Pheochromocytoma in pregnancy

• Tumour arises from the chromaffin cells of adrenal medulla in 90% of cases or remnants of the neural crest. 

- 10% are bilateral and 10% are malignant

• Presents in pregnancy with hypertensive crisis / paroxysmal hypertension +/- cerebral haemorrhage or heart failure. 
- May also present with circulatory collapse following delivery, palpitations, anxiety, headache, vomiting and glucose intolerance

• Differential diagnoses include pregnancy induced hypertension and thyrotoxicosis.

• Fetal loss rate 15 - 50%

• Elevated urinary excretion of catecholamines and their metabolites such as vanillymandelic acid is diagnostic. 

- False positive results may occur in women on methyldopa or labetalol

(Increased urinary 5-HIAA i.e. 5-hydroxyindoleaceticacid, occurs in carcinoid tumours)