Primary Hyperaldosteronism

1. Clinical Overview

Primary Hyperaldosteronism (PA) represents autonomous, inappropriate aldosterone secretion from the adrenal glands that is not suppressed by sodium loading and occurs independently of the renin-angiotensin system. [1,2] This condition has emerged as the most common cause of secondary hypertension, accounting for 5-10% of all hypertensive patients and up to 20% of those with resistant hypertension. [3]

Historical Context

First described by Jerome Conn in 1955 as a syndrome of hypertension, hypokalaemia, and adrenal adenoma, PA was initially considered rare. [13] However, the introduction of the aldosterone-renin ratio (ARR) as a screening test in the 1980s revealed that PA is far more prevalent than previously recognized, leading to what Young termed the "primary aldosteronism renaissance." [13]

Classification of Primary Hyperaldosteronism

Why Primary Hyperaldosteronism Matters

1. Excess Cardiovascular Risk: Patients with PA experience higher rates of stroke, myocardial infarction, atrial fibrillation, and left ventricular hypertrophy compared to patients with essential hypertension matched for the same blood pressure levels. [7,11] This excess risk is attributed to direct mineralocorticoid-mediated cardiovascular toxicity independent of blood pressure elevation.

2. Potentially Curable Hypertension: Unilateral disease (APA) can be cured by laparoscopic adrenalectomy, with complete resolution of hypokalaemia in nearly 100% of cases and cure or substantial improvement in hypertension in the majority. [8,18]

3. Targeted Pharmacotherapy: Bilateral disease responds specifically to mineralocorticoid receptor antagonists (MRAs) such as spironolactone, which may be more effective than standard antihypertensive therapy. The PATHWAY-2 trial demonstrated spironolactone's superiority in resistant hypertension. [2]

4. Under-diagnosed: Despite its prevalence, PA remains significantly under-diagnosed, with most cases of secondary hypertension missed in routine clinical practice. [3,14]

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2. Epidemiology

Prevalence

The reported prevalence of PA varies widely depending on the population studied and screening methodology employed:

A landmark study by Monticone et al. (2017) screened 1,672 consecutive primary care hypertensive patients and found a prevalence of 6% when using confirmatory testing, increasing to 12.7% with liberal ARR interpretation. [3]

Age and Sex Distribution

• Peak Incidence: 30-60 years of age [1]
• Sex Distribution: Historically considered more common in women (female:male ratio 2:1 for APA), but recent large screening studies suggest similar prevalence between sexes when BAH is included [3]
• Familial Forms: Present in childhood or early adulthood, particularly FH-I (GRA) and FH-III [12]

Ethnic and Geographic Variation

Limited data exist on ethnic differences. Japanese and Chinese populations may have higher prevalence of PA, potentially related to genetic factors and dietary sodium intake. [16]

Risk Factors

• Resistant hypertension (most important clinical predictor)
• Severe hypertension (stage 2: ≥160/100 mmHg)
• Hypertension at young age (less than 40 years)
• Hypokalaemia (spontaneous or diuretic-induced)
• Adrenal incidentaloma discovered on imaging
• Family history of early-onset hypertension or cerebrovascular accident
• Obstructive sleep apnoea (associated, not causal)

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3. Aetiology and Pathophysiology

Normal Renin-Angiotensin-Aldosterone System (RAAS)

Under physiological conditions, aldosterone secretion is tightly regulated:

1. Stimulus: Decreased renal perfusion, reduced sodium delivery to macula densa, or sympathetic stimulation
2. Renin Release: Juxtaglomerular cells in kidney secrete renin
3. Angiotensin Cascade: Renin converts angiotensinogen → Angiotensin I → Angiotensin II (via ACE)
4. Aldosterone Secretion: Angiotensin II stimulates zona glomerulosa of adrenal cortex to produce aldosterone
5. Negative Feedback: Sodium retention → volume expansion → suppression of renin

Other physiological stimuli for aldosterone secretion include hyperkalaemia (direct adrenal stimulation) and ACTH (minor, circadian effect).

Pathophysiology of Primary Hyperaldosteronism

┌─────────────────────────────────────────────────────────────────────────────┐
│                  PRIMARY HYPERALDOSTERONISM PATHOPHYSIOLOGY                 │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │         AUTONOMOUS ALDOSTERONE SECRETION                            │   │
│   │  • Aldosterone-Producing Adenoma (APA): Somatic mutations           │   │
│   │  • Bilateral Adrenal Hyperplasia (BAH): Micro/macro-nodular         │   │
│   │  • Independent of Renin-Angiotensin II control                      │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│                                    ↓                                        │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │              ELEVATED CIRCULATING ALDOSTERONE                       │   │
│   │  • Plasma Aldosterone Concentration (PAC) increased                 │   │
│   │  • NOT suppressed by sodium loading                                 │   │
│   │  • NOT regulated by angiotensin II                                  │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│                                    ↓                                        │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │         RENAL EFFECTS (Distal Convoluted Tubule & Collecting Duct)  │   │
│   │  1. Upregulation of ENaC (Epithelial Sodium Channel)               │   │
│   │     → ↑↑ Sodium Reabsorption                                        │   │
│   │     → Water Retention → VOLUME EXPANSION → HYPERTENSION             │   │
│   │                                                                     │   │
│   │  2. Increased activity of Na⁺/K⁺-ATPase pump                        │   │
│   │     → ↑↑ Potassium Secretion → HYPOKALAEMIA                         │   │
│   │                                                                     │   │
│   │  3. Increased H⁺ secretion via H⁺-ATPase                            │   │
│   │     → ↑ Hydrogen Ion Excretion → METABOLIC ALKALOSIS                │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│                                    ↓                                        │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │                  NEGATIVE FEEDBACK SUPPRESSION                      │   │
│   │  • Volume expansion → ↑ Renal Perfusion Pressure                    │   │
│   │  • Hypernatraemia → ↑ Sodium delivery to macula densa               │   │
│   │  • Result: PROFOUND RENIN SUPPRESSION                               │   │
│   │  • HALLMARK: High Aldosterone + Low Renin                           │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│                                    ↓                                        │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │      EXTRA-RENAL CARDIOVASCULAR EFFECTS (Tissue MR activation)      │   │
│   │  • Myocardial fibrosis (collagen deposition)                        │   │
│   │  • Vascular inflammation and remodelling                            │   │
│   │  • Endothelial dysfunction (↓ NO bioavailability)                   │   │
│   │  • Oxidative stress (NADPH oxidase activation)                      │   │
│   │  • Atrial fibrosis → Atrial Fibrillation                            │   │
│   │  • Proteinuria and glomerular injury                                │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘

Molecular Mechanisms: Somatic Mutations in APA

Recent genomic studies have identified recurrent somatic mutations in aldosterone-producing adenomas: [5,6]

Common Pathway: All mutations lead to increased intracellular calcium concentration in zona glomerulosa cells → activation of Ca²⁺-dependent signaling → increased CYP11B2 (aldosterone synthase) expression → autonomous aldosterone production. [6]

Exam Detail: ### Familial Hyperaldosteronism: Genetic Forms

FH-I: Glucocorticoid-Remediable Aldosteronism (GRA)

• Genetics: Autosomal dominant; unequal crossover between CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase) genes
• Result: Chimeric gene with ACTH-responsive promoter fused to aldosterone synthase coding sequence
• Consequence: Aldosterone production driven by ACTH (not angiotensin II)
• Clinical: Early-onset severe hypertension, cerebral hemorrhage risk (aneurysms), variable hypokalaemia
• Diagnosis: Elevated urinary 18-oxocortisol and 18-hydroxycortisol; genetic testing
• Treatment: Low-dose dexamethasone (0.125-0.25 mg/day) suppresses ACTH → normalizes aldosterone and BP [12]

FH-II

• Genetics: Autosomal dominant; locus on chromosome 7p22 (gene unknown)
• Clinical: Indistinguishable from sporadic PA (can be APA or BAH)
• Diagnosis: Family history of PA; genetic testing not clinically available
• Treatment: As per APA or BAH subtype

