Persistent Hyperammonemia and Cerebral Edema Following Gastrostomy Tube Placement in a Post-bariatric Patient: A Diagnostic Dilemma
Department
Radiology
Document Type
Article
Publication Title
Cureus
Abstract
A 45-year-old woman with a history of Roux-en-Y gastric bypass (RYGB) and recent cholangitis presented with acute encephalopathy, seizures, and concern for anoxic brain injury. She was intubated for acute respiratory failure and found to have striking hyperammonemia with serum ammonia levels exceeding 300 µmol/L, in the absence of overt liver dysfunction. Her clinical course was complicated by septic shock, multifocal pneumonia, and gastrostomy tube (G-tube) malfunction. Despite aggressive medical management, including broad-spectrum antibiotics and lactulose, ammonia levels remained persistently elevated. CT and MRI of the brain revealed cerebral edema and diffuse cortical diffusion abnormalities concerning for metabolic encephalopathy or anoxic injury. Continuous renal replacement therapy (CRRT) was initiated due to worsening encephalopathy and acute kidney injury (AKI). Notably, imaging demonstrated malposition of the G-tube with distal placement in the excluded gastric remnant; an anatomic reservoir bypassed in Roux-en-Y that is not exposed to normal enteric flow. G-tube revision and eventual conversion to gastrojejunostomy tube (GJ-tube) led to a rapid decline in ammonia levels and improvement in neurologic status. We present a severe and unusual case of non-hepatic hyperammonemia, likely precipitated by altered post-bariatric anatomy and nitrogenous substrate accumulation in the excluded gastric remnant. While hyperammonemia is a well-described complication of liver failure and urea cycle disorders, it is rarely attributed to anatomical disruption in gastrointestinal transit. This report underscores the importance of considering altered post-surgical anatomy in the differential for unexplained metabolic encephalopathy and supports early imaging of enteral access in patients with Roux-en-Y anatomy and neurologic decline. Timely recognition and intervention may prevent irreversible neurologic injury and reduce the need for prolonged renal support.
First Page
e90875
DOI
10.7759/cureus.90875
Volume
17
Issue
8
Publication Date
8-1-2025
PubMed ID
40995286
Recommended Citation
Burk, A., Merchant, A., Rahman, H., Patel, A., Deshmukh, I., Aisogun, V., Yu, A., Irani, Z., Patel, S., & Lambroussis, C. G. (2025). Persistent Hyperammonemia and Cerebral Edema Following Gastrostomy Tube Placement in a Post-bariatric Patient: A Diagnostic Dilemma. Cureus, 17 (8), e90875. https://doi.org/10.7759/cureus.90875