Did you hear the one about the Texas man who became drunk without touching a drop of alcohol?

That’s no joke. It’s a case study published last year that should be required reading for every gastroenterologist, say authors and experts in gastroenterology.

In a paper published in the International Journal of Clinical Medicine (2013;4:309-312), authors Barbara Cordell, RN, PhD, dean of nursing at Panola College in Carthage, Texas, and Justin McCarthy, MD, a gastroenterologist in Lubbock, Texas, detail how a man spent five years becoming inexplicably drunk before doctors realized the cause was an overgrowth of Saccharomyces cerevisiae, also known as brewer’s yeast.

The 61-year-old man was treated with antifungals and a strict low-carbohydrate diet. Ten weeks after treatment started, the man’s stool cultures were negative for the yeast and his episodes of drunkenness ceased.

This relatively unknown phenomenon is called “gut fermentation syndrome” or “auto-brewery syndrome.” The underlying mechanism is thought to be an overgrowth of yeast in the gut: The yeast ferments sugars in the diet from carbohydrates into ethanol, resulting in high blood alcohol levels (BALs). Only a handful of cases has ever been reported.

“This is a rare syndrome but should be recognized because of the social implications such as loss of job, relationship difficulties, stigma and even possible arrest and incarceration,” the authors wrote.

“It would behoove health care providers to listen more carefully to the intoxicated patient.”

This latest case study adds to a growing body of evidence demonstrating the broad health effects of dysbiosis, which occurs when an imbalance in the bacteria and fungi that live within the gastrointestinal (GI) tract exists, said William D. Chey, MD, professor of internal medicine at the University of Michigan, Ann Arbor.

“In this case, alcohol is the byproduct of that interaction between carbohydrates and certain types of organisms in the GI [gastrointestinal] tract,” Dr. Chey explained.

Gastroenterologists should be aware of the syndrome, although it is very rare, he said.

“Certainly, it’s biologically possible. Gastroenterologists and physicians in general need to be open-minded to the possibility that patients who present with symptoms of intoxication without history of ethanol ingestion might indeed have a physiologically plausible explanation,” said Dr. Chey.

Symptoms and Treatment

In this case, the man’s bouts of baffling intoxication began in 2004, not long after he underwent surgery for a broken foot and treatment with antibiotics. He began to seem excessively intoxicated after two drinks and on occasion appeared drunk despite not drinking. His wife, a nurse, began to document the phenomenon with a Department of Transportation–approved alcohol breathalyzer. The man’s BALs frequently reached 0.40%. The alcohol level at which an individual is considered legally impaired in the United States is 0.08%.

In the following years, the man’s episodes of intoxication began to increase in severity and frequency. In November 2009, he arrived at the emergency department with a blood alcohol concentration of 371, or 0.37%. The physicians believed him to be a “closet drinker.”

Several months later, the patient presented to Dr. McCarthy’s gastroenterology practice where he underwent a complete GI workup. He denied taking any type of yeast as nutritional supplementation and reported no history of GI disorders or treatments.

The patient’s stool cultures were positive for rare budding yeast and S. cerevisiae. The man was admitted to the hospital for a 24-hour observation period during which no visitors were permitted. He underwent a glucose challenge with a high-carbohydrate diet and snacks throughout the day. BALs were measured at regular intervals. At one point during the afternoon, the man’s BAL rose to 0.12%.

For treatment, the patient was given an oral course of fluconazole 100 mg daily for three weeks, followed by a three-week course of Nystatin 500,000 IU, four times daily. He also took daily acidophilus tablets and followed a strict no-sugar, no-carbohydrate diet.

The patient also received a course of tetracycline for the treatment of Helicobacter pylori, which had been isolated from his stomach during initial testing. The authors believe that H. pylori may have been a confounding variable, although the man’s symptoms resolved with treatment for S. cerevisiae.

Dr. Cordell said that eight other patients with possible gut fermentation syndrome have contacted her since the article was published. In each case, the individuals have complained of autointoxication but have been sent home by hospitals or physicians.

She called on gastroenterologists and physicians to be open-minded and listen carefully to patients who deny drinking.

“Be an investigator who digs to try to find answers for patients,” she said. “The people I am talking to are desperate and frightened to death because they don’t know what’s going on with their bodies.”

Dr. Chey said that the increased attention given to gut fermentation syndrome could lead to a better understanding of many postprandial effects. Autointoxication may represent an extreme form of the subtle postprandial syndromes that patients often talk about—things like headaches and sleepiness, which have long been thought to result from blood diversion to the stomach after digestion, may be related to products of fermentation, he said.

“It’s a previously unrecognized possibility that holds all sorts of interesting and potentially important implications in regards to diet and manipulations of the microbiome,” Dr. Chey said.