A 4-month-old exclusively breastfed infant presents with tachycardia, cardiomegaly, and biventricular heart failure. The infant has a weak hoarse cry and absent deep tendon reflexes. The mother reports her own diet consists almost entirely of polished rice. Which of the following is the MOST likely diagnosis?

• A Congenital dilated cardiomyopathy
• B Endocardial fibroelastosis
• C Infantile beriberi (thiamine deficiency) ✓
• D Carnitine deficiency

Explanation

Shoshin beriberi presents in breastfed infants aged 2 to 6 months with high-output cardiac failure, tachycardia, cardiomegaly, aphonia, and areflexia when the lactating mother consumes a polished rice diet lacking thiamine. Rapid dramatic improvement after parenteral thiamine confirms the diagnosis. Congenital cardiomyopathy does not explain the hoarse cry and areflexia, which reflect peripheral neuropathy from thiamine deficiency.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.