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4. Pediatrics MCQs

Practice Set 240 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 4781

Topic: Pediatric Upper Extremity & Spine

A 13-year-old Risser 1 female presents with a right thoracic curve of 35 degrees. What is the most appropriate management?

. Observation with repeat radiographs in 6 months
. Physical therapy and core strengthening
. Part-time (nighttime only) bracing
. Full-time TLSO bracing (at least 18 hours/day)
. Posterior spinal fusion

Correct Answer & Explanation

. Observation with repeat radiographs in 6 months

Explanation

In a skeletally immature patient (Risser 0-2) with an AIS curve between 25 and 45 degrees, full-time bracing (TLSO) for 16-18+ hours per day is recommended to prevent curve progression.

Question 4782

Topic: 4. Pediatrics

A 6-year-old boy presents with a low posterior hairline, short webbed neck, and limited cervical range of motion. Radiographs show multiple fused cervical vertebrae. Which of the following systems is most crucial to evaluate in this patient?

. Cardiovascular system
. Gastrointestinal tract
. Genitourinary system
. Endocrine system
. Hematologic system

Correct Answer & Explanation

. Cardiovascular system

Explanation

Klippel-Feil syndrome is characterized by congenital fusion of cervical vertebrae. It is highly associated with congenital anomalies of the genitourinary system (up to 30%), most commonly unilateral renal agenesis. Therefore, a renal ultrasound is routinely recommended.

Question 4783

Topic: 4. Pediatrics

A 5-year-old boy presents with a short neck, low posterior hairline, and limited cervical range of motion. Radiographs reveal congenital fusion of the C3-C4 and C5-C6 vertebral bodies. Which of the following is the most appropriate next screening test to evaluate for commonly associated anomalies?

. Magnetic resonance imaging of the lumbar spine
. Renal ultrasound
. Computed tomography of the chest
. Genetic testing for FGFR3 mutation
. Erythrocyte sedimentation rate and C-reactive protein

Correct Answer & Explanation

. Magnetic resonance imaging of the lumbar spine

Explanation

This patient exhibits the classic clinical triad of Klippel-Feil syndrome. Because the condition results from abnormal development of mesodermal tissue during embryogenesis, it is highly associated with other systemic anomalies. Genitourinary anomalies (up to 30% of patients), particularly unilateral renal agenesis, are common, making a baseline renal ultrasound an essential screening step. Cardiovascular anomalies (e.g., VSD) and Sprengel deformity are also frequent.

Question 4784

Topic: Pediatric Upper Extremity & Spine

During correction of an adolescent idiopathic scoliosis deformity, there is a sudden and sustained loss of motor evoked potentials (MEPs) bilaterally, while somatosensory evoked potentials (SSEPs) remain at baseline. The patient's mean arterial pressure (MAP) is currently 85 mmHg. What is the most appropriate immediate step in management?

. Perform an immediate wake-up test before altering the surgical construct
. Increase the depth of inhalational anesthesia to reduce metabolic demand
. Administer high-dose intravenous methylprednisolone
. Release distraction and loosen the deformity correction immediately
. Continue the procedure as SSEP preservation ensures sensory tract viability

Correct Answer & Explanation

. Perform an immediate wake-up test before altering the surgical construct

Explanation

Isolated loss of MEPs with intact SSEPs suggests an anterior cord issue affecting the motor tracts, often due to mechanical stretch or ischemia. After informing the surgeon, optimizing hemodynamics (MAP > 85-90), and ensuring there is no technical/anesthetic failure, the immediate surgical step is to release the corrective distraction forces. Waiting to perform a wake-up test or continuing the procedure wastes critical time during which ischemic injury can become permanent.

Question 4785

Topic: Pediatric Upper Extremity & Spine

When applying the Lenke classification system for adolescent idiopathic scoliosis, a minor curve must be included in the surgical fusion construct if it is deemed 'structural'. What radiographic criterion defines a structural minor curve in the coronal plane?

. Cobb angle > 10 degrees on side-bending radiographs
. Cobb angle > 25 degrees on side-bending radiographs
. Cobb angle > 20 degrees on standing radiographs
. Apical vertebral translation > 2 cm
. Nash-Moe rotation > Grade 2

Correct Answer & Explanation

. Cobb angle > 10 degrees on side-bending radiographs

Explanation

In the Lenke classification, a minor curve is considered structural if it fails to bend out to less than 25 degrees on dynamic supine side-bending radiographs, or if there is kyphosis of at least +20 degrees across that region.

