Fibromyalgia
Summary
Fibromyalgia is a chronic widespread pain disorder characterised by generalised musculoskeletal pain, fatigue, non-restorative sleep, and cognitive dysfunction ("fibro fog"). It is considered a central sensitisation syndrome, where the central nervous system amplifies pain signals. Fibromyalgia affects approximately 2-4% of the population, predominantly women (9:1 ratio), and often coexists with other functional syndromes including irritable bowel syndrome, chronic fatigue syndrome, and migraine. Diagnosis is clinical, based on the ACR 2016 criteria, after exclusion of other conditions. Management is multimodal: patient education, graded aerobic exercise, and pharmacotherapy (duloxetine, pregabalin, or amitriptyline). Opioids are NOT recommended as they worsen outcomes. Cognitive behavioural therapy can improve coping and function.
Key Facts
- Definition: Chronic widespread pain with central sensitisation; not an inflammatory or degenerative disease
- Prevalence: 2-4% of the population; 80-90% female
- Peak age: 30-50 years
- Core symptoms: Chronic widespread pain, fatigue, non-restorative sleep, cognitive dysfunction
- Diagnostic criteria: ACR 2016 (Widespread Pain Index + Symptom Severity Scale)
- Key pharmacotherapy: Duloxetine, pregabalin, amitriptyline (low dose)
- NOT recommended: Opioids, NSAIDs (ineffective)
Clinical Pearls
Fibromyalgia is REAL Pain: The pain is not "in the patient's head" — neuroimaging shows altered central pain processing. Validating the patient's experience is essential for therapeutic relationship.
The Big Three Comorbidities: IBS, migraine, and depression are the three most common comorbidities. If you diagnose one, screen for the others.
Opioids Make It Worse: Counter-intuitively, opioids do not help and may worsen outcomes by promoting opioid-induced hyperalgesia and dependence. They are NOT recommended by any international guideline.
Why This Matters Clinically
Fibromyalgia is common, debilitating, and frequently misunderstood. Patients often feel disbelieved and have typically consulted multiple specialists before diagnosis. A clear explanation, validation, and evidence-based management plan can be transformative. Conversely, inappropriate investigations, diagnostic uncertainty, and opioid prescribing worsen outcomes.
Incidence & Prevalence
- Prevalence: 2-4% of the population (varies by diagnostic criteria used)
- Sex ratio: Female:Male 9:1 (though this may be narrowing with newer criteria)
- Peak onset: 30-50 years
- Trend: Increasing recognition; prevalence stable
Demographics
| Factor | Details |
|---|---|
| Age | Onset typically 30-50 years; can occur at any age including adolescence |
| Sex | 80-90% female |
| Ethnicity | All ethnic groups |
| Socioeconomic | All socioeconomic groups; higher reported disability in lower SES |
Risk Factors
Non-Modifiable:
- Female sex
- Family history of fibromyalgia (genetic component)
- History of physical or emotional trauma
Modifiable:
| Risk Factor | Association |
|---|---|
| Poor sleep | Strong bidirectional relationship |
| Physical deconditioning | Worsens symptoms |
| Psychological distress | Anxiety, depression exacerbate |
| Obesity | Associated with worse outcomes |
| History of chronic regional pain | May generalise to fibromyalgia |
Mechanism
Step 1: Genetic and Environmental Predisposition
- Genetic factors affect pain processing (e.g., serotonin transporter gene polymorphisms)
- Environmental triggers: physical trauma, infection, psychological stress
- These factors may initiate chronic pain pathway dysfunction
Step 2: Central Sensitisation
- Central nervous system amplifies pain signals
- Reduced descending pain inhibition from brainstem
