Case Presentation: 47-year-old man, with history of traumatic brain injury, seizure disorder, gastroesophageal reflux disease with Barrett’s esophagus, brought in by his mother with slurred speech and unsteady gait. His vitals, labs and imaging were unremarkable, and his symptoms resolved with fluids, within hours in the ED. He was admitted to the hospital for further workup as this was 4th episode in 2 years, with similar presentation of varying severity. He underwent extensive workup for his encephalopathy including extensive neurological, cardiac workup which were all unremarkable. His alcohol level on presentation was 10 mg/dL, which was significant as he did not have any history of alcohol intake nor access to alcohol. His prior episodes also had elevated alcohol levels during prior ED presentations between 5-10 mg/dL. He underwent a glucose challenge test with a loading dose of 200 g of glucose followed by blood alcohol testing at 30 minutes, 1 hour, 2, 4, 8, 16 and 24 hours. His ethanol level increased from undetectable at start of test to 11 mg/dL. He was discharged on Fluconazole 200 mg once daily for 14 days, with low carbohydrate diet. On a 6-month follow-up, he did not have any further episodes and his diet was liberalized using post meal breathalyzer tests.

Discussion: Auto-brewery syndrome (ABS), or gut fermentation syndrome, is a rare condition reported in fewer than 100 patients, characterized by presence of ethanol without exogenous alcohol use. Based on available literature, alteration in gut microbiome specifically, fungal (Saccharomyces cerevisiae, candida sp), and recently bacterial colonization (Klebsiella, Enterococcus) have been implicated in endogenous fermentation of dietary carbohydrates to produce increased levels of ethanol. Cases have been described in men and women equally, and described in all ages, with the youngest case in a 3-year-old with a short bowel syndrome, and 71-year-old with Crohn’s disease. Patient related risk factors are high carbohydrate intake, obesity, prolonged antibiotic use, fatty liver disease, diabetes type 2, gastrointestinal surgery, inflammatory bowel disease and gastrointestinal hypomotility. Diagnosis of ABS is challenging, and likely several cases remain undiagnosed. Interestingly, a significant number of a case reports were diagnosed as medicolegal cases with charges of driving under influence. Diagnosis is made after extensive history taking, ruling out surreptitious alcohol intake, detection of fungal and bacterial species in stool culture or secretions taken during endoscopy, detailed dietary carbohydrate intake with blood alcohol and breath alcohol concentrations. The confirmatory test for ABS is carbohydrate challenge test with 200g of glucose load followed by timed interval of blood alcohol testing for 24 hours. The mainstay of management is antifungal treatment and avoidance of high carbohydrate diet. Use of probiotics and fecal microbiota transplantation to assist with recolonization of a healthy gut microbiota has been successful in some cases, but their clinical role as treatment modalities requires further research. Alcohol dependence and alcohol withdrawal have also been noted in some patients with ABS.

Conclusions: While alcohol intoxication and alcohol use disorder are common, diagnosis of ABS should be considered in patients who deny alcohol use with features of alcohol intoxication. Further research is needed in pathophysiology , genetic predisposition and changes in gut microbiome in ABS.