Chronic diarrhoea-author's response

I thank Mr Marston for his comments regarding our article (JRSM 2007;100: 379). ¹ He raises two issues. Regarding the first, I agree that the patient may have been saved from all the invasive investigations if the thyromegaly and cervical lymph node enlargement had been identified earlier. I can only surmise that the clinical findings in the neck were not present or were subtle at the time of initial assessment. This case highlights the point that general physical examination of a patient provides vital clues to the diagnosis-a fact that is sometimes overlooked. It is our responsibility to emphasize the importance of this to the next generation of clinicians.

As for the second point, the causes of chronic diarrhoea were taken from a reputable peer-reviewed journal (Gut). ² Ischaemia of the gut has been given different nomenclatures, including mesenteric ischaemia, gut ischaemia, bowel ischaemia and intestinal ischaemia. There is evidence that colonic ischaemia can present as chronic colitis, with endoscopy changes mimicking those seen in inflammatory bowel disease. In most cases, no cause is found and the episodes are considered to be due to localized non-occlusive ischaemia, perhaps due to small vessel disease. ³

Mesenteric atherosclerosis can cause chronic mesenteric ischaemia (intestinal angina) where patients present with post-prandial abdominal pain, nausea, bloating and episodic diarrhoea. Malabsorption or constipation can occur. Objective evidence of ischaemia to small bowel causing these symptoms is difficult to obtain. However, focal segmental necrosis of the small bowel can cause symptoms indistinct from Crohn's disease. ³ There is a case report of small bowel ischaemic necrosis diagnosed by video capsule endoscopy. ⁴ This investigation and double balloon enteroscopy may shed more light on the pathophysiological changes that occur in the small bowel secondary to mesenteric ischaemia.