Phaeochromocytoma

- associated with MEN II , Sturge Weber syndrome and von Hippel Lindau syndrome
- presents with hypertension, headache, palpitation, excessive sweating, anxiety
- symptoms are precipitated by sneezing, stress, surgery, cheese, alcohol, TCA
- rule of 10 - 10% extra-adrenal, 10% bilateral, 10% malignant, 10% familial, 10% not associated with hypertension
- familial phaeochromocytoma almost always arise from adrenal medulla
- adrenal medulla has cells that contain phenylethanolamine-N-methyltransferase that converts norepinephrine to epinephrine. This enzyme is lacking in other sympathetic ganglia.
- diagnosis by raised urinary catecholamines over 24 hours and MIBG (metaiodobenzylguanidine) scan of adrenals
- treatment for hypertension is with alpha-blockade (phenoxybenzamine) prior to beta-blockade