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4. Pediatrics MCQs

Practice Set 267 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 5321

Topic: 4. Pediatrics

An 8-year-old girl with cerebral palsy (GMFCS Level V) presents for routine follow-up. Her AP pelvis radiograph demonstrates a Reimers' migration percentage of 55% in the right hip. There is no evidence of advanced degenerative changes. What is the most appropriate management?

. Observation and serial radiographs in 6 months
. Botulinum toxin injections to the adductors
. Adductor tenotomy alone
. Varus derotational osteotomy (VDRO) of the proximal femur and pelvic osteotomy
. Proximal femoral resection arthroplasty

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) of the proximal femur and pelvic osteotomy

Explanation

A migration percentage over 50% in a spastic CP hip is highly unlikely to resolve with soft tissue releases alone. Bony reconstruction with a VDRO and concomitant pelvic osteotomy is the standard of care to achieve stable coverage.

Question 5322

Topic: Pediatric Hip

A 13-year-old boy with a BMI in the 95th percentile presents with 3 weeks of knee pain and a limp. Radiographs demonstrate a stable slipped capital femoral epiphysis (SCFE) of the left hip. He is treated with single in-situ cannulated screw fixation. Two months later, he complains of global restriction of hip motion and severe pain. Radiographs reveal diffuse joint space narrowing. Which of the following factors most significantly increases the risk of this specific complication?

. Unrecognized endocrine disorder
. Anterior positioning of the screw in the femoral head
. Unrecognized intra-articular screw penetration
. Use of a fully threaded screw
. Failure to perform a prophylactic pinning of the contralateral side

Correct Answer & Explanation

. Unrecognized intra-articular screw penetration

Explanation

Chondrolysis is characterized by diffuse joint space narrowing and stiffness after SCFE fixation. Unrecognized intra-articular hardware penetration is the most significant preventable risk factor.

Question 5323

Topic: 4. Pediatrics

An 18-month-old male infant presents with bilateral bowing of the lower extremities. Radiographs demonstrate a metaphyseal-diaphyseal angle (Drennan angle) of 18 degrees bilaterally, with lateral thrust during gait. Which of the following is the most appropriate initial management for this condition?

. Observation and reassurance
. High-dose Vitamin D supplementation
. Knee-ankle-foot orthoses (KAFOs)
. Proximal tibial valgus osteotomies
. Guided growth with tension band plates

Correct Answer & Explanation

. Knee-ankle-foot orthoses (KAFOs)

Explanation

A metaphyseal-diaphyseal angle greater than 16 degrees strongly indicates infantile Blount's disease rather than physiologic bowing. Initial management for children under age 3 involves bracing (KAFOs) to offload the medial physis.

Question 5324

Topic: 4. Pediatrics

A neonate is diagnosed with achondroplasia. Which of the following routine screening evaluations is most critical in the first year of life to prevent sudden death?

. Echocardiogram for structural heart defects
. Sleep study and cervical spine MRI to evaluate the foramen magnum
. Renal ultrasound for congenital anomalies
. Serial casting for associated clubfoot
. Thoracolumbar radiographs to monitor for kyphosis

Correct Answer & Explanation

. Sleep study and cervical spine MRI to evaluate the foramen magnum

Explanation

Infants with achondroplasia are at high risk for foramen magnum stenosis, which can cause cervicomedullary compression and central sleep apnea. Early screening with a polysomnogram and MRI is critical to identify those needing suboccipital decompression.

Question 5325

Topic: Pediatric Lower Extremity
A 4-year-old boy, initially treated for idiopathic clubfoot with the Ponseti method, presents with recurrent deformity. During gait analysis, he demonstrates dynamic supination of the foot during the swing phase. Passive range of motion is full and symmetric to the contralateral side. Which of the following is the most appropriate surgical management?
. Posterior medial release
. Split anterior tibial tendon transfer (SPLATT)
. Anterior tibial tendon transfer to the lateral cuneiform
. Extensor hallucis longus transfer to the first metatarsal neck (Jones procedure)
. Calcaneal sliding osteotomy

Correct Answer & Explanation

. Anterior tibial tendon transfer to the lateral cuneiform

Explanation

Dynamic supination during the swing phase in a recurrent clubfoot with supple passive ROM is a classic indication for a whole anterior tibial tendon transfer to the lateral cuneiform (or cuboid). This rebalances the foot without tethering the dynamic inversion forces.

