💡 Hypertension in phaeochromocytoma is best treated with phenoxybenzamine, a non-selective α-blocker. ⚠️ Careful perioperative preparation is lifesaving: always establish α-blockade before β-blockade to avoid catastrophic hypertensive crises.

🔎 About

Rare but important cause of secondary hypertension, particularly relevant in perioperative medicine and emergency presentations.
Arises from chromaffin cells of the sympathetic nervous system, usually in the adrenal medulla (but may be extra-adrenal = paraganglioma).

🧬 Aetiology

Secretes catecholamines: adrenaline, noradrenaline, dopamine.
Occasionally secretes other peptides (opioids, endothelin, erythropoietin, neuropeptide Y).
More common on the right; ectopic sites include bladder, mediastinum, thorax.

📊 The “10 × 10” Rule (classic)

10% malignant
10% extra-adrenal (paragangliomas)
10% familial (MEN2, VHL, NF1)
10% bilateral
10% in children
10% calcify
10% recur after removal
10% in bladder
10% in thorax

🔎 Update: With modern genetics, familial cases are closer to 30%.

🔬 Pathology

Grey, vascular tumours; highly vascular on imaging.
Paragangliomas = extra-adrenal phaeochromocytomas.

🧾 Genetic Associations

👁️ Von Hippel–Lindau syndrome (VHL)
🌿 Neurofibromatosis type 1 (NF1)
🧬 Multiple Endocrine Neoplasia type 2a & 2b (MEN2)

🩺 Clinical Features

📍 Classic triad: headache + sweating + palpitations (with hypertension).
Hypertension: paroxysmal (spikes) or sustained.
Other: tremor, pallor, nausea, sense of impending doom, weight loss, postural hypotension.
Complications: arrhythmias, ACS, cardiomyopathy, stroke, hyperglycaemia.

🧪 Investigations

Biochemistry: – 24h urinary catecholamines/metanephrines (≈98% sensitive). – Plasma metanephrines increasingly used. – FBC, U&E, calcium (screen for MEN).
Imaging: CT/MRI adrenal. MIBG scintigraphy if equivocal or metastatic suspicion.
Dynamic test: Clonidine suppression – catecholamines fall in normals, not in phaeochromocytoma.
⚠️ Never biopsy/FNA → risk of hypertensive crisis.

💊 Management

Step 1 – α-blockade (always first) – Phenoxybenzamine (non-selective, long-acting) 10 mg BD PO → titrate. – Doxazosin (selective α1-blocker) 2–32 mg OD PO. – Phentolamine (short-acting IV) for acute crisis.
Step 2 – β-blockade – Only after adequate α-blockade (to prevent unopposed α). – For tachycardia, arrhythmias, ACS.
Step 3 – Surgical resection – Adrenalectomy after 2–3 weeks α-blockade. – Ensure salt & fluid preload before surgery (to avoid post-op hypotension). – Anaesthetic expertise critical: expect hypertensive crises intra-op, then sudden hypotension post-resection.

⚠️ Complications

Cardiomyopathy (catecholamine-induced).
Arrhythmias: AF, SVT, VT.
Diabetes mellitus (catecholamine-driven gluconeogenesis).
Stroke, hypertensive encephalopathy.

📚 Exam Pearls: – Always block α before β. – Classic triad = headache + sweating + palpitations. – “Rule of 10s” is exam-friendly but genetics show ~30% are familial. – Post-op hypotension is common → pre-op salt/fluid loading is vital.

Cases - Phaeochromocytoma

Case 1 - Classic triad ⚡: A 42-year-old woman presents with recurrent episodes of pounding headaches, palpitations, and sweating. During attacks, her blood pressure spikes to 220/120 mmHg. 24-hour urinary catecholamines: markedly elevated. MRI: adrenal mass. Diagnosis: adrenal phaeochromocytoma. Managed with α-blockade (phenoxybenzamine), then β-blockade, followed by laparoscopic adrenalectomy.
Case 2 - Incidentaloma with resistant hypertension 🧬: A 38-year-old man with long-standing hypertension is found to have an incidental adrenal mass on CT for renal stones. Symptoms: episodic palpitations and anxiety. Plasma metanephrines elevated. Genetic testing reveals RET mutation (MEN2A). Diagnosis: phaeochromocytoma associated with MEN2. Managed with α-blockade and surgical excision; family screening arranged.
Case 3 - Extra-adrenal paraganglioma 🌍: A 50-year-old man presents with episodic sweating, headaches, and orthostatic hypotension. BP fluctuates widely during admissions. CT abdomen: no adrenal mass. MIBG scan: para-aortic tumour consistent with paraganglioma. Diagnosis: extra-adrenal phaeochromocytoma (paraganglioma). Managed with α-blockade, surgical resection, and long-term follow-up for recurrence.

Teaching Point 🩺: Phaeochromocytoma = catecholamine-secreting tumour (usually adrenal medulla, sometimes extra-adrenal). Classic triad: headache, sweating, palpitations with paroxysmal or resistant hypertension. Investigations: plasma or 24-hour urinary metanephrines, imaging (MRI/CT, MIBG). Management: α-blockade before β-blockade, then surgical excision. Associations: MEN2, VHL, NF1. ⚠️ Always stabilise medically before surgery → risk of hypertensive crisis intra-op.

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Phaeochromocytoma