Question 4786

Topic: Pediatric Hip
A 45-year-old female with developmental dysplasia of the hip (DDH) presents for THA. Preoperative radiographs show the femoral head is subluxated, with 80% proximal migration relative to the height of the normal true acetabulum. Based on the Crowe classification, what type of dysplasia does she have?
. Crowe Type I
. Crowe Type II
. Crowe Type III
. Crowe Type IV
. Crowe Type V

Correct Answer & Explanation

. Crowe Type III

Explanation

The Crowe classification of DDH evaluates the degree of proximal migration of the femoral head: Type I: <50% subluxation; Type II: 50-75% subluxation; Type III: 75-100% subluxation; Type IV: >100% subluxation (complete dislocation). With 80% proximal migration, the patient falls into the Crowe Type III category.

Question 4787

Topic: Pediatric Hip
A 35-year-old female with developmental dysplasia of the hip (DDH) Crowe Type IV is undergoing THA. The surgeon plans to place the acetabular component in the true anatomic hip center. If the leg is lengthened >4 cm without a subtrochanteric shortening osteotomy, which nerve division is most susceptible to traction injury?
. Femoral nerve
. Obturator nerve
. Superior gluteal nerve
. Sciatic nerve (peroneal division)
. Sciatic nerve (tibial division)

Correct Answer & Explanation

. Sciatic nerve (peroneal division)

Explanation

Bringing the hip center down to the true anatomic acetabulum in Crowe IV DDH can cause significant limb lengthening. Lengthening >4 cm puts the sciatic nerve at high risk for a traction palsy. The peroneal division of the sciatic nerve is tethered at the fibular head and has less connective tissue support, making it much more susceptible to injury than the tibial division.

Question 4788

Topic: 4. Pediatrics

A 13-year-old elite baseball pitcher complains of insidious onset, activity-related pain in his throwing shoulder. Radiographs reveal widening of the proximal humeral physis. What is the recommended initial management?

. Arthroscopic SLAP repair
. Complete cessation of throwing for 3-6 months
. Open reduction and internal fixation
. Intra-articular corticosteroid injection
. Resection of the distal clavicle

Correct Answer & Explanation

. Arthroscopic SLAP repair

Explanation

'Little League Shoulder' is a proximal humeral epiphysiolysis caused by repetitive rotational stress across the open growth plate. It is an overuse injury. The absolute mainstay of treatment is complete rest from throwing (usually 3-6 months) until the pain fully resolves and radiographs show healing/closure of the physis.

Question 4789

Topic: 4. Pediatrics

A 13-year-old elite baseball pitcher presents with right shoulder pain when throwing. Radiographs demonstrate widening of the proximal humeral physis on the affected side compared to the contralateral side. What is the recommended initial management?

. Immobilization in a sling for 6 weeks
. Corticosteroid injection into the subacromial space
. Absolute rest from throwing for 3 months followed by a progressive throwing program
. Arthroscopic labral repair
. Percutaneous pinning of the proximal humerus

Correct Answer & Explanation

. Immobilization in a sling for 6 weeks

Explanation

The patient has "Little League shoulder," which is a stress injury (epiphysiolysis) to the proximal humeral physis caused by repetitive rotational stresses during throwing. The standard treatment is absolute rest from throwing for approximately 3 months, or until symptoms resolve and radiographs normalize, followed by a gradual and structured return-to-throwing program.

Question 4790

Topic: 4. Pediatrics

A 13-year-old male baseball pitcher complains of right shoulder pain during throwing. Radiographs demonstrate widening and lateral fragmentation of the proximal humeral physis. What is the most appropriate initial treatment?

. Immediate surgical pinning of the proximal humeral physis
. Corticosteroid injection into the subacromial space
. Absolute rest from throwing for 3 months followed by a progressive throwing program
. Physical therapy emphasizing aggressive stretching into external rotation
. Arthroscopic labral repair

Correct Answer & Explanation

. Immediate surgical pinning of the proximal humeral physis

Explanation

The patient has Little League Shoulder (proximal humeral epiphysiolysis), which is a stress injury to the proximal humeral physis caused by repetitive overhead throwing. The gold standard treatment is absolute rest from throwing (typically for 3 months) until symptoms resolve and imaging normalizes, followed by physical therapy and a structured return-to-throwing program.