Question 5326

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a completely displaced, extension-type supracondylar humerus fracture. On initial presentation, his hand is pulseless but pink, warm, and has a capillary refill time of 1.5 seconds. After successful closed reduction and percutaneous pinning, the radial pulse remains unpalpable, but the hand remains pink and warm with excellent capillary refill. What is the most appropriate next step in management?

. Immediate exploration of the brachial artery
. Vascular surgery consultation for an emergent angiogram
. Observation and hospital admission for close monitoring
. Immediate release of the anterior forearm fascia
. Removal of the pins and transition to open reduction

Correct Answer & Explanation

. Observation and hospital admission for close monitoring

Explanation

A 'pulseless but pink' hand after anatomic closed reduction and pinning of a supracondylar humerus fracture is an indication for observation. As long as perfusion is clinically adequate, collateral circulation is sufficient, and the pulse often returns within a few days.

Question 5327

Topic: Pediatric Hip

A 13-year-old boy undergoes in situ single-screw fixation for a stable, moderate Slipped Capital Femoral Epiphysis (SCFE). Six months later, he complains of increasing hip pain and profound global stiffness. Radiographs demonstrate concentric joint space narrowing of the affected hip without segmental collapse. What is the most likely etiology of this complication?

. Avascular necrosis secondary to retinacular vessel injury
. Failure of the implant to provide adequate stability
. Impingement of the femoral neck on the anterior acetabular rim
. Chondrolysis caused by unrecognized intra-articular pin penetration
. Septic arthritis introduced during the operative procedure

Correct Answer & Explanation

. Chondrolysis caused by unrecognized intra-articular pin penetration

Explanation

Chondrolysis in the setting of SCFE is strongly associated with unrecognized pin penetration into the joint space. It presents with progressive global stiffness, pain, and concentric joint space narrowing on radiographs.

Question 5328

Topic: Pediatric Hip

A 6-week-old female infant is currently being treated in a Pavlik harness for Developmental Dysplasia of the Hip (DDH). Her mother notes that the infant has stopped kicking her right leg over the past 24 hours. Physical examination reveals an absence of active knee extension on the right, but withdrawal to a needle prick remains intact. What is the most appropriate next step in management?

. Discontinue the Pavlik harness immediately to allow for neurologic recovery
. Adjust the anterior straps to increase hip flexion past 120 degrees
. Transition the patient immediately to a rigid abduction orthosis
. Order an urgent MRI of the lumbar spine
. Reassure the mother and continue the current harness settings

Correct Answer & Explanation

. Discontinue the Pavlik harness immediately to allow for neurologic recovery

Explanation

The patient is presenting with a femoral nerve palsy, the most common nerve injury associated with the Pavlik harness (often due to hyperflexion). The harness should be discontinued or modified significantly until active quadriceps function returns.

Question 5329

Topic: 4. Pediatrics

A 6-year-old girl with spastic diplegic cerebral palsy (GMFCS Level IV) is evaluated during routine hip surveillance. Her radiographs reveal a Reimers' migration percentage of 55% in the left hip with associated acetabular dysplasia. Under general anesthesia, the hip is easily reducible and abducts to 45 degrees. What is the most appropriate surgical intervention?

. Adductor and iliopsoas tenotomies alone
. Varus derotational osteotomy (VDRO) of the proximal femur alone
. Open reduction and capsulorrhaphy
. Pelvic osteotomy alone (e.g., Dega or San Diego)
. Concurrent proximal femur VDRO and pelvic osteotomy

Correct Answer & Explanation

. Concurrent proximal femur VDRO and pelvic osteotomy

Explanation

In children with CP and a migration percentage > 50% with associated acetabular dysplasia, soft tissue release alone is insufficient. Comprehensive reconstruction with both a proximal femoral VDRO and a volume-reducing pelvic osteotomy is indicated.

Question 5330

Topic: Pediatric Upper Extremity & Spine

A 12-year-old premenarchal female presents with Adolescent Idiopathic Scoliosis (AIS). Her standing PA spine radiograph reveals a right thoracic curve of 34 degrees. Her Risser stage is 0. According to the standard guidelines, what is the most appropriate management?

. Observation with repeat radiographs in 6 months
. Physical therapy focusing on core strengthening
. Thoracolumbosacral orthosis (TLSO) brace wear for 16-23 hours daily
. Posterior spinal fusion with pedicle screw instrumentation
. Anterior vertebral body tethering (AVBT)

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) brace wear for 16-23 hours daily

Explanation

Bracing is indicated for a growing child (Risser 0-2, premenarchal) with a scoliotic curve between 25 and 45 degrees. A TLSO worn for at least 16-18 hours per day is the standard of care to halt progression.

