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4. Pediatrics MCQs

Practice Set 130 of 334

This practice set contains high-yield board review questions covering key concepts in 4. Pediatrics. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2581

Topic: 4. Pediatrics
A 13-year-old girl is diagnosed with a triplane fracture of the distal tibia following a fall. Which combination of Salter-Harris fracture patterns is classically observed on the standard anteroposterior (AP) and lateral radiographs of the ankle, respectively?
. Salter-Harris II on AP, Salter-Harris III on lateral
. Salter-Harris III on AP, Salter-Harris II on lateral
. Salter-Harris IV on AP, Salter-Harris II on lateral
. Salter-Harris I on AP, Salter-Harris IV on lateral
. Salter-Harris III on AP, Salter-Harris IV on lateral

Correct Answer & Explanation

. Salter-Harris III on AP, Salter-Harris II on lateral

Explanation

A triplane fracture typically appears as a Salter-Harris type III fracture on the AP radiograph (vertical fracture line through the epiphysis) and a Salter-Harris type II fracture on the lateral radiograph (posterior metaphyseal Thurston-Holland fragment).

Question 2582

Topic: Pediatric Hip

A 12-year-old obese boy presents to the emergency department with severe acute hip pain and inability to bear weight. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Because he cannot bear weight, even with crutches, this is classified as an unstable SCFE. Which of the following complications is significantly higher in this patient compared to a stable SCFE?

. Chondrolysis
. Avascular necrosis (AVN)
. Femoroacetabular impingement (FAI)
. Slipped contralateral epiphysis
. Septic arthritis

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

An unstable SCFE is defined clinically by the inability to bear weight. This instability implies a disruption of the epiphyseal vascular supply, carrying a much higher risk of avascular necrosis (up to 47%) compared to stable slips.

Question 2583

Topic: Pediatric Hip

A 3-month-old girl with developmental dysplasia of the hip (DDH) is treated with a Pavlik harness. At her follow-up visit, the parents report that she is no longer actively extending her left knee. Which improper adjustment of the Pavlik harness is the most likely cause of this finding?

. The anterior strap is too loose
. The anterior strap is too tight causing hyperflexion
. The posterior strap is too tight causing hyperabduction
. The posterior strap is too loose causing adduction
. The chest strap is fastened too tightly

Correct Answer & Explanation

. The anterior strap is too tight causing hyperflexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by excessive hip flexion (typically >120 degrees). This occurs when the anterior straps are pulled too tightly, compressing the nerve against the pubis.

Question 2584

Topic: 4. Pediatrics

An 8-year-old girl is evaluated for a leg length discrepancy 2 years after a distal femur fracture. MRI demonstrates a central physeal bar occupying 25% of the cross-sectional area of the distal femoral physis. The remaining physis is open and healthy. What is the most appropriate surgical management?

. Observation until skeletal maturity
. Resection of the physeal bar and interposition of an inert material
. Complete epiphysiodesis of the distal femur
. Distal femoral varus osteotomy
. Contralateral distal femur epiphysiodesis

Correct Answer & Explanation

. Resection of the physeal bar and interposition of an inert material

Explanation

Physeal bar resection is indicated if the bar involves less than 50% of the physis and the child has at least 2 years or 2 cm of growth remaining. Interposition of fat or cranioplast prevents bar reformation.

Question 2585

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvรฉ-Perthes disease. Radiographs demonstrate that the lateral pillar of the femoral head maintains 60% of its normal height. According to the Herring Lateral Pillar Classification, which group does this represent, and what is the general prognosis?
. Group A; excellent prognosis
. Group B; better prognosis than Group C, but surgery may be indicated if older than 8
. Group C; poor prognosis
. Group B/C; universal progression to severe osteoarthritis
. Group A; guarded prognosis requiring immediate osteotomy

Correct Answer & Explanation

. Group B; better prognosis than Group C, but surgery may be indicated if older than 8

Explanation

Group B of the Herring classification is defined by >50% maintenance of the lateral pillar height. It carries a better prognosis than Group C (<50%), though children older than 8 years in Group B benefit significantly from surgical containment.

Question 2586

Topic: 4. Pediatrics

A 2.5-year-old child presents with worsening bilateral genu varum. Standing radiographs reveal medial metaphyseal beaking of the proximal tibia and a metaphyseal-diaphyseal angle of 18 degrees. What is the most appropriate initial management for this stage of infantile Blount's disease?

. Reassurance and annual radiographic observation
. Treatment with daytime knee-ankle-foot orthoses (KAFOs)
. Bilateral proximal tibial valgus osteotomies
. Medial proximal tibial epiphysiodesis
. Guided growth using lateral tension band plates

Correct Answer & Explanation

. Treatment with daytime knee-ankle-foot orthoses (KAFOs)

Explanation

Infantile Blount's disease in a child under 3 to 4 years old with a metaphyseal-diaphyseal angle > 16 degrees should initially be treated with bracing (KAFOs). Surgery is considered if bracing fails or if the child is older than 4.

