Beriberi

Editor-In-Chief: Timothy R. Koch, M.D., Professor of Medicine, Gastroenterology, Georgetown University School of Medicine. You can email Dr. Koch [mailto:Timothy.R.Koch@MedStar.net here]; Bikram Bal, M.D., Section of Gastroenterology, Washington Hospital Center.

Associate Editor-in-Chief: C. Michael Gibson, M.S., M.D.

Overview
Beriberi is a dietary-deficiency disease caused by a lack of thiamine in the diet. Thiamine, initially named "the anti-beriberi factor" in 1926 was the first B vitamin to be identified and is therefore referred to as vitamin B1. Thiamine is soluble in water and partly soluble in alcohol. It consists of a pyrimidine and a thiazole moiety, both of which are essential for its activity.

Thiamine functions in the decarboxylation of α-ketoacids, such as pyruvate α-ketoglutarate, and branched-chain amino acids and thus is a source of energy generation. In addition, thiamine pyrophosphate acts as a coenzyme for a transketolase reaction that mediates the conversion of hexose and pentose phosphates.

Etymology
The origin of the word is from a Sinhalese phrase meaning "I cannot, I cannot", the word being doubled for emphasis.

History
It is a disease that has killed probably close to a million people worldwide. References to this disease can be found in Chinese medical texts dating as far back as 2697 BC. In the 19th century it was the “national disease” of Japan. It first attracted the attention of Western scientists in the 1880s, when Dutch military personnel experienced an epidemic of the disease while operating in Sumatra. Its association with the consumption of highly polished rice was noted in the first decade of the twentieth century. It took some 50 years and lifetimes of dedication by dozens of scientists from many different fields and of various nationalities before the mysteries of beriberi were unraveled. Christiaan Eijkman a Dutch physician and pathologist first demonstrated that beriberi is caused by poor diet led to the discovery of vitamins. Together with Sir Frederick Hopkins, he was awarded the 1929 Nobel Prize for Physiology or Medicine for the discovery. But the ability to produce a synthetic vitamin on a commercial scale has been by no means the end of the story.

Differential Diagnosis of Underlying Causes
Thiamine deficiency can be a result of:

1. Inadequate intake:
 * Alcoholism
 * Anorexia
 * Intentional dieting
 * Starvation
 * Bulimia
 * Protein energy malnutrition in developing countries
 * Total parenteral nutrition
 * Infants breast fed by thiamine deficient mothers

2. Increased losses:
 * Protracted vomiting in chemotherapy patients
 * Hyperemesis gravidarum in pregnant women

3. Inadequate absorption
 * Post gastric bypass surgery patients
 * Genetic loss of ability to absorb thiamine

Signs and Symptoms
Cardiovascular or wet beriberi: is manifested by heart hypertrophy and dilatation (particularly of the right ventricle), tachycardia, respiratory distress, edema of the legs and heart failure with high cardiac output. Severe lactic acidosis is characteristic (1).

Neurological or dry beriberi: is manifested by exaggeration of deep tendon reflexes, polyneuritis (sometimes associated with paralysis) that typically affects lower extremities and in a subsequent stage, upper extremities, muscle weakness and pain, and convulsions.

Gastrointestinal beriberi: Gastrointestinal symptoms are primarily due to the delayed emptying of the stomach and dilation of the colon. Loss of appetite, vague abdominal complaints, and constipation are common manifestations. As the disease progresses nausea and vomiting may occur.

Wernicke-Korsakoff syndrome: Wernicke's disease is a triad of nystagmus, ophthalmoplegia, and ataxia, along with confusion. Korsakoff's psychosis is impaired short-term memory and confabulation with otherwise grossly normal cognition. This combination is almost exclusively described in chronic alcoholics with thiamine deficiency. The two entities are not separate diseases, but a spectrum of signs and symptoms. Genetic abnormalities may underlie a predisposition to Wernicke-Korsakoff syndrome.

Bariatric beriberi: Thiamine deficiency after Roux-en-Y gastric bypass surgery is common. After Roux-en-Y gastric bypass, thiamine deficiency has been reported in 18% of patients at one year post-surgical follow-up in a university hospital setting. Our group previously published that persistent thiamine deficiency is associated with small bowel bacterial overgrowth following gastric bypass surgery. Oral thiamine supplementation does not reverse thiamine deficiency in this patient population. Concurrent treatment of small intestinal bacterial overgrowth with antibiotics is needed to adequately treat the condition.

Psychotic beriberi: Psychotic beriberi manifesting with auditory and visual hallucinations, odd and aggressive behavior has been recently described in gastric bypass patients.

Laboratory Studies
The diagnosis of beriberi is assisted by a dietary history suggestive of a low thiamine intake and clinical manifestations. However, objective biochemical tests of thiamine status, particularly measurement of erythrocyte transketolase activity (ETKA) and the thiamine pyrophosphate effect (TPPE), provide a sensitive test for thiamine deficiency.

Treatment
Treatment is with thiamine hydrochloride, either in tablet form or injection. A rapid and dramatic recovery within hours can be made when this is administered to patients with beriberi. Thiamine occurs naturally in unrefined cereals and fresh foods, particularly fresh meat, legumes, green vegetables, fruit, and milk.