Fatal Nonhepatic Hyperammonemia in ICU Setting: A Rare but Serious Complication following Bariatric Surgery

Abstract

Bariatric surgery is well established in reducing weight and improving the obesity-associated morbidity and mortality. Hyperammonemic encephalopathy following bariatric surgery is rare but highly fatal if not diagnosed in time and managed aggressively. Both macro- and micronutrients deficiencies play a role. A 42-year-old Hispanic female with a history of Roux-en-Y Gastric Bypass Procedure was brought to ED for progressive altered mental status. Physical exam was remarkable for drowsiness with Glasgow Coma Scale 11, ascites, and bilateral pedal edema. Labs showed elevated ammonia, low hemoglobin, low serum prealbumin, albumin, HDL, and positive toxicology. She remained obtunded despite the treatment with Narcan and flumazenil and the serum ammonia level fluctuated despite standard treatment with lactulose and rifaximin. Laboratory investigations helped to elucidate the etiology of the hyperammonemia most likely secondary to unmasking the functional deficiency of the urea cycle enzymes. Hyperammonemia in the context of normal liver function tests becomes diagnostically challenging for physicians. Severe hyperammonemia is highly fatal. Early diagnosis and aggressive treatment can alter the prognosis favorably.

Hyperammonemia: What Urea-lly Need to Know: Case Report of Severe Noncirrhotic Hyperammonemic Encephalopathy and Review of the Literature

“…Several case reports have described acute onset of hyperammonemia due to late-onset inborn errors of metabolism in previously healthy adolescents or adults. The majority of these cases are fatal [ 89 – 92 ]. Panlaqui et al report a case of a 48-year-old man with preceding subacute cognitive decline and sudden encephalopathy, an ammonia level of 390 μ mol/L, MRI findings of diffuse cortical edema and T2 hyperintensities, successfully treated with hemodialysis, and however persistent significant cognitive deficits at 6-month follow-up [ 93 ].…”

Russian Consensus “Hyperammonemia in Adults”

“…Определение Описаны случаи постбариатрической гипераммониемической энцефалопатии после хирургического шунтирования желудка Roux-en-Y (RYGB), самой распространенной процедурой снижения веса, проводимой в США [35,36,37,38,]. Высокий риск гипераммонемической энцефалопатии после операции Roux-en-Y, при котором смертность приближается к 50%, установлен у женщин в возрастной группе 34-69 лет, даже не имевших в анамнезе к-л заболевания печени [39][40][41][42][43][44][45][46][47][48][49][50][51][52]. Риск фатального исхода может быть обусловлен и тем фактом, что постбариатрическия гипераммониемия не сопровождается какими-либо изменениями биохимических показателей печеночного метаболизма.…”

An overview of complications affecting the Central Nervous System following bariatric surgery

“…44 It is hypothesized that nutritional complications following gastric BS may unmask preexisting subclinical urea cycle disorder such as ornithine transcarbamylase deficiency (OTC) which can lead to fatal hyperammonemia. [45][46][47] In a retrospective review of 20 patients with gastric bypass associated hyperammonemia (GaBHA), 95% of patients were female. Weight loss, HAE associated with increased plasma glutamine levels, lack of evidence of cirrhosis, low serum albumin levels and reduced plasma zinc levels were commonly identified features.…”