Clinical Reasoning: A Teenager with Shortness of Breath and Difficulty Walking.

A 13-year-old boy presented to an urgent care clinic with 4 days of fatigue, vomiting, shortness of breath, and difficulty ambulating. Aside from a recent viral upper respiratory infection, he was healthy. He was sent to the emergency department, where weakness was noted in his lower extremities and right arm. Within hours, he declined, was emergently intubated for respiratory distress, and was transferred to a children's hospital.