Surgery MCQ Answer 54

Answer: a, b, e

Chylous ascites is accumulation within the peritoneal cavity of chyle, a lymphatic fluid with a high lipid content. Access of intestinal lipids to the circulation is via mesenteric lymphatics that enter the cisterna chyle, which in turn becomes the thoracic duct which eventually enters the venous system at the junction of the left subclavian and internal jugular veins. The cisterna chyli lies at the anterior surface of the first and second lumbar vertebrae slightly to the right of the aorta. Chylous ascites may result from injury to major lymphatic duct or the cisterna. However for lymphatic leakage to persist, widespread occlusion of lymphaticovenous collaterals within the abdomen must be present. Malignancy is the predominant cause (88%) of spontaneous chylous ascites in adults, with lymphoma the most common malignancy. Diagnostic studies must include not only documentation of lymphatic origin of the abdominal fluid but also an attempt to delineate the cause of chylous ascites. Paracentesis and analysis of chylous fluid typically reveals elevated triglycerides, protein, and leukocyte levels, with a predominance of lymphocytes. Unfortunately, cytology is seldom positive despite the presence of malignancy. Lymphangiography may define the site of lymphatic leak for patients in whom the leak is from the cisterna or retroperitoneal lymphatics but not when from the mesenteric or hepatic lymphatics. Of noninvasive studies, CT is the test of choice, with a high diagnostic yield in nontraumatic chylous ascites in adults. Frequently, laparotomy with node biopsy is required for histology and typing in cases suspected to be cancer, particularly for lymphoma.

Treatments for chylous ascites have been directed toward decreasing lymph and triglyceride accumulation.

Successful resolution of chylous ascites has been achieved using a fat-restricted diet with added medium-chain triglycerides in an attempt to reduce lymphatic transport of triglycerides and perhaps intestinal lymph flow. Although there have been reports of success using such dietary manipulation, many failures have been reported. Therefore, in most patients with chylous ascites, treatment is likely to be successful only when directed toward the underlying cause. For patients with lymphoma, therapy effective against lymphoma is likely to eliminate chylous ascites.

The prognosis for patients with chylous ascites is much better in infants and children than in adults, principally because of the differences in causes of the condition. A mortality of 21% is reported in infants and children whereas a mortality of 88% has been noted in adults. Patients with chylous ascites with associated neoplasms typically have the gravest prognosis.

Category: Surgery MCQs