Critical Care: Fellow Case Report Slide: Critical Care I |

An Unusual Case of Encephalopathy in a Critically Ill Patient FREE TO VIEW

Anil Singh, MBBS; Jonathan Dewald, MD; Elise Schriver, MD; Michael McCormack, MD; Tina Dudney, MD; JF Turner, MD
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UTMCK, Knoxville, TN

Copyright 2016, American College of Chest Physicians. All Rights Reserved.

Chest. 2016;150(4_S):261A. doi:10.1016/j.chest.2016.08.274
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SESSION TITLE: Fellow Case Report Slide: Critical Care I

SESSION TYPE: Affiliate Case Report Slide

PRESENTED ON: Sunday, October 23, 2016 at 03:15 PM - 04:15 PM

INTRODUCTION: The etiology of encephalopathy is broad in intensive care setting and has important prognostic implications. We present a case of a young female with an unusual cause of coma.

CASE PRESENTATION: A 46- year old female with history of fibromyalgia presented with memory changes and abdominal discomfort for two weeks. In Emergency Department rapid decline in mental status and acute hypoxic respiratory failure was noted requiring endotracheal intubation and admission to intensive care unit. Initial investigations showed leukocytosis with neutrophilia, mild transaminitis and minimally elevated ammonia level, 77 uMol/l (nl 18- 72). Serum and urine drug screens were positive for tricyclic antidepressants with prolong cQT interval. Chest imaging revealed dependent pulmonary infiltrates.Computed tomography (CT) of head was unremarkable. CT abdomen showed hepatic steatosis with no features of cirrhosis. She was treated with bicarbonate infusion, lactulose and rifaximin. Subsequently on day three, ammonia levels rose to 317 and repeat CT head showed diffuse cerebral edema. In view of medically refractory hyperammonemia, continuous venovenous hemodialysis (CVVHD) was initiated with subsequent reduction in ammonia levels. Liver biopsy revealed with stage II fibrosis with negative copper and iron stains, insufficient to result in portosystemic shunting. Finally urine studies showed elevated orotic acid levels and glutamine levels with low citrulline amino acid consistent with ornithine transcarbamylase (OTC) deficiency, an enzyme in urea cycle. Patient subsequently underwent percutaneous tracheostomy and gastrostomy in view of poor neurologic recovery.

DISCUSSION: Late-onset OTC leads to partial enzyme deficiency sufficient to metabolize normal nitrogenous waste into urea. However in catabolic states, this enzymatic capacity is overwhelmed and rapid accumulation of ammonia results in neurotoxicity. The goal of treatment in such circumstances is to emergently lower ammonia levels, use of ammonia scavenger, such as sodium benzonate and supportive care to minimize catabolism.

CONCLUSIONS: Critical care practitioners should have high suspicion of index for the possibility of late onset OTC syndrome in adults especially around the time of stress - TCA poisoning in our patient. Timely diagnosis and active management of hyperammonemia due to OTC deficiency can be lifesaving and may prevent permanent neurologic damage.

Reference #1: Blair NF, et al. Pract Neurol 2015;15: 45-48

DISCLOSURE: The following authors have nothing to disclose: Anil Singh, Jonathan Dewald, Elise Schriver, Michael McCormack, Tina Dudney, JF Turner

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