Endocrine Abstracts

A 72 year old gentleman with an eight month history of chronic, episodic diarrhoea had been investigated as an out-patient. Colonoscopy and biopsies, barium meal and follow-through, coeliac screen and thyroid function tests were all normal. He subsequently presented with an acute deterioration in diarrhoea, and severe hypokalaemia, acute renal failure and a profound metabolic acidosis. Haemofiltration and aggressive fluid management were required to compensate for gastro-intestinal losses of up to 6 litres per day. Stool analysis revealed a secretory diarrhoea (sodium 126 millimol per litre, potassium 25.0 millimol per litre). Gut hormone profile revealed a vasoactive intestinal polypeptide level of 103 picomol per litre (normal less than 30), a pancreatic polypeptide level of over 500 picomol per litre (normal less than 300), and a chromogranin B level of 204 picomol per litre (normal less than 60). A repeat profile when the patient had normal renal function revealed levels of 29, over 500, and 184 picomol per litre respectively. A tentative diagnosis of a VIPoma or PPoma was made, and octreotide injections commenced. Improvement in the diarrhoea occurred overnight. Subsequent CT scanning and MRI revealed an 8cm tumour within the head of the pancreas. A positive octreotide scan confirmed the absence of metastases, and presence of a large pancreatic tumour. The patient is currently awaiting surgical removal and histological staining of the tumour.

Neuroendocrine tumours of the pancreas may present with chronic, intermittent diarrhoea secondary to the secretion of gut hormones. These are normally excreted via the kidneys. In this context however, the patient's worsening diarrhoea triggered a vicious cycle of renal failure, elevated gut hormone levels, and the manifestation of devastating, profuse diarrhoea, ultimately leading to the unmasking of his neuroendocrine tumour.