Thiamine Deficiency May Cause Brain Damage

A deficiency of vitamin B1 (thiamine) can cause a potentially fatal brain disorder called Wernicke encephalopathy. Symptoms can include confusion, hallucinations, coma, loss of muscle coordination, and vision problems such as double vision and involuntary eye movements. Untreated, the condition can lead to irreversible brain damage and death, according toneurologists at Loyola University Medical Center.

In the developed world, Wernicke encephalopathy typically occurs in people who have disorders such as alcoholism and anorexia that lead to malnourishment. Wernicke encephalopathy is an example of the wide range of brain diseases, called encephalopathies, that are caused by metabolic disorders and toxic substances, according to a report by Loyola neurologists Matthew McCoyd, MD; Sean Ruland, DO; and Jose Biller, MD, in the journal Scientific American Medicine.

Acute encephalopathy has a rapid onset of between hours and days. It's commonly due to toxic and metabolic factors. "Toxic and metabolic encephalopathies may range in severity from the acute confusionalstate to frank coma," the neurologists wrote. "As permanent injury may occur, an organized approach is needed to make an accurate and rapid diagnosis."

The hallmark of toxic and metabolic encephalopathies is altered sensorium. This can range from mild attention impairment, such as difficulty spelling a word backwards, to coma. Toxic encephalopathy can be caused by illegal drugs, environmental toxins, and reactions to prescription drugs.

Thiamine deficiency is among the nutritional deficiencies that can cause brain diseases such as Wernicke encephalopathy. The condition likely is underdiagnosed. Although clinical studies find a rate of 0.13% orless, autopsy studies show prevalence as high as 2.8%.

"Particularly in those who suffer from alcoholism or AIDS, the diagnosis is missed on clinical examination in 75% to 80% of cases," the Loyola neurologists wrote.

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 symptoms can include apathy, anxiety, and confabulation (fabricating imaginary experiences to compensate for memory loss).

About 80% of Wernicke encephalopathy patients develop Korsakoff syndrome, and once this occurs, only about 20% of patients recover.

Wernicke encephalopathy is a medical emergency that requires immediate thiamine treatment, either by injection or IV. "In the absence of treatment, deficiency can lead to irreversible brain damage and death with an estimated mortality of 20%," the Loyola neurologists wrote.

Source: Loyola University Health System