Hypocalcemic tetany in a toddler with undiagnosed rickets.

A 17-month-old black girl presented to the pediatric emergency department with sudden onset of her hands and feet "drawing up." A diagnosis of vitamin D deficiency rickets with tetany was made on a history of exclusive breast-feeding, low serum calcium, phosphorus, and 25-hydroxyvitamin D levels, and bone radiographs. Nutritional rickets should be considered in the differential diagnosis of acute hypocalcemia.