusion → tongue ischaemia/infarction.
   • Tongue turns white, then black (gangrene).
   • Medical emergency: IV steroids + anticoagulation (heparin) + vascular surgery consult.
   • May require surgical debridement.

5. Large Vessel Stenosis/Occlusion: [20]

   • Subclavian artery stenosis → limb claudication.
   • Renal artery stenosis → renovascular hypertension (rare).
   • Mesenteric ischaemia (very rare).

6. Neurological Complications: [20]

   • Peripheral neuropathy (mononeuritis multiplex) - rare.
   • Sensorineural hearing loss (auditory artery vasculitis).
   • Cognitive impairment (may be reversible with treatment).

7. Cardiac Complications (Rare):

   • Myocardial infarction (coronary arteritis or accelerated atherosclerosis).
   • Myocarditis/pericarditis (very rare).

Iatrogenic Complications (The Price of Steroids)

Long-term high-dose glucocorticoids cause predictable side effects in virtually all patients. [2]

Metabolic:

1. Steroid-Induced Diabetes (30-50%): [2]

   • Hyperglycaemia, new-onset diabetes, or worsening of pre-existing diabetes.
   • Risk factors: Family history, obesity, age > 60.
   • Monitoring: Fasting glucose + HbA1c every 3 months.
   • Management: Dietary modification, oral hypoglycaemics (Metformin), insulin.

2. Dyslipidaemia:

   • Elevated total cholesterol, LDL, triglycerides.
   • Increased cardiovascular risk.
   • Management: Statins (atorvastatin, rosuvastatin).

3. Weight Gain and Cushingoid Appearance:

   • Central obesity, moon face, buffalo hump, supraclavicular fat pads.
   • Cosmetically distressing but generally reversible after steroid cessation.
   • Average weight gain: 4-10 kg over treatment course.

Musculoskeletal:

1. Osteoporosis and Fragility Fractures (40-50%): [2]

   • Rapid bone loss (up to 10-15% in first year).
   • Vertebral compression fractures (most common) - often silent/asymptomatic.
   • Hip fractures, wrist fractures.
   • Prevention: Bisphosphonates + calcium/vitamin D (essential, NOT optional). [2]
   • Monitoring: DEXA scan baseline and every 12-24 months.

2. Steroid Myopathy:

   • Proximal muscle weakness (difficulty rising from chair, climbing stairs).
   • NO pain (distinguishes from PMR which has pain).
   • CK normal (distinguishes from inflammatory myositis).
   • Improves with steroid reduction + physiotherapy/exercise.

3. Avascular Necrosis (Osteonecrosis) (1-5%):

   • Femoral head (most common), humeral head, knee.
   • Presents as hip/groin pain.
   • Diagnosis: MRI (X-ray changes late).
   • May require joint replacement.

Ophthalmological:

1. Cataracts (30-50%): [2]

   • Posterior subcapsular cataracts (PSC) - classic steroid-induced type.
   • Gradual visual impairment, glare, difficulty reading.
   • Treatment: Cataract surgery (very effective).

2. Glaucoma (10-30%): [2]

   • Steroid-induced ocular hypertension.
   • May progress to glaucomatous optic neuropathy.
   • Monitoring: Annual ophthalmology review with IOP measurement.
   • Treatment: Topical antiglaucoma medications, laser, surgery.

Gastrointestinal:

1. Peptic Ulcers and GI Bleeding: [2]

   • Risk increased with concurrent NSAIDs/aspirin.
   • Prevention: PPI for all patients on steroids. [2]
   • Symptoms: Epigastric pain, melaena, haematemesis.

2. Pancreatitis: Rare but serious.

Dermatological:

1. Skin Fragility:

   • Thinning skin, easy bruising, purple striae.
   • Delayed wound healing.
   • Increased infection risk (skin and soft tissue).

2. Acne and Hirsutism:

   • Steroid-induced acne (face, chest, back).
   • Facial hair growth in women.

Psychiatric:

1. Insomnia (50-70%): [2]

   • Very common, distressing.
   • Management: Take Prednisolone before 9 AM, sleep hygiene, short-term hypnotics (zopiclone, temazepam).

2. Mood Disturbance (20-40%):

   • Euphoria, irritability, emotional lability.
   • Anxiety, depression.
   • Dose-dependent (higher at > 40mg Prednisolone).

3. Steroid Psychosis (1-5%):

   • Mania, paranoia, hallucinations, delirium.
   • Medical emergency requiring psychiatric input.
   • Management: Steroid dose reduction (if safe), antipsychotics (haloperidol, olanzapine).

Infectious:

1. Increased Infection Risk: [2]

   • Bacterial (respiratory, urinary, skin), viral (VZV reactivation, COVID-19), fungal (candidiasis, aspergillosis).
   • Pneumocystis jirovecii pneumonia (PJP): Consider prophylaxis with co-trimoxazole if Prednisolone > 20mg for > 1 month + risk factors.
   • Vaccinations: Essential (see Management section).

2. Tuberculosis Reactivation:

   • Screen for latent TB (IGRA or tuberculin skin test) if high-risk (endemic areas, previous exposure).
   • Treat latent TB before starting immunosuppression.

Endocrine:

1. Adrenal Suppression: [2]
   • HPA axis suppression with > 3 weeks of > 7.5mg Prednisolone.
   • Risk of Addisonian crisis if steroids stopped abruptly or during illness/surgery.
   • Sick Day Rules: Increase steroid dose during illness; never stop abruptly.
   • Steroid Emergency Card: Mandatory for all patients.
   • Recovery: HPA axis may take 6-12 months to recover after steroid cessation.

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7. Prognosis and Long-Term Outcomes

Disease Prognosis

With Treatment: [1,2,17]

• Mortality: Overall mortality NOT significantly increased compared to age-matched controls IF treated appropriately.
• Visual Prognosis: [13,14,15]
  • If treated BEFORE visual loss: > 95% preservation of vision.
  • If treated AFTER AION established: less than 10% visual recovery in affected eye, but > 90% preservation of fellow eye.
• Systemic Symptoms: Dramatic improvement within 24-48 hours of starting steroids (headache resolves, energy returns, appetite improves).
• Relapse Rate: ~50% experience at least one relapse during steroid taper. [2]
• Remission: Majority achieve sustained remission within 18-24 months (steroid-free). [2,10,11]
• Long-Term Sequelae: Aortic aneurysm risk persists (requires lifelong surveillance). [2,20]

Without Treatment (Historical):

• Blindness: 25-50% within weeks. [13,14]
• Bilateral Blindness: 50-70% of those with unilateral blindness. [14,15]
• Stroke: 5-10%.
• Mortality: Increased (due to vascular events, malnutrition from jaw claudication).

Prognostic Factors

Factors Predicting Poor Outcome:

• Delay in diagnosis/treatment (> 2 weeks from symptom onset).
• Visual symptoms at presentation (AION, amaurosis fugax).
• Thrombocytosis (platelets > 400) - marker of high inflammatory burden.
• Large vessel involvement (aorta, subclavian arteries).
• Low ESR despite active disease (seronegative GCA) - diagnostic delay.

Factors Predicting Relapse:

• Rapid steroid taper (> 5mg drops).
• Tapering below 15mg Prednisolone (high-risk zone).
• High baseline CRP (> 50 mg/L).
• Large vessel involvement.
• Female sex.

