Diagnostic peritoneal lavage in acute pancreatitis--the value of microscopy of the lavage fluid.

In only 2 of 98 cases with a clinical diagnosis of acute pancreatitis submitted to peritoneal lavage in order to assess severity was the diagnosis found to be wrong. These two cases (one was biliary peritonitis and the other mesenteric infarction) were not differentiated from severe pancreatitis by clinical examination, measurement of plasma amylase, the appearance of the lavage fluid or its amylase or white cell count. One case was exceptional in that the lavage fluid had a faecal odour, and both cases were found to have large numbers of intestinal organisms which were clearly visible on routine microscopy. Scanty commensals (? contaminants) were seen in the lavage fluid of 2 of the 96 patients with acute pancreatitis but no intestinal organisms were found. If peritoneal lavage is used in the management of acute pancreatitis, microscopy of the lavage fluid, carried out as an emergency investigation, might help to detect the occasional case with a false diagnosis.