Thiamine deficiency is caused by a low level of thiamine (vitamin B1) in the body, and when severe, a deficiency may manifest in adults as beriberi.
There are two main forms:
- wet beriberi: high-output cardiac failure predominates
- Shoshin beriberi : severe acute wet form with high mortality
- dry beriberi: neurological dysfunction predominates
In practice patients may present with mixed beriberi, i.e. with elements of both the wet and dry forms.
- congestive high output heart failure: dyspnea, palpitations, edema
- altered mentation
- visual disturbance
- sensory and/or motor deficits
Laboratory testing of the serum thiamine level can confirm the diagnosis.
In general, those individuals with a poor diet are most likely to develop thiamine deficiency. However due to low body stores of this vitamin, as little as two weeks without thiamine in the diet can lead to beriberi.
- eating disorders
- anorexia nervosa
- bulimia nervosa
- chronic illness
- prolonged TPN
- GI malabsorptive conditions e.g. Crohn disease, celiac disease, infective enteritis
- dialysis patients: haemodialysis and peritoneal dialysis
- post-starvation refeeding syndrome
- bariatric surgery e.g. gastric banding
The imaging features of beriberi reflect its underlying manifestations, and therefore in dry beriberi, cardiomegaly, pulmonary edema, dilated cardiomyopathy may be seen; however there are no pathognomonic cardiac imaging findings .
In wet beriberi the classic MRI features of Wernicke encephalopathy may be seen.
In general radiology is a corroborative tool in beriberi. The diagnosis is usually clinical with response to supplemental thiamine confirmatory.
Treatment and prognosis
Optimal treatment of beriberi relies upon a two-pronged approach:
- thiamine supplementation
- supportive therapies e.g. cardiac support
Recovery is often rapid once thiamine supplements are started.
History and etymology
Beriberi derives from the Sinhalese for "weak, weak", a deliberate duplication of the same word to emphasize how poorly a patient with the condition feels .