1. General Principles & Basic Science MCQs

A 55-year-old female with a history of Roux-en-Y gastric bypass presents with diffuse bone pain and muscle weakness. Radiographs reveal bilateral transverse radiolucent bands in the medial femoral necks. Lab tests show low vitamin D and elevated PTH. What is the radiologic finding called?

A newborn is diagnosed with diastrophic dysplasia. Which of the following clinical findings is classic for this condition?

A 62-year-old female on hemodialysis presents with chronic bone pain. Radiographs of her hands show subperiosteal bone resorption on the radial aspect of the middle phalanges. Which histologic finding is most characteristic of her underlying bone disease?

A 70-year-old female with severe postmenopausal osteoporosis has sustained multiple vertebral compression fractures despite bisphosphonate therapy. Her physician recommends initiating teriparatide. Which of the following is an absolute contraindication to this medication?

A 7-year-old boy with sickle cell disease presents with fever, leg pain, and elevated inflammatory markers. Blood cultures grow Salmonella. What is the primary pathogenic mechanism for Salmonella osteomyelitis in sickle cell patients?

A 45-year-old patient on long-term hemodialysis develops severe bone pain and is diagnosed with adynamic bone disease. Which laboratory profile is most consistent with this diagnosis?

A 4-year-old child presents with a 2-day history of refusal to bear weight on the left leg, fever of 39.0 C, an ESR of 55 mm/hr, and a synovial fluid WBC count of 85,000 cells/uL. Gram stain is pending. Based on current trends in community-acquired pediatric bone and joint infections, empiric antibiotic therapy must cover which of the following organisms?

A 5-year-old girl presents with progressive lower extremity bowing. Labs show normal serum calcium, significantly low serum phosphate, and elevated alkaline phosphatase. Genetic testing reveals a PHEX gene mutation. What is the most targeted contemporary medical treatment for this condition?

A 9-year-old boy presents to the orthopedic clinic. Examination reveals delayed closure of cranial fontanelles, the ability to appose his shoulders anteriorly at the midline, and a wide pubic symphysis on radiographs. This condition is associated with a mutation in which of the following genes?

A 60-year-old diabetic patient presents with extreme pain in the lower leg, diffuse erythema, swelling, and palpable crepitus. The patient is tachycardic and hypotensive. Plain films show gas tracking along the fascial planes. What is the most critical initial step in management?

A 3-year-old severely malnourished child presents with refusal to walk, bleeding gums, and corkscrew hairs. Radiographs of the knee show a dense zone of provisional calcification (white line of Frankel) and a ringed epiphysis (Wimberger ring sign). The primary biochemical defect in this disorder impairs which process?

A 12-year-old child presents with recurrent fractures, anemia, hepatosplenomegaly, and cranial nerve palsies. Radiographs show diffuse osteosclerosis and 'Erlenmeyer flask' deformities of the distal femora. What is the fundamental pathophysiology underlying this disease?

A 7-year-old boy presents with a waddling gait and delayed eruption of secondary teeth. Radiographs reveal bilateral absence of the clavicles and widened cranial sutures. A mutation in which of the following transcription factors is most likely responsible?

A 65-year-old man presents with progressive bowing of his right tibia and hearing loss. Radiographs show cortical thickening, coarse trabeculae, and anterior bowing. Bone biopsy reveals a mosaic pattern of lamellar bone. A mutation in which gene is commonly associated with the familial form of this disease?

A 14-year-old boy presents with progressive knee valgus. Labs show normal serum calcium, decreased serum phosphate, normal PTH, normal 25-OH vitamin D, and elevated alkaline phosphatase. Which of the following is the most likely diagnosis?

A 12-year-old girl presents with a chronic, sterile, multifocal inflammatory bone disease primarily affecting her clavicle and distal tibia. Biopsies have repeatedly shown non-infectious inflammation. She is diagnosed with Chronic Recurrent Multifocal Osteomyelitis (CRMO). Which of the following is the most appropriate initial medical therapy?

A 45-year-old patient with end-stage renal disease on hemodialysis presents with bone pain. Radiographs demonstrate subperiosteal resorption of the radial aspects of the middle phalanges and a "rugger jersey" spine. What is the primary pathophysiologic driver of this patient's bone disease?

A 2-year-old presents with fever, refusal to bear weight on the right leg, and elevated CRP. A joint aspiration of the knee yields a WBC count of 65,000 cells/mcL. Standard cultures are negative after 48 hours. What is the most likely fastidious organism, which is best isolated by inoculating synovial fluid into aerobic blood culture bottles?