Acute Unilateral Lower Extremity Weakness in a 7-year-old Girl.

A 7-year-old previously healthy girl presents to the pediatric emergency department with left leg weakness and inability to bear weight. Yesterday the patient awoke with left leg “numbness,” which has not resolved, and mild weakness. The family noticed a limp, but the patient was still able to ambulate independently. Today, the patient is unable to move her left leg or bear weight. She describes diffuse muscular aching of the left leg but denies any focal areas of pain. The parents also report 1 week of fevers (to 101.1F [38.4C]), cough, congestion, rhinorrhea, bilateral ear pain, headaches, and 1 episode of nonbilious emesis. She denies vision changes, facial and neck pain, and urinary or gastrointestinal changes/incontinence. The patient’s sister also had symptoms of fever, cough, and congestion, but her illness resolved within a few days.