Question 4791

Topic: 4. Pediatrics

A 13-year-old male baseball pitcher presents with generalized shoulder pain that occurs when throwing. Radiographs demonstrate widening and sclerosis of the proximal humeral physis. What is the most appropriate initial management for this condition?

. Immediate surgical pinning of the physis
. Corticosteroid injection into the glenohumeral joint
. Complete rest from throwing for 3 to 6 months
. Physical therapy focusing on immediate aggressive stretching of the posterior capsule
. MRI to prepare for arthroscopic labral repair

Correct Answer & Explanation

. Immediate surgical pinning of the physis

Explanation

The clinical and radiographic findings are diagnostic of Little Leaguer's Shoulder (proximal humeral epiphysiolysis), which is a Salter-Harris type I stress fracture of the proximal humeral physis due to repetitive rotational torque. The standard of care is complete cessation of throwing for 3 to 6 months until the physis heals and symptoms resolve, followed by a graduated throwing program.

Question 4792

Topic: 4. Pediatrics

What defines an 'unstable' slipped capital femoral epiphysis (SCFE) according to the Loder classification, and what is its primary prognostic significance?

. Inability to ambulate even with crutches; highest risk for osteonecrosis
. Slip angle greater than 50 degrees; highest risk for chondrolysis
. Symptom duration less than 3 weeks; highest risk for contralateral slip
. Disruption of the anterior physis on MRI; highest risk for premature physeal closure
. Joint effusion greater than 5mm on ultrasound; highest risk for septic arthritis

Correct Answer & Explanation

. Inability to ambulate even with crutches; highest risk for osteonecrosis

Explanation

The Loder classification divides SCFE into stable and unstable based on the patient's ability to bear weight. An unstable SCFE is defined by the inability to ambulate, even with the assistance of crutches. The primary prognostic significance of this classification is the high rate of osteonecrosis associated with unstable slips (up to 47%), compared to a nearly 0% rate in stable slips.

Question 4793

Topic: Pediatric Upper Extremity & Spine
A 6-year-old male sustains a Gartland type III supracondylar humerus fracture. On presentation, his hand is pink and warm, but the radial pulse is absent. After a successful closed reduction and percutaneous pinning, the hand remains pink and warm with brisk capillary refill, but the radial pulse remains unpalpable. What is the most appropriate next step in management?
. Immediate open exploration of the brachial artery
. Observation with close clinical monitoring for 24 to 48 hours
. Emergent CT angiography of the upper extremity
. Administration of intravenous heparin
. Prophylactic fasciotomy of the volar forearm

Correct Answer & Explanation

. Observation with close clinical monitoring for 24 to 48 hours

Explanation

The management of the 'pink, pulseless hand' following reduction of a supracondylar humerus fracture is a well-tested topic. If the hand remains well-perfused (pink, warm, capillary refill < 2 seconds) despite the absence of a palpable pulse, the collateral circulation is sufficient. The most appropriate next step is observation with close monitoring. Open vascular exploration or angiography is reserved for the 'white, pulseless hand' that remains dysvascular after fracture reduction.

Question 4794

Topic: Pediatric Upper Extremity & Spine

In the Lenke classification for adolescent idiopathic scoliosis, a proximal thoracic curve is defined as a 'structural' minor curve if its side-bending Cobb angle fails to correct below what threshold?

. 10 degrees
. 15 degrees
. 20 degrees
. 25 degrees
. 30 degrees

Correct Answer & Explanation

. 10 degrees

Explanation

The Lenke classification system dictates that a minor curve is considered 'structural' if the Cobb angle remains greater than or equal to 25 degrees on coronal side-bending radiographs. If it reduces to less than 25 degrees, it is considered nonstructural. For proximal thoracic curves, a T2-T5 kyphosis of >20 degrees is also a criterion for structural definition, but the coronal bending threshold is 25 degrees.

Question 4795

Topic: 4. Pediatrics

According to current cerebral palsy hip surveillance guidelines, what is the most critical radiographic metric used to dictate the need for surgical intervention to prevent hip dislocation, and at what threshold is the hip considered 'at risk' for displacement?

