pit Flashcards
name 3 familial syndromes that are strongly related to phaechromocytoma
- MEN type 2
- Von Hippel-Lindau syndrome
- Neurofibromatosis type 1
what is MEN T2 characterised by (3)
- medullary thyroid cancer
- phaechromocytoma
- hyperparathyroidism
inheritance of MEN T2
autosomal dominant
causative mutation in MEN T2
RET proto-oncogene mutation
derm features of Neurofibromatosis T1
cafe au lait spots
&
axillary and inguinal freckling
neuroendocrine tumour of chromaffin cells
Phaechromocytoma
phaechromocytoma triad?
- pounding episodic headache
- sweating
- tachycardia
phaechromocytoma rule of 10
10% bilateral
10% cancerous
10% located outside adrenal
metabolite of adrenaline?
metanephrines
test for low probability phaechromocytoma
urinary fractionated metanephrines
test for high probability phaechromocytoma
plasma free metanephrines
why should beta blockers never be used as single therapy for phaechromocytoma?
can precipitate a hypertensive crisis from unopposed alpha-adrenergic stimulation… because peripheral beta-receptors have a vasodilatory effect
alpha blockers for phaechromocytoma
- phenoxybenzamine
- doxazocin
alternative to alpha blockers?
calcium channel blockers: amlodopine
medication for patients that can not tolerate alpha or beta blockers
metyrosine
- inhibits catecholamine synthesis
- SE: depression, anxiety, nightmares