FH-III

• Genetics: Germline mutations in KCNJ5 (same gene as somatic APA mutations)
• Clinical: Severe, early-onset PA; massive bilateral adrenal hyperplasia
• Diagnosis: Genetic testing; often presents in childhood
• Treatment: Bilateral adrenalectomy may be required; MRAs

FH-IV

• Genetics: Germline mutations in CACNA1H
• Clinical: PA with variable presentation
• Diagnosis: Genetic testing
• Treatment: Variable; often MRAs

The "Aldosterone Escape" Phenomenon

Despite sodium retention, patients with PA do not develop oedema. This is due to "aldosterone escape":

1. Volume expansion → ↑ ANP (atrial natriuretic peptide)
2. ↑ Renal perfusion pressure → pressure natriuresis
3. Downregulation of proximal tubule sodium reabsorption
4. Net effect: Sodium balance restored (at higher total body sodium), preventing oedema but maintaining hypertension

Direct Cardiovascular Toxicity of Aldosterone

Mineralocorticoid receptors (MR) are expressed in non-epithelial tissues including heart, blood vessels, and brain. Aldosterone excess causes: [7,11]

Cardiac Effects:

• Myocardial fibrosis (collagen I and III deposition)
• Left ventricular hypertrophy (independent of blood pressure)
• Diastolic dysfunction
• Atrial fibrosis → atrial fibrillation

Vascular Effects:

• Vascular inflammation (↑ inflammatory cytokines)
• Endothelial dysfunction (↓ nitric oxide, ↑ endothelin-1)
• Arterial stiffness
• Atherosclerosis acceleration

Renal Effects:

• Glomerular hyperfiltration followed by sclerosis
• Podocyte injury → proteinuria
• Tubulointerstitial fibrosis
• Progressive CKD [19]

This explains why PA patients have higher cardiovascular event rates than BP-matched essential hypertensive controls. [7]

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4. Clinical Presentation

Symptoms

The majority of PA patients are asymptomatic, with hypertension discovered incidentally. When present, symptoms relate to:

Hypokalaemia (when K⁺ less than 3.5 mmol/L):

• Muscle weakness (proximal > distal)
• Muscle cramps, especially nocturnal
• Paraesthesias
• Periodic paralysis (severe cases, especially in Asian populations)
• Polyuria and polydipsia (nephrogenic diabetes insipidus from hypokalaemia)
• Palpitations (ventricular ectopy)

Hypertension:

• Headaches
• Blurred vision
• Epistaxis (severe hypertension)

IMPORTANT: > 50% of PA patients have normal serum potassium. [1,14] Absence of hypokalaemia does NOT exclude PA. Hypokalaemia may only manifest after diuretic initiation.

Who to Screen: Endocrine Society Guidelines (2016)

The Endocrine Society recommends screening with ARR in the following groups: [1]

Physical Examination

Physical examination is typically unremarkable and non-specific. There are no pathognomonic signs of PA (unlike Cushing's syndrome).

Blood Pressure:

• Consistently elevated
• May be severely elevated (> 180/110)
• Resistant to multiple antihypertensive agents

No Oedema:

• Absence of peripheral oedema despite sodium retention (due to aldosterone escape)

Neuromuscular (if hypokalaemic):

• Proximal muscle weakness (difficulty rising from chair, climbing stairs)
• Reduced deep tendon reflexes
• Chvostek/Trousseau signs (if concurrent alkalosis causes ↓ ionized calcium)

Cardiovascular:

• Irregularly irregular pulse (if atrial fibrillation)
• Heaving apex (left ventricular hypertrophy)
• Fourth heart sound (S4) - LVH

No Cushingoid Features:

• Absence of central adiposity, striae, bruising, proximal myopathy (distinguishes from Cushing's)

Clinical Pearl: Examination Pearls for Clinical Exams:

1. Check supine and standing BP: Orthostatic hypotension is rare (volume-replete state) unless over-diuresis
2. Assess for radio-radial delay and radio-femoral delay: Exclude coarctation of aorta (another secondary cause)
3. Auscultate for renal bruits: Exclude renovascular hypertension (causes secondary hyperaldosteronism, not primary)
4. Fundoscopy: Look for hypertensive retinopathy (grade III/IV suggests chronicity and end-organ damage)
5. Assess JVP: Normal or elevated (volume expansion), not low
6. Palpate for adrenal masses: Not possible (retroperitoneal), but check for other causes of secondary HTN

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5. Differential Diagnosis

The key differential diagnostic challenge is distinguishing primary from secondary hyperaldosteronism, and differentiating PA from other causes of mineralocorticoid excess.

Primary vs Secondary Hyperaldosteronism

Other Causes of Hypokalaemia + Hypertension

Differentiating APA from BAH (After PA Confirmed)

This distinction is critical as it determines treatment (surgery vs medical):

CRITICAL: CT/MRI findings alone are insufficient to distinguish APA from BAH because:

• Non-functioning adrenal incidentalomas are common (4-10% of general population > 40 years)
• BAH may have asymmetric nodules mimicking adenoma
• APA may be small and not visible on imaging

Adrenal Vein Sampling (AVS) is mandatory before surgical decision-making (except in young patients less than 35 years with clear unilateral lesion > 1 cm and very high ARR). [1,4,10]

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6. Investigations

The diagnostic workup for PA involves three sequential steps:

1. Case Detection (Screening): ARR
2. Confirmation: Suppression testing
3. Subtype Classification: Imaging and AVS

Step 1: Case Detection — Aldosterone-Renin Ratio (ARR)

The Screening Test of Choice: ARR is the recommended screening test for PA. [1,14]

Principle: In PA, aldosterone is high and renin is suppressed → elevated ratio.

Measurement:

• Plasma Aldosterone Concentration (PAC): ng/dL or pmol/L
• Plasma Renin Activity (PRA): ng/mL/h
• OR Direct Renin Concentration (DRC): mU/L or pmol/L

Calculation:

• ARR = PAC (ng/dL) ÷ PRA (ng/mL/h)

Interpretation (varies by assay and units):

A positive screen requires BOTH:

1. Elevated ARR (> 20-40)
2. Elevated PAC (> 15 ng/dL or 414 pmol/L)

Pre-Test Preparation and Medication Interference

Many antihypertensive medications interfere with ARR interpretation: [1,15]

Recommended Washout Protocol:

1. Stop interfering medications (see table above)
2. Bridge with non-interfering agents: alpha-blockers (doxazosin), non-dihydropyridine CCBs (verapamil), hydralazine
3. Washout period: 2 weeks minimum (4-6 weeks for MRAs)
4. Correct hypokalaemia before testing (low K⁺ → suppressed aldosterone → false negative)
5. Liberalize dietary sodium (≥6 g/day for 3 days) to suppress renin maximally

Patient Positioning:

• Traditionally measured after 2 hours upright (to maximize renin and aldosterone)
• Some centres use mid-morning seated samples after 5-15 minutes rest
• Method should be consistent within institution

Limitations of ARR:

• Affected by medications (see above)
• Affected by potassium status (hypokalaemia suppresses aldosterone)
• Affected by sodium intake
• Assay variability (no universal cutoff)
• High sensitivity (~90%) but moderate specificity (~70%) → requires confirmation [1,17]

Step 2: Confirmatory Testing

Who Needs Confirmation? Most patients with positive ARR require confirmatory testing. [1]

Exception (confirmation may be omitted):

• Spontaneous hypokalaemia (K⁺ less than 3.5 mmol/L off diuretics)
• AND suppressed PRA (less than 1 ng/mL/h)
• AND PAC > 20 ng/dL (550 pmol/L)
• → High probability of PA; can proceed to subtype testing [1]

Principle of Confirmatory Tests: Demonstrate failure to suppress aldosterone with sodium loading (unlike normal physiology).

