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A5592 - New Onset Hyperammonemic Encephalopathy in a Cystic Fibrosis (CF) Patient with CF- Related Liver Disease Associated with GI Obstruction
Author Block: P. Cheng1, R. C. Rubenstein2; 1Division of Pulmonary Medicine and Cystic Fibrosis Center, Children's Hospital of Philadelphia, Philadelphia, PA, United States, 2Childrens Hosp of Philadelphia, Philadelphia, PA, United States.
Introduction: Hepatic encephalopathy is categorized by the underlying disease, the severity of manifestations, the time course, and the presence of precipitating factors. We report a case of new onset hepatic encephalopathy in a cystic fibrosis (CF) patient associated with GI obstruction.
Case Presentation: The patient is a 15-year-old male with CF and CF-related liver disease with resultant cirrhosis, portal hypertension, and varices with multiple GI bleeds s/p transjugular intrahepatic portosystemic shunt (TIPSS), who presented with altered mental status. On presentation, he had a Glasgow Coma Scale (GCS) of 8, agitated, and without response to verbal commands. His vitals were remarkable for respiratory rate of 26, heart rate of 114, and normal oxyhemoglobin saturation. His physical exam had diffuse hyperreflexia, as well as ammonia-scented breath. Labs showed normal CBC, VBG with pH 7.44 and PCO2 of 28 with HCO3 of 18, normal blood sugar, electrolytes, and liver enzymes. Ammonia level was markedly elevated at 328 umol/L, and a lactate was 2.6 mmol/L. Urine toxicology screen was negative, and head CT showed no acute hemorrhage or cerebral edema. CXR showed a new right middle lobe infiltrate and AXR was concerning for distal intestinal obstruction syndrome (DIOS) with stool burden throughout colon. RUQ ultrasound with Doppler showed a patent TIPSS without thrombosis and with unchanged liver cirrhosis. He was admitted to our PICU, and GI consultation recommended starting lactulose and neomycin. Because of concern that his hyperammonemic encephalopathy was due to bowel obstruction, he underwent a gastrograffin enema and received a scheduled bowel regimen with laxatives. His ammonia level began to downtrend and normalized over several days, and his mental status improved rapidly. He was discharged to home at his baseline mental status after one week of treatment.
Discussion: Several cases of hepatic encephalopathy associated with bowel obstruction are reported in the literature. While the mechanism is unclear, it is hypothesized that there is increased ammonia production by gut bacteria as a result of stasis of the intestinal contents and bacterial overgrowth. In addition, having a TIPSS is another independent risk factor; a TIPSS allows shunting of ammonia- containing blood to the systemic circulation, bypassing the liver which normally clears ammonia. Precipitating factors include GI bleeds, infections, hypovolemia, sedatives, electrolyte abnormalities, renal failure, muscle wasting and, especially in CF, constipation or intestinal obstruction. It is important to recognize these risk factors as patients with CF are often at risk of these conditions.