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4. Pediatrics MCQs

Practice Set 177 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 3521

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for a dislocated left hip. After 4 weeks of strict full-time wear, ultrasound shows the hip remains persistently dislocated. What is the most severe complication of continuing the Pavlik harness in this scenario?

. Avascular necrosis of the femoral head
. Femoral nerve palsy
. Acetabular dysplasia
. Posterior acetabular wall damage
. Knee flexion contracture

Correct Answer & Explanation

. Posterior acetabular wall damage

Explanation

Prolonged use of a Pavlik harness in a persistently dislocated hip causes posterior acetabular wear ('Pavlik disease'). The harness should be discontinued after 3 to 4 weeks if reduction is not achieved.

Question 3522

Topic: Pediatric Lower Extremity

During the Ponseti method for the treatment of idiopathic clubfoot, what is the first component of the deformity that must be corrected?

. Equinus
. Hindfoot varus
. Forefoot adductus
. Midfoot cavus
. Forefoot pronation

Correct Answer & Explanation

. Midfoot cavus

Explanation

The CAVE acronym denotes the sequence of correction: Cavus, Adductus, Varus, Equinus. Cavus is corrected first by supinating the forefoot to align the first ray with the rest of the foot.

Question 3523

Topic: Pediatric Upper Extremity & Spine

A 5-year-old girl falls from monkey bars and sustains a widely displaced extension-type supracondylar humerus fracture. On examination, she cannot flex her thumb interphalangeal joint or index finger distal interphalangeal joint. What is the most likely injured nerve structure?

. Radial nerve
. Ulnar nerve
. Anterior interosseous nerve
. Posterior interosseous nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type supracondylar fractures. It innervates the flexor pollicis longus and the flexor digitorum profundus to the index finger.

Question 3524

Topic: Pediatric Hip
Which of the following is the most significant risk factor for a poor clinical outcome in Legg-Calvé-Perthes disease?
. Male gender
. Obesity
. Age at onset greater than 8 years
. Bilateral involvement
. Delayed bone age

Correct Answer & Explanation

. Age at onset greater than 8 years

Explanation

Age at onset is the single most important prognostic factor in Legg-Calvé-Perthes disease. Children older than 8 years have less remodeling potential and a higher risk of early osteoarthritis.

Question 3525

Topic: Pediatric Lower Extremity

A newborn boy is noted to have a shortened right lower extremity. Radiographs reveal an absent fibula, anterior bowing of the tibia, and an equinovalgus foot with three toes. What is the most common ankle anomaly associated with this condition?

. Tarsal coalition
. Ball-and-socket ankle joint
. Congenital vertical talus
. Clubfoot
. Pes planovalgus

Correct Answer & Explanation

. Ball-and-socket ankle joint

Explanation

Fibular hemimelia is classically associated with an absent lateral ray, an equinovalgus foot deformity, and a ball-and-socket ankle joint.

Question 3526

Topic: 4. Pediatrics

A 2-year-old child presents with anterior bowing of the left tibia. Radiographs show anterolateral bowing with narrowing of the medullary canal and cortical thickening. The parents report a family history of skin lesions. What is the most likely associated diagnosis?

. Osteogenesis imperfecta
. Neurofibromatosis type 1
. Achondroplasia
. Cleidocranial dysplasia
. McCune-Albright syndrome

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Anterolateral bowing of the tibia is characteristic of congenital pseudarthrosis of the tibia. This condition is strongly associated with Neurofibromatosis type 1.

Question 3527

Topic: 4. Pediatrics
A newborn infant presents with radial longitudinal deficiency (radial clubhand). The parents are counseled regarding associated systemic conditions. Which of the following congenital syndromes is NOT typically associated with this anomaly?
. TAR syndrome
. Holt-Oram syndrome
. VACTERL association
. Fanconi anemia
. Neurofibromatosis type 1

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Neurofibromatosis type 1 is not associated with radial clubhand. TAR, Holt-Oram, VACTERL, and Fanconi anemia are classically associated syndromes.

Question 3528

Topic: Pediatric Upper Extremity & Spine

A 12-year-old girl with adolescent idiopathic scoliosis presents with a right thoracic curve. She has not reached menarche and her Risser stage is 0. Her curve measures 35 degrees. What is the most appropriate management?

. Observation with serial radiographs every 6 months
. Physical therapy and core strengthening
. TLSO bracing
. Posterior spinal fusion
. Anterior tethering

Correct Answer & Explanation

. TLSO bracing

Explanation

In a skeletally immature patient (premenarchal, Risser 0-2) with a progressive curve between 25 and 45 degrees, bracing is the standard of care to prevent further progression.