- Increased excitatory neurotransmitters (glutamate, substance P)
- Decreased inhibitory neurotransmitters (serotonin, noradrenaline, GABA)
Step 3: Altered Brain Activity
- Functional MRI shows increased activity in pain-processing regions
- Reduced grey matter volume in areas involved in pain modulation
- Increased connectivity between pain matrix regions
Step 4: Peripheral and Secondary Changes
- Small fibre neuropathy may contribute in some patients
- Muscle deconditioning from reduced activity
- Sleep disruption further reduces pain threshold
- Cognitive dysfunction from chronic pain and poor sleep
Classification
| Subtype | Features |
|---|---|
| Pure fibromyalgia | Widespread pain without significant mood disorder |
| Fibromyalgia with depression | Prominent mood symptoms |
| Fibromyalgia with somatic symptoms | Multiple overlapping syndromes (IBS, migraine, TMJ) |
| Secondary fibromyalgia | Occurring alongside another chronic pain condition (e.g., OA, RA) |
Associated Conditions
| Condition | Prevalence in Fibromyalgia |
|---|---|
| Irritable bowel syndrome (IBS) | 30-70% |
| Chronic fatigue syndrome | 20-70% |
| Migraine/tension headache | 50% |
| Depression | 20-40% |
| Anxiety disorders | 30-60% |
| Temporomandibular disorder (TMD) | 25% |
| Interstitial cystitis | 10-20% |
Symptoms
Core Symptoms:
Other Common Symptoms:
Atypical Presentations:
Signs
General:
Musculoskeletal:
Neurological:
Red Flags
[!CAUTION] Red Flags — Exclude other diagnoses if:
- Inflammatory markers elevated (ESR, CRP) — consider PMR, inflammatory arthritis
- Joint swelling — inflammatory arthritis
- Objective weakness — myopathy, myositis
- Neurological signs — MS, neuropathy, spinal pathology
- Weight loss, night sweats — malignancy
- New onset after age 50 with proximal stiffness — PMR
- Abnormal reflexes — neurological disease
Structured Approach
General:
- Assess general demeanour (often tired, frustrated)
- Note previous consultations and investigations
Musculoskeletal:
- Full joint examination: look for synovitis, effusion, deformity (should be absent)
- Assess range of movement (typically normal)
- Palpate for tenderness (widespread, not localised to joints)
Neurological:
- Power, reflexes, sensation — should be normal
- Look for objective deficit (not present in fibromyalgia)
Classic Tender Points (Historical — Not Required for Diagnosis):
- 18 specific tender points (9 pairs) used in 1990 ACR criteria
- Now replaced by Widespread Pain Index in 2016 criteria
- Still useful for clinical demonstration
Special Tests
| Test | Technique | Positive Finding | Clinical Significance |
|---|---|---|---|
| Tender point exam | Apply 4kg pressure to classic sites | Tenderness at ≥11/18 points | Supports fibromyalgia (historical) |
| Normal inflammatory markers | ESR, CRP | Normal | Helps exclude inflammatory conditions |
| Normal strength testing | Manual muscle testing | No objective weakness | Excludes myopathy |
| Normal reflexes | Deep tendon reflexes | Normal | Excludes neurological pathology |
First-Line (Bedside)
- Clinical diagnosis — Based on history and examination
- BMI — Obesity common and worsens symptoms
Laboratory Tests
| Test | Expected Finding | Purpose |
|---|---|---|
| FBC | Normal | Exclude anaemia |
| ESR | Normal | Exclude inflammatory disease |
| CRP | Normal | Exclude inflammatory disease |
| TFTs | Normal | Exclude hypothyroidism |
| Vitamin D | May be low (should correct) | Associated with diffuse pain |
| Calcium | Normal | Exclude hypercalcaemia |
| HbA1c/Glucose | Normal | Diabetes screen |
| ANA, RF | Negative (unless coexisting AI disease) | Exclude SLE, RA |
Key Point: Investigations are used to EXCLUDE other conditions, not to diagnose fibromyalgia.
