What is the treatment for thiamine (Vitamin B1) deficiency in infants?

Treatment of Thiamine Deficiency in Infants

For infants with suspected or confirmed thiamine deficiency, administer 25-50 mg intramuscular thiamine daily for 14 days, with immediate treatment in severe cases presenting with cardiac failure, lactic acidosis, or neurological symptoms. 1, 2

Clinical Recognition and Urgency

Thiamine deficiency in infants presents in three distinct clinical patterns that require immediate recognition:

• Acidotic form (most common, youngest infants, mean age 67 days): Presents with irritability, reflux history, acidotic breathing, and lactic acidosis. This can rapidly progress to shock (46%) and acute respiratory failure (50%). 3

• Cardiac form: Characterized by hoarseness of voice (aphonia), irritability, pulmonary arterial hypertension with prominent pulmonary conus on chest X-ray, and may progress to congestive heart failure. 3

• Wernicke's encephalopathy (oldest infants, mean age 190 days): Presents with bilateral ptosis, encephalopathy, vomiting, and hyperechoic basal ganglia on head ultrasound. 3

Critical point: Do not delay treatment while awaiting laboratory confirmation—thiamine deficiency can cause death within days to weeks if untreated. 4

Treatment Protocol

Acute/Severe Presentation

For infantile beriberi with collapse or severe symptoms, administer 25 mg thiamine cautiously by IV route. 1

• For mild infantile beriberi, oral therapy may be sufficient, but parenteral administration is preferred when any doubt exists. 1

• Treatment with intramuscular thiamine 50 mg/day for 14 days combined with formula change resulted in complete resolution in documented outbreak cases. 2

• Clinical improvement typically occurs within hours to 1 day of thiamine administration in severe cases. 2

Maintenance and Prevention

After acute treatment, continue with oral thiamine 5-10 mg daily for one month to achieve tissue saturation. 1

• For infants on parenteral nutrition, provide 0.35-0.50 mg/kg/day thiamine. 4

• The parenteral recommendation may be too low; dosages up to 500 μg/kg per day (0.5 mg/kg/day) appear more appropriate based on functional thiamine status studies. 4

High-Risk Populations Requiring Vigilance

Suspect thiamine deficiency in infants with:

• Exclusive breastfeeding by mothers with inadequate thiamine intake (polished rice diets, food avoidance practices). 5

• Soy-based or defective formula feeding. 2

• Prolonged vomiting or feeding difficulties. 2, 3

• Concurrent infection (present in all outbreak cases, which may unmask subclinical deficiency). 2

• Failure to thrive with chronic formula feeding (>2 months). 2

Diagnostic Approach

Laboratory confirmation should not delay treatment, but when obtained:

• Measure erythrocyte transketolase activity (TPPE): >25% indicates severe deficiency, 15-25% indicates deficiency. 2

• Blood lactate levels are universally elevated in the acidotic form (normal: 0.5-2 mmol/L). 2, 3

• Response to thiamine challenge within 24-72 hours confirms diagnosis retrospectively. 2, 3

Critical Management Pearls

Never administer dextrose-containing IV fluids before thiamine in at-risk infants—this can precipitate acute cardiac failure. 1

• Thiamine reserves can be depleted within 20 days of inadequate intake. 6, 7

• There is no established upper limit for thiamine toxicity; excess is excreted in urine. 6, 8

• Echocardiographic response in cardiac cases occurs uniformly within 3 days. 3

• Neurologic cases may have residual sequelae despite treatment if diagnosis is delayed. 2

Maternal and Breastfeeding Considerations

Treat lactating mothers suspected of thiamine deficiency with 200-300 mg oral thiamine daily to prevent infantile deficiency. 4, 9

• Pregnant women with suspected deficiency should receive treatment before delivery. 9

• Supplement both mother and infant during breastfeeding in high-risk populations. 9

• In endemic areas, infantile thiamine deficiency accounts for up to 3.6% of infant mortality, with peak deaths at 1-3 months. 5