Question 5331

Topic: 4. Pediatrics

An infant is evaluated for short stature. Examination reveals rhizomelic shortening of the limbs, frontal bossing, midface hypoplasia, and a normal trunk length. Both parents are of average height. What is the genetic basis of this child's condition?

. A de novo mutation in the FGFR3 gene
. An autosomal recessive mutation in the COMP gene
. An autosomal dominant mutation in the COL1A1 gene
. An X-linked dominant mutation in the PHEX gene
. A chromosomal deletion at 15q11-q13

Correct Answer & Explanation

. A de novo mutation in the FGFR3 gene

Explanation

The child has classic features of achondroplasia. While achondroplasia is autosomal dominant, roughly 80% of cases occur via a de novo (spontaneous) mutation in the FGFR3 gene, explaining why both parents are of normal height.

Question 5332

Topic: 4. Pediatrics
A 14-year-old boy sustains an ankle injury while sliding into second base. Radiographs reveal a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis (Tillaux fracture). Which of the following best describes the physeal closure pattern that predisposes to this specific fracture pattern?
. Closure occurs from lateral to medial, leaving the medial physis vulnerable
. Closure occurs from anterior to posterior, leaving the posterior physis vulnerable
. Closure begins centrally, then posteromedially, and finally anterolaterally
. Closure begins peripherally and advances centrally
. Closure occurs simultaneously across the entire physis, but the anterolateral ligament is strongest

Correct Answer & Explanation

. Closure begins centrally, then posteromedially, and finally anterolaterally

Explanation

The distal tibial physis closes in an asymmetric pattern: central first, then anteromedial, then posteromedial, and finally the anterolateral portion. The open anterolateral physis is avulsed by the anterior inferior tibiofibular ligament (AITFL).

Question 5333

Topic: 4. Pediatrics

A 2-year-old girl is diagnosed with complete congenital absence of the fibula (Fibular Hemimelia). In addition to an equinovalgus foot deformity and significant limb length discrepancy, what is the most common associated anomaly within her ipsilateral knee?

. Medial collateral ligament absence
. Anterior cruciate ligament deficiency
. Congenital patellar dislocation
. Posterior cruciate ligament deficiency
. Bipartite patella

Correct Answer & Explanation

. Anterior cruciate ligament deficiency

Explanation

Fibular hemimelia is highly associated with a hypoplastic or absent anterior cruciate ligament (ACL), resulting in anteroposterior instability of the knee, as well as tarsal coalition and ball-and-socket ankle joints.

Question 5334

Topic: 4. Pediatrics
A 4-year-old girl presents with severe bilateral genu varum and an observable lateral thrust during gait. Radiographs show a sharply downsloping medial tibial metaphysis with an apparent bony bridge crossing the medial physis. According to the Langenskiöld classification, this corresponds to Stage IV Blount's disease. What is the most appropriate surgical intervention?
. Guided growth via lateral tension band plating
. Proximal tibial valgus producing osteotomy without physeal exploration
. Observation and long-leg bracing
. Resection of the medial physeal bar and concurrent proximal tibial valgus osteotomy
. Epiphysiodesis of the contralateral proximal tibia

Correct Answer & Explanation

. Resection of the medial physeal bar and concurrent proximal tibial valgus osteotomy

Explanation

In Langenskiöld Stage IV (or higher) infantile Blount's disease, a medial physeal bar has formed. Successful treatment requires both excision of the tethering bony bar (epiphyseolysis) and a corrective proximal tibial osteotomy.

Question 5335

Topic: Pediatric Hip

An 8-year-old boy with a BMI in the 50th percentile (normal weight) presents with a 2-month history of a left-sided limp and obligatory external rotation when the left hip is flexed. Radiographs confirm a slipped capital femoral epiphysis (SCFE). Given the patient's presentation, which of the following laboratory evaluations is most critical?

. Thyroid stimulating hormone (TSH) and free T4
. Complete blood count (CBC) and erythrocyte sedimentation rate (ESR)
. Rheumatoid factor (RF) and Anti-CCP antibodies
. Serum protein electrophoresis (SPEP)
. Hemoglobin A1c and fasting blood glucose

Correct Answer & Explanation

. Thyroid stimulating hormone (TSH) and free T4

Explanation

SCFE occurring in a child under the age of 10 or outside the typical demographic (non-obese) should raise high clinical suspicion for an underlying endocrine disorder, most commonly hypothyroidism or renal osteodystrophy.