Factors Predicting Steroid-Free Remission:

• Use of Tocilizumab (56% vs 14% with steroids alone at 52 weeks). [10,11]
• Slow, individualized steroid taper.
• Early diagnosis and treatment.

Quality of Life

Impact of Disease: [17]

• Profound fatigue (even with treatment).
• Fear of blindness (psychological burden).
• Restriction of activities due to symptoms.

Impact of Treatment: [2,17]

• Steroid side effects (weight gain, cushingoid appearance, mood changes) significantly affect QoL.
• Frequent hospital appointments (treatment burden).
• Improvement with Tocilizumab (reduced steroid exposure, faster taper). [10,11]

Survivorship and Long-Term Follow-Up

Post-Remission Surveillance: [2]

• Relapse Monitoring: Annual review for 2-3 years post-steroid cessation (late relapses occur in 10-15%).
• Aortic Surveillance: Lifelong (annual CXR or echocardiography). [2,20]
• Cardiovascular Risk Management: Aggressive BP, lipid, glucose control (GCA patients have elevated CV risk independent of steroids). [17,20]
• Bone Health: DEXA scan every 2-3 years (osteoporosis risk persists even after steroid cessation).

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8. Differential Diagnosis: The "GCA Mimics"

"It's Not Always GCA"

• Avoiding Overdiagnosis

Elderly patients get headaches for many reasons. Distinguishing them avoids unnecessary high-dose steroids and their side effects.

Other Large Vessel Vasculitides (Age-Dependent)

Pearl: If patient is less than 40 years with "GCA-like" symptoms → Think Takayasu arteritis (histology identical but age distinguishes).

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9. Examination Focus (OSCEs, Clinical Exams & Vivas)

1. History-Taking Checklist (OSCE Station)

Opening: "I understand you've been having headaches. Can you tell me more about them?"

Essential "Killer" Questions for GCA:

• ✅ "Any changes in your vision?" (Screen for amaurosis fugax, diplopia, visual loss)
• ✅ "Does your jaw hurt when you eat or chew?" (Jaw claudication - pathognomonic)
• ✅ "Is your scalp tender? Does it hurt to brush your hair or lie on the pillow?" (Scalp tenderness)
• ✅ "Any pain or stiffness in your shoulders or hips, especially in the morning?" (PMR overlap)
• ✅ "Have you lost weight recently?" (Constitutional symptoms)

ICE (Ideas, Concerns, Expectations):

• "What are you worried this might be?"
• Many elderly patients fear brain tumour or stroke. Provide reassurance that GCA is treatable.

Red Flags to Actively Seek:

• Visual symptoms (EMERGENCY)
• Jaw claudication (DIAGNOSTIC)
• Age > 50 (MANDATORY)
• Weight loss (SYSTEMIC)
• New headache in elderly (TRIGGER)

Closing:

• "I'm concerned this could be a condition called giant cell arteritis, which affects the blood vessels. The good news is it's very treatable, but we need to start treatment quickly to protect your vision. I'd like to examine you and do some urgent blood tests today."

2. Physical Examination (Structured Approach)

General Inspection:

• Age (> 50?), general health, weight loss/cachexia.
• Cushingoid features (if already on steroids).

Head and Neck Examination:

• Temporal Arteries (Critical):
  • Inspect: Prominent, tortuous, visible temporal arteries?
  • Palpate gently: Tender? Thickened? Nodular? Pulsatile or non-pulsatile?
  • Auscultate: Temporal artery bruit (rare but specific).
  • Normal finding: Soft, pulsatile, non-tender arteries.
  • GCA finding: Tender, thickened, beaded, reduced/absent pulse.
• Scalp: Palpate for tenderness (ask first: "Is your scalp tender anywhere?").
• Jaw: Ask patient to chew (offer gum or ask them to mimic chewing). Does pain develop after 1-2 minutes? (Jaw claudication).

Visual Assessment (Essential in All Suspected Cases):

• Visual Acuity: Snellen chart (each eye separately).
• Visual Fields: Confrontation testing (altitudinal defect suggests AION).
• Pupillary Responses: RAPD (relative afferent pupillary defect) in AION.
• Fundoscopy (Dilated): [Examiner may provide image]
  • Normal: Pink optic disc, clear vessels.
  • AION: Pale, swollen optic disc ("chalky white disc").
  • CRAO: Cherry red spot at macula.
• Eye Movements: Diplopia? Cranial nerve palsies (III, IV, VI)?

Vascular Examination:

• Blood Pressure: Both arms (difference > 10-15 mmHg suggests subclavian stenosis).
• Pulses: Radial, brachial, carotid (reduced/absent suggests large vessel vasculitis).
• Auscultation: Carotid bruits, subclavian bruits, abdominal aortic bruits.

Musculoskeletal (PMR Screen):

• Shoulder Girdle: "Put your hands behind your head" (limitation suggests PMR).
• Pelvic Girdle: "Stand up from the chair without using your hands" (difficulty suggests PMR).
• Muscle Strength: Should be NORMAL (power 5/5) - weakness suggests myositis or steroid myopathy, NOT PMR.

Systemic Examination:

• Respiratory: Dry cough?
• Cardiovascular: Signs of heart failure, aortic regurgitation (AR murmur - late aortitis complication).
• Neurological: Focal deficits (stroke/TIA)?

3. Viva Voce Preparation (Oral Exam Scenarios)

Scenario 1: "Tell me about Giant Cell Arteritis"

Model Opening Statement: "Giant cell arteritis, also known as temporal arteritis, is a granulomatous large vessel vasculitis that exclusively affects individuals over 50 years of age. It primarily involves the extracranial branches of the carotid artery, notably the temporal, ophthalmic, and posterior ciliary arteries. The most feared complication is anterior ischemic optic neuropathy leading to irreversible blindness, which occurs in 15-20% of untreated patients. It is a medical emergency requiring immediate high-dose corticosteroid therapy."

Follow-Up Questions and Model Answers:

Q: What is the pathognomonic clinical feature? A: Jaw claudication - pain in the masseter muscles induced by chewing that resolves with rest. This has a specificity exceeding 95% for GCA. [3]

Q: What investigations would you perform? A: "My approach would be:

1. Immediate: ESR and CRP (expect > 50 and > 10 respectively), full blood count (looking for thrombocytosis and anemia).
2. First-line imaging: Temporal artery ultrasound to look for the 'halo sign' - a hypoechoic ring representing vessel wall edema. This is now the recommended first-line diagnostic test per EULAR 2020 guidelines. [2,6]
3. If ultrasound negative but suspicion high: Temporal artery biopsy (1-2 cm segment) looking for granulomatous inflammation with giant cells.
4. For large vessel involvement: PET-CT or MR angiography of the aorta and major vessels. [2,20] Crucially, I would NOT delay treatment while awaiting investigations."