. Acetabular index greater than 25 degrees
. Reimers migration percentage greater than 30%
. Neck-shaft angle greater than 140 degrees
. Disruption of Shenton's line by more than 5mm
. Pelvic obliquity greater than 10 degrees

Correct Answer & Explanation

. Acetabular index greater than 25 degrees

Explanation

The Reimers migration percentage is the standard measurement used in hip surveillance for children with cerebral palsy. It measures the percentage of the femoral head extruded laterally past the edge of the acetabulum (Perkin's line). A migration percentage > 30% defines a hip that is 'subluxated' or at significant risk for progressive displacement, triggering closer surveillance and often soft-tissue or bony surgical intervention.

Question 4796

Topic: Pediatric Hip

A 13-year-old boy presents with an inability to bear weight on his right leg after a minor fall. Radiographs show a slipped capital femoral epiphysis (SCFE). He is unable to walk even with the assistance of crutches. What is the most significant prognostic factor for the subsequent development of avascular necrosis (AVN) in this patient?

. Degree of the slip angle on the lateral radiograph
. Patient age at the time of presentation
. Stability of the slip
. Delay to surgical intervention greater than 24 hours
. The specific method of surgical fixation utilized

Correct Answer & Explanation

. Degree of the slip angle on the lateral radiograph

Explanation

According to the Loder classification, an unstable SCFE is defined strictly by the patient's inability to bear weight, even with crutches. Unstable slips have a drastically higher rate of AVN (up to 47-50%) compared to stable slips, where the AVN rate approaches zero. While time to surgery is debated, stability is the most definitively proven prognostic factor for AVN.

Question 4797

Topic: Pediatric Hip

A 4-month-old girl is being treated for developmental dysplasia of the hip (DDH) with a Pavlik harness. At her 2-week follow-up, the parents note that she is no longer actively kicking her left leg. On examination, the infant lacks active knee extension on the left side, though distal perfusion and other movements are intact. What is the most appropriate next step in management?

. Continue the harness unchanged and order an MRI of the lumbar spine
. Adjust the harness straps to increase hip flexion beyond 120 degrees
. Discontinue the harness immediately to allow for spontaneous neurological recovery
. Transition the patient immediately to a rigid bilateral hip spica cast
. Perform an immediate closed reduction under general anesthesia

Correct Answer & Explanation

. Continue the harness unchanged and order an MRI of the lumbar spine

Explanation

The infant has developed a femoral nerve palsy, a known complication of Pavlik harness treatment, usually caused by excessive hip hyperflexion compressing the femoral nerve against the inguinal ligament. The standard of care is to immediately discontinue the harness to allow the nerve to recover, which usually occurs within days to weeks, before reassessing treatment options.

Question 4798

Topic: Pediatric Lower Extremity

When utilizing the Ponseti method for the serial casting and correction of idiopathic clubfoot (talipes equinovarus), which of the following sequences correctly represents the order in which the deformity components are addressed?

. Equinus -> Varus -> Adductus -> Cavus
. Cavus -> Adductus -> Varus -> Equinus
. Adductus -> Varus -> Cavus -> Equinus
. Varus -> Cavus -> Adductus -> Equinus
. Cavus -> Equinus -> Adductus -> Varus

Correct Answer & Explanation

. Equinus -> Varus -> Adductus -> Cavus

Explanation

The Ponseti method dictates correcting the components of a clubfoot in a strict sequence, classically remembered by the mnemonic CAVE: Cavus, Adductus, Varus, Equinus. The first step involves elevating the first ray to correct the cavus. Next, the forefoot adductus and hindfoot varus are corrected simultaneously by abducting the foot around the fixed talar head. Finally, the equinus is corrected, which often necessitates a percutaneous Achilles tenotomy.

Question 4799

Topic: Pediatric Hip

In a severe, stable slipped capital femoral epiphysis (SCFE) treated with in situ single screw fixation, what is the most significant consequence of unrecognized pin penetration into the anterior-superior quadrant of the joint?

. Avascular necrosis of the femoral head
. Chondrolysis
. Cam-type femoroacetabular impingement
. Femoral neck fracture
. Premature physeal closure

Correