A 10-day-old boy presented with lethargy, poor feeding, repeated vomiting, and recurrent hypoglycemic fits not responding to IV glucose

(E). ln maple syrup urine disease, affected infants who are normal at birth develop poor feeding and vomiting in the lst wk of life; lethargy and coma may ensue within a few days. Physical examination reveals hypertonicity and muscular rigidity with severe opisthotonos. Periods of hypertonicity may alternate with bouts of flaccidity manifested as repetitive movements of the extremities (boxing and bicycling). Cerebral edema may be present; convulsions occur in most infants, and hypoglycemia is common.