Beriberi is now confined to the poorest areas of South East Asia. It can be prevented by eating undermilled or par-boiled rice, or by fortification of rice with thiamine.
Probably the most important factor in the reduction of beriberi is the general increase in overall food consumption so that the staple diet is varied and contains legumes and pulses, which contain a large amount of thiamin.
There are two main clinical types of beriberi, which, surprisingly, only rarely occur together.
Dry beriberi usually presents insidiously with a symmetrical polyneuropathy. The initial symptoms are heaviness and stiffness of the legs, followed by weakness, numbness, and pins and needles.
The ankle jerk reflexes are lost and eventually all the signs of polyneuropathy that may involve the trunk and arms are found. Cerebral involvement occurs, producing the picture of the Wernicke-Korsakoff syndrome.
In endemic areas, mild symptoms and signs may be present for years without unduly affecting the patient.
Wet beriberi causes oedema. Initially this is of the legs, but it can extend to involve the whole body, with ascites and pleural effusions. The peripheral oedema may mask the accompanying features of dry beriberi.
Infantile beriberi occurs, usually acutely, in breast-fed babies at approximately 3 months of age. The mothers show no signs of thiamin deficiency but presumably their body stores must be virtually nil.
The infant becomes anorexic, develops oedema and has some degree of aphonia. Tachycardia and tachypnoea develop and, unless treatment is instituted, death occurs quickly.
Diagnosis of Beriberi
In endemic areas the diagnosis of beriberi should always be suspected and if in doubt treatment with thiamine should be instituted. A rapid disappearance of oedema after thiamine (50 mg i.m.) is diagnostic.
Other causes of oedema must be considered (e.g. renal or liver disease), and the polyneuropathy is indistinguishable from that due to other causes.
The diagnosis is confirmed by measurement of transketolase activity in red cells using fresh heparinized blood. This enzyme is dependent on TPP. The assay is performed with and without added TPP; an increase in activity of 25% with TPP indicates deficiency.
Treatment of Beriberi
Thiamine 50 mg i.m. is given for 3 days, followed by 25 mg of thiamine daily by mouth. The response in wet beriberi occurs in hours, giving dramatic improvement, but in dry beriberi improvement is often slow to occur.
In most cases all the B vitamins are given because of multiple deficiency. Infantile beriberi is treated by giving thiamine to the mother, which is then passed on to the infant via the breast milk.
Beriberi and Vitamin B1 deficiencies