(162) Intoxicated without a drop to drink: A case report of auto-brewery syndrome

Abstract: Introduction

Auto-brewery syndrome, also known as gut fermentation syndrome, is a rarely described condition in which one’s gut microbiota is altered by certain strains of yeast and bacteria that causes carbohydrates and sugars to be fermented into ethanol¹. High levels of ethanol has been linked to high anion gap metabolic acidosis which can cause encephalopathies and psychosis^2,3. We describe a previously unreported case of metabolic encephalopathy manifesting as psychosis due to auto-brewery syndrome. Clinicians need to be aware of this syndrome when considering potential etiologies for psychosis secondary to metabolic encephalopathy.



Case Presentation

A 64 year-old Caucasian male with a history dementia, agitation, and falls presented to the emergency department (ED) for aggressive behavior at home. Patient’s physical exam was notable for agitation and confusion in the ED. No nystagmus, scleral icterus, or asterixis was noted. His laboratory findings were significant for an elevated blood ethyl alcohol at 184mg/dL, a decreased CO2 at 17 (21-32mmol/L), and an elevated anion gap of 18 (8-12mmol/L). His ammonia was also elevated at 50 (11-32).

Patient and family denied alcohol consumption by the patient prior to admission, but did report patient was eating pizza and candy bars. Patient underwent carbohydrate challenges with blood alcohol concentration (BAC) testing at serial intervals that confirmed the diagnosis of auto-brewery syndrome. With intravenous hydration and cessation of carbohydrate consumption, the patient’s anion gap closed and his metabolic encephalopathy and psychosis resolved.



Conclusion

The history and laboratory testing in this case confirmed the diagnosis of auto-brewery syndrome. The patient’s psychotic symptoms resolved as his blood BAC lowered and his anion gap closed. Metabolic encephalopathies have been known to cause psychosis³ and an anion gap is also known to cause metabolic encephalopathies⁴. This is the first case describing psychosis secondary to auto-brewery induced metabolic encephalopathy.