Confirmatory Test Options

1. Saline Infusion Test (SIT) - Most widely used

Protocol:

• Infuse 2 litres of 0.9% NaCl IV over 4 hours (morning, supine position)
• Measure PAC and renin at baseline and 4 hours
• Monitor BP, heart rate (caution in heart failure, severe hypertension, renal impairment)

Interpretation:

• Positive (PA confirmed): PAC > 10 ng/dL (277 pmol/L) at 4 hours
• Negative (PA excluded): PAC less than 5 ng/dL (138 pmol/L)
• Indeterminate: PAC 5-10 ng/dL (consider alternative test)

Contraindications: Heart failure, severe uncontrolled hypertension, arrhythmia, renal insufficiency

2. Oral Sodium Loading Test

Protocol:

• High sodium diet (6 g/day, ~200 mmol/day) for 3 days
• Measure 24-hour urinary aldosterone on day 3
• Ensure adequate sodium intake (24h urinary sodium > 200 mmol confirms compliance)

Interpretation:

• Positive: 24h urinary aldosterone > 12 mcg/24h (33 nmol/24h)
• Negative: less than 10 mcg/24h

Advantage: Outpatient, no IV access required Disadvantage: Requires patient compliance, less standardized

3. Fludrocortisone Suppression Test

Protocol:

• Fludrocortisone 0.1 mg every 6 hours for 4 days
• High sodium diet
• Potassium supplementation (to maintain K⁺ 4.0 mmol/L)
• Measure upright PAC on day 4

Interpretation:

• Positive: PAC > 6 ng/dL (166 pmol/L)

Disadvantage: Complex, prolonged, requires monitoring, risk of hypokalaemia and hypertension

4. Captopril Challenge Test (Rarely used now)

Protocol:

• Captopril 25-50 mg PO
• Measure PAC and renin at baseline and 1-2 hours

Interpretation:

• Positive: Failure to suppress PAC

Limitation: Lower sensitivity and specificity than other tests; largely replaced by SIT [17]

Most Centres Use: Saline infusion test (SIT) as first-line confirmatory test due to standardization and convenience. [1,17]

Step 3: Subtype Classification (Localization)

Goal: Distinguish unilateral disease (APA, unilateral hyperplasia → surgical) from bilateral disease (BAH → medical).

3a. CT or MRI Adrenals

Purpose:

• Identify adrenal masses
• Exclude adrenal carcinoma (large > 4 cm, heterogeneous, irregular)
• Provide anatomical roadmap for AVS

Protocol:

• Thin-cut (≤3 mm) dedicated adrenal CT, pre- and post-contrast
• OR adrenal MRI with chemical shift imaging

Findings:

• APA: Unilateral adenoma, typically less than 2 cm, homogeneous, low attenuation (less than 10 HU unenhanced)
• BAH: Normal-appearing adrenals or bilateral micro/macronodular hyperplasia
• Incidentaloma: Non-functioning adenoma (common, cannot distinguish from APA on imaging alone)

CRITICAL LIMITATION: CT/MRI cannot reliably differentiate functional from non-functional adenomas. [1,4]

• Non-functioning incidentalomas present in 4-10% of population > 40 years
• Up to 25% of APAs are less than 1 cm and not visible on CT
• BAH may have unilateral dominant nodule mimicking APA

Conclusion: Imaging is NOT sufficient for surgical decision-making (except in specific circumstances below).

3b. Adrenal Vein Sampling (AVS) — GOLD STANDARD

Indication: AVS is essential before adrenalectomy to confirm lateralization of aldosterone excess (unless patient not a surgical candidate). [1,4,10]

Exception (AVS may be omitted):

• Age less than 35 years
• Clear unilateral adenoma > 1 cm on CT
• Marked aldosterone excess (PAC > 30 ng/dL)
• Normal contralateral adrenal

Even in this scenario, some centres still perform AVS due to risk of false localization.

Principle: Directly sample adrenal vein blood from both adrenals and compare cortisol-corrected aldosterone levels.

Procedure:

1. Access: Femoral vein catheterization
2. Cannulation:
   • Right adrenal vein: Short, drains directly into IVC (difficult, success ~90%)
   • Left adrenal vein: Drains into left renal vein (easier, success > 95%)
3. Samples:
   • Right adrenal vein
   • Left adrenal vein
   • Inferior vena cava (IVC) below renal veins (peripheral sample)
4. ACTH (Cosyntropin) Stimulation (optional but recommended):
   • 250 mcg IV bolus at start, OR 50 mcg/h infusion
   • Maximizes cortisol secretion → easier to confirm selective cannulation
   • Maximizes aldosterone gradient
5. Measurements: Aldosterone and cortisol from each sample

Interpretation:

A. Selectivity Index (SI): Confirms successful cannulation

• SI = (Adrenal vein cortisol) ÷ (IVC cortisol)
• Without ACTH: SI > 2.0 (right), > 3.0 (left) = successful
• With ACTH: SI > 5.0 (both sides) = successful

If SI inadequate → repeat AVS (unsuccessful cannulation)

B. Lateralization Index (LI): Determines unilateral vs bilateral disease

• LI = (Aldosterone/Cortisol ratio on dominant side) ÷ (Aldosterone/Cortisol ratio on non-dominant side)

Cutoffs:

• LI ≥4.0: Unilateral disease → Surgery indicated
• LI 3.0-4.0: Indeterminate (some centres use 3.0 as cutoff)
• LI less than 3.0: Bilateral disease → Medical management

C. Contralateral Suppression Index (CSI): Additional criterion

• CSI = (Aldosterone/Cortisol ratio on non-dominant side) ÷ (IVC aldosterone/cortisol ratio)
• CSI less than 1.0 suggests contralateral suppression (supports unilateral disease)

Example:

Right adrenal vein: Aldosterone 2000 ng/dL, Cortisol 400 mcg/dL → A/C = 5.0
Left adrenal vein: Aldosterone 20,000 ng/dL, Cortisol 450 mcg/dL → A/C = 44.4
IVC: Aldosterone 20 ng/dL, Cortisol 15 mcg/dL

Left SI = 450/15 = 30 ✓ (successful)
Right SI = 400/15 = 27 ✓ (successful)

Lateralization Index = 44.4 / 5.0 = 8.9 → LEFT-sided disease → LEFT adrenalectomy

Complications of AVS: (Rare, ~2-3%)

• Adrenal vein rupture/haemorrhage
• Adrenal infarction
• Contrast reaction
• Groin haematoma

Success Rate:

• Expert centres: > 95% bilateral successful cannulation
• Non-expert centres: 50-80%
• Right adrenal vein most difficult

Centres of Excellence: AVS should be performed by experienced interventional radiologists with > 50 cases. The AVIS-2 study demonstrated higher success and diagnostic accuracy at high-volume centres. [10]

Exam Detail: Why AVS is Essential (High-Yield Viva Topic):

Scenario: 52-year-old man, resistant hypertension, K⁺ 3.0 mmol/L. ARR positive. CT shows 1.5 cm left adrenal adenoma. Can you proceed to left adrenalectomy?

Answer: No. AVS is required because:

1. Non-functioning adenomas are common (prevalence 4-10% in this age group)
2. The adenoma may be incidental, with bilateral hyperplasia causing the PA
3. Imaging cannot distinguish functional from non-functional adenomas
4. Risk of unsuccessful surgery if wrong side operated
5. Risk of permanent hypoadrenalism if bilateral disease and unilateral adrenalectomy performed without AVS confirmation

Only exception: Age less than 35 with clear unilateral adenoma > 1 cm and marked biochemical abnormality (even then, many centres still perform AVS).

3c. Additional Investigations

Genetic Testing:

• Consider in:
  • Age less than 20 years with PA
  • Family history of PA or early-onset hypertension
  • Severe PA in young patient
• Tests:
  • "FH-I (GRA): ↑ urinary 18-oxocortisol and 18-hydroxycortisol; genetic test for chimeric gene"
  • "FH-III: KCNJ5 germline sequencing"
  • "FH-IV: CACNA1H sequencing"

Baseline Investigations:

• Serum Potassium: May be low (but normal in > 50% of cases)
• Serum Bicarbonate: Elevated (metabolic alkalosis)
• Serum Magnesium: Often low (urinary Mg loss accompanies K loss)
• Urinary Potassium: Inappropriately high (> 30 mmol/day despite hypokalaemia)
• ECG: LVH, U waves (hypokalaemia), prolonged QT
• Echocardiography: LVH, diastolic dysfunction
• 24h Ambulatory BP: Non-dipping pattern common

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7. Management

Management strategy depends on subtype (unilateral vs bilateral disease) and patient factors (surgical candidacy).