Question 5336

Topic: 4. Pediatrics
A 3-year-old boy presents with marked anterolateral bowing of the right tibia. Radiographs demonstrate diaphyseal narrowing and an impending fracture at the apex of the deformity. Physical examination reveals six large café-au-lait macules on his trunk. What is the inheritance pattern of the most likely underlying syndrome?
. Autosomal recessive
. X-linked recessive
. Autosomal dominant
. Mitochondrial
. X-linked dominant

Correct Answer & Explanation

. Autosomal dominant

Explanation

The clinical picture is classic for congenital pseudarthrosis of the tibia (CPT) associated with Neurofibromatosis Type 1 (NF1). NF1 is inherited in an autosomal dominant pattern.

Question 5337

Topic: 4. Pediatrics

An 11-year-old boy sustains a completely displaced Salter-Harris II fracture of the distal femur. He is treated with anatomic closed reduction and percutaneous crossed pinning. Despite achieving an anatomic reduction, what is the most significant and frequent long-term complication associated with this specific injury?

. Nonunion of the metaphyseal fragment
. Avascular necrosis of the distal femoral epiphysis
. Chronic osteomyelitis
. Heterotopic ossification
. Physeal growth arrest leading to limb length discrepancy or angular deformity

Correct Answer & Explanation

. Physeal growth arrest leading to limb length discrepancy or angular deformity

Explanation

Distal femoral physeal fractures have a notoriously high rate of growth arrest (up to 50%), largely due to the undulating, highly complex anatomy of the physis, which sustains significant trauma even in Salter-Harris I and II patterns.

Question 5338

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease (LCPD). His radiographs demonstrate that the lateral pillar of the femoral head has maintained approximately 60% of its original height. When determining his long-term prognosis and likelihood of developing early osteoarthritis, which of the following is considered the most critical independent prognostic factor?
. His gender
. His age at the onset of symptoms
. His weight and body mass index
. The duration of symptoms prior to diagnosis
. The presence of a subchondral fracture line (Crescent sign)

Correct Answer & Explanation

. His age at the onset of symptoms

Explanation

In Legg-Calvé-Perthes disease, age at clinical onset is the most significant independent prognostic factor. Children diagnosed after the age of 8 typically have much poorer remodeling potential and clinical outcomes compared to younger children.

Question 5339

Topic: 4. Pediatrics

A 14-year-old elite baseball pitcher complains of vague, progressive right shoulder pain over the past 3 months. The pain is exacerbated by throwing. AP external rotation radiographs reveal a widened proximal humerus physis compared to the contralateral side. What is the primary pathophysiology underlying this condition?

. Avascular necrosis of the humeral head secondary to repeated microtrauma
. Traction apophysitis of the greater tuberosity
. Subacromial impingement of the supraspinatus tendon
. Stress fracture through the hypertrophic zone of the proximal humerus physis
. A SLAP tear leading to physeal instability

Correct Answer & Explanation

. Stress fracture through the hypertrophic zone of the proximal humerus physis

Explanation

The patient has 'Little League Shoulder', which is essentially a chronic stress fracture (epiphysiolysis) through the hypertrophic zone of the proximal humeral physis due to repetitive rotational and distraction forces.

Question 5340

Topic: 4. Pediatrics

A 2-month-old infant presents to the emergency department with a fresh femur fracture following a routine diaper change. Examination reveals blue sclerae, generalized osteopenia, and evidence of multiple healing rib fractures on radiographs. A diagnosis of Osteogenesis Imperfecta (OI) Type I is suspected. At the molecular level, this condition is primarily caused by a defect in which of the following?

. Aggrecan synthesis in the cartilage extracellular matrix
. Fibroblast growth factor receptor 3 (FGFR3)
. Production of Type I collagen (COL1A1 or COL1A2 genes)
. Type II collagen assembly
. Osteoclast apoptosis regulation via RANKL

Correct Answer & Explanation

. Production of Type I collagen (COL1A1 or COL1A2 genes)

Explanation

Osteogenesis Imperfecta is a genetic disorder of connective tissue caused primarily by qualitative or quantitative defects in Type I collagen, coded by the COL1A1 and COL1A2 genes.

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