Auto-brewery syndrome - updated

A medical condition of which I was previously totally unaware.

The man’s troubles began in 2004, when, having moved from China to attend college in Australia, he got really drunk. That would hardly have been a noteworthy event, except that the man hadn’t consumed any alcohol—only fruit juice.

The bizarre incident soon turned into a pattern. About once a month, and out of the blue, he’d become severely inebriated without drinking any alcohol... his mother cared for him while monitoring him with a Breathalyzer. His blood-alcohol levels, she found, would erratically and inexplicably soar to 10 times the legal limit for driving...

The man was diagnosed with a rare condition aptly known as auto-brewery syndrome, in which microbes in a person’s gut ferment carbohydrates into excessive amounts of alcohol... The microbial culprits are usually yeasts—the same fungi used to brew beer and wine—and the condition can often be treated with antifungal drugs... analyzed the man’s stool samples and found that the alcohol in his body was being produced not by yeast, but by bacteria [Klebsiella pneumoniae].

That is a rare disorder, but this corollary has more clinical relevance:

... people with nonalcoholic fatty liver disease (NAFLD) build up fatty deposits in their liver in the style of heavy drinkers, despite touching little or no alcohol. This condition is very common, affecting 30 to 40 percent of American adults; the causes are still unclear and likely varied. Yuan wondered if Klebsiella might be involved, and when she analyzed 43 Chinese people with NAFLD, she found that 61 percent had the same high-alcohol strains as the man with auto-brewery syndrome. By contrast, just 6 percent of people with a healthy liver carry those strains.

Continue reading at Ed Yong's excellent article in The Atlantic.

Reposted from 2019 to add some data about a case originating from yeast in a woman's bladder:

Her urine was full of alcohol.  The 61-year-old woman, who was seeking a liver transplant, insisted she had not been drinking. Her doctors hesitated to believe her.

The liver transplant team at the first hospital she visited ushered her into an alcohol abuse treatment program, suspecting she had lied to obscure an addiction that may have contributed to her failing organ, according to a case study published Monday in the journal Annals of Internal Medicine.

When the doctors drew blood and tested her plasma, they did not find any trace of ethanol. They tested the woman’s urine for ethyl glucuronide and ethyl sulfate, two chemicals the body produces as it metabolizes alcohol and then expels it through the urinary tract. Neither showed up in the lab tests.

But her urine did contain sugar and yeast — the two key ingredients for fermentation.

Unlike the first case, where the man presented with symptoms of intoxication, this lady was not intoxicated because there is no back-diffusion of bladder contents through that organ's epithelium as there is from the upper GI tract, but it did present an unusual clinical conundrum.