Management Algorithm

┌─────────────────────────────────────────────────────────────────────────────┐
│              PRIMARY HYPERALDOSTERONISM MANAGEMENT PATHWAY                  │
├─────────────────────────────────────────────────────────────────────────────┤
│                                                                             │
│                        PA DIAGNOSIS CONFIRMED                               │
│                                 ↓                                           │
│                     CT/MRI ADRENAL GLANDS                                   │
│                                 ↓                                           │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │              IS PATIENT A SURGICAL CANDIDATE?                       │   │
│   │  • Willing to undergo surgery?                                      │   │
│   │  • Acceptable anaesthetic risk?                                     │   │
│   │  • No severe comorbidities precluding surgery?                      │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│          ↓ YES                                         ↓ NO                 │
│   ┌──────────────────────────┐            ┌────────────────────────────┐    │
│   │ ADRENAL VEIN SAMPLING    │            │  MEDICAL MANAGEMENT        │    │
│   │ (Determine Laterality)   │            │  (MRA: Spironolactone or   │    │
│   │                          │            │   Eplerenone)              │    │
│   │ *Can omit if:            │            │                            │    │
│   │  - Age less than 35 years         │            │  Target: BP less than 130/80        │    │
│   │  - Unilateral adenoma    │            │  K⁺ 4.0-5.0 mmol/L         │    │
│   │    > 1 cm on CT           │            │                            │    │
│   │  - Very high PAC         │            │  Follow-up lifelong        │    │
│   └──────────────────────────┘            └────────────────────────────┘    │
│            ↓                                                                │
│   ┌─────────────────────────────────────────────────────────────────────┐   │
│   │              INTERPRET AVS LATERALIZATION INDEX (LI)                │   │
│   └─────────────────────────────────────────────────────────────────────┘   │
│            ↓                                        ↓                        │
│   ┌──────────────────────┐             ┌──────────────────────────┐         │
│   │ LI ≥4.0 (or ≥3.0)    │             │ LI less than 3.0                  │         │
│   │ UNILATERAL DISEASE   │             │ BILATERAL DISEASE        │         │
│   └──────────────────────┘             └──────────────────────────┘         │
│            ↓                                        ↓                        │
│   ┌─────────────────────────────────┐  ┌────────────────────────────────┐   │
│   │ LAPAROSCOPIC ADRENALECTOMY      │  │ MEDICAL MANAGEMENT             │   │
│   │ (Unilateral)                    │  │ (MRA Therapy)                  │   │
│   │                                 │  │                                │   │
│   │ Pre-op preparation:             │  │ • Spironolactone 12.5-50 mg/d  │   │
│   │ • Normalize K⁺ (MRA)            │  │ • Eplerenone 25-100 mg/d       │   │
│   │ • Control BP                    │  │ • Amiloride 5-20 mg/d          │   │
│   │                                 │  │ • Add CCB/others as needed     │   │
│   │ Outcomes:                       │  │                                │   │
│   │ • Cure hypokalaemia: ~100%      │  │ Monitor K⁺, Cr every 1-2 wks  │   │
│   │ • Cure hypertension: 30-60%     │  │ initially, then 3-6 monthly    │   │
│   │ • Improve HTN: ~95%             │  │                                │   │
│   │ • Reduce pill burden            │  └────────────────────────────────┘   │
│   └─────────────────────────────────┘                                       │
│            ↓                                                                │
│   POST-OP MONITORING:                                                       │
│   • Risk of transient HYPERkalaemia (contralateral suppression)             │
│   • Check K⁺, BP at 1, 3, 6, 12 months                                      │
│   • Apply PASO criteria for outcome assessment                              │
│   └─────────────────────────────────────────────────────────────────────────┘

Surgical Management: Laparoscopic Adrenalectomy

Indications:

• Unilateral disease confirmed by AVS (LI ≥4.0 or ≥3.0 depending on centre)
• Patient willing and fit for surgery
• No prohibitive anaesthetic risk

Pre-operative Preparation:

1. Correct Hypokalaemia:
   • Start spironolactone 25-50 mg/day or amiloride 10-20 mg/day
   • Oral potassium supplementation if needed
   • Target K⁺ > 4.0 mmol/L
2. Optimize Blood Pressure Control:
   • Use MRA, CCBs, alpha-blockers
   • Target BP less than 140/90
3. Correct Hypomagnesaemia (if present)

Surgical Technique:

• Laparoscopic transperitoneal adrenalectomy (preferred)
• OR posterior retroperitoneoscopic adrenalectomy
• Unilateral (side determined by AVS)
• Open surgery rarely required (very large tumours > 6 cm, suspected malignancy)

Outcomes:

Biochemical Cure:

• Hypokalaemia resolution: 100% (immediate) [8,18]
• ARR normalization: > 90%

Blood Pressure Outcomes (PASO Criteria): [9]

The Primary Aldosteronism Surgical Outcome (PASO) study established standardized definitions:

Overall: 94-100% of patients experience improvement in BP or reduction in medication burden. [9,18]

Predictors of Hypertension Cure:

• Shorter duration of hypertension (less than 5 years)
• Age less than 50 years
• Female sex
• Fewer antihypertensive medications pre-operatively (≤2 drugs)
• No family history of hypertension
• Absence of chronic kidney disease

Why Cure Rate is Not 100%: Even with successful adrenalectomy for APA:

• Concurrent essential hypertension may coexist
• Long-standing hypertension → irreversible vascular remodelling
• Genetic predisposition to hypertension

Post-operative Complications:

Early:

• Bleeding, infection (rare, less than 2%)
• Adrenal insufficiency (if bilateral disease inadvertently present, very rare less than 1%)
• Transient HYPERKALAEMIA (unique to PA surgery)

Hyperkalaemia Post-Adrenalectomy:

• Occurs in 5-10% of patients
• Mechanism: Prolonged suppression of contralateral zona glomerulosa → temporary hypoaldosteronism
• Usually transient (resolves within weeks to months)
• Management: Low-potassium diet, discontinue MRAs, monitor K⁺ closely

Long-term:

• Excellent prognosis
• Regression of LVH, proteinuria, CV risk reduction [8]

Post-operative Follow-up:

• K⁺ and BP at 1, 3, 6, 12 months
• Discontinue MRA post-operatively (risk of hyperkalaemia)
• Reassess need for other antihypertensives
• Repeat ARR at 6-12 months to confirm biochemical cure

Medical Management: Mineralocorticoid Receptor Antagonists (MRA)

Indications:

• Bilateral adrenal hyperplasia (BAH)
• Unilateral disease in non-surgical candidate
• Patient refuses surgery
• Bridge therapy before surgery

Goal:

• BP less than 130/80 mmHg (or less than 140/90 in elderly)
• K⁺ 4.0-5.0 mmol/L
• Minimize cardiovascular and renal complications

First-Line: Spironolactone

Mechanism:

• Non-selective mineralocorticoid receptor antagonist
• Blocks aldosterone binding to MR in kidney, heart, vessels
• Also has anti-androgen activity (blocks androgen receptor, inhibits 5α-reductase)

Dosing:

• Start: 12.5-25 mg once daily
• Titrate every 4-6 weeks based on BP and K⁺
• Usual dose: 25-50 mg/day
• Maximum: 100 mg/day (divided doses if > 50 mg)

Monitoring:

• K⁺ and creatinine at 1 week, 2 weeks, 4 weeks, then every 3 months
• BP at each visit
• Watch for hyperkalaemia (K⁺ > 5.5 mmol/L)

Side Effects:

