A 4-month-old infant presents with macrocephaly, hepatosplenomegaly, and severe anemia. The parents report he seems less responsive to sounds and visual stimuli than his older sibling was at this age. Radiographs reveal diffuse bone sclerosis with a “bone-within-bone” appearance. Molecular testing confirms autosomal recessive osteopetrosis. Which of the following genetic defects would prevent successful treatment with hematopoietic stem cell transplantation (HSCT)?
A high school football player reports a transient episode of unilateral burning pain and numbness radiating from his shoulder down into his hand after a tackle. The symptoms resolve completely within minutes, and he has a normal neurological exam, including full strength and range of motion of the neck. What is the most likely diagnosis?
A 13-year-old girl with a history of an inherited neuropathy presents with a progressive high-arched foot and difficulty with shoe wear. Examination reveals plantarflexion of the forefoot on the hindfoot, an elevated medial longitudinal arch, and a hindfoot that rolls into varus to achieve a plantigrade position. What is the most likely diagnosis?
A 14-year-old competitive gymnast presents with chronic, deep knee pain. An MRI is ordered to evaluate for juvenile osteochondritis dissecans (OCD). Which of the following MRI findings is the most definitive indicator of an unstable lesion requiring surgical intervention?
An 18-month-old infant presents with failure to thrive, irritability, and a rachitic chest deformity. Laboratory studies reveal a markedly low serum alkaline phosphatase for age, hypercalcemia, and hypercalciuria. Radiographs show irregular metaphyseal ossification and punched-out areas of lucency. Which of the following is the most likely long-term complication if this child survives infancy without specific treatment?
A high school football player collapses during practice on a hot, humid day. He is delirious, has profuse sweating, and his rectal temperature is measured at 40.5°C (104.9°F). What is the single most effective and immediate on-site treatment for this medical emergency?
A 13-year-old premenarchal female with a Risser sign of 0 is diagnosed with adolescent idiopathic scoliosis. Her initial posteroanterior radiograph reveals a thoracic curve of 35 degrees. She is asymptomatic. What is the most appropriate next step in management for this patient?
A 5-year-old girl is evaluated for dental abnormalities. Her primary teeth are retained, and radiographs show multiple supernumerary teeth. On examination, she has a prominent forehead and sloping shoulders, which she can bring to the midline. Which of the following radiographic findings would be expected in this patient?
A male infant is delivered prematurely at 32 weeks gestation to a mother with polyhydramnios. At birth, he has a large head with a cloverleaf skull deformity, extremely short limbs, and a long, narrow thorax, leading to severe respiratory distress. Radiographs show curved, telephone receiver-shaped femurs. Which of the following genetic findings is most consistent with this infant’s presentation?
A 10-year-old boy twists his ankle playing soccer. He is unable to bear weight immediately after the injury. According to the Ottawa ankle rules, which physical finding would mandate obtaining ankle radiographs?
