A Diagnosis Easily Missed?

I gave a presentation this week at the hospital medical teaching meeting which focused on a case presentation: a diagnosis easily missed. A women in her 40s presents with headache, palpitations, intermittent sweating and flushing (particularly at night time) for about a month. Past medical history was unremarkable except for hypertension, treated with an ACE Inhitor, beta blocker and calcium channel blocker. Fundoscopy reveals hypertensive retinopathy and blood pressure is markedly elevated on examination. Blood results show acute kidney injury, but the full blood count, liver function tests and inflammatory markers are normal. A fasting blood glucose is also normal. Renal US scan identifies a cystic mass in the adrenal gland. Urine catecholamines measured over 24 hours are markedly elevated, as are plasma metanephrines. 

The diagnosis is: phaemochromocytoma. this is a rare tumour arising from the chromaffin cells located in the adrenal medulla. It has a very low population prevalence and there is often a delay of on average three years between initial symptoms and diagnosis. Approximately 1/4 of phaeochromocytomas may be incidental findings when a scan is carried out for another reason and in these cases the patient may be completely asymptomatic. In cases where patients experience symptoms such as the ones described here, they are thought to be casued by the secretion of catecholamines (adrenaline, noradrenaline) from the tumour, often in a cyclical pattern. The management of phaeochromocytomas is alpha-receptor blockade to reduce the effects of vasoconstriction caused by excess catecholmamines. Beta blockers may make the condition worse (think of a phaeochromocytoma in the hypertensive patient who gets worse after a beta blocker has been given). The definitive management is laparoscopic adrenalectomy to remove the tumour and the prognosis following this is excellent. It is worth noting that approximately 10% of phaeochrmocytomas are malignant and patients should be investigated for malignancy. Phaeochromocytomas may also be familial and are seen in conditions such as Multiple Endocrine Neoplasia 2A/2B, and Von-Hippel Lindau syndrome. 

So hopefully not a diagnosis easily missed any more after reading this!