• Gynaecomastia (10-50% of men, dose-dependent)
• Breast tenderness (men and women)
• Erectile dysfunction, decreased libido (anti-androgen effect)
• Menstrual irregularities (women)
• Hyperkalaemia (especially if CKD, diabetes, concurrent ACEi/ARB)
• GI upset (rare)

PATHWAY-2 Trial Evidence: [2] Landmark crossover RCT in resistant hypertension demonstrated:

• Spironolactone (25-50 mg) reduced BP by -8.7/-4.3 mmHg more than placebo
• Superior to doxazosin and bisoprolol
• Suggests undiagnosed PA drives much resistant hypertension

Second-Line: Eplerenone

Mechanism:

• Selective mineralocorticoid receptor antagonist
• No anti-androgen activity

Dosing:

• Start: 25 mg once daily
• Titrate to 50 mg once daily, maximum 100 mg/day (divided)

Advantages:

• Fewer sexual side effects (no gynaecomastia)
• Better tolerated in men

Disadvantages:

• Less potent than spironolactone (may require higher doses)
• More expensive
• Twice-daily dosing often needed
• Same hyperkalaemia risk

Indications for Eplerenone over Spironolactone:

• Men with gynaecomastia or sexual dysfunction on spironolactone
• Patient preference
• Intolerance to spironolactone

Third-Line: Amiloride

Mechanism:

• Epithelial sodium channel (ENaC) blocker
• Potassium-sparing diuretic
• Does NOT block mineralocorticoid receptor

Dosing:

• 5-10 mg once daily, up to 20 mg/day

Role:

• Add-on to MRA if BP not controlled
• Alternative if MRA not tolerated
• First-line in Liddle syndrome (where MRA ineffective)

Advantage:

• No hormonal side effects

Disadvantage:

• Less effective than MRA for PA

Adjunctive Antihypertensives

Many patients require additional agents:

Preferred:

• Calcium channel blockers (amlodipine, verapamil)
• Alpha-blockers (doxazosin)
• Thiazide diuretics (if eGFR > 30; caution with hypokalaemia, use only with MRA)

Use with Caution:

• ACE inhibitors / ARBs: Risk of hyperkalaemia when combined with MRA (especially if CKD)
• Monitor K⁺ closely if using combination

Generally Avoid:

• Beta-blockers (less effective in low-renin states, metabolic effects)

Special Scenarios

Glucocorticoid-Remediable Aldosteronism (FH-I)

Treatment:

• Low-dose Dexamethasone 0.125-0.25 mg at bedtime
• Suppresses ACTH → suppresses chimeric gene expression → normalizes aldosterone
• Monitor for Cushingoid side effects (use lowest effective dose)
• Alternative: Spironolactone or eplerenone

PA in Pregnancy

Challenges:

• Physiological increase in aldosterone during pregnancy (normal adaptation)
• MRAs are contraindicated (anti-androgen effects, feminization of male foetus)

Management:

• Amiloride: Safe in pregnancy (category B)
• Methyldopa, labetalol, nifedipine: Safe antihypertensives
• Defer definitive workup (AVS, surgery) until post-partum
• If APA suspected, can proceed with adrenalectomy in 2nd trimester if essential

PA with Chronic Kidney Disease

Considerations:

• Higher risk of hyperkalaemia with MRA
• Start at lower dose (spironolactone 12.5 mg)
• Frequent K⁺ monitoring (weekly initially)
• May need to limit dose or discontinue if eGFR less than 30 mL/min
• Consider amiloride alternative

Benefit:

• PA accelerates CKD progression → treatment improves renal outcomes [19]

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8. Complications

Primary hyperaldosteronism, if untreated or inadequately treated, causes significant morbidity beyond hypertension alone. Patients with PA have higher cardiovascular event rates than BP-matched essential hypertensive controls, indicating direct aldosterone-mediated organ damage. [7]

Cardiovascular Complications

Left Ventricular Hypertrophy (LVH):

• Prevalence: 60-70% of PA patients [11]
• Mechanism: Direct aldosterone-mediated myocardial fibrosis (collagen deposition)
• More severe than in essential HTN with same BP
• Reversible with treatment (MRA or adrenalectomy) [8]

Atrial Fibrillation:

• 7-fold increased risk compared to essential HTN [7]
• Mechanism: Atrial fibrosis from aldosterone excess
• Often presents as new-onset AF in young patient with hypertension
• Risk decreases after treatment

Myocardial Infarction and Stroke:

• 4-fold increased risk of stroke vs matched essential HTN [7]
• 2-fold increased risk of MI
• Mechanisms: Endothelial dysfunction, vascular inflammation, prothrombotic state, LVH
• Independent of BP level

Heart Failure:

• Diastolic dysfunction (impaired relaxation due to fibrosis)
• Progression to systolic heart failure if untreated

Vascular Dysfunction:

• Arterial stiffness (reduced compliance)
• Endothelial dysfunction (reduced NO, increased endothelin)
• Accelerated atherosclerosis

Renal Complications

Chronic Kidney Disease:

• Prevalence of CKD (eGFR less than 60): 20-30% in PA [19]
• Mechanisms:
  • Glomerular hyperfiltration → glomerulosclerosis
  • Podocyte injury
  • Tubulointerstitial fibrosis
• Albuminuria: Present in 40-60%, marker of renal and CV risk
• Progression to ESRD if untreated
• Reversible with MRA therapy or adrenalectomy [19]

Nephrogenic Diabetes Insipidus:

• Hypokalaemia → impaired urinary concentrating ability
• Polyuria, polydipsia
• Resolves with K⁺ correction

Metabolic Complications

Glucose Intolerance / Diabetes:

• Hypokalaemia → impaired insulin secretion (K⁺-ATP channels in beta cells)
• Aldosterone may have direct effects on glucose metabolism
• Prevalence of DM higher in PA than essential HTN
• May improve with treatment and K⁺ normalization

Metabolic Syndrome:

• Increased prevalence of dyslipidaemia, central obesity
• Mechanisms unclear

Musculoskeletal Complications

Muscle Weakness:

• Chronic hypokalaemia → myopathy
• Proximal muscle weakness

Hypokalaemic Periodic Paralysis:

• Acute, severe hypokalaemia (K⁺ less than 2.5 mmol/L)
• Sudden-onset flaccid paralysis (legs > arms)
• Preserved consciousness, respiratory muscles usually spared
• Medical emergency
• More common in Asian populations
• Triggered by carbohydrate load, rest after exercise

Osteoporosis:

• Possible increased fracture risk (data limited)
• Mechanism: Renal calcium wasting

Neurological Complications

Stroke:

• See cardiovascular section

Intracranial Aneurysm:

• Increased risk, especially in FH-I (GRA) [12]
• Screen with MRA brain in young PA patients with family history

Quality of Life

Symptoms:

• Fatigue, weakness (hypokalaemia)
• Polyuria, nocturia
• Headaches (hypertension)
• Sexual dysfunction (if on spironolactone)

Psychological:

• Anxiety related to uncontrolled BP, medication burden

Improvement with Treatment:

• Most symptoms resolve with K⁺ normalization and BP control
• QOL significantly improves after adrenalectomy [18]

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9. Prognosis

With Treatment

Post-Adrenalectomy (Unilateral Disease):

Biochemical Outcomes:

• Hypokalaemia cure: 100% [8,18]
• ARR normalization: > 90%

Blood Pressure Outcomes (PASO Criteria): [9]

• Complete clinical success (cure, off meds): 30-40%
• Partial clinical success (improved, fewer meds): 40-50%
• Overall success (cure or improvement): 94-100%

Cardiovascular Outcomes:

• Regression of LVH over 6-12 months [8]
• Reduction in atrial fibrillation risk
• Decreased stroke and MI risk
• Reduction in albuminuria and CKD progression [19]

Quality of Life:

• Significant improvement in energy, symptoms
• Reduction in medication burden (average 1.5 fewer drugs)

Long-term:

• Excellent prognosis
• Even if hypertension persists, easier to control and reduced CV risk
• Lifelong follow-up recommended (annual BP check)

Medical Management (Bilateral Disease or MRA Therapy):

Blood Pressure Control:

• Majority achieve BP target with MRA ± additional agents
• PATHWAY-2: Spironolactone highly effective in resistant HTN [2]

Cardiovascular Protection:

• MRA therapy reduces LVH, proteinuria, CV events
• Benefits independent of BP reduction (direct MR blockade)

Compliance:

• Lifelong treatment required
• Side effects (gynaecomastia) may limit adherence

Prognosis:

• Good if adequately treated
• Requires ongoing monitoring

Without Treatment

Natural History (Untreated):

• Progressive, uncontrolled hypertension
• High cardiovascular morbidity and mortality:
  • Stroke risk 4x higher than essential HTN [7]
  • MI risk 2x higher
  • Atrial fibrillation 7x higher
• Progressive CKD → ESRD
• Reduced life expectancy

Importance of Diagnosis: PA is a treatable and often curable cause of hypertension. Early diagnosis and intervention prevent long-term complications.

