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) levels are increased when a person has muscle damage, making option A the correct answer. CK is an enzyme found in muscle cells, and its levels rise in response to muscle injury or damage. This increase occurs because CK is released into the bloodstream when muscle cells are disrupted, such as in cases of trauma, overexertion, or certain muscle diseases. Option B, rheumatoid arthritis, is an autoimmune condition that primarily affects the joints, not the muscles. Option C, spondyloarthritis, also primarily affects the joints, particularly the spine and pelvis. Option D, systemic lupus erythematosus, is a systemic autoimmune disease that can affect multiple organs, but it does not typically directly impact muscle tissue to the extent that it would significantly elevate CK levels. In an educational context, understanding the relationship between serum CK levels and muscle damage is crucial for healthcare professionals, especially those in fields like sports medicine, physical therapy, and orthopedics. Monitoring CK levels can help in diagnosing and assessing the severity of muscle injuries, guiding treatment decisions, and tracking recovery progress in patients with musculoskeletal disorders. This knowledge also underscores the importance of considering the specific pathophysiology of different conditions when interpreting laboratory results to make accurate clinical judgments.

Correct Answer: C

Rationale: The correct answer to the question is C) X-rays. X-rays are typically the first imaging test done to detect suspected bone abnormalities due to their ability to provide a clear image of bones, joints, and surrounding tissues. X-rays are widely available, relatively low-cost, and offer a quick way to assess for fractures, tumors, infections, and other bone-related conditions. Option A) Computed tomography (CT) is a more advanced imaging modality that may be used if further detail is required after an abnormality is detected on an x-ray. CT scans provide detailed cross-sectional images and are helpful for evaluating complex fractures or detecting subtle bone abnormalities. Option B) Dual-energy x-ray absorptiometry (DXA) is primarily used to measure bone mineral density and diagnose osteoporosis. It is not typically the first test done to detect suspected bone abnormalities. Option D) Ultrasonography is more commonly used to visualize soft tissues like tendons, ligaments, and muscles. While it can be useful in certain musculoskeletal conditions, it is not the primary imaging modality for detecting suspected bone abnormalities. In an educational context, understanding the appropriate use of different imaging modalities in diagnosing musculoskeletal disorders is crucial for healthcare professionals. Knowing when to order specific tests based on the clinical presentation can lead to accurate and timely diagnoses, ultimately improving patient outcomes. It is important to prioritize cost-effective and efficient imaging modalities like x-rays as the initial step in evaluating suspected bone abnormalities before considering more advanced imaging techniques.