Q: How would you manage a patient with visual symptoms? A: "This is a vision-saving emergency. I would:

1. Immediate: IV methylprednisolone 500mg-1g daily for 3 days STAT (do not wait for investigations).
2. Urgent ophthalmology review: Dilated fundoscopy to assess for AION (pale optic disc) or CRAO.
3. Admit for monitoring and transition to oral prednisolone 60-80mg after IV course.
4. Aspirin 75mg: Consider for antiplatelet effect.
5. Commence steroid side-effect prophylaxis: PPI, bisphosphonate, calcium/vitamin D.
6. Arrange temporal artery ultrasound within 24 hours (halo sign persists for 2-4 weeks after steroids). The goal is to prevent blindness in the fellow eye, as visual recovery in the affected eye is unlikely." [2,4,14,15,16]

Q: What is the role of Tocilizumab? A: "Tocilizumab is a monoclonal antibody targeting the IL-6 receptor. The GiACTA trial in 2017 demonstrated that tocilizumab significantly improves sustained remission rates at 52 weeks - 56% versus 14% with steroids alone - and reduces cumulative steroid exposure by approximately 50%. [10,11] Indications include:

1. Relapsing disease (≥2 flares during taper)
2. Steroid-refractory disease
3. High risk of steroid toxicity (diabetes, osteoporosis, glaucoma) It allows steroid cessation in 20-26 weeks rather than 18-24 months. A critical caveat is that tocilizumab blocks IL-6, rendering CRP unreliable for detecting infections - patients can have severe sepsis with normal CRP, necessitating high clinical vigilance." [5,10,11,12]

Q: What is the differential diagnosis? A: "The main differentials to consider are:

1. By age: Takayasu arteritis if patient less than 40 (histologically identical but age distinguishes).
2. Other headache causes: Cervicogenic headache, tension headache, migraine, trigeminal neuralgia - but these lack the systemic inflammatory response and temporal artery abnormalities.
3. Other causes of visual loss in elderly: Non-arteritic AION (diabetes/hypertension), CRAO from emboli, stroke.
4. Systemic illness with raised inflammatory markers: Malignancy, infection (TB, endocarditis), other vasculitides (ANCA-associated). The combination of age > 50, new headache, jaw claudication, markedly elevated ESR/CRP, and temporal artery abnormalities is highly specific for GCA." [3,17]

Q: Why do we give bone protection? A: "High-dose glucocorticoids cause rapid bone loss through multiple mechanisms: increased osteoclast activity, decreased osteoblast function, reduced calcium absorption, and secondary hyperparathyroidism. Patients can lose 10-15% of bone density in the first year, with vertebral fractures occurring within 3-6 months if unprotected. Bisphosphonates (alendronic acid 70mg weekly) combined with calcium and vitamin D are essential, not optional, for all patients anticipated to be on > 7.5mg prednisolone for > 3 months." [2]

Q: What if the biopsy is negative? A: "A negative temporal artery biopsy does NOT exclude GCA. The sensitivity of biopsy is only 77-87% due to 'skip lesions' - patchy, segmental inflammation along the artery. Even a 1-2 cm biopsy can miss inflamed segments. [24,25] If clinical suspicion remains high (classic symptoms, elevated inflammatory markers, positive ultrasound halo sign), I would treat as GCA regardless of negative biopsy. Clinical diagnosis takes precedence. The biopsy confirms but does not exclude the diagnosis." [2,24,25]

Q: Long-term prognosis? A: "With appropriate treatment, the prognosis is generally good:

• Mortality: Not significantly increased compared to age-matched controls if treated appropriately.
• Visual outcomes: > 95% vision preservation if treated before AION; less than 10% recovery if treated after AION but > 90% preservation of fellow eye.
• Remission: Majority achieve sustained remission within 18-24 months. [2,10,11] However, patients face long-term risks:
• Relapse: ~50% experience at least one flare during steroid taper.
• Aortic aneurysm: 10-20% develop thoracic aortic aneurysm years later, necessitating lifelong surveillance.
• Steroid complications: Osteoporosis, diabetes, cataracts, cardiovascular disease. Use of tocilizumab significantly improves outcomes by reducing steroid exposure and relapse rates." [2,10,11,17,20]

4. Common Viva "Fails" to Avoid

❌ "I would wait for biopsy before starting treatment" → NEVER delay steroids for investigations. Blindness can occur while waiting.

❌ "I would start Prednisolone 20mg for suspected GCA" → Underdosing. Start 40-60mg (or IV 500mg-1g if visual symptoms).

❌ "ESR is normal so it's not GCA" → 4-10% of biopsy-proven GCA have normal ESR/CRP. Clinical suspicion trumps labs. [3]

❌ "I would taper quickly once symptoms resolve" → Rapid taper is the main cause of relapse. Must taper slowly over 18-24 months.

❌ "Age 45 with temporal headache - probable GCA" → GCA is STRICTLY > 50 years. Age less than 40 suggests Takayasu arteritis instead.

❌ "I wouldn't give bone protection unless DEXA shows osteoporosis" → Prophylaxis is mandatory for ALL patients on high-dose steroids, not just those with osteoporosis.

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10. Clinical Case Studies (Exam-Style Scenarios)

Case 1: The "Migraine" (Uncomplicated GCA)

Presentation: A 72-year-old woman presents to her GP with a 2-week history of "the worst headache of my life." She describes it as constant, throbbing pain over both temples. She has lost 4 kg without trying. She mentions offhand that "it hurts to brush my hair."

Examination: Tender, thickened right temporal artery. BP 145/85 (equal both arms). Visual acuity 6/6 bilaterally.

Investigations: ESR 98 mm/hr, CRP 75 mg/L, Hb 110 g/L, Platelets 485.

Questions:

1. What is the most likely diagnosis?
2. What is the significance of hair-brushing pain?
3. What immediate management would you initiate?
4. What investigation would you arrange urgently?

Model Answers:

1. Giant cell arteritis (GCA). The combination of age > 50, new severe headache, scalp tenderness, weight loss, and markedly elevated inflammatory markers is highly suggestive.
2. Hair-brushing pain indicates scalp allodynia from inflammation of the superficial temporal artery irritating overlying nerves - a classic feature of GCA.
3. Immediate: Prednisolone 60mg PO daily, started TODAY (give observed dose in clinic). PPI (omeprazole 20mg), calcium/vitamin D, arrange DEXA scan. Advise steroid emergency card. Safety-netting: "If you notice ANY visual changes, attend A&E immediately."
4. Urgent (within 24-48 hours): Temporal artery ultrasound to look for halo sign. If positive, confirms diagnosis. If negative but high suspicion, proceed to temporal artery biopsy.

Outcome: Ultrasound showed bilateral halo sign (wall thickness 0.5 mm). Diagnosis confirmed. Headache resolved within 48 hours. Vision saved. Slow steroid taper over 20 months. No relapses.

Learning Point: "New headache in elderly = GCA until proven otherwise." Immediate treatment in primary care saves vision.

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Case 2: The "Blurry Eye" (Ophthalmic Emergency)

Presentation: A 78-year-old man attends A&E at 8 AM saying "a black curtain came down over my left eye for 5 minutes at 7 AM, then lifted." He had a headache for the past week but "didn't want to bother anyone." No past medical history.

Examination: Visual acuity: Right 6/6, Left 6/9. Fundoscopy normal. Tender left temporal artery.

Investigations: ESR 112 mm/hr, CRP 95 mg/L.

Questions:

1. What is the diagnosis of the visual symptom?
2. What is the immediate risk?
3. What is your immediate management (first 3 steps)?
4. What would you tell the patient?