---

10. Prevention and Screening

Primary Prevention

No established primary prevention (genetic counselling for familial forms).

Secondary Prevention: Case Detection

Key Message: PA is common (5-10% of hypertension) and under-diagnosed. Routine screening in high-risk groups improves detection. [1,3]

Who to Screen: (Endocrine Society 2016) [1]

• See Section 4: Clinical Presentation

Screening Test:

• Aldosterone-Renin Ratio (ARR)

Barriers to Screening:

• Lack of awareness among clinicians
• Complexity of medication washout
• Access to specialized testing (AVS)

Strategies to Improve Detection:

• Education of primary care and general physicians
• Simplified screening protocols
• ARR as routine test in resistant hypertension

Tertiary Prevention: Complication Surveillance

After Diagnosis and Treatment:

Annual Monitoring:

• Blood pressure
• Serum potassium
• Renal function (eGFR, ACR)
• ECG (if prior arrhythmia)
• Echocardiography if LVH present (repeat at 1 year post-treatment)

Post-Adrenalectomy:

• Lifelong annual BP monitoring (hypertension may recur)
• ARR at 6-12 months to confirm cure
• No need for lifelong endocrine follow-up if cured

On Medical Therapy:

• 3-6 monthly K⁺, creatinine, BP checks
• Annual review of medication tolerance and compliance
• Repeat imaging if symptoms change (exclude adrenal growth)

Genetic Counselling

Familial Forms (FH-I, FH-II, FH-III, FH-IV):

• Autosomal dominant inheritance
• Screen first-degree relatives with ARR
• Consider genetic testing for confirmed familial cases
• MRA or brain imaging in FH-I (aneurysm risk)

---

11. Key Guidelines and Evidence

Major Clinical Practice Guidelines

Landmark Trials and Studies

1. PATHWAY-2 (2015) [2]

• Design: Crossover RCT, 285 patients with resistant hypertension
• Intervention: Spironolactone 25-50 mg vs doxazosin vs bisoprolol vs placebo (as 4th agent)
• Result: Spironolactone reduced BP by -8.7/-4.3 mmHg more than placebo, superior to other agents
• Implication: Confirms aldosterone excess as major driver of resistant HTN; spironolactone highly effective

2. PAPY Study (2006) [4]

• Design: Prospective study, 205 PA patients undergoing AVS
• Result: CT correctly lateralized in only 53% vs AVS gold standard
• Implication: AVS essential; cannot rely on CT alone

3. AVIS-2 Study (2020) [10]

• Design: Prospective study, 465 patients, AVS at 20 centres
• Result: High-volume centres had higher success rates and better outcomes
• Implication: AVS should be performed at expert centres

4. Prevalence Studies (Monticone et al., 2017) [3]

• Design: Screening of 1,672 consecutive primary care hypertensive patients
• Result: PA prevalence 6.0% (with confirmatory testing)
• Implication: PA more common than previously thought in unselected populations

5. Cardiovascular Outcomes (Milliez et al., 2005) [7]

• Design: Matched case-control study, 124 PA vs 465 essential HTN (matched BP)
• Result: PA had 4x stroke risk, 6.5x AF risk, 2x MI risk vs essential HTN
• Implication: Aldosterone causes CV damage independent of BP

6. Post-Adrenalectomy Outcomes (Vorselaars et al., 2019) [18]

• Design: Systematic review and meta-analysis, 3,838 patients
• Result: Clinical cure 30-40%, improvement 94-100%; hypokalaemia cure 100%
• Implication: Surgery highly effective for unilateral disease

7. PASO Study (Williams et al., 2017) [9]

• Design: International consensus for defining surgical outcomes
• Result: Standardized criteria for complete/partial/absent clinical success
• Implication: Allows comparison across studies; most patients benefit from surgery

8. Renal Outcomes (Hundemer et al., 2018) [19]

• Design: Cohort study comparing PA vs essential HTN
• Result: PA associated with faster eGFR decline, higher albuminuria; improvement with MRA/surgery
• Implication: PA accelerates CKD; treatment renoprotective

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12. Examination Focus

High-Yield Viva Scenarios

Exam Detail: #### Scenario 1: Approach to Suspected PA

Viva Question: "A 45-year-old woman presents with resistant hypertension on three medications including a diuretic. Her BP is 165/95 mmHg. Blood tests show potassium 3.0 mmol/L, bicarbonate 32 mmol/L. How would you investigate?"

Model Answer:

"This patient has resistant hypertension with hypokalaemia and metabolic alkalosis, raising suspicion for primary hyperaldosteronism. My approach would be:

1. Confirm True Resistant Hypertension:

• Exclude white-coat effect with ambulatory BP monitoring
• Check compliance with medications
• Assess for secondary causes (PA, renovascular disease, renal parenchymal disease)

2. Initial Investigations:

• Confirm hypokalaemia (repeat), check magnesium
• Urinary potassium (expect inappropriately high > 30 mmol/day)
• Renal function, urinalysis

3. Screen for Primary Aldosteronism:

• Aldosterone-Renin Ratio (ARR) - screening test of choice

4. Pre-Test Preparation for ARR:

• Correct hypokalaemia first (low K⁺ suppresses aldosterone → false negative)
• Medication washout:
  • "STOP 4-6 weeks before: Spironolactone/eplerenone"
  • "STOP 2 weeks before: Beta-blockers, ACEi/ARBs, diuretics (if possible)"
  • "SAFE to continue: Alpha-blockers (doxazosin), CCBs (verapamil), hydralazine"
• Liberalize sodium intake
• Measure after 2h upright (or per local protocol)

5. Interpretation:

• ARR > 20-40 (ng/dL per ng/mL/h) AND PAC > 15 ng/dL → Positive screen

6. Next Steps if ARR Positive:

• Confirmatory testing (saline infusion test preferred)
• If confirmed, proceed to subtype differentiation with CT and adrenal vein sampling"

Examiner Follow-Up: "Why can't you just do a CT scan to decide on surgery?"

Answer: "CT alone is insufficient because:

1. Non-functioning adrenal incidentalomas are very common (4-10% of population > 40 years)
2. Imaging cannot distinguish functional from non-functional adenomas
3. Bilateral hyperplasia may have asymmetric nodules mimicking unilateral disease
4. Risk of removing wrong side or unnecessary surgery

Adrenal vein sampling (AVS) is the gold standard to confirm lateralization before adrenalectomy, with lateralization index ≥4.0 indicating unilateral disease suitable for surgery."

---

Scenario 2: Interpreting AVS Results

Viva Question: "You perform adrenal vein sampling. The results are:

• Right adrenal vein: Aldosterone 3000 ng/dL, Cortisol 500 mcg/dL
• Left adrenal vein: Aldosterone 800 ng/dL, Cortisol 400 mcg/dL
• IVC: Aldosterone 25 ng/dL, Cortisol 20 mcg/dL

How do you interpret this?"

