An overweight adolescent boy complains of pain in his hip that radiates to the medial aspect of his knee. He denies trauma and has not had a fever. You note upon exam that he is walking with a limp. The most likely diagnosis is:

Correct Answer: A

Rationale: Slipped capital femoral epiphysis (SCFE) (A) is common in overweight adolescents, presenting with hip pain radiating to the knee and a limp, without trauma or fever. Transient synovitis (B) is more common in younger children, Legg-Calve-Perthes (C) typically affects younger kids, and septic arthritis (D) usually involves fever.

Correct Answer: B

Rationale: This is classic for nursemaid’s elbow (radial head subluxation), common after pulling injuries in young children. Gentle supination and flexion (B) often reduces it. Immobilization and referral (A) or x-ray (D) are unnecessary unless reduction fails, and maltreatment (C) isn’t indicated without other signs.

Correct Answer: A

Rationale: Serum creatine kinase (CK) is elevated with muscle damage (A), such as in muscular dystrophy or trauma, as it’s released from injured muscle cells. Rheumatoid arthritis (B), spondyloarthritis (C), and SLE (D) typically don’t elevate CK unless muscle involvement occurs, which is rare.

Correct Answer: C

Rationale: X-rays (C) are the initial imaging test for suspected bone abnormalities due to their availability, cost-effectiveness, and ability to detect fractures or deformities. CT (A) and DXA (B) are more specialized, and ultrasonography (D) is less effective for bone.