Beta-2-Transferrin to Detect Cerebrospinal Fluid Ascites: A Case Report

Abstract

Purpose: Abdominal ascites is a rare complication of ventriculoperitoneal shunts with few documented case reports. The diagnosis is one of exclusion and a formidable challenge. A 20 year old Caucasian female presented with new onset ascites. Her past medical history was significant for a pinealoblastoma diagnosed at age 5 which was treated successfully with chemotherapy and radiation. She had a ventriculoperitoneal shunt which had been functional for many years without any complications. Physical exam showed moderate ascites but no other signs of chronic liver disease. Initial labs showed normal Bilirubin, CBC, BUN, Creatinine, liver enzymes and prothrombin time. HIV and viral hepatitis serologies were negative. An abdominal US showed normal liver parenchyma. Peritoneal fluid analysis showed a WBC count of 4000 with 60% neutrophils and an albumin of 2.1 gm/dl with a serum ascites albumin gradient less than 1.1. Ascites and CSF fluid cultures including fungal and TB cultures were negative. CA-125 levels were elevated at 6815, but without any evidence of malignancy on CT scans of the chest, abdomen and pelvis, a whole body PET scan and peritoneal fluid cytology. An MRI of the abdomen and pelvis showed moderate ascites with layering of debris material within the fluid, multiple hepatic adenomas, as well as peritoneal and omental thickening. A CT guided omental biopsy showed severe acute inflammation without any evidence of malignancy. Neurosurgery evaluated the patient and deemed her shunt functional. The patient was discharged without a definite etiology for her ascites. Over the next few months she required multiple large volume paracentesis for control of ascites. Fluid analysis showed a gradual decline in WBC count. CA 125 levels also gradually decreased. A Beta-2-transferrin assay was sent on the peritoneal fluid and came back positive. This result along with unexplained refractory ascites pointed to the possibility of VP shunt-induced ascites. The patient underwent conversion to a ventriculo-atrial shunt with subsequent resolution of ascites. This case of recurrent ascites in the setting of a VP shunt demonstrates the use of beta 2 transferrin as a reliable marker for shunt-induced ascites. Beta 2 transferrin is a desialated isoform of the transferrin protein confined almost exclusively to the CSF with the exception of the perilymph of the cochlea and the vitreous humor of the eye. It has been widely studied as a sensitive and specific marker for suspected CSF leakage in the setting of rhinorrhea and otorrhea. For our patient, use of beta 2 transferrin earlier could have prevented extraneous testing and decreased overall hospital costs.