Subacute onset of abnormal gait and head drop in a 3-year-old with history of extreme prematurity.

A 3-year-old boy who had been a 23-week premature infant had subacute onset of abnormal gait, which progressed to generalized weakness with severe weakness of neck extensors. He had U waves on electrocardiography. His serum potassium was 1.8 mmol/L. The patient had a gastrostomy tube due to chronic feeding issues and was treated with inhaled albuterol for chronic lung disease. When his oral intake regressed, his family administered one of his oral supplements through the gastrostomy tube; the supplement was low in potassium. This feeding regression continued for several months. He had no additional gastrointestinal or renal loss of potassium. He had frequent exacerbations of his bronchopulmonary dysplasia. His history suggested he had chronic potassium depletion and that albuterol may have led to further potassium redistribution, exacerbating his hypokalemia. As more extremely premature infants survive with chronic feeding and respiratory issues, this presentation may become more common.