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4. Pediatrics MCQs

Practice Set 18 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 341

Topic: 4. Pediatrics

Congenital pseudarthrosis of the tibia (CPT) presents with anterolateral bowing of the tibia and subsequent fracture that fails to heal. This condition is most strongly associated with which underlying systemic disorder?

. Cleidocranial dysplasia
. Neurofibromatosis Type 1
. Marfan syndrome
. Achondroplasia
. Osteogenesis Imperfecta

Correct Answer & Explanation

. Neurofibromatosis Type 1

Explanation

Approximately 50% of children presenting with congenital pseudarthrosis of the tibia have an underlying diagnosis of Neurofibromatosis Type 1 (NF1).

Question 342

Topic: 4. Pediatrics

A 12-year-old elite baseball pitcher complains of vague shoulder pain during the late cocking phase of throwing. Radiographs demonstrate widening of the proximal humeral physis. What is the most appropriate initial management?

. Immediate percutaneous pinning
. Corticosteroid injection into the subacromial space
. Absolute rest from throwing for 3 months
. Aggressive physical therapy focusing on internal rotation
. Sling immobilization for 6 weeks

Correct Answer & Explanation

. Absolute rest from throwing for 3 months

Explanation

Little League Shoulder (proximal humeral epiphysiolysis) is a stress-related injury. The definitive initial treatment is absolute cessation of throwing (usually for 3 months) until symptoms resolve and radiographs normalize.

Question 343

Topic: Pediatric Hip

Which of the following clinical scenarios most strongly indicates the need for prophylactic in situ pinning of the contralateral hip in a patient presenting with unilateral Slipped Capital Femoral Epiphysis (SCFE)?

. Male gender, aged 13 years
. Patient with an underlying endocrine disorder (e.g., hypothyroidism)
. Body mass index > 95th percentile
. African American descent
. Presence of a stable, mild slip on the affected side

Correct Answer & Explanation

. Patient with an underlying endocrine disorder (e.g., hypothyroidism)

Explanation

Patients with underlying endocrinopathies, metabolic disorders, or those undergoing radiation therapy have an extremely high rate of bilateral SCFE (up to 100%), making prophylactic pinning of the contralateral hip highly recommended.

Question 344

Topic: 4. Pediatrics

What is the primary mechanism of injury leading to a medial epicondyle avulsion fracture in a pediatric patient?

. Direct blow to the medial aspect of the elbow
. Valgus stress with forceful contraction of the flexor-pronator mass
. Varus stress with forceful contraction of the extensor mass
. Hyperextension injury of the elbow
. Axial loading on a flexed elbow

Correct Answer & Explanation

. Valgus stress with forceful contraction of the flexor-pronator mass

Explanation

Medial epicondyle fractures typically result from an acute valgus stress coupled with a forceful contraction of the flexor-pronator muscle mass, often seen in throwing sports or falls on an outstretched hand.

Question 345

Topic: 4. Pediatrics
An 8-year-old boy with Legg-Calvé-Perthes disease presents with a painless limp. Which of the following radiographic findings is considered a Catterall "head-at-risk" sign, indicating a poorer prognosis?
. Medial subluxation of the femoral head
. Calcification lateral to the epiphysis (Gage sign)
. Widening of the medial joint space
. Intact lateral pillar
. Mild coxa magna

Correct Answer & Explanation

. Calcification lateral to the epiphysis (Gage sign)

Explanation

Gage's sign (a V-shaped radiolucency in the lateral portion of the epiphysis/metaphysis), lateral subluxation, horizontal physis, and diffuse metaphyseal cysts are classic Catterall "head-at-risk" signs that correlate with poor outcomes.

Question 346

Topic: Pediatric Hip

An obese 13-year-old boy presents with left knee pain and an antalgic gait. Radiographs demonstrate a displaced slipped capital femoral epiphysis (SCFE).

What is the most appropriate initial treatment for a stable, moderate SCFE?

. In situ single screw fixation
. Spica cast application
. Open reduction and internal fixation
. Proximal femoral osteotomy
. Closed reduction and pinning

Correct Answer & Explanation

. In situ single screw fixation

Explanation

In situ fixation with a single cannulated screw placed in the center of the epiphysis is the gold standard for stable SCFE to prevent further slip. Closed reduction increases the risk of avascular necrosis and should be avoided.

Question 347

Topic: Pediatric Hip

A 4-month-old female with developmental dysplasia of the hip is being treated with a Pavlik harness. During a follow-up visit, she is noted to have decreased active extension of the knee on the affected side. What is the most likely cause of this finding?

. Femoral nerve palsy due to excessive hyperflexion
. Sciatic nerve palsy from excessive abduction
. Obturator nerve palsy
. Avascular necrosis of the femoral head
. Patellar dislocation

Correct Answer & Explanation

. Femoral nerve palsy due to excessive hyperflexion

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment caused by excessive hip flexion. The harness should be adjusted or temporarily discontinued until nerve function recovers.