Question 3529

Topic: 4. Pediatrics

An 8-year-old boy presents with a mass in the popliteal fossa. The mass is painless, transilluminates, and is most prominent with the knee fully extended. What is the most appropriate management for this condition?

. Immediate surgical excision
. Arthroscopic partial meniscectomy
. Aspiration and corticosteroid injection
. Observation and reassurance
. Oral antibiotics

Correct Answer & Explanation

. Observation and reassurance

Explanation

Pediatric popliteal (Baker's) cysts rarely communicate with the joint and almost never indicate intra-articular pathology. Observation and reassurance are indicated as they typically resolve spontaneously.

Question 3530

Topic: 4. Pediatrics

A 6-month-old girl is noted to have her head consistently tilted to the right and rotated to the left. A palpable mass is present in the right neck. What is the primary muscle involved in this condition?

. Trapezius
. Scalene
. Sternocleidomastoid
. Levator scapulae
. Splenius capitis

Correct Answer & Explanation

. Sternocleidomastoid

Explanation

Congenital muscular torticollis results from contracture of the sternocleidomastoid muscle. It presents with ipsilateral head tilt and contralateral rotation.

Question 3531

Topic: Pediatric Hip

A 12-year-old boy with a BMI in the 95th percentile undergoes in situ pinning of a left stable slipped capital femoral epiphysis (SCFE). Which of the following is the strongest clinical or radiographic predictor for determining the risk of a contralateral slip, warranting prophylactic pinning?

. Initial slip angle greater than 50 degrees
. Modified Oxford bone age corresponding to open triradiate cartilage
. Male sex and African American descent
. A decreased femoral neck-shaft angle (coxa vara)
. Duration of symptoms greater than 6 months prior to presentation

Correct Answer & Explanation

. Modified Oxford bone age corresponding to open triradiate cartilage

Explanation

The status of the triradiate cartilage (modified Oxford bone age) is the strongest predictor of bilateral SCFE. Patients with an open triradiate cartilage or younger chronological age (typically <10 years) are at the highest risk for developing a contralateral slip.

Question 3532

Topic: Pediatric Hip

A 5-week-old female with an irreducible developmental dysplasia of the hip (DDH) is treated with a Pavlik harness. At her 3-week ultrasound follow-up, the hip remains dislocated. What is the most appropriate next step in management?

. Continue the Pavlik harness for an additional 3 weeks
. Add a secondary abduction brace over the Pavlik harness
. Discontinue the Pavlik harness and perform a closed reduction and spica casting
. Immediate open reduction and capsulorrhaphy
. Administer Botulinum toxin to the hip adductors and resume the Pavlik harness

Correct Answer & Explanation

. Discontinue the Pavlik harness and perform a closed reduction and spica casting

Explanation

Failure to achieve reduction in a Pavlik harness after 3 to 4 weeks is an indication to abandon the harness to prevent 'Pavlik disease' (acetabular erosion) and transition to a closed reduction and spica casting, or alternatively, trial a rigid abduction orthosis.

Question 3533

Topic: Pediatric Hip

An 11-year-old girl with primary hypothyroidism presents with unilateral groin pain and a limp. Radiographs demonstrate a mild slipped capital femoral epiphysis (SCFE) of the symptomatic hip. What is the most appropriate management?

. Observe and prescribe non-weight-bearing with crutches
. In situ pinning of the symptomatic hip only
. In situ pinning of the symptomatic hip and prophylactic pinning of the contralateral hip
. Spica casting
. Open reduction and internal fixation of the symptomatic hip

Correct Answer & Explanation

. In situ pinning of the symptomatic hip and prophylactic pinning of the contralateral hip

Explanation

Patients with endocrine disorders, such as hypothyroidism, have a significantly higher risk of bilateral SCFE. Prophylactic pinning of the contralateral asymptomatic hip is strongly indicated to prevent subsequent displacement.

Question 3534

Topic: Pediatric Hip

A 5-month-old girl with developmental dysplasia of the hip (DDH) has been treated with a Pavlik harness for 4 weeks. Repeat ultrasound reveals an alpha angle of 45 degrees, and the hip remains persistently subluxated. What is the next most appropriate step in management?

. Observation
. Continue the Pavlik harness for 4 more weeks
. Transition to a rigid abduction orthosis or attempt closed reduction
. Open reduction and capsulorrhaphy
. Varus derotational osteotomy

Correct Answer & Explanation

. Transition to a rigid abduction orthosis or attempt closed reduction

Explanation

Continuing a Pavlik harness in an persistently dislocated or subluxated hip beyond 3 to 4 weeks risks 'Pavlik harness disease' (posterior acetabular wear). Transitioning to a rigid abduction orthosis (e.g., Rhino cruiser) or proceeding to closed reduction and spica casting is the standard next step.

