Endocrine - Phaeochromocytoma Flashcards
What is a phaeochromocytoma?
Tumour of the adrenal glands that releases excessive amount of catecholamines
What is the pathophysiology of phaeochromocytomas?
Adrenaline produced by chromaffin cells in the medulla of the adrenal glands
Phaeochromocytoma is a tumour of the chromaffin cells that secretes excess adrenaline, tends to be secreted in bursts hence intermittent symptoms
What conditions are phaeochromocytomas more common in?
- Multiple endocrine neoplasia type 2 (MEN2)
- Neurofibromatosis type 1
- Von Hippel-Lindau disease
What is the 10% rule to describe the patterns of tumours?
10% bilateral
10% cancerous
10% outside the adrenal gland
Why do signs and symptoms fluctuate in patients with phaeochromocytomas?
Pulsatile release of adrenaline from the tumour
Not always releasing adrenaline
What are the symptoms of phaeochromocytomas?
Related to excess adrenaline
- Anxiety
- Sweating
- Tremor
- Palpitations
- Tachycardia
- Hypertension
What are the initial tests for diagnosis of a phaeochromocytoma?
Plasma free metanephrines
24-hour urine catecholamines
Why are urine catecholamines measured for 24 hours?
Levels of adrenaline fluctuate and have a very short half life, thus unreliable
So must measure for prolonged periods of time
What are metanephrines?
Breakdown product of adrenaline
Have a longer half life so more reliable
What imaging is used for diagnosing phaeochromocytomas?
CT
MRI
What is advised for patients with a phaeochromocytoma?
Genetic testing
Test relatives too
What is the management of a phaeochromocytoma?
Alpha blockers
Phenoxybenzamine or doxazosin
Beta blockers
Only when on alpha blockers
Surgical removal
Patients must have their symptoms controlled first