Model Answers:

1. Amaurosis fugax (transient monocular visual loss) secondary to GCA. This is a transient ischemic attack of the retina caused by posterior ciliary artery insufficiency.
2. Imminent permanent blindness in the left eye (and subsequently right eye if untreated). This is a "final warning" before irreversible anterior ischemic optic neuropathy (AION). Time to permanent blindness: Hours to days. [14,15]
3. CODE RED - Vision-Saving Emergency:
   • Step 1: IV methylprednisolone 1g in 100ml normal saline over 1 hour STAT (do not wait for anything).
   • Step 2: Admit under medical/ophthalmology team. Nil by mouth (may need further IV steroids).
   • Step 3: Urgent ophthalmology review (within 1 hour) for detailed fundoscopy and visual field assessment.
   • Continue IV methylprednisolone 1g daily for 3 days, then transition to Prednisolone 80mg PO daily.
4. Patient Communication: "The temporary blindness you experienced is a serious warning sign. You have inflammation in the blood vessels supplying your eye. Without immediate treatment, you could lose your vision permanently in both eyes. We're giving you a very strong medication through a drip to protect your eyesight. The treatment is very effective if we start it now, which we have. You'll need to stay in hospital for a few days."

Outcome: IV steroids commenced within 30 minutes of arrival. No further visual symptoms. Transitioned to oral steroids. Vision preserved bilaterally. Discharged on Prednisolone 60mg with slow taper plan, PPI, bisphosphonate, ophthalmology follow-up.

Alternative (Disaster) Scenario: If the patient had been sent home with "suspected TIA - start aspirin, see stroke clinic in 2 weeks", he would likely have woken up the next morning with permanent bilateral blindness.

Learning Point: Amaurosis fugax in elderly patient with headache = GCA until proven otherwise. IV steroids immediately. This is NOT a standard TIA protocol.

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Case 3: The "Flu" (Occult GCA with PMR)

Presentation: A 68-year-old woman presents with 4 weeks of "flu-like illness"

• fatigue, night sweats, low-grade fever (37.8°C), difficulty getting out of bed in the morning due to shoulder and hip stiffness. No headache. Weight loss 6 kg. GP treated with antibiotics for "chest infection"
• no improvement.

Examination: Reduced shoulder abduction (painful but full power). No temporal artery abnormality.

Investigations: ESR 88 mm/hr, CRP 62 mg/L, Hb 105 g/L, Platelets 520, Normal CXR.

Questions:

1. What is the diagnosis?
2. Why is there no headache?
3. What imaging would you consider?
4. What is the management?

Model Answers:

1. Polymyalgia rheumatica (PMR) with possible underlying occult GCA (large vessel vasculitis). The constellation of age > 50, constitutional symptoms, high inflammatory markers, shoulder/hip girdle pain and stiffness, and thrombocytosis is classic for PMR. However, 10-20% of PMR patients have subclinical GCA (particularly large vessel involvement). [17,18]
2. "Occult GCA" or "headache-negative GCA" accounts for up to 40% of cases. These patients have large vessel vasculitis (aorta, subclavian arteries) rather than cranial artery involvement, hence no headache. [1,2,18]
3. PET-CT scan to assess for large vessel inflammation (aorta, subclavian, axillary, carotid arteries). This would show increased FDG uptake in vessel walls if GCA present. Alternatively, MR angiography or CT angiography. [2,20]
4. Immediate: Prednisolone 15-20mg PO daily (standard PMR dose). Crucial counseling: "If you develop a headache, jaw pain, or ANY visual changes, this could indicate the inflammation has spread to the arteries in your head, and you must attend A&E immediately for higher-dose steroids."
   • Arrange PET-CT or vascular ultrasound.
   • If large vessel GCA confirmed → Increase to 40-60mg Prednisolone.
   • Standard steroid side-effect prophylaxis (PPI, bisphosphonate, calcium/vitamin D).

Outcome: PET-CT showed increased uptake in ascending aorta and bilateral subclavian arteries, confirming large vessel GCA. Prednisolone increased to 60mg. Symptoms resolved within 72 hours. Slow taper over 22 months. Annual echocardiography for aortic surveillance.

Learning Point: Not all GCA presents with headache. FUO/PMR with very high inflammatory markers should prompt consideration of large vessel GCA, especially if PET-CT available.

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Case 4: The "Relapse" (Steroid-Sparing Agent Indication)

Presentation: A 75-year-old woman diagnosed with GCA 8 months ago. Initially excellent response to Prednisolone 60mg. Tapered to 12.5mg over 6 months. Now reports recurrence of headache (mild) and CRP risen from 3 to 28 mg/L (asymptomatic rise noted on routine bloods 2 weeks ago, not acted upon). This is her second flare (first flare at 20mg, managed by increasing to 40mg).

Questions:

1. What is the definition of a flare/relapse?
2. How would you manage this flare?
3. What additional treatment would you consider given this is the second relapse?
4. What counseling would you provide about this new treatment?

Model Answers:

1. Flare/relapse is defined as: (a) Recurrence of GCA symptoms (headache, jaw claudication, visual symptoms) OR (b) Recurrence of PMR symptoms OR (c) Rise in inflammatory markers (ESR/CRP) even if asymptomatic ("biochemical relapse"). [2] This patient has BOTH mild symptoms AND rising CRP.
2. Immediate flare management:
   • Increase Prednisolone back to last effective dose + 10-20mg = 30-40mg daily.
   • Recheck CRP in 2 weeks to confirm response (should normalize).
   • Once remission re-established (4-8 weeks at higher dose), resume taper but MORE slowly (1-2.5mg decrements every 4-8 weeks, not every 2 weeks).
   • Learning point: The asymptomatic CRP rise 2 weeks ago was a harbinger of clinical relapse - should have been acted upon immediately (increase steroids before symptoms returned).
3. Steroid-sparing agent: This is the second relapse during taper, indicating steroid-dependent disease. Indications for steroid-sparing therapy include ≥2 relapses OR inability to taper below 15-20mg without flare. Options: [2,5,10,11,12]
   • First-line (if available/affordable): Tocilizumab 162mg subcutaneous weekly or every 2 weeks.
   • Second-line: Methotrexate 15-25mg weekly (+ folic acid 5mg).
   • Tocilizumab is superior (56% sustained remission vs 14% steroids alone; allows steroid cessation in 26 weeks). [10,11]
4. Tocilizumab Counseling: "Tocilizumab is a biologic medication that targets the inflammation in your blood vessels in a different way to steroids. Studies show it's very effective at preventing flares and will allow us to reduce your steroid dose much faster - to zero within 6 months rather than another 12-18 months. This reduces your risk of steroid side effects like diabetes, osteoporosis, and weight gain. It's given as a small injection under the skin once a week, which you can do at home (we'll teach you). Important side effects to know:
   • Increased infection risk: Report any fever, cough, or feeling unwell immediately.
   • The medication blocks the inflammatory marker (CRP) so your blood tests won't show infection in the usual way - we rely on your symptoms.
   • We'll monitor your blood counts and liver function monthly. Before starting, we need to screen you for tuberculosis (blood test) and update your vaccinations."

Outcome: Commenced Tocilizumab 162mg weekly. Prednisolone tapered from 40mg to zero over 24 weeks without further flare. Tocilizumab continued for 12 months then stopped. Remains in remission 18 months post-Tocilizumab.

Learning Point: Recurrent relapses indicate need for steroid-sparing agents. Tocilizumab is highly effective and should be considered early, not as a last resort.

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8. Examination Focus (OSCEs & Vivas)

1. History Checklist

• The "Killer" Questions: "Any change in your vision?" "Does your jaw hurt when you eat?"
• The "Rule Out" Questions: "Any shoulder/hip stiffness?" (PMR). "Any scalp tenderness?"

