Bilateral Renal Vein Thrombosis and Chylous Ascites in Phospholipase A2 Receptor-Associated Membranous Nephropathy: A Case Report.

Phospholipase A2 receptor (PLA2R)-associated membranous nephropathy is an important cause of nephrotic syndrome that can lead to a variety of systemic manifestations. Chylous ascites and bilateral renal vein thrombosis are rare manifestations in adult nephrotic syndrome, and there have been no reported cases demonstrating both chylous ascites and bilateral renal vein thrombosis in patients with PLA2R-associated membranous nephropathy. Here, we report the first case of PLA2R-associated membranous nephropathy complicated by renal vein thrombosis and chylous ascites successfully treated with anticoagulation and rituximab. A 65-year-old African American male presented with abdominal pain for four days, hematochezia for one day, and lower extremity edema for one year. Blood pressure was 158/73 mmHg and other vital signs were normal. Physical examination revealed abdominal distention, periumbilical tenderness, and bilateral lower extremity edema. Laboratory analysis showed high serum creatinine, hypoalbuminemia, hyperlipidemia, and proteinuria on 24-hour urine chemistry, all consistent with nephrotic syndrome. Abdominal computed tomography scan demonstrated nonocclusive bilateral renal vein thrombosis with ascites. Paracentesis revealed chylous ascites. Continuous heparin infusion was started for thrombosis. Esophagoduodenoscopy and colonoscopy did not reveal a source of bleeding. Serum anti-PLA2R was found positive, suggesting membranous nephropathy. Rituximab, along with warfarin switched from heparin, successfully controlled disease activity. Chylous ascites in nephrotic syndrome is thought to be associated with bowel edema. In our case, we hypothesize that renal vein thrombosis caused lymphatic fluid leakage by increasing lymphatic pressure. The case illustrates the importance of considering membranous nephropathy as a cause of chylous ascites and renal vein thrombosis. Development of lymphatic imaging techniques is warranted to clarify the pathophysiology.