Question 348

Topic: 4. Pediatrics
A 3-year-old obese child presents with bilateral bowing of the lower extremities. Radiographs show prominent medial metaphyseal beaking and an abnormal metaphyseal-diaphyseal angle of 18 degrees. Which of the following is the most appropriate management?
. Observation with reassurance
. Knee-ankle-foot orthosis (KAFO) bracing
. Proximal tibial osteotomy
. Guided growth with tension band plates
. Calcium and vitamin D supplementation

Correct Answer & Explanation

. Knee-ankle-foot orthosis (KAFO) bracing

Explanation

For early-onset (infantile) Blount disease in a child under 4 years of age with Langenskiöld stage I-II, KAFO bracing is indicated. Surgery is reserved for older children, failure of bracing, or advanced stages.

Question 349

Topic: Pediatric Hip
An 8-year-old boy presents with a painless limp. Radiographs demonstrate fragmentation of the capital femoral epiphysis with lateral subluxation. According to the Herring lateral pillar classification, greater than 50% of the lateral pillar height is maintained. What is the classification and recommended treatment?
. Herring A; observation
. Herring B; containment surgery
. Herring C; containment surgery
. Herring B; spica cast
. Herring C; salvage osteotomy

Correct Answer & Explanation

. Herring B; containment surgery

Explanation

This describes a Herring B (lateral pillar >50% maintained) Legg-Calvé-Perthes disease. In children over 8 years old, containment surgery (e.g., femoral or pelvic osteotomy) yields significantly better outcomes than nonoperative treatment.

Question 350

Topic: Pediatric Lower Extremity

In the Ponseti method for treating idiopathic clubfoot, what is the correct sequence of deformity correction?

. Cavus, Adductus, Varus, Equinus
. Equinus, Varus, Adductus, Cavus
. Cavus, Varus, Adductus, Equinus
. Adductus, Cavus, Equinus, Varus
. Varus, Cavus, Adductus, Equinus

Correct Answer & Explanation

. Cavus, Varus, Adductus, Equinus

Explanation

The mnemonic CAVE dictates the sequence of correction in the Ponseti method: Cavus (elevating the first ray), Adductus, Varus, and finally Equinus (often requiring a percutaneous Achilles tenotomy).

Question 351

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal female (Risser 0) presents with adolescent idiopathic scoliosis. Standing PA radiographs reveal a right thoracic curve of 35 degrees. What is the most appropriate management?

. Observation and follow-up in 6 months
. Physical therapy and core strengthening
. TLSO bracing for 16-23 hours per day
. Posterior spinal fusion
. Anterior tethering

Correct Answer & Explanation

. TLSO bracing for 16-23 hours per day

Explanation

In a skeletally immature patient (Risser 0-2) with a curve between 25 and 45 degrees, full-time bracing (TLSO) is indicated to halt progression. Observation is primarily reserved for curves less than 25 degrees.

Question 352

Topic: Pediatric Lower Extremity

A newborn is diagnosed with fibular hemimelia. Which of the following associated anomalies is most consistently seen in this condition?

. Acetabular dysplasia
. Anteromedial tibial bowing
. Absent medial rays of the foot
. Tarsal coalition
. Cruciate ligament deficiency

Correct Answer & Explanation

. Cruciate ligament deficiency

Explanation

Fibular hemimelia is frequently associated with anterolateral tibial bowing, absent lateral rays, ball-and-socket ankle, and knee anomalies including anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) deficiency.

Question 353

Topic: 4. Pediatrics
A 2-year-old child presents with a congenital spinal deformity. Radiographs show a fully segmented hemivertebra at T8. Which of the following is the most appropriate next step in evaluation to rule out associated anomalies?
. Echocardiogram and renal ultrasound
. Brain MRI
. Upper extremity radiographs
. Lower extremity arterial Doppler
. Bone densitometry

Correct Answer & Explanation

. Echocardiogram and renal ultrasound

Explanation

Congenital scoliosis is highly associated with VACTERL anomalies. Cardiac (e.g., septal defects) and genitourinary anomalies (e.g., unilateral renal agenesis) must be evaluated using echocardiography and renal ultrasound.

Question 354

Topic: 4. Pediatrics

A 6-year-old boy with spastic quadriplegic cerebral palsy (GMFCS Level V) is evaluated for hip surveillance. AP pelvis radiograph reveals a migration percentage (Reimer's migration index) of 45% bilaterally. What is the most appropriate management?