Model Answer:

"I need to calculate three indices:

1. Selectivity Index (confirms successful cannulation):

• Right SI = 500/20 = 25 ✓ (adequate, threshold > 5 with ACTH)
• Left SI = 400/20 = 20 ✓ (adequate)
• Both adrenal veins successfully cannulated

2. Aldosterone/Cortisol Ratios:

• Right A/C = 3000/500 = 6.0
• Left A/C = 800/400 = 2.0

3. Lateralization Index:

• LI = Dominant side A/C ÷ Non-dominant side A/C
• LI = 6.0 / 2.0 = 3.0

Interpretation:

• LI = 3.0 is borderline (some centres use ≥3.0, others ≥4.0 as cutoff for lateralization)
• At centres using ≥3.0, this indicates right-sided disease → candidate for right laparoscopic adrenalectomy
• At centres using ≥4.0, this is indeterminate → may require repeat AVS or medical management

I would discuss with the multidisciplinary team (endocrinology, interventional radiology, surgery) and review the patient's imaging and clinical features before making a surgical recommendation. If borderline, I might favour medical management with spironolactone as a safer initial approach, or proceed with surgery if patient strongly desires and imaging concordant."

---

Scenario 3: Managing Gynaecomastia on Spironolactone

Viva Question: "A 55-year-old man with bilateral adrenal hyperplasia has been on spironolactone 50 mg for 6 months. His BP is well-controlled at 130/80, and potassium is 4.5 mmol/L. However, he develops painful bilateral gynaecomastia. What do you do?"

Model Answer:

"Gynaecomastia is a common side effect of spironolactone, occurring in 10-50% of men due to its anti-androgen activity. Management options:

1. Assess Severity and Impact:

• Duration and degree of breast enlargement
• Presence of pain/tenderness
• Impact on quality of life and compliance

2. Confirm Gynaecomastia:

• Examine: subareolar glandular tissue (vs adipomastia)
• Exclude other causes (rare): prolactinoma, testicular/liver disease (unlikely given timing with spironolactone)

3. Management Options:

Option A: Switch to Eplerenone (preferred)

• Eplerenone is a selective MRA without anti-androgen effects
• Dosing: Start 25 mg daily, titrate to 50-100 mg (usually requires higher dose than spironolactone equivalent)
• Monitor K⁺ and BP closely during transition
• Gynaecomastia typically resolves over 3-6 months after stopping spironolactone

Option B: Switch to Amiloride

• ENaC blocker, no hormonal effects
• Dosing: 10-20 mg daily
• Less effective than MRA but avoids anti-androgen effects

Option C: Reduce Spironolactone Dose

• If symptoms mild, try 25 mg daily
• May compromise BP control

Option D: Add Other Antihypertensives and Stop Spironolactone

• CCB, alpha-blocker, or thiazide diuretic (with caution for K⁺)
• Less ideal as loses specific MR blockade benefit

My Approach: I would switch to eplerenone 50 mg daily as first-line, monitor K⁺ at 1-2 weeks, and titrate BP medications as needed. I would reassure the patient that gynaecomastia will improve over several months."

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Scenario 4: Post-Operative Hyperkalaemia

Viva Question: "A 40-year-old woman undergoes left adrenalectomy for aldosterone-producing adenoma. On day 3 post-op, her potassium is 5.8 mmol/L. Pre-operatively it was 3.2 mmol/L. What's happening and how do you manage it?"

Model Answer:

"This is post-adrenalectomy hyperkalaemia, a recognized complication occurring in 5-10% of patients.

Pathophysiology:

• Pre-operatively, the contralateral (right) adrenal gland was suppressed by chronic autonomous aldosterone secretion from the left adenoma
• After removing the adenoma, there is temporary hypoaldosteronism until the contralateral zona glomerulosa recovers (takes weeks to months)
• The patient effectively has transient adrenal insufficiency for aldosterone only (cortisol production unaffected)

Assessment:

1. Confirm hyperkalaemia (repeat, exclude haemolysis, check sample quality)
2. Check renal function (Cr, eGFR)
3. Review medications (ensure MRA stopped pre-op)
4. Check cortisol if any doubt about adequacy (should be normal)
5. ECG (look for hyperkalaemia changes: tall T waves, prolonged PR, wide QRS)

Management:

If K⁺ 5.5-6.0 mmol/L and asymptomatic, ECG normal:

• Dietary potassium restriction (less than 2 g/day)
• Stop potassium-sparing medications (ensure spironolactone already stopped)
• Avoid ACEi/ARBs, NSAIDs if used
• Potassium binder if persistent: Sodium zirconium cyclosilicate (Lokelma) or Patiromer
• Monitor K⁺ closely (daily initially, then weekly)

If K⁺ > 6.5 mmol/L or ECG changes:

• Acute hyperkalaemia management:
  • IV Calcium gluconate 10% 10 mL (cardiac protection)
  • Insulin-dextrose (10 units Actrapid in 50 mL 50% dextrose)
  • Salbutamol nebulizers
  • Sodium bicarbonate if acidotic
• Potassium binders
• Consider short-term fludrocortisone (mineralocorticoid replacement) if severe and prolonged
  • 50-100 mcg daily, taper over weeks

Prognosis:

• Hyperkalaemia typically resolves spontaneously over 4-12 weeks as contralateral gland recovers
• Very rarely, permanent hypoaldosteronism requiring lifelong fludrocortisone (less than 1%)

Prevention:

• Pre-operative counselling about risk
• Stop spironolactone at least 48h before surgery (or earlier)
• Post-operative K⁺ monitoring protocol"

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Scenario 5: Young Patient with Severe PA

Viva Question: "A 22-year-old man presents with severe hypertension (BP 190/110), K⁺ 2.8 mmol/L. Family history reveals his father had a stroke at age 38. ARR is markedly elevated. What specific subtype are you concerned about and what test would you order?"

Model Answer:

"Given the young age, severe hypertension, hypokalaemia, and strong family history of early stroke, I am concerned about Familial Hyperaldosteronism Type I (FH-I), also known as Glucocorticoid-Remediable Aldosteronism (GRA).

Why FH-I?

• Autosomal dominant inheritance (family history)
• Early-onset, severe hypertension
• High risk of cerebrovascular events, including intracranial aneurysms (father's early stroke)

Pathophysiology:

• Chimeric gene mutation: unequal crossover between CYP11B1 (11β-hydroxylase) and CYP11B2 (aldosterone synthase)
• Result: Aldosterone production driven by ACTH (not angiotensin II)
• ACTH-responsive promoter controls aldosterone synthase

Diagnostic Tests for FH-I:

1. Urinary Hybrid Steroids:

• Measure 24h urinary 18-oxocortisol and 18-hydroxycortisol
• Markedly elevated in GRA (> 100x normal)
• These are hybrid steroids produced by the chimeric enzyme acting on cortisol precursors

2. Genetic Testing:

• Long-range PCR or Southern blot to detect chimeric CYP11B1/CYP11B2 gene
• Confirms diagnosis

3. Dexamethasone Suppression Test:

• Give dexamethasone 0.5 mg qid for 48h
• Suppresses ACTH → suppresses aldosterone production (unique to GRA)
• Normalizes BP and aldosterone

Additional Investigations:

• MRA or CTA brain: Screen for intracranial aneurysms (5-10% prevalence in FH-I) [12]
• Screen first-degree relatives with ARR

Treatment:

• Low-dose dexamethasone 0.125-0.25 mg at bedtime (suppresses ACTH, normalizes aldosterone and BP)
• OR Spironolactone/Eplerenone (if patient prefers to avoid steroids)
• Monitor for Cushingoid side effects (use lowest effective dose)
• Neurosurgical referral if aneurysm detected

Prognosis:

• Excellent with treatment
• Family screening and genetic counselling recommended"

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Common Exam Pitfalls

1. "No hypokalaemia = no PA": FALSE. > 50% of PA patients are normokalaemic. [1,14]

2. "CT shows adenoma, so operate": WRONG. AVS is mandatory to confirm lateralization (unless young less than 35 with classic features). [1,4]

3. "ARR is diagnostic": NO. ARR is a screening test; confirmatory testing required. [1]

4. "You can screen while on spironolactone": NO. Must stop MRA 4-6 weeks before ARR (causes false results). [1,15]

5. "Aldosterone suppression test uses dexamethasone": NO. Dexamethasone is for Cushing's and GRA. PA confirmation uses saline loading. [1]

6. "PA only causes hypertension": FALSE. Causes direct cardiovascular, renal, and metabolic damage independent of BP. [7,11,19]

7. "Surgery cures hypertension in all APA patients": FALSE. Cure rate 30-60%; improvement in > 95%. [9,18]

8. "Spironolactone is safe in all patients": NO. Risk of hyperkalaemia, especially with CKD, diabetes, concurrent ACEi/ARB. Monitor K⁺ closely.

