Endocrine Abstracts

The case describes a 49-year-old woman with a history of previous biliopancreatic diversion and duodenal switch procedure carried out in 2010. She was known to the local bariatric service with multiple micronutrient deficiencies and had no prior history of liver disease. She was admitted to hospital in 2023 with a widespread rash, proximal myopathy, multiple nutrient deficiencies, acute kidney injury, and spontaneous bleeding into the psoas muscle. She was seen by a dietitian and weight management physician early during the admission and her relatives disclosed poor compliance with supplements. One week into the admission she became acutely confused, and due to an acute drop in GCS required intubation and admission to the intensive care unit. Bloods showed an albumin of 25 g/l (25-50), ALT 54 U/l (10-40), zinc 3.8 umol/l (10-20), and normal bilirubin and ALP. A CT head showed normal intracranial appearances and a sepsis screen and cerebrospinal fluid analysis were normal. Electroencephalogram confirmed severe encephalopathy. Ammonia and glutamine levels were markedly elevated: 199 umol/l (<50) and 1566 umol/l (544-836) respectively. An ultrasound of the liver showed moderate diffuse fatty change with no evidence of cirrhosis. Her case was discussed with the local Biochemistry and Hepatology teams, and it was felt that the results were in keeping with non-hepatic hyperammonaemic encephalopathy. There was no evidence of an underlying inherited metabolic disorder. She was started on lactulose and rifaximin with normalisation of ammonia levels. She also received ongoing dietetic input to minimise protein catabolism and manage her electrolyte and micronutrient abnormalities. Her encephalopathy resolved and she made a full recovery. Non-hepatic hyperammonaemic encephalopathy following malabsorptive bariatric surgery is a rare complication which is associated with a high mortality rate and can occur at any stage post-surgery. Most reports have been in women with previous Roux-en-Y Gastric Bypass surgery, but it has also been described in individuals with biliopancreatic diversion procedures, which are associated with a higher risk of nutritional deficiencies. Accumulation of ammonia is thought to occur due to increased protein catabolism and functional inhibition of urea cycle enzymes involved in its clearance. Zinc and essential amino acid deficiencies are thought to be major contributors to the pathophysiology. This case highlights the need to counsel patients post bariatric surgery about the risks of non-compliance with nutritional supplements. Ammonia levels should also be checked in any patient with a history of bariatric surgery presenting with acute confusion and nutrient deficiencies regardless of liver function.