. Observation and repeat radiographs in 1 year
. Adductor and psoas tenotomies
. Bilateral varus derotational femoral osteotomies (VDRO) with pelvic osteotomies
. Total hip arthroplasty
. Proximal femoral resection (Girdlestone)

Correct Answer & Explanation

. Bilateral varus derotational femoral osteotomies (VDRO) with pelvic osteotomies

Explanation

A migration percentage >40% in a child with spastic CP indicates significant subluxation requiring bony reconstruction. Soft tissue releases alone are insufficient; VDRO with or without pelvic osteotomy is the standard of care.

Question 355

Topic: 4. Pediatrics

A 14-year-old boy sustains an ankle injury. Radiographs reveal an intra-articular fracture of the anterolateral distal tibial epiphysis. This fracture pattern (Tillaux) occurs because of which of the following physeal closure sequences?

. Central, then anteromedial, then posterolateral
. Central, then posteromedial, then anterolateral
. Anterolateral, then central, then posteromedial
. Posterolateral, then central, then anteromedial
. Anteromedial, then posteromedial, then central

Correct Answer & Explanation

. Central, then anteromedial, then posterolateral

Explanation

The distal tibial physis closes from central to anteromedial to posteromedial, and finally anterolateral. The anterolateral portion remains open longest, making it susceptible to avulsion by the anterior inferior tibiofibular ligament.

Question 356

Topic: Pediatric Upper Extremity & Spine
A 6-year-old falls from monkey bars and sustains a widely displaced Gartland type III extension-type supracondylar humerus fracture. The hand is pink, but the radial pulse is absent. What is the immediate next step in management?
. Emergent open exploration of the brachial artery
. Urgent closed reduction and percutaneous pinning
. CT angiography of the upper extremity
. Fasciotomy of the forearm
. Application of a warm compress and elevation

Correct Answer & Explanation

. Urgent closed reduction and percutaneous pinning

Explanation

In a 'pink, pulseless' hand associated with a displaced supracondylar humerus fracture, the initial step is urgent closed reduction and percutaneous pinning. The pulse often returns after fracture reduction.

Question 357

Topic: 4. Pediatrics

A 4-year-old child presents with multiple long bone fractures after minimal trauma, blue sclerae, and dentinogenesis imperfecta.

Which of the following is the underlying genetic defect in the most common form of this condition?

. Defect in FGFR3
. Mutation in the COL1A1 or COL1A2 genes
. Mutation in the COMP gene
. Mutation in the Runx2 gene
. Defect in the EXT1 gene

Correct Answer & Explanation

. Mutation in the COL1A1 or COL1A2 genes

Explanation

Osteogenesis Imperfecta (OI) is most commonly caused by autosomal dominant mutations in the COL1A1 or COL1A2 genes. This leads to quantitative or qualitative defects in Type I collagen.

Question 358

Topic: Pediatric Hip

A 13-year-old obese male presents with acute on chronic left groin pain. Radiographs reveal a severe unstable slipped capital femoral epiphysis (SCFE). He undergoes in situ pinning. What is the most significant risk associated with an unstable SCFE compared to a stable one?

. Chondrolysis
. Avascular necrosis (AVN)
. Premature physeal closure
. Femoroacetabular impingement
. Slip progression

Correct Answer & Explanation

. Avascular necrosis (AVN)

Explanation

Unstable SCFE (defined as the inability to bear weight even with crutches) carries a much higher risk of AVN (up to 47%) compared to stable SCFE. Urgent decompression or careful positioning is debated, but AVN risk is definitively the most significant and devastating complication.

Question 359

Topic: 4. Pediatrics

An 8-week-old infant is being treated with a Pavlik harness for a dislocated left hip. During a follow-up visit, you notice the infant lacks active knee extension on the left side, though sensation appears intact. Which of the following is the most appropriate next step in management?

. Adjust the anterior straps to increase hip flexion
. Adjust the posterior straps to decrease hip abduction
. Discontinue the Pavlik harness immediately
. Continue the harness and schedule an EMG
. Switch to a rigid hip spica cast

Correct Answer & Explanation

. Discontinue the Pavlik harness immediately

Explanation

The infant has developed a femoral nerve palsy, a known complication of extreme hyperflexion in a Pavlik harness. The harness must be discontinued or significantly relaxed immediately to allow for neurologic recovery, which usually occurs within days to weeks.

Question 360

Topic: Pediatric Lower Extremity

A 2-week-old infant is undergoing Ponseti casting for idiopathic clubfoot. The deformity is being corrected sequentially. What is the final component of the clubfoot deformity to be corrected before application of the final cast?

. Cavus
. Adductus
. Varus
. Equinus
. Supination

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method corrects deformities in the specific order of CAVE (Cavus, Adductus, Varus, Equinus). Equinus is corrected last, frequently requiring a percutaneous Achilles tenotomy to achieve adequate dorsiflexion.

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