Question 3535

Topic: Pediatric Hip
An 8-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Radiographs classify the hip as Lateral Pillar B/C. According to current evidence-based guidelines, which treatment yields the best radiographic outcome for this patient?
. Observation and protected weight-bearing
. A-frame bracing
. Surgical containment via femoral varus osteotomy or pelvic osteotomy
. Core decompression of the femoral head
. Hip arthrodesis

Correct Answer & Explanation

. Surgical containment via femoral varus osteotomy or pelvic osteotomy

Explanation

For children over the age of 8 with Lateral Pillar B or B/C involvement, surgical containment provides superior radiographic outcomes compared to nonoperative management. Osteotomies redirect the femoral head into the acetabulum to maintain sphericity during the healing phase.

Question 3536

Topic: Pediatric Lower Extremity

A 3-year-old boy previously treated with the Ponseti method for bilateral idiopathic clubfeet presents with a relapsed deformity. Gait evaluation reveals dynamic supination of the foot during the swing phase. What is the most appropriate surgical intervention?

. Split tibialis posterior tendon transfer
. Tibialis anterior tendon transfer to the lateral cuneiform
. Triple arthrodesis
. Achilles tendon lengthening alone
. Lateral column lengthening osteotomy

Correct Answer & Explanation

. Tibialis anterior tendon transfer to the lateral cuneiform

Explanation

Dynamic supination during the swing phase is a classic sign of relapsed clubfoot following Ponseti casting. Transferring the tibialis anterior tendon to the lateral cuneiform balances the foot and minimizes further relapse.

Question 3537

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy sustains an extension-type Gartland III supracondylar humerus fracture. Upon initial presentation, the hand is pink but pulseless. After anatomical closed reduction and percutaneous pinning, the hand remains pink and well-perfused, but the radial pulse remains absent. What is the next best step?
. Observe and admit for serial neurovascular examinations
. Remove the pins and attempt closed reduction again
. Immediate exploration of the brachial artery
. Perform a CT angiogram
. Administer a sympathetic nerve block

Correct Answer & Explanation

. Observe and admit for serial neurovascular examinations

Explanation

A pink, pulseless hand after an anatomic reduction of a supracondylar fracture indicates adequate collateral perfusion. The standard of care is close observation, as the pulse often returns spontaneously within 24 to 48 hours without the need for vascular exploration.

Question 3538

Topic: 4. Pediatrics

An 8-year-old girl with spastic diplegic cerebral palsy is evaluated for progressive hip subluxation. Pelvic radiographs show a migration percentage of 45% bilaterally. What is the recommended management?

. Observation and annual radiographs
. Botulinum toxin injections to the adductor muscles
. Bilateral adductor tenotomies
. Bilateral varus derotational osteotomies (VDRO)
. Selective dorsal rhizotomy

Correct Answer & Explanation

. Bilateral varus derotational osteotomies (VDRO)

Explanation

In children with spastic cerebral palsy, a hip migration percentage greater than 40% usually dictates bony reconstructive surgery. Bilateral varus derotational osteotomies (VDRO), often combined with pelvic osteotomies, provide the necessary correction to stabilize the hips.

Question 3539

Topic: Pediatric Upper Extremity & Spine

A 13-year-old premenarchal girl (Risser stage 0) is diagnosed with a right thoracic adolescent idiopathic scoliosis measuring 35 degrees on standing radiographs. What is the most appropriate initial management?

. Observation with radiographs in 6 months
. Physical therapy focusing on core strengthening
. Thoracolumbosacral orthosis (TLSO) bracing
. Posterior spinal fusion
. Anterior vertebral body tethering

Correct Answer & Explanation

. Thoracolumbosacral orthosis (TLSO) bracing

Explanation

TLSO bracing is indicated for skeletally immature patients (Risser 0-2) with adolescent idiopathic scoliosis curves between 25 and 45 degrees. Bracing effectively halts curve progression and reduces the need for surgical intervention when compliance is high.

Question 3540

Topic: 4. Pediatrics

An 18-month-old boy is evaluated for anterolateral bowing of the tibia. Radiographs demonstrate a sclerotic, narrowed tibial diaphysis consistent with impending congenital pseudarthrosis. Which systemic condition is most strongly associated with this finding?

. Osteogenesis imperfecta
. Fibrous dysplasia
. Neurofibromatosis type 1
. Achondroplasia
. Marfan syndrome

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Anterolateral bowing of the tibia and congenital pseudarthrosis of the tibia (CPT) are hallmark musculoskeletal manifestations of Neurofibromatosis type 1. This condition is caused by a mutation in the neurofibromin gene on chromosome 17.

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