Imaging
| Modality | Indication |
|---|---|
| X-rays | NOT routine; if concern for OA or inflammatory arthritis |
| MRI | NOT routine; if neurological signs or specific joint pathology suspected |
Diagnostic Criteria
ACR 2016 Criteria for Fibromyalgia:
Widespread Pain Index (WPI): Score 0-19 Count of painful regions in past week from list of 19 areas
Symptom Severity Scale (SSS): Score 0-12 Rate 0-3 each for:
- Fatigue
- Waking unrefreshed
- Cognitive symptoms
- Plus presence of somatic symptoms (headache, abdominal pain, depression)
Diagnosis if:
- WPI ≥7 AND SSS ≥5 OR
- WPI 4-6 AND SSS ≥9
- Symptoms present for ≥3 months
- No other disorder that would explain the pain
Management Algorithm
Conservative Management (Foundation of Treatment)
Education:
- Explain fibromyalgia as a real condition with altered pain processing
- Validate the patient's experience
- Set realistic expectations (improvement, not cure)
- Provide written information (arthritis.org, versusarthritis.org)
Exercise (MOST EFFECTIVE Intervention):
- Graded aerobic exercise: walking, swimming, cycling
- "Start low, go slow" — avoid boom-bust patterns
- 20-30 minutes, 2-3 times per week initially
- Gradual increase in intensity and duration
- Strength training also beneficial
Sleep Hygiene:
- Regular sleep-wake schedule
- Limit caffeine, alcohol, screen time before bed
- Address obstructive sleep apnoea if present
Medical Management
| Drug Class | Drug | Dose | Key Points |
|---|---|---|---|
| TCA | Amitriptyline | 10-25mg nocte | First-line; improves sleep and pain |
| SNRI | Duloxetine | 30-60mg daily | First-line; also treats comorbid depression |
| Anticonvulsant | Pregabalin | 75mg BD, up to 300mg BD | First-line; helps sleep and pain |
| SNRI | Milnacipran | 50mg BD | Alternative; less commonly used |
| Muscle relaxant | Cyclobenzaprine | 10mg nocte | Short-term use; improves sleep |
Drugs to AVOID:
| Drug Class | Reason |
|---|---|
| Opioids | Ineffective; worsen outcomes; hyperalgesia |
| NSAIDs | Ineffective for central pain |
| Benzodiazepines | Dependence; worsen sleep quality long-term |
| Corticosteroids | Ineffective; significant side effects |
Psychological Management
- CBT: Improves coping, reduces catastrophising
- ACT (Acceptance and Commitment Therapy): Promotes acceptance and values-based action
- Mindfulness-based stress reduction: Reduces pain perception
- Address comorbidities: Treat depression and anxiety if present
Disposition
- Primary care management: Majority of patients
- Rheumatology referral: Diagnostic uncertainty, failed initial treatment
- Pain clinic referral: Refractory cases, complex polypharmacy
- Psychology/psychiatry: Significant mood disorder, complex psychosocial factors
- Follow-up: Regular (3-6 monthly) to monitor symptoms, adjust medications
Immediate (Treatment-Related)
| Complication | Treatment | Management |
|---|---|---|
| Medication side effects | Amitriptyline: dry mouth, drowsiness | Reduce dose, take earlier in evening |
| Pregabalin: weight gain, oedema | - | Consider alternative |
| Duloxetine: nausea | - | Take with food, titrate slowly |
Early (Months)
- Physical deconditioning: From avoiding activity; worsens symptoms
- Iatrogenic harm: From inappropriate opioids, polypharmacy, excessive investigations
- Mood disorders: Depression and anxiety very common
Late (Years)
- Chronic disability: Significant proportion have long-term functional impairment
- Opioid dependence: If inappropriately prescribed
- Social isolation: From reduced activity and misunderstanding of condition
- Economic impact: Reduced work capacity, healthcare utilisation
Natural History
- Chronic condition: Symptoms persist for years in most patients
- Fluctuating course: Periods of relative improvement and flares
- Complete remission: Rare (less than 25%), but significant improvement possible
Outcomes with Treatment
| Variable | Outcome |
|---|---|
| Improvement with multimodal therapy | 25-50% report significant improvement |
| Full remission | Less than 25% |
| Work disability | 25-50% have difficulty maintaining employment |
| Response to exercise | NNT approximately 3 for clinically significant improvement |
| Mortality | No increased mortality from fibromyalgia itself |
Prognostic Factors
Good Prognosis:
- Shorter symptom duration at diagnosis
- Engaged in regular exercise
- Low catastrophising
- Good social support
- Absence of comorbid depression
- Younger age
Poor Prognosis:
- Long duration before diagnosis
- Comorbid depression/anxiety
- Opioid use
- High catastrophising
- Disability claims/litigation
- Poor sleep
Key Guidelines
- EULAR 2016 — Revised recommendations for fibromyalgia management. Emphasises patient education and exercise first, then pharmacotherapy. EULAR
- ACR 2016 Diagnostic Criteria — Updated criteria using WPI and SSS. ACR
- NICE CG193 (2021) — Chronic pain: assessment and management. NICE
- Canadian Guidelines (2012) — Comprehensive fibromyalgia management guideline. CMAJ
Landmark Trials
Crofford et al. (2005) — Pregabalin for fibromyalgia
- 529 patients randomised to pregabalin vs placebo
- Key finding: Pregabalin significantly reduced pain and improved function
- Clinical Impact: Pregabalin approved for fibromyalgia
Arnold et al. (2004) — Duloxetine for fibromyalgia
- 207 patients randomised
- Key finding: Duloxetine 60mg significantly improved pain and function
- Clinical Impact: Duloxetine approved for fibromyalgia
Busch et al. (2007) — Cochrane review of exercise
- Systematic review of exercise interventions
- Key finding: Aerobic exercise improves pain, physical function, and well-being
- Clinical Impact: Established exercise as cornerstone of treatment
Evidence Strength
| Intervention | Level | Key Evidence |
|---|---|---|
| Aerobic exercise | 1a | Cochrane review |
| CBT | 1a | Multiple RCTs |
| Pregabalin | 1b | Crofford RCT |
| Duloxetine | 1b | Arnold RCT |
| Amitriptyline | 1b | Multiple RCTs |
| Opioids NOT recommended | 1a | Systematic reviews; guideline consensus |
What is Fibromyalgia?
