EUH Morning Report: What is auto-brewery syndrome and how do you evaluate it?

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The Bottom Line:

Auto-brewery syndrome or gut fermentation syndrome is a condition in which ethanol is produced through endogenous fermentation by fungi or bacteria in the gastrointestinal (GI) system.

Patients with auto-brewery syndrome present with many of the signs and symptoms of alcohol intoxication while denying an intake of alcohol and often report a high-sugar, high-carbohydrate diet.

The production of endogenous ethanol occurs in minute quantities as part of normal digestion, but when fermenting yeast or bacteria become pathogenic, extreme blood alcohol levels may result. Auto-brewery syndrome is more prevalent in patients with co-morbidities such as diabetes, obesity, and Crohn disease [1][2] but can occur in otherwise healthy individuals.[3] Several strains of fermenting yeasts and rare bacteria are identified as the pathogens. While auto-brewery syndrome is rarely diagnosed, it is probably underdiagnosed.[4]

Auto-brewery syndrome is more likely in a patient with chronic intestinal obstruction, gastroparesis, diabetes, or liver dysfunction such as non-alcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH). An interprofessional approach that includes a psychiatric evaluation should be employed. Auto-brewery syndrome should also be included in the differential diagnosis for D-lactic acidosis.[18]

Evaluation should include:

  • A complete history and physical; include history from family members regarding diet and alcohol intake and episodes of unexplained intoxication
  • Lab tests including CBC, metabolic panel, blood alcohol level, drug screen, and stool culture and sensitivity (bacterial and fungal)
  • Elimination of other primary causes such as head injury, secret drinking, psych diagnosis
  • Carbohydrate challenge of 200g glucose with BAC and BrAC testing at intervals of 0, 1/2, 1, 2, 4, 8, 16, and 24 hours; confirmation of auto-brewery syndrome if levels are elevated during the test.
  • Upper and lower endoscopy with samples for culture and sensitivity (bacterial and fungal).[4]

See also: Gut fermentation syndrome: A systematic review of case reports

Painter K, Cordell BJ, Sticco KL. Auto-brewery Syndrome. [Updated 2020 Oct 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK513346/