John Robinson, BCCCP, PharmD
Critical Care Pharmacist
Kingman Regional Medical Center
Disclosure information not submitted.
Ordessia Charran, MD
Pulmonary & Critical Care Medicine Attending Physician
n/a
Kingman, Arizona
Disclosure information not submitted.
Tyson Dietrich, PharmD, BCIDP
Clinical Pharmacy Specialist – Infectious Diseases & Antimicrobial Stewardship
Kingman Regional Medical Center
Kingman, Arizona, United States
Disclosure information not submitted.
Title: Hyperammonemia After Roux-en-Y Gastric Bypass
Introduction: Gastric bypass-related hyperammonemia (GaBHA) is a rare complication of bariatric surgery with less than 40 cases total reported with >90% of reports being female patients. Early diagnostic suspicion for GaBHA is critical to mitigate high rates of mortality for this life-threatening syndrome.
Description: A 52-year-old male with BMI 39.9, non-alcoholic fatty liver disease, Roux-en-Y gastric bypass surgery (7 years prior), and internal hernia repair (5 months prior) presented with severe protein malnutrition and altered mentation requiring intubation for airway protection. The patient’s family reported that the patient had a prolonged history of non-compliance and was not taking oral vitamins as advised by his physician. Computed tomography of the head was negative for acute pathology and initial serum ammonia was 102 mmol/L (reference, 9-30 mmol/L). The patient received aggressive ammonia-reducing therapy, including enteral and rectal lactulose administered every 6 hours, rifaximin every 12 hours, and zinc supplementation. The patient also received empiric vitamin supplementation with ascorbic acid every 12 hours and a multivitamin with minerals every 12 hours. Despite multiple (more than three) bowel movements per day, serum ammonia level remained elevated and increased to 176 mmol/L after 48 hours. The use of hemodialysis as a treatment modality for refractory hyperammonemia was not initiated because it was against the patient’s wishes. On hospital day three there was no improvement in mental status and the patient underwent compassionate extubation and expired. Laboratory confirmation of vitamin deficiencies resulted after the patient expired. Serum zinc level was 21 mcg/dL (reference, 66-110 mcg/dL), ceruloplasmin 13.2 mg/dL (reference, 20-35 mg/dL), pyridoxal 5-phosphate < 2 mcg/mL (reference, 5-50 mcg/mL), and 25-hydroxy vitamin D total 11 ng/mL (reference, 20-50 ng/mL).
Discussion: GaBHA should be suspected in patients with a history of bariatric surgery presenting with altered mentation. This syndrome is life-threatening and may be refractory to standard treatment with lactulose and rifaximin requiring early initiation of renal replacement therapy.