Fibromyalgia is a condition that causes pain all over your body, along with extreme tiredness, difficulties sleeping, and problems with memory and concentration (often called "fibro fog"). It is not caused by inflammation or damage to your muscles or joints — instead, it is due to the way your brain and nervous system process pain signals. This means the pain is very real, but the problem lies in the "volume control" for pain being turned up too high.
Is it serious?
Fibromyalgia is not life-threatening and does not damage your joints or organs. However, it can significantly affect your quality of life, your ability to work, and your relationships. The good news is that with the right approach, many people can manage their symptoms and lead fulfilling lives.
How is it treated?
- Education: Understanding what fibromyalgia is (and isn't) is the first step to managing it.
- Exercise: Gentle, regular exercise like walking, swimming, or cycling is the most effective treatment. It may feel hard at first, so start slowly and build up gradually.
- Medication: Drugs like amitriptyline (low dose at night), duloxetine, or pregabalin can help reduce pain and improve sleep. Surprisingly, strong painkillers like opioids (morphine, codeine) do NOT help and can make things worse.
- Psychological support: Therapies like CBT (cognitive behavioural therapy) can help you manage pain and improve your quality of life.
- Sleep: Improving your sleep quality is important. Good sleep habits and sometimes medication can help.
What to expect
- There is no "cure" for fibromyalgia, but symptoms can be managed
- Many people see significant improvement with exercise and the right treatment
- Symptoms may fluctuate — there will be good days and bad days
- Building a support network and pacing your activities helps
When to seek help
See your doctor if:
- Your pain is getting significantly worse
- You develop new symptoms like joint swelling, fever, or weakness
- You are struggling to cope emotionally
- Your current treatments are not helping
Primary Guidelines
- Macfarlane GJ, et al. EULAR revised recommendations for the management of fibromyalgia. Ann Rheum Dis. 2017;76(2):318-328. PMID: 27377815
- Wolfe F, et al. 2016 Revisions to the 2010/2011 fibromyalgia diagnostic criteria. Semin Arthritis Rheum. 2016;46(3):319-329. PMID: 27916278
Key Trials
- Crofford LJ, et al. Pregabalin for the treatment of fibromyalgia syndrome: results of a randomized, double-blind, placebo-controlled trial. Arthritis Rheum. 2005;52(4):1264-1273. PMID: 15818684
- Arnold LM, et al. A double-blind, multicenter trial comparing duloxetine with placebo in the treatment of fibromyalgia patients with or without major depressive disorder. Arthritis Rheum. 2004;50(9):2974-2984. PMID: 15457467
- Busch AJ, et al. Exercise for treating fibromyalgia syndrome. Cochrane Database Syst Rev. 2007;(4):CD003786. PMID: 17943797
Further Resources
- Versus Arthritis Fibromyalgia: versusarthritis.org/about-arthritis/conditions/fibromyalgia
- Fibromyalgia Action UK: fmauk.org
- NHS Fibromyalgia: nhs.uk/conditions/fibromyalgia
Medical Disclaimer: MedVellum content is for educational purposes and clinical reference. Fibromyalgia management should be individualised. Consult a healthcare professional for personal advice.