Author: Kyle Pontiff, MD
Co Author #1: Brian Harvey, DO
Co Author #2: Greg Canty, MD
Senior Editor: Margaret Gibson, MD, FAMSSM
Editor: Elizabeth Portin, DO

Patient Presentation:
A 13-year-old male presented to the sports medicine clinic with 5-weeks of fatigue during conditioning and difficulty running.

History:
The patient reported feeling like he “couldn’t do it anymore” during his conditioning and weight lifting sessions. He also noted thigh weakness and a small amount of pain behind his bilateral knees after running. His father recorded him bear crawling and running and noticed that his legs looked weak. He denied any lower extremity color change, swelling, numbness or tingling. He reported some shortness of breath with activity but denied any other respiratory symptoms. He denied any fever, chills, headache, visual changes, abdominal pain or peripheral vascular changes. Bilateral knee x-rays and pelvis x-rays were obtained and were normal Case Photo #1 , Case Photo #2 , Case Photo #3 . He was prescribed physical therapy, and while his perceived strength improved with therapy, his overall weakness and fatigue persisted.

Physical Exam:
On the initial exam, his height was 163 cm, weight was 43 kg and BMI was 16. There was no muscle wasting, swelling or bruising. He had no tenderness to palpation of the ankle, calf, knee or hip, and he had full range of motion throughout. Sensation and reflexes were normal. However, his bilateral hip flexion and abduction strength was 4/5. His tone and heel-to-shin coordination test were both normal. He had no difficulty with duck walk and was able to stand-up without difficulty. In the physical therapy gym, his jogging, running and speed skating were normal.

Click here to continue. Challenge yourself by writing down a broad differential diagnosis before moving to the next slide.