Clinical Pearls & Morning Reports
Published May 11, 2022
Chylous ascites is a rare form of ascites that is characterized by the accumulation of protein-rich and chylomicron-rich lymphatic fluid in the peritoneal cavity. Read the NEJM Case Records of the Massachusetts General Hospital here.
Q: How are cases of chylous ascites categorized?
A: It can be useful to divide the causes of chylous ascites into two physiological categories. The first category includes conditions that cause disruption of the lymphatic vasculature, resulting in leakage of lymph from the lymphatic system into the peritoneal space. Lymphatic disruption is usually caused by duct damage from abdominal surgery; nonsurgical trauma is a less common cause. The second category includes conditions that cause obstruction of the lymphatic vasculature. Lymphatic obstruction can occur through either direct blockage of the lymphatics or impaired drainage into the venous system, the latter of which can be caused by congestive heart failure or portal hypertension due to cirrhosis.
Q: Name some of the causes of lymphatic obstruction that can result in chylous ascites.
A: Diseases that cause lymphatic obstruction can be grouped as inflammatory, infectious, and cancer-related causes of obstruction. Inflammatory causes of lymphatic obstruction include sarcoidosis, radiation exposure, and peritoneal fibrosis. Infectious causes of lymphatic obstruction include filariasis and mycobacterial disease. B-cell lymphomas often manifest with lymphatic disease and are an important cause of chylous ascites.
A: According to the 2017 World Health Organization classification, HGBL is defined by either the presence of a rearrangement in MYC, BCL2, or BCL6 (or a combination thereof) or the presence of blastoid morphologic features or features intermediate between diffuse large B-cell lymphoma and Burkitt’s lymphoma in the absence of criteria for other types of lymphoma. HGBL, not otherwise specified (NOS), accounts for a heterogeneous group of aggressive mature B-cell lymphomas. The evolving classification of HGBL, NOS, makes the selection of treatment challenging. There are few retrospective studies and limited prospective data that specifically address the treatment of this condition.
A: The first step in the management of chylous ascites is to address the underlying cause. Chylous ascites can be managed with serial paracentesis. However, reliance on serial paracentesis places the patient at risk for procedural complications and secondary infectious peritonitis, which can be life-threatening. Chylous ascites can also be managed by reducing the production of chylomicrons, thereby reducing the production of lymph. Strategies include reducing long-chain fatty acids in the diet, as well as administering pharmacologic treatment with orlistat, which prevents triglycerides from being processed into free fatty acids by lipases in the gut. Lymph production can also be reduced by decreasing splanchnic blood flow with the use of octreotide. Chylous ascites does not abate with the administration of diuretics in most cases.