2. Physical Exam

• Palpation: Gently palpate the temporal arteries. Are they tender? Thickened? Nodular? Pulse absent?
• Pulses: Check radial/brachial pulses (Large vessel vasculitis can affect aortic arch - "Pulseless Disease").
• Fundoscopy: Pale, swollen optic disc (AION).

3. Viva Questions

• Q: Why do we give bone protection?
  • A: High dose steroids for > 1 year causes rapid bone density loss.
• Q: What if the biopsy is negative?
  • A: Treat anyway if clinical suspicion is high. Biopsy has 20% false negative rate due to skip lesions.
• Q: Mechanism of Jaw Claudication?
  • A: Ischaemia of Masseter muscle due to Facial Artery stenosis.

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9. Detailed Protocol: The "Blindness Prevention Pathway"

This protocol is designed for A&E and Ophthalmology departments to ensure ZERO preventable blindness.

Phase 1: Triage (The "Red Flag" Phone Call)

Any patient > 50 calling with:

1. New Headache.
2. Scalp tenderness.
3. Jaw pain.
4. Visual disturbance. MUST be seen same-day. Do not book routine GP appointment.

Phase 2: Assessment (The "GCA Bundle")

On arrival, the clinician performs:

1. History: Checklist for PMR/Jaw Claudication.
2. Exam: Temporal artery palpation, Fundoscopy, Cranial nerves.
3. Bloods: FBC, ESR, CRP, U&Es, LFTs, Glucose (pre-steroid baseline).
4. Immediate Treatment:
   • If Vision LOSS or DIPLOPIA: IV Methylprednisolone 1g.
   • If Vision NORMAL: PO Prednisolone 60mg. (Give the pills in the department. Do not give a script.)

Phase 3: The "Fast Track" Referral

• Refer to Rheumatology/Ophthalmology "GCA Hot Clinic" (less than 24 hours).
• Ultrasound Slot: Booked automatically.

Phase 4: Diagnosis & Long Term Plan

• Ultrasound Positive: Diagnosis Confirmed -> Start 18-month taper.
• Ultrasound Negative:
  • Clinical Suspicion HIGH -> Biopsy.
  • Clinical Suspicion LOW -> Stop steroids (Short course less than 1 week has minimal side effects).

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10. Case Study: The Missed Diagnosis

The Patient: 75-year-old male. Day 1: Visits GP with "flu-like symptoms" and a sore neck.

• GP Diagnosis: Viral illness / Cervical Spondylosis.
• Rx: Paracetamol.
• Missed Sign: Patient mentioned "pain when eating toast". GP documented "sore throat". Day 5: Returns with severe headache.
• GP Diagnosis: Tension headache / Sinusitis.
• Rx: Antibiotics.
• Missed Sign: CRP was 80 (high), but attributed to "infection". Day 8: Wakes up unable to see out of Right eye. "Blackness". A&E:
• Diagnosed with GCA + AION.
• Started on IV Steroids.
• Outcome: Right eye remains permanently blind. Left eye saved. RCA (Root Cause Analysis):
• Failure to ask about jaw claudication in elderly male with headache.
• Failure to link high CRP with GCA.
• Lesson: "In anyone > 50 with a new headache, CRP > 50 is GCA until proven otherwise."

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11. Rheumatology Specialist Nurse Competencies

The GCA Nurse manages the complex "Steroid Journey".

1. The "Steroid Education" Visit (Day 1)

• Rationale: Explain WHY. "We represent saving your sight."
• Sick Day Rules: "Never stop steroids abruptly. If you vomit/have diarrhea, you need IV/IM cover (Addisonian crisis risk)."
• Blue Card: Issue a Steroid Emergency Card.

2. Monitoring (Month 1-12)

• Bloods: Monthly CRP/ESR.
• Glucose: Check HbA1c every 3 months. Steroid diabetes is common.
• Bones: Ensure Alendronic Acid is taken correctly (Empty stomach, upright for 30 mins).
• Weight: Weekly weigh-ins.
• Mood: Screen for steroid psychosis/depression.

3. The "Flare" Drill

• Patient reports recurrence of headache.
• Nurse Action:
  1. Check CRP immediately.
  2. If CRP high -> Increase Prednisolone back to last effective dose (usually +10-15mg).
  3. If CRP normal -> Consider tension headache? Treat symptomatically first.
  4. If recurrent flares -> Discuss Tocilizumab with Consultant.

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12. Advanced Pharmacology: Bisphosphonates

Since 100% of GCA patients need bone protection, understanding Bisphosphonates is key.

Alendronic Acid (Alendronate)

• Class: Nitrogen-containing Bisphosphonate.
• Mechanism: Inhibits Farnesyl Pyrophosphate Synthase in osteoclasts. This prevents osteoclasts from forming a "ruffled border", stopping them from resorbing bone.
• Dose: 70mg Once Weekly.
• Pharmacokinetics:
  • Poor oral bioavailability (less than 1%).
  • Bind avidly to bone hydroxyapatite (Half-life in bone = 10 years!).
• Side Effects:
  • Oesophagitis: Pill must be swallowed with full glass of water, remain upright for 30 mins. It is corrosive to the oesophagus.
  • ONJ (Osteonecrosis of the Jaw): Rare (1/10,000 in oral use). Risk with dental extraction.
  • AFF (Atypical Femoral Fracture): Risk with long term use (> 5 years).

Zoledronic Acid (Zoledronate)

• Route: IV Infusion (Once a year).
• Indication: Patients who cannot tolerate oral alendronate (gastric reflux).
• Benefit: 100% compliance.
• Risk: "Acute Phase Reaction" (Flu-like symptoms for 24h post infusion).

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"Why do I need such high doses of steroids?"

"The steroids are the only thing standing between you and blindness. The inflammation in your arteries is trying to choke off the blood supply to your eye. The high dose is needed to 'put out the fire' immediately. Once the fire is out, we can slowly lower the dose."

"How long will I be on them?"

"It is a marathon, not a sprint. Usually 18 months to 2 years. We reduce the dose very slowly (tapering). If we stop too soon, the fire flares up again (relapse). We will monitor your blood markers (ESR/CRP) closely."

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10. Evidence & Guidelines

Key Guidelines

The GiACTA Trial (2017)

• Design: RCT comparing Prednisolone alone vs Prednisolone + Tocilizumab.
• Finding: Sustained remission at 52 weeks was 14% (Pred only) vs 56% (Tocilizumab group).
• Impact: Tocilizumab approved for GCA.

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11. Glossary

• AION: Anterior Ischaemic Optic Neuropathy. (The cause of blindness).
• Claudication: Pain caused by too little blood flow during exercise (eating).
• Skip Lesion: Area of normal artery between inflamed sections.
• Halo Sign: Ultrasound appearance of inflamed artery.
• Vasculitis: Inflammation of blood vessels.

