Auto-brewery syndrome (ABS), also known as gut fermentation syndrome, is a rarely diagnosed medical condition where ingested carbohydrates are converted to alcohol by fungi in the gastrointestinal tract. Patients with this condition become inebriated and suffer all the medical and social implications of alcoholism, including arrest for drunken driving. This report details the case of a patient who manifested many of the alcohol-related symptoms yet claimed repeatedly that he had not ingested any alcohol. Fungi are not commonly known to be present in the stomach and upper small intestine of healthy subjects. 1 The colon, however, can harbour some fungi which live commensally.

Case history

A previously active, healthy, 46-year-old man (height, 6 feet 2 inches; weight, 230 lbs; body mass index, 30 kg/m2) with no significant medical or psychiatric history sought our help for the confirmation and treatment of ABS. He was not taking any medications, including herbal or over-the-counter drugs. He complained of having had memory loss, mental changes, and episodes of depression for over 6 years starting in January of 2011. These changes started to occur after he received antibiotic therapy (cephalexin 250 mg orally three times a day for 3 weeks) for a complicated traumatic thumb injury. One week after the completion of his antibiotic therapy, personality changes with episodes of depression, ‘brain fog’, and aggressive behaviour became apparent, which was very uncharacteristic for him. He was initially evaluated by his primary care physician (PCP) for the first time in January of 2014 before being referred to a psychiatrist who treated him with lorazepam and fluoxetine.

One morning, he was arrested for presumed driving while intoxicated (DWI). He refused a breathalyser analysis and was hospitalised. His initial blood alcohol level was 200 mg/dL. The hospital personnel and police refused to believe him when he repeatedly denied alcohol ingestion. He recovered fully and was discharged.

After hearing about a similar successfully treated case by a physician in Ohio, his aunt purchased a breathalyser to record his breath alcohol levels and persuaded him to visit Ohio for the treatment, where basic laboratory testing (complete blood count, comprehensive metabolic panel, immunology panel, and urinalysis) were all normal. A comprehensive stool analysis was negative for Giardia and Cryptosporidium. The patient’s lactoferrin, calprotectin, and lysozyme levels and stool malabsorption studies were also normal. Saccharomyces cerevisiae (brewer’s yeast) and S. boulardii were detected in his stool addition to his normal stool bacterial flora. On antifungal sensitivity testing, these Saccharomyces strains were found to be sensitive to azoles and nystatin.

To confirm the diagnosis of ABS, the patient was given a carbohydrate meal, and his blood alcohol levels were monitored under observation. After 8 hours, his blood alcohol level was elevated to 57 mg/dL. He was then treated for the Saccharomyces fungi found in his stool with oral fluconazole 150 mg per day for 14 days. In the absence of improvement, on day 10, this was changed to nystatin 500 000 IU three times a day for another 10 days. His symptoms improved, and he was discharged on a strict carbohydrate-free diet along with special supplements given by his Ohio physician, but no further antifungal therapy was prescribed.

After a few weeks of being asymptomatic, intermittent ‘flares’ returned. He was seen by many internists, psychiatrists, neurologists, and gastroenterologists who were unable to help him to return to his previous state of health. The most significant event caused by one of his inebriations was a fall that caused intracranial bleeding and necessitated a transfer to a regional neurosurgical centre, where he had a complete spontaneous recovery in 10 days. In this institution, his blood alcohol levels ranged from 50 to 400 mg/dL. Here too, the medical staff refused to believe that he did not drink alcohol despite his persistent denials.

Due to worsening symptoms, he searched for help from an online support group and contacted us. This patient physical examination was entirely normal. Prior to his thumb injury, he had been a light social drinker but completely abstained from alcohol thereafter. His construction company was involved in restoring hurricane-damaged houses, many of which had mould contamination. To investigate this patient’s condition further, we collected gastrointestinal secretions using upper and lower endoscopy to detect fungi. The patient’s upper and lower endoscopic procedures were normal. Fungal cultures obtained from the upper small gut and cecal secretions grew Candida albicans and C. parapsilosis. Antifungal sensitivity testing was done for these fungi, and both were sensitive to azoles. His secretory immunoglobulin A was elevated to 607 mg/dL. Helicobacter pylori infection was not detected in his gastric antral biopsy. The patient agreed to be treated in collaboration with his local PCP because he lived far away from our hospital.

Given his prior exposure to fluconazole, we decided to use oral itraconazole 150 mg per day as an initial antifungal therapy for S. cerevisiae and Candida species. After 10 days, as his symptoms did not improve, so this dose was increased to 200 mg per day, and the patient became completely asymptomatic. Unbeknownst to us, he ate pizza and drank soda while on this treatment, resulting in a severe ABS relapse. We then decided to treat him with intravenous micafungin 150 mg per day for 6 weeks.

After completing this therapy, his gastrointestinal secretions were again studied and cultured by repeat upper and lower endoscopy. At this time, no fungal growth was present. The patient monitored his breath alcohol levels two times a day throughout the treatment process with instructions to inform us immediately if positive. He was started on a probiotic (single-strain Lactobacillus acidophilus with 3 billion colony-forming units per capsule) to competitively inhibit fungi and help to normalise his gut flora.2 Carbohydrates were then gradually introduced in his diet, and a repeat carbohydrate challenge test was negative. After 6 weeks, this probiotic was changed to a multi-strain probiotic, which contains 12 different bacterial organisms without any fungi.3 4 He has since continued this treatment. Approximately 1.5 years later, he remains asymptomatic and has resumed his previous lifestyle, including eating a normal diet while still checking his breath alcohol levels sporadically. A summarise format of the time course of events and interventions is presented in table 1.