314: EXTRACORPOREAL LIVER ASSIST DEVICE FOR ACUTE LIVER INJURY DUE TO LIKELY PARTIAL UREA CYCLE DISORDER

Abstract

Introduction: Extracorporeal liver assist device (ELAD) is used to bridge patients in acute liver failure to transplant or in severe acute liver injury until spontaneous recovery. ELAD employs an albumin circuit to dialyze albumin-bound toxins from the blood stream. Urea is an albumin bound molecule formed in the liver as a result of nitrogen breakdown. Urea Cycle Disorders (UCDs) are a rare group of genetic enzymatic deficiencies that typically manifest early in life but partial enzymatic deficiencies can present later in life in times of metabolic stress. Description: A 38-year-old female presented with progressive encephalopathy 2 months after being diagnosed with alcoholic hepatitis at which time she had stopped drinking alcohol. She had no prior liver disease. Initial labs showed an elevated ammonia level of 87 mcmol/L, despite decrease in total bilirubin from 33 mg/dL to 3.5mg/dL, and INR of 1.9 to 1.4 since the peak of her alcoholic hepatitis. She had no imaging evidence of cirrhosis and had normal aminotransferases, platelets, and renal function. Initial head CT, infectious evaluation, and work-up for alternate etiologies of acute liver injury were unremarkable. She was intubated for progressive hepatic encephalopathy on hospital day 9. Her ammonia level significantly rose to 203 mcmol/L and a repeat head CT showed diffuse cerebral edema. Due to a rising ammonia level to 247 mcmol/L and CT evidence of progressive cerebral edema despite mannitol, therapeutic hyperventilation, and sedation. She was started on MARS (TM) therapy on hospital day 11. After one 7-hour session, her ammonia level decreased to 101 mcmol/L, mental status improved and head CT showed improved cerebral edema. A urinary orotic acid level was elevated at 1.8 mmol per mol of creatinine. Discussion: A partial UCD was suspected due to atypical time course of encephalopathy and hyperammonemia in the context of improving liver synthetic function and absence of cirrhosis. Genetic testing is pending however, a partial UCD is likely given the elevated urinary orotic acid. A single case report exists of confirmed acquired glutamine synthetase deficiency after orthotopic liver transplant that also improved after a single MARS session. Our report adds to the scarce literature on this topic.