Diagnosis

If the diagnosis of thiamine deficiency is in doubt, then treat. There should be a high index of suspicion in areas of endemic thiamine deficiency.

In cases of suspected wet beri-beri, a rapid improvement in the cardiac function following thiamine administration is diagnostic.

Blood biochemistry is deranged in thiamine deficiency states:

• lactate and pyruvate concentrations are raised
• transketolase activity of erythrocytes is low in the absence of added thiamine pyrophosphate but increases by more than 30% upon addition of thiamine pyrophosphate to the patient
• reduced urinary thiamine excretion