[Diagnosis of chylous ascites with oral administration of 13C-palmitic acid].

12 cases of chylous ascites in PUMC hospital in the recent 30 years were analysed. The etiology of this disease includes non-traumatic (83.3%) and traumatic (16.7%) causes. All the patients received isotope examination or lymphangiography, but only in 8 patients the site of the lesion was found. As these two kinds of examination can only show the lesions in the right and left lumbar lymph trunks, cisterna chyli and throacic duct but not the intestinal lymph truck, the authors set up a method by administering orally 13C-palmitic acid to detect the lesion of intestinal lymph trunk. Palmitic acid is a long-chain fatty acid, which enters directly into the intestinal lymph trunk after absorption. Palmitic acid labelled with 13C could be detected in the ascitic fluid if there is a leak from intestinal lymph trunk. This new method was used to examine a patients who had negative results with isotope examination and lymphangiography; 13C could be detected in the ascitic fluid 30 minutes after oral administration but not in exhaled air. It can be concluded that cyhle leaked into the peritoneal cavity from the intestinal lymph trunk. This method is also of help to determine the possible site of leakage and the degree of obstruction, so it is quite useful for the diagnosis of chylous ascities.