Question 2587

Topic: 4. Pediatrics

A defect in the substitution of glycine by bulkier amino acids in the triple helix formation of type I collagen is the primary pathophysiologic mechanism for which of the following conditions?

. Achondroplasia
. Osteogenesis imperfecta
. Marfan syndrome
. Ehlers-Danlos syndrome
. Osteopetrosis

Correct Answer & Explanation

. Osteogenesis imperfecta

Explanation

Osteogenesis imperfecta is most commonly caused by mutations in the COL1A1 or COL1A2 genes. This leads to the substitution of glycine, which is essential for the tight spatial packing of the collagen triple helix, resulting in mechanically weakened bone.

Question 2588

Topic: 4. Pediatrics

During physeal growth and endochondral ossification, the primary site of longitudinal growth occurs in which zone of the physis?

. Reserve zone
. Proliferative zone
. Hypertrophic zone
. Calcified zone
. Primary spongiosa

Correct Answer & Explanation

. Proliferative zone

Explanation

The proliferative zone is responsible for longitudinal growth via chondrocyte division and matrix production. The hypertrophic zone is responsible for matrix calcification and is the weakest zone where most physeal fractures occur.

Question 2589

Topic: Pediatric Upper Extremity & Spine

The Injury Severity Score (ISS) is a validated anatomical scoring system used globally for polytrauma patients. How is the ISS mathematically derived from the Abbreviated Injury Scale (AIS)?

. Sum of the AIS scores of the three most severely injured body regions
. Sum of the squares of the highest AIS scores in the three most severely injured body regions
. Sum of the squares of all documented AIS scores
. The highest single AIS score multiplied by 3
. The square of the highest overall AIS score

Correct Answer & Explanation

. Sum of the squares of the highest AIS scores in the three most severely injured body regions

Explanation

The Injury Severity Score (ISS) correlates with mortality and is calculated by summing the squares of the highest Abbreviated Injury Scale (AIS) scores in the three most severely injured physiological regions.

Question 2590

Topic: Pediatric Upper Extremity & Spine

A 25-year-old man sustains a C6 spinal cord injury. He has no motor function below the level of injury but has preserved pinprick sensation in the perianal area and voluntary anal contraction. How is his injury classified according to the ASIA Impairment Scale (AIS)?

. AIS A
. AIS B
. AIS C
. AIS D
. AIS E

Correct Answer & Explanation

. AIS B

Explanation

An ASIA B (sensory incomplete) injury is characterized by the preservation of sensory function (including sacral segments S4-S5) but no motor function below the neurological level of injury. The presence of perianal sensation and anal contraction confirms sacral sparing.

Question 2591

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl with adolescent idiopathic scoliosis (AIS) has a right main thoracic curve of 55 degrees and a left lumbar curve of 35 degrees. On lateral bending radiographs, the lumbar curve reduces to 15 degrees. According to the Lenke classification, what type of curve pattern is this?

. Lenke 1 (Main Thoracic)
. Lenke 2 (Double Thoracic)
. Lenke 3 (Double Major)
. Lenke 5 (Thoracolumbar/Lumbar)
. Lenke 6 (Thoracolumbar/Lumbar-Main Thoracic)

Correct Answer & Explanation

. Lenke 1 (Main Thoracic)

Explanation

A structural main thoracic curve with a non-structural lumbar curve (which bends out to less than 25 degrees) is classified as a Lenke 1 curve. This typically requires a selective thoracic fusion.

Question 2592

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl with adolescent idiopathic scoliosis has a primary right thoracic curve of 55 degrees and a left lumbar curve of 35 degrees. On lateral bending radiographs, the lumbar curve corrects to 15 degrees. According to the Lenke classification, what type of curve does she have?

. Type 1 (Main Thoracic)
. Type 2 (Double Thoracic)
. Type 3 (Double Major)
. Type 5 (Thoracolumbar/Lumbar)
. Type 6 (Thoracolumbar/Lumbar - Main Thoracic)

Correct Answer & Explanation

. Type 1 (Main Thoracic)

Explanation

This is a Lenke Type 1 (Main Thoracic) curve. The lumbar curve is nonstructural because it corrects to less than 25 degrees on lateral bending radiographs.

Question 2593

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl with adolescent idiopathic scoliosis presents with a right thoracic curve measuring 55 degrees on standing radiographs. Her Risser stage is 0 and she is pre-menarchal. What is the most appropriate management?

. Observation with radiographs every 6 months
. Full-time TLSO bracing
. Nighttime bending brace
. Posterior spinal fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Posterior spinal fusion

Explanation

Curves greater than 50 degrees in growing adolescents have a high risk of continued progression into adulthood and typically warrant surgical correction. Posterior spinal fusion is the standard of care for a progressive 55-degree curve in a Risser 0 patient.

Question 2594

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal female (Risser stage 0) presents for evaluation of a spinal deformity. Radiographs confirm adolescent idiopathic scoliosis with a primary right thoracic curve measuring 35 degrees. What is the most appropriate evidence-based management strategy for this patient?