9. "Eplerenone is better than spironolactone": Not necessarily. Eplerenone is more selective (fewer hormonal side effects) but less potent and more expensive. Spironolactone remains first-line unless side effects. [1]

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Key Facts for Rapid Recall

• Most common cause of secondary hypertension: Primary aldosteronism (5-10% of all HTN)
• Screening test: Aldosterone-Renin Ratio (ARR)
• Confirmatory test: Saline infusion test (SIT) - failure to suppress aldosterone
• Gold standard for lateralization: Adrenal vein sampling (AVS), LI ≥4.0
• Most common subtype: Bilateral adrenal hyperplasia (60-70%)
• Conn's Syndrome: Aldosterone-producing adenoma (APA), 30-40%
• Treatment:
  • Unilateral (APA) → Laparoscopic adrenalectomy
  • Bilateral (BAH) → Spironolactone or eplerenone (MRA)
• Surgical outcome: Hypokalaemia cure 100%; HTN cure 30-60%; improvement > 95%
• Medication washout: Spironolactone STOP 4-6 weeks; ACEi/ARB/BB STOP 2 weeks; Safe: Doxazosin, CCB, hydralazine
• FH-I (GRA): Treat with low-dose dexamethasone; screen for intracranial aneurysms
• Post-op complication: Transient hyperkalaemia (contralateral suppression)
• PATHWAY-2 trial: Spironolactone superior to doxazosin/bisoprolol in resistant HTN
• CV risk: 4x stroke, 7x AF vs BP-matched essential HTN (independent aldosterone effect)

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13. Patient and Layperson Explanation

What is Primary Hyperaldosteronism?

"Primary hyperaldosteronism, sometimes called Conn's Syndrome, is a condition where one or both of your adrenal glands (small glands that sit on top of your kidneys) produce too much of a hormone called aldosterone.

Aldosterone's job is to control salt and water balance in your body. When there's too much of it, your kidneys hold onto extra salt, which holds onto water, causing your blood pressure to rise. At the same time, you lose too much potassium in your urine, which can make you feel weak or cause muscle cramps.

This condition is more common than we used to think—it affects about 1 in 10-20 people with high blood pressure. The good news is that it's treatable and, in some cases, curable with surgery."

Why Do I Need All These Tests?

"We're doing tests in stages to figure out exactly what's causing the problem and how best to treat it."

Stage 1: Blood Test (Aldosterone-Renin Ratio)

• This is a screening test to see if your body is making too much aldosterone
• We measure two hormones: aldosterone (which is high) and renin (which is low)
• If the ratio is abnormal, we move to Stage 2

Stage 2: Confirmation Test (Saline Infusion)

• We give you salty water through a drip over 4 hours
• Normally, this would tell your body to stop making aldosterone
• If you have primary hyperaldosteronism, your aldosterone stays high (your glands ignore the signal)

Stage 3: CT Scan

• This is a detailed picture of your adrenal glands to see if there's a lump (adenoma)

Stage 4: Adrenal Vein Sampling (AVS)

• This is the most important test if we're considering surgery
• We take tiny blood samples directly from the veins draining each adrenal gland
• This tells us which side is making too much hormone
• It's like a GPS to find the exact source

Why Can't You Just Rely on the CT Scan?

"Great question! Here's the problem: lumps on the adrenal glands are very common as we get older (about 1 in 10 people over 40 have one). Most of these lumps are completely innocent and do nothing.

The CT scan might show a lump on your left adrenal gland, but that lump might just be a harmless coincidence, while the right gland (which looks normal on the scan) is actually the one causing the problem.

If we operated based on the CT scan alone, we might:

• Remove the wrong side (your problem continues)
• Remove a gland that wasn't causing the issue (unnecessary surgery)

The adrenal vein sampling is the only way to be 100% sure which side is the culprit before surgery."

What Are My Treatment Options?

If the problem is on ONE side (Unilateral - Adenoma):

Surgery (Laparoscopic Adrenalectomy):

• We remove the affected adrenal gland through small keyhole incisions
• This is minimally invasive with quick recovery (usually home in 1-2 days)
• Results:
  • Your potassium will return to normal immediately (100% success)
  • About 1 in 3 people can stop blood pressure tablets completely
  • The other 2 in 3 will need fewer tablets and have much better control
• One adrenal gland is enough—the other side takes over all the functions you need

If the problem is on BOTH sides (Bilateral Hyperplasia):

Medication:

• A tablet called spironolactone (or eplerenone)
• This blocks the effect of too much aldosterone
• Highly effective at controlling blood pressure and correcting potassium
• Taken lifelong
• Side effects: Men may develop tender breast tissue (gynaecomastia)—if this happens, we can switch to eplerenone

Will Surgery Cure My Blood Pressure?

"It depends on how long you've had high blood pressure and whether there are other causes.

If your high blood pressure is entirely due to the aldosterone-producing adenoma, and we remove it early, there's a good chance you can come off tablets completely.

However, if you've had high blood pressure for many years, the blood vessels may have become stiff and damaged. In this case, removing the adenoma will make your blood pressure much easier to control, but you might still need one or two tablets.

Either way, almost everyone benefits from surgery—either complete cure or significant improvement."

What Happens If I Don't Get Treated?

"Untreated primary hyperaldosteronism causes more damage than just high blood pressure. The excess aldosterone directly harms your heart, blood vessels, and kidneys:

• Heart: Thickening of the heart muscle, irregular heart rhythm (atrial fibrillation)
• Brain: Higher risk of stroke
• Kidneys: Progressive kidney damage
• Overall: Higher risk of heart attack and early death

The good news is that these risks go down significantly once we treat the condition with surgery or medication."

What Should I Expect After Surgery?

First Few Days:

• Keyhole surgery, so small scars
• Some pain/discomfort (controlled with painkillers)
• Home within 1-2 days

First Few Weeks:

• Potassium levels return to normal immediately
• Blood pressure starts to improve (may take weeks to months to stabilize)
• We'll monitor your potassium closely (sometimes it can go too high temporarily as the other gland "wakes up")

Long-Term:

• Most people feel much better—more energy, no muscle cramps
• Fewer blood pressure tablets
• Annual BP check to monitor

What Do I Need to Know About the Medication (Spironolactone)?

How It Works:

• Blocks the aldosterone receptor, stopping the hormone from working

Dosing:

• Usually 25-50 mg once daily

Side Effects:

• Men: May cause breast tenderness or enlargement (gynaecomastia) in 10-50%
  • If this happens, we switch to eplerenone (same effect, no breast side effects)
• Women: Possible menstrual irregularities
• Everyone: Needs regular blood tests to check potassium (risk of it going too high)

Monitoring:

• Blood test (potassium, kidney function) every few weeks initially, then every 3-6 months

Important:

• Do NOT stop the medication without discussing with your doctor
• Avoid potassium supplements or salt substitutes (contain potassium)

Can I Lead a Normal Life?

Yes, absolutely.

• With surgery or medication, your blood pressure and potassium will be controlled
• You can exercise, work, travel normally
• Lifespan is normal if treated
• Quality of life is excellent

Key Points:

• If on medication: take it daily, attend regular blood tests
• If post-surgery: annual BP check
• Live a healthy lifestyle (diet, exercise, avoid smoking)

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