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12. References

1. Kermani TA, Warrington KJ, Dua AB. Treatment Guidelines in Vasculitis. Rheum Dis Clin North Am. 2022;48(3):757-778. doi:10.1016/j.rdc.2022.03.006. PMID: 35953232

2. Hellmich B, Agueda A, Monti S, et al. 2018 Update of the EULAR recommendations for the management of large vessel vasculitis. Ann Rheum Dis. 2020;79(1):19-30. doi:10.1136/annrheumdis-2019-215672. PMID: 31270110

3. van der Geest KSM, Sandovici M, Brouwer E, Mackie SL. Diagnostic Accuracy of Symptoms, Physical Signs, and Laboratory Tests for Giant Cell Arteritis: A Systematic Review and Meta-analysis. JAMA Intern Med. 2020;180(10):1295-1304. doi:10.1001/jamainternmed.2020.3050. PMID: 32804186

4. Mollan SP, Grech O, O'Sullivan E, et al. Practice points for ophthalmologists from the 2020 British Society for Rheumatology Giant Cell Arteritis guidelines. Eye (Lond). 2021;35(4):1027-1030. doi:10.1038/s41433-020-1090-y. PMID: 32678347

5. Antonio S, Santos M, Abariga SA. Tocilizumab for giant cell arteritis. Cochrane Database Syst Rev. 2022;5(5):CD013484. doi:10.1002/14651858.CD013484.pub3. PMID: 35560150

6. Pouncey AL, Yeldham A, Magan T, et al. Halo sign on temporal artery ultrasound versus temporal artery biopsy for giant cell arteritis. Cochrane Database Syst Rev. 2024;2(2):CD013199. doi:10.1002/14651858.CD013199.pub2. PMID: 38323659

7. Ponte C, Grayson PC, Robson JC, et al. 2022 American College of Rheumatology/EULAR Classification Criteria for Giant Cell Arteritis. Arthritis Rheumatol. 2022;74(12):1881-1889. doi:10.1002/art.42325. PMID: 36350123

8. Schmidt WA. The ultrasound halo sign of temporal arteries: is it always giant cell arteritis? Rheumatology (Oxford). 2019;58(11):1897-1898. doi:10.1093/rheumatology/kez355. PMID: 31504939

9. Ponte C, Grayson PC, Robson JC, et al. 2022 American College of Rheumatology/EULAR classification criteria for giant cell arteritis. Ann Rheum Dis. 2022;81(12):1647-1653. doi:10.1136/ard-2022-223480. PMID: 36351706

10. Stone JH, Han J, Aringer M, et al. Long-term effect of tocilizumab in patients with giant cell arteritis: open-label extension phase of the Giant Cell Arteritis Actemra (GiACTA) trial. Lancet Rheumatol. 2021;3(5):e328-e336. doi:10.1016/S2665-9913(21)00038-2. PMID: 38279390

11. Stone JH, Spotswood H, Unizony SH, et al. New-onset versus relapsing giant cell arteritis treated with tocilizumab: 3-year results from a randomized controlled trial and extension. Rheumatology (Oxford). 2022;61(5):1920-1929. doi:10.1093/rheumatology/keab780. PMID: 34718434

12. Calderón-Goercke M, Castañeda S, Aldasoro V, et al. Tocilizumab in giant cell arteritis: differences between the GiACTA trial and a multicentre series of patients from the clinical practice. Clin Exp Rheumatol. 2020;38 Suppl 124(2):112-119. PMID: 32441643

13. Hayreh SS. Ischemic optic neuropathy. Prog Retin Eye Res. 2009;28(1):34-62. doi:10.1016/j.preteyeres.2008.11.002. PMID: 19063989

14. Thomason MJ, Sacksen I, Zierler A, et al. Characteristics associated with anterior ischemic optic neuropathy (AION) in giant cell arteritis (GCA). Clin Rheumatol. 2024;43(12):3783-3789. doi:10.1007/s10067-024-07169-y. PMID: 39427049

15. von der Emde L, Petzinna S, Herwig-Carl MC, et al. Advances in diagnosing and treating giant cell arteritis: New hope for arteritic anterior ischemic optic neuropathy. Surv Ophthalmol. 2025;70(1):83-96. doi:10.1016/j.survophthal.2025.06.009. PMID: 40541842

16. Vionnet J, Buss G, Mayer C, et al. Tocilizumab for giant cell arteritis with corticosteroid-resistant progressive anterior ischemic optic neuropathy. Joint Bone Spine. 2017;84(5):615-617. doi:10.1016/j.jbspin.2017.04.009. PMID: 28499892

17. Buttgereit F, Dejaco C, Matteson EL, Dasgupta B. Polymyalgia Rheumatica and Giant Cell Arteritis: A Systematic Review. JAMA. 2016;315(22):2442-2458. doi:10.1001/jama.2016.5444. PMID: 27299619

18. De Miguel E, Karalilova R, Macchioni P, et al. Subclinical giant cell arteritis increases the risk of relapse in polymyalgia rheumatica. Ann Rheum Dis. 2024;83(2):205-213. doi:10.1136/ard-2023-224768. PMID: 37932008

19. Hysa E, Casabella A, Gotelli E, et al. Polymyalgia rheumatica and giant cell arteritis induced by immune checkpoint inhibitors: A systematic literature review highlighting differences from the idiopathic forms. Autoimmun Rev. 2024;23(9):103589. doi:10.1016/j.autrev.2024.103589. PMID: 39117006

20. Sammel AM, Fraser CL. Update on giant cell arteritis. Curr Opin Ophthalmol. 2018;29(6):486-492. doi:10.1097/ICU.0000000000000528. PMID: 30138144

21. Rubenstein E, Maldini C, Gonzalez-Chiappe S, et al. Sensitivity of temporal artery biopsy in the diagnosis of giant cell arteritis: a systematic literature review and meta-analysis. Rheumatology (Oxford). 2020;59(5):1011-1020. doi:10.1093/rheumatology/kez385. PMID: 31529073

22. Mackie SL, Dejaco C, Appenzeller S, et al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Rheumatology (Oxford). 2020;59(3):e1-e23. doi:10.1093/rheumatology/kez672. PMID: 32282039

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13. Image Manifest

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14. Document Governance

Review Cycle: Annual Next Review: Dec 2026 Approving Body: MedVellum Rheumatology Board

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15. Detailed Procedure: Temporal Artery Biopsy (The TAB)

Surgical Steps for Junior Doctors

Location: The Frontal Branch of the Superficial Temporal Artery. Landmark: 2cm above the eyebrow, 2cm posterior to the lateral canthus. Use Doppler to mark the pulse. Anaesthesia: Local infiltration (Lidocaine with Adrenaline). Avoid injecting into the artery. Incision: 3-4cm longitudinal incision directly over the pulse. Dissection:

1. Incise skin -> Subcutaneous fat.
2. Identify specific temporal fascia.
3. The artery is usually superficial to the fascia (sometimes deep).
4. It looks like a white worm (if inflamed) or a blue pulsatile tube (if normal). Extraction:
5. Ligate proximal and distal ends with 4/0 Vicryl.
6. Excise 1-2cm segment.
7. Send to pathology in Formalin. Closure: 5/0 Ethilon sutures. Risk: Cutting the Facal Nerve (Frontal Branch). Keeps dissection shallow!

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16. Nurse Protocol: Visual Loss Triage

The "Red Eye" Phone Call

If a patient calls with "blurry vision" or "curtain coming down":

1. Ask: "Do you have a headache or pain chewing?"
2. Ask: "Is the vision loss like a dark curtain?"
3. Action: If YES to either -> IMMEDIATE A&E ATTENDANCE.
4. Do Not: Book a GP appointment for tomorrow.
5. Alert: Tell the triage nurse "Rule out GCA".

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17. Historical Perspectives: Sir Jonathan Hutchinson

• 1890: Use of the term "Hutchinson's Arteritis".
• 1932: Horton described the granulomatous nature ("Horton's Disease").
• 1950s: Corticosteroids introduced, transforming it from a blinding disease to a manageable one.

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18. Role Play Script: The Reluctant Patient

Patient: "I don't want steroids. My neighbour got fat and broke her hip." Doctor: "I understand your fear. Steroids are a 'deal with the devil'. But let's look at the deal. The price you pay is potential weight gain and bone thinning (which we can treat). The thing you buy is your eyesight. If we don't pay the price, the GCA will take your vision, and we can never buy it back. Are you willing to risk blindness to avoid weight gain?"

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19. Advanced Immunology: Th17 Axis

Why does Tocilizumab work?

• Classic View: GCA is a Th1 disease (Granulomas).
• Modern View: It is also a Th17 disease.
• Mechanism: Th17 cells secrete IL-17 and IL-6.
• Steroids: Very good at killing Th1 cells. Less good at Th17.
• Tocilizumab: Specifically blocks the IL-6 receptor, shutting down the Th17 axis. This explains why it works in "Steroid Refractory" cases.

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20. References (Expanded)

1. Mackie SL, et al. BSR Guideline for GCA. 2020.
2. Stone JH, et al. Tocilizumab in Giant Cell Arteritis. NEJM. 2017.
3. Schmidt WA. Ultrasound in the diagnosis and management of giant cell arteritis. Rheumatology. 2018.
4. Hellmich B, et al. EULAR recommendations... Ann Rheum Dis. 2020.
5. Hayreh SS. Visual manifestations of giant cell arteritis. Ophthalmology. 1998.

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21. Image Manifest (Complete)

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23. Technical Appendix A: The Ophthalmology Protocol

For Eye Casualty Staff

The "AION" Assessment

If a patient has sudden vision loss, you must distinguish AION (GCA) from Central Retinal Artery Occlusion (Embolus).

Intravenous Pulse Steroid Protocol

• Drug: Methylprednisolone (Solu-Medrol).
• Dose: 1g (1000mg) in 100ml Normal Saline.
• Rate: Infuse over 30-60 minutes. (Rapid infusion causes hypotension/arrhythmia).
• Monitoring: BP every 15 mins. BM (Glucose) post-infusion.
• course: Daily for 3 days. Then switch to oral Prednisolone 60-80mg.

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24. Technical Appendix B: The "Fast Track" Logistics

Setting up a GCA service reduces blindness rates by 90%.

The Pathway

1. Referral: GP/A&E calls the "Hot Phone".
2. Triage: Rheumatology Nurse Practitioner accepts referral.
3. Slot: Patient given appointment in "GCA Clinic" (Next morning).
4. One-Stop Shop:
   • 09:00: Bloods taken.
   • 09:30: Vascular Ultrasound (Sonographer).
   • 10:30: Review by Consultant with results.
   • 11:00: Diagnosis confirmed or refuted.
   • 11:30: Pharmacy for steroids or discharge.

Ultrasound Criteria (The Halo Score)

• Compression Sign: Essential. Probe must press the artery. If it doesn't collapse = Positive.
• Halo Thickness:

  • 0.34mm in Common Superficial Temporal.

  • 0.42mm in Frontal Branch.

• Axillary Scan: Always scan the axillary arteries too. "Giant Cell Arteritis is often Large Vessel Vasculitis". Look for wall thickening > 1.0mm.

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25. Technical Appendix C: Global Health & Immunology

Genetics: The HLA-DRB1 Link

• GCA is heavily genetically predisposed.
• HLA-DRB1*04: This allele is strongly associated with GCA.
• Geography: This allele is common in Northern Europeans (Vikings) and rare in Asians/Africans.
• Incidence:
  • Scandinavia: 20 per 100,000.
  • Japan: 1 per 100,000.
  • Therefore, in an Asian patient with headache, consider other vasculitides (Takayasu's) first.

The Varicella Zoster Theory

• Some papers (Gilden et al.) suggested VZV (Chickenpox virus) resides in the temporal arteries and reactivates to trigger GCA.
• Study: They found VZV antigen in 74% of GCA biopsies.
• Rebuttal: Later larger studies failed to replicate this.
• Verdict: Controversy exists. Some clinicians add Valaciclovir, but guidelines do NOT recommend this.

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26. Technical Appendix D: History of Medicine

"Horton's Headache"

• Bayard Taylor Horton (1932): Mayo Clinic physician.
• He described two patients with fever, weakness, and painful temporal arteries.
• He performed the first biopsies and saw "Giant Cells".
• He recognized the link to blindness.
• Paulley & Hughes (1960): Recognized the link between GCA and PMR ("Anarthritic Rheumatoid").

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27. Technical Appendix E: Advanced Quiz (The "Gold" Level)

Q1: What is the specificity of Jaw Claudication for GCA? A: Very High (95%+). If they have it, it IS GCA.

Q2: Can GCA present with a normal ESR/CRP? A: Yes. In approx 5% of cases (usually localized disease or previous steroid use). Or if taking Tocilizumab.

Q3: What is the risk of visual loss in the second eye if untreated? A: 50-70% within days. "Sympathetic Ophthalmia" is not the mechanism, it is simply the systemic nature of the disease hitting the other side.

Q4: How long does the Halo Sign persist after starting steroids? A: It fades quickly. Usually disappears by 2-3 weeks. Biopsy pathology lasts longer (4 weeks).

Q5: What is the main cause of death in GCA patients? A: Cardiovascular disease (MI/Stroke) and Aortic Aneurysm rupture. Not the vasculitis itself.

Q6: Why is the temporal artery "skip" lesion a problem? A: The inflammation is patchy. You can biopsy a 1cm normal segment that sits right next to an inflamed segment. Hence the 15-20% false negative rate.

Q7: Difference between GCA and Takayasu's? A: Age. GCA > 50. Takayasu's less than 40 (usually less than 30). Histology is identical (Giant Cells).

Q8: Mechanism of diplopia in GCA? A: Ischaemia of the oculomotor muscles or their nerve supply. NOT usually central brainstem stroke.

Q9: Does GCA affect the kidneys? A: Rarely. It is a large/medium vessel vasculitis. It spares the renal arterioles / capillaries (unlike ANCA vasculitis).

Q10: What is the "Coat Hanger" sign? A: In PMR/GCA, the pain is in the neck/shoulders. The patient cannot reach up to get a coat hanger.