. Observation with serial standing radiographs every 6 months until skeletal maturity
. Treatment with a full-time custom thoracolumbosacral orthosis (TLSO)
. Treatment with a nighttime-only bending brace
. Posterior spinal instrumentation and fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Treatment with a full-time custom thoracolumbosacral orthosis (TLSO)

Explanation

For a skeletally immature patient (Risser 0-2, premenarchal) with an adolescent idiopathic scoliosis curve measuring between 25 and 45 degrees, the standard of care to prevent progression to a surgical threshold is full-time bracing (TLSO).

Question 2595

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl is diagnosed with Adolescent Idiopathic Scoliosis (AIS). Her standing radiographs show a right thoracic curve of 55 degrees and a left lumbar curve of 35 degrees. On side-bending radiographs, the lumbar curve corrects to 15 degrees. According to the Lenke classification system, what type of curve pattern does she have?

. Type 1 (Main Thoracic)
. Type 2 (Double Thoracic)
. Type 3 (Double Major)
. Type 5 (Thoracolumbar/Lumbar)
. Type 6 (Thoracolumbar/Lumbar-Main Thoracic)

Correct Answer & Explanation

. Type 1 (Main Thoracic)

Explanation

The patient has a structural main thoracic curve (greater than 25 degrees on bending) and a non-structural lumbar curve (corrects to less than 25 degrees on bending). This classifies as a Lenke Type 1 curve.

Question 2596

Topic: Pediatric Upper Extremity & Spine

A 13-year-old girl presents with adolescent idiopathic scoliosis. She has a right thoracic curve of 55 degrees. She is Risser 0 and premenarchal. What is the most appropriate management?

. Observation with clinical follow-up in 6 months
. Part-time bracing (8 hours/day)
. Full-time bracing (18-23 hours/day)
. Posterior spinal fusion
. Anterior tethering surgery

Correct Answer & Explanation

. Posterior spinal fusion

Explanation

Bracing is typically indicated for curves between 25 and 45 degrees in growing children. For a curve of 55 degrees with significant remaining growth potential (Risser 0), surgical correction with posterior spinal fusion is indicated.

Question 2597

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl with adolescent idiopathic scoliosis (AIS) has a right thoracic curve of 55 degrees and a left lumbar curve of 35 degrees. On lateral bending radiographs, the thoracic curve corrects to 30 degrees, while the lumbar curve corrects to 15 degrees. According to the Lenke classification, what is her curve type?

. Type 1 (Main Thoracic)
. Type 2 (Double Thoracic)
. Type 3 (Double Major)
. Type 4 (Triple Major)
. Type 5 (Thoracolumbar/Lumbar)

Correct Answer & Explanation

. Type 1 (Main Thoracic)

Explanation

This is a Lenke Type 1 (Main Thoracic) curve. The lumbar curve is non-structural because it bends out to 25 degrees or less (in this case, 15 degrees) on side-bending radiographs.

Question 2598

Topic: Pediatric Upper Extremity & Spine

A 12-year-old premenarchal girl presents with a right thoracic curve measuring 32 degrees on standing posteroanterior radiographs. Her Risser stage is 0. What is the most appropriate management?

. Observation with follow-up radiographs in 1 year
. Physical therapy and core strengthening
. Full-time bracing with a thoracolumbosacral orthosis (TLSO)
. Posterior spinal fusion
. Anterior tethering procedure

Correct Answer & Explanation

. Full-time bracing with a thoracolumbosacral orthosis (TLSO)

Explanation

This patient is skeletally immature (premenarchal, Risser 0) and has an adolescent idiopathic scoliosis curve between 25 and 45 degrees. She is at high risk for progression, making her an ideal candidate for full-time TLSO bracing.

Question 2599

Topic: 4. Pediatrics
A 14-year-old boy sustains a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. Which of the following ligaments is responsible for avulsing this fragment?
. Anterior talofibular ligament
. Calcaneofibular ligament
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is an avulsion of the anterolateral distal tibial epiphysis. It is caused by the strong pull of the anterior inferior tibiofibular ligament (AITFL) occurring after the central and medial physis has already closed.

Question 2600

Topic: 4. Pediatrics
A 14-year-old boy sustains an ankle injury while skateboarding. Radiographs show a Salter-Harris III fracture of the anterolateral distal tibia. Which ligament is responsible for the avulsion of this specific fracture fragment?
. Anterior talofibular ligament (ATFL)
. Calcaneofibular ligament (CFL)
. Anterior inferior tibiofibular ligament (AITFL)
. Posterior inferior tibiofibular ligament (PITFL)
. Deltoid ligament

Correct Answer & Explanation

. Anterior inferior tibiofibular ligament (AITFL)

Explanation

A Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibia that occurs as the medial physis closes before the lateral physis. The anterior inferior tibiofibular ligament (AITFL) avulses the anterolateral fragment due to an external rotation force.

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