A 12 y/o male is brought to the ED with his mother because of an 8-day history of dull, intermittent, non-radiating pain in the left groin and occasional knee pain. He cannot recall any specific trauma, denies fevers, shakes, chills or rashes. He is on a soccer team, however, over the past week he has stopped playing as the pain worsens with activity and is alleviated by rest. His mother has noticed that he occasionally has a limp.
On exam: T: 36.9 HR: 65 RR: 15 BP: 120/80, Weight = 58 kg (>90th%), height = 146cm (50th percentile) MSK exam reveals tenderness over the left anterior hip with decreased internal rotation, abduction and flexion. When you ask him to stand on his left leg, you notice his pelvis tilts to the right side. He has normal right and left knee exams. The rest of his exam is unremarkable Based on the history and physical exam, what are the differential diagnoses: …
