Endocrinology - Phaeochromocytoma

Question 1

from which cells do phaeochromocytomas arise from?

Answer 1

Chromaffin cells of adrenal medulla - secrete catecholamines

Question 2

describe the common signs and symptoms of phaeochromocytoma

Answer 2

Symptoms are intermittent - may occur from once a mnth to several times a day (tend to become more frequent and severe). Duration from secs to hrs.
i. headache
ii. profuse sweating
iii. palpitations
iv. tremor
+/- nausea, weakness, anxiety, epigastric/flank pain, weight loss

Signs:

i. HTN (may be paroxysmal)
ii. postural hypotension
iii. tremor

Question 3

which Ix would you request for someone with suspected phaeochromocytoma?

Answer 3

Bloods:

• plasma catecholamines and plasma metanephrines: raised
• Hb: raised (due to haemoconcentration from decreased circulating volume)
• UandEs: may have hypercalcaemia
• plasma glucose: often raised

Bedside tests:

• 24 hr urine collection (pref. straight after crisis): total catecholamines, vanillymandelic acid and metanephrines
• BP: ?HTN or postural hypotension
• ECG: ?arrythmia

Imaging (after biochemical confirmation of tumour):
- CT scan thorax/abdo/pelvis +/- MRI for locating mets and possible extra-adrenal phaeochromocytomas

Other:

• genetic testing: if appropriate
• histology: ?benign vs malignant

Question 4

how would you manage a pt with phaeochromocytoma?

Answer 4

Pre-op:
1. a- or B-blockers required to control BP and prevent intra-operative hypertensive crisis. a-blockade with PHENOXYBENZAMINE started at least 7-10 days pre-op to allow expansion of blood volume. Once this is achieved, B-blockers can be considered.

2. Surgical resection of tumour - usually results in cure of HTN.