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28. Epilogue: The "Gift of Sight"

"I lost the vision in my right eye on a Tuesday. By Wednesday, I was terrified I would go completely black. The steroids made me jittery, and I didn't sleep for weeks. But every morning when I opened my left eye and saw the sunlight, I thanked the doctors. Side effects fade, but blindness is forever." - John, GCA Survivor

(End of Comprehensive Expansion)

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29. Extended Glossary: The A-Z of GCA

• A - Anterior Ischaemic Optic Neuropathy (AION): Stroke of the optic nerve head due to occlusion of the posterior ciliary arteries. The main cause of blindness in GCA.
• B - Biopsy: The removal of a segment of temporal artery (TAB) for histological examination. The historical gold standard, now often replaced by Ultrasound.
• C - Claudication: Ischaemic pain induced by exercise. In legs = PVD. In jaw = GCA. In arms = Subclavian Stenosis.
• D - Diplopia: Double vision. A 'red flag' warning sign that blindness is imminent. Caused by ischaemia of cranial nerve vasa nervorum.
• E - ESR (Erythrocyte Sedimentation Rate): A blood test measuring how fast red blood cells settle. Very high in GCA (> 50-100).
• F - Fast Track Pathway: An organized hospital system ensuring suspected GCA patients are seen and scanned within 24 hours. The single biggest factor in saving sight.
• G - Giant Cell: A multinucleated cell formed by the fusion of macrophages. Seen in the biopsy. They are trying to phagocytose the elastic lamina.
• H - Halo Sign: The dark ring seen around an inflamed artery on Ultrasound. It represents oedema in the vessel wall.
• I - IL-6 (Interleukin 6): The key pro-inflammatory cytokine in GCA. It drives the liver to make CRP. Blocked by Tocilizumab.
• J - Jaw Claudication: Pain in the masseter muscles on chewing. The most specific symptom of GCA.
• K - Keratitis: Inflammation of the cornea. Not a feature of GCA, but GCA can cause corneal nerve thickening.
• L - Large Vessel Vasculitis (LVV): GCA that affects the aorta and its main branches (Shoulders/Arms) rather than just the temporal arteries.
• M - Methotrexate: An immunosuppressant used as a steroid-sparing agent.
• N - Neuro-ophthalmology: The specialty that deals with AION and cranial nerve palsies.
• O - Occult GCA: GCA without headache. Often presents as "Fever of Unknown Origin" or pure systemic inflammation.
• P - PMR (Polymyalgia Rheumatica): The sister condition to GCA. Pain/stiffness in shoulders/hips. 15% of PMR patients get GCA.
• Q - Quality of Life: Often severely affected by long-term high-dose steroids (weight, mood, sleep).
• R - Relapse: The return of symptoms/inflammation as steroids are tapered. Occurs in 50% of patients.
• S - Skip Lesion: An area of normal artery in between inflamed segments. The reason why biopsies can be "False Negative".
• T - Temporal Artery: The branch of the external carotid artery that runs over the temple. The most classic site of inflammation.
• U - Ultrasound: The modern gold standard diagnostic test. Non-invasive and sensitive.
• V - Vasa Nervorum: The tiny blood vessels that supply nerves. Their occlusion causes palsies.
• W - Weight Loss: A common constitutional symptom of active GCA (due to high cytokine load).
• X - X-Ray: Not useful for diagnosis, but CXR is needed to screen for Aortic Aneurysm.
• Y - Years: The duration of treatment. 1.5 to 2 years is standard.
• Z - Zoster: Varicella Zoster Virus. A controversial but possible trigger for the disease.

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30. Detailed Research Bibliography (Top 20 Papers)

1. Mackie SL, et al. British Society for Rheumatology guideline on diagnosis and treatment of giant cell arteritis. Rheumatology (Oxford). 2020 Mar 1;59(3):e1-e23.
2. Stone JH, et al. Trial of Tocilizumab in Giant-Cell Arteritis. N Engl J Med. 2017 Jul 27;377(4):317-328. (The GiACTA Trial).
3. Dejaco C, et al. EULAR recommendations for the use of imaging in large vessel vasculitis in clinical practice. Ann Rheum Dis. 2018 May;77(5):636-643.
4. Luqmani R, et al. The Role of Ultrasound Compared to Biopsy of Temporal Arteries in the Diagnosis and Treatment of Giant Cell Arteritis (TABUL): a diagnostic accuracy and cost-effectiveness study. Health Technol Assess. 2016 Nov;20(90):1-238.
5. Hellmich B, et al. 2018 Update of the EULAR recommendations for the management of large vessel vasculitis. Ann Rheum Dis. 2020 Jan;79(1):19-30.
6. Hayreh SS, et al. Visual manifestations of giant cell arteritis. Trends and clinical spectrum in 161 patients. Medicine (Baltimore). 1998 Jul;77(4):261-97.
7. Salvarani C, et al. Polymyalgia rheumatica and giant-cell arteritis. N Engl J Med. 2002 Jul 25;347(4):261-71.
8. Genereau T, et al. Active giant cell arteritis with positive temporal artery biopsy: a study of 50 patients to identify predictive factors of relapse. J Rheumatol. 1999.
9. Schmidt WA, et al. Color duplex ultrasonography in the diagnosis of temporal arteritis. N Engl J Med. 1997.
10. Weyand CM, et al. Correlation between the topography of angiogenic T cell functions and the clinical picture of giant cell arteritis. Arthritis Rheum. 2005.
11. Hoffman GS, et al. A multicenter, randomized, double-blind, placebo-controlled trial of adjuvant methotrexate treatment for giant cell arteritis. Arthritis Rheum. 2002.
12. Jover JA, et al. Combined treatment of giant-cell arteritis with methotrexate and prednisone. a randomized, double-blind, placebo-controlled trial. Ann Intern Med. 2001.
13. Unizony S, et al. Tocilizumab for the treatment of large-vessel vasculitis (How to treat). Clin Exp Rheumatol. 2016.
14. Dasgupta B, et al. BSR and BHPR guidelines for the management of giant cell arteritis. Rheumatology. 2010.
15. Hunder GG, et al. The American College of Rheumatology 1990 criteria for the classification of giant cell arteritis. Arthritis Rheum. 1990.
16. Ness T, et al. The diagnosis and treatment of giant cell arteritis. Dtsch Arztebl Int. 2013.
17. Berger CT, et al. Emerging treatment options for GCA and PMR. Rheumatology. 2018.
18. Liozon E, et al. Incidence and prevalence of biopsy-proven giant cell arteritis in France. J Rheumatol. 2018.
19. Gonzalez-Gay MA, et al. Giant cell arteritis: disease patterns of clinical presentation and impact on outcome. Autoimmun Rev. 2016.
20. Goyal N, et al. The MedVellum Protocols. AI Medicine. 2025.

(End of File)

31. Deep Dive: Differential Diagnosis of the "GCA Headache"

"It's not always GCA." Elderly people get headaches for other reasons. Distinguishing them avoids unnecessary high-dose steroids.

32. Patient Life: Driving & Work

"Can I drive, Doctor?"

• Visual Loss: If a patient has visual field loss from AION, they likely do not meet driving standards (DVLA in UK). They must inform the authority.
• Diplopia: Absolute bar to driving until resolved (usually patches within weeks of steroid).
• Visual Acuity: Must be 6/12 (Snellen) with both eyes open.
• The "Steroid Fog": High dose prednisolone causes jitteriness, insomnia, and poor concentration. Patients should be advised to avoid long drives initially.

"Can I Work?"

• Most patients need 4-6 weeks off work during the "Induction Phase" (High dose steroids + frequent appointments).
• Fatigue is a major symptom of both the disease and the treatment crash.

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33. Technical Appendix F: The "Steroid Tapering Strategy" (Detailed)

The "Slow and Steady" Approach. The BSR 2020 recommended taper for uncomplicated GCA:

• Flare Rule: If symptoms recur, increase dose to the last effective dose plus 5-10mg. Maintain for 4 weeks before trying to taper again.

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34. Final Summary

GCA is a medical emergency that requires a "shoot first, ask questions later" approach regarding steroid initiation. The cost of delay is permanent blindness. The advent of Ultrasound and Tocilizumab has modernized the pathway, making diagnosis faster and treatment safer, but clinical vigilance remains the cornerstone of care.