There is a medical issue that some people have that causes their bodies to create alcohol on its own, which in turn raises their blood alcohol levels. Crazy but true. This condition is called auto-brewery syndrome. Those in Texas who have been charged with drunk driving even though they have not consumed any impairing substances may have their cases dismissed if they can document that they suffer from this ailment.
How does auto-brewery syndrome work? If an individual has this disorder, the amount of yeast growing in his or her body is excessive. The body then takes the extra yeast and ferments it into ethanol. This then raises the individual's blood alcohol content to the point of being "intoxicated." This disorder is thought to be a rare condition; however, more cases continue to be reported in the news.
As people with auto-brewery syndrome deal with this on a daily basis, they can generally function pretty well even when their BACs are higher than normal. There are some, though, who may show signs of impairment. This can affect their driving and ability to perform a number of other tasks safely.
One of the biggest issues with auto-brewery syndrome is that the people who have it most likely do not know that they have it. It is not something for which medical providers commonly test. If one would like to use this as a criminal defense for a drunk driving charge, it will require a medical diagnosis. Achieving that is not necessarily easy, but it is possible. Texas residents who believe that this or any other medical condition contributed to their increased BAC levels can work with their criminal defense attorneys and medical professionals in order to fight the charges filed against them.
Source: nurse-practitioners-and-physician-assistants.advanceweb.com, "Auto-Brewery Syndrome", Chelsea Lacey-Mabe, Accessed on July 4, 2017