Basically a tumour that originates from chromaffin cells of the adrenal medulla. Chromaffin calls are also called phaeochrome bodies due to their dark colour (phaeo=dark, chromo=colour) when stained with chromium salts, hence the long winded name of chromaffin cell tumours.
These tumours commonly arise from the adrenal medulla as that's where chromaffin cells are found, however sometimes extra-adrenal chromaffin cells (found outside of the adrenal gland that fail to regress after birth) can lead to extra-adrenal phaeochromocytomas (aka paragangliomas).
The job of chromaffin cells is to produce catecholamines (fight-or-flight hormones), so having a tumour of chromaffin cells will lead to a huge increase in catecholamines, which as you've guessed will lead to a clinical presentation exemplary of an exaggerated fight-or-flight/sympathetic response.
It can happen sporadically (90%!) or in certain familial syndromes (10%)
Familial causes of phaeochromocytoma (autosomal dominant)
(A quick visual aid I made to remember the causes: 1 brainy man riding a hippo :)
The indivdual causes of the above conditions are pretty boring, but the main take-home stuff is:
As mentioned before, the patient will have an over-excited sympathetic response, which can lead to a plethora of clinical features.
Symptoms tend to occur intermittently (most likely due to the intermittent release of catecholaimes from the chromaffin cell tumour).
The main episodic hyperadrenergic symptoms are:
(Don't confuse with the 6P's of acute ischaemia!)
Phaeochromocytomas are a very rare (<0.1%) cause of hypertension; and so failure to exclude phaeochromocytoma can lead to a hypertensive crisis!
(Cl looks like α and clonIdIne has two "i"s, so α2 agonist :)
(phenOXybenzamine, An ox is really heavy; so hard to move it out of the α-receptor :)
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