A deficiency of vitamin B1 (thiamine) can cause a potentially fatal brain disorder called Wernicke Encephalopathy which mimics dementia and other neurodegenerative conditions, according to a recent study.

Symptoms of the neurologic disease can include confusion, hallucinations, coma, loss of muscle coordination and vision problems such as double vision and involuntary eye movements. According to neurologists at Loyola University Medical Center, the condition can lead to irreversible brain damage and death if it is untreated.

In the developed world, Wernicke encephalopathy typically occurs in people who have disorders such as alcoholism and anorexia that lead to malnourishment. It is an example of the wide range of brain disease, called encephalopathies that are caused by metabolic disorders and toxic substances.

"Toxic and metabolic encephalopathies may range in severity from the acute confusional state to frank coma," researchers said in the study. "As permanent injury may occur, an organized approach is needed to make an accurate and rapid diagnosis."

The condition likely is underdiagnosed. Although clinical studies find a rate of 0.13 percent or less, autopsy studies show a prevalence as high as 2.8 percent.

"Particularly in those who suffer from alcoholism or AIDS, the diagnosis is missed on clinical examination in 75 to 80 percent of cases," according to researchers.

Untreated Wernicke encephalopathy can lead to Korsakoff syndrome, characterized by profound memory loss and inability to form memories -- patients often can't remember events within the past 30 minutes. Other KS symptoms can include apathy, anxiety and confabulation (fabricating imaginary experiences to compensate for memory loss). About 80 percent of Wernicke encephalopathy patients develop KS, and once this occurs, only about 20 percent of patients recover.

""In the absence of treatment, deficiency can lead to irreversible brain damage and death with an estimated mortality of 20 percent," the Loyola neurologists wrote, emphasizing that Wernicke encephalopathy is a medical emergency that requires immediate treatment.