Secondary hypertensive disorders - phaeochromocytoma
Description
- Catecholamine-secreting tumour of chromaffin cells
- Phaeochromocytoma = adrenal medulla (~80-90%)
- Paraganglioma = extra-adrenal sympathetic (abdominal, organ of Zuckerkandl) or parasympathetic (head and neck - usually non-secretory)
- *All are potentially malignant - there is no benign histology. "Malignant" is defined only by metastasis to a site where chromaffin tissue does not normally occur*
The rule of tens - outdated but examined
- 10% extra-adrenal, 10% bilateral, 10% malignant, 10% familial
- *Now: ~40% are germline, ~15-20% metastasise, ~15-20% extra-adrenal* - the genetics figure is the one that has changed most
Secretory phenotype predicts the syndrome
| Phenotype | Genes | Clinical |
|---|---|---|
| Adrenergic (adrenaline + noradrenaline) | RET, NF1, sporadic adrenal | Paroxysmal, palpitations, anxiety, hyperglycaemia |
| Noradrenergic | VHL, SDHx | Sustained hypertension, fewer spells |
| Dopaminergic | SDHB, SDHD | Normotensive or hypotensive, nausea; often missed |
Presentation
- Headache ~90%, hypertension (sustained or paroxysmal) 85-95%, sweating 60-70%
- Triad of headache + palpitations + diaphoresis: sensitivity ~89%, specificity ~67%
- Paroxysms lasting minutes: pallor (not flushing), tremor, anxiety/impending doom, chest or abdominal pain
- Orthostatic hypotension in an untreated hypertensive is a classic clue (chronic volume contraction + desensitised receptors)
- Weight loss, hyperglycaemia, constipation
- Catecholamine cardiomyopathy, arrhythmia, pulmonary oedema
- ~10-15% are found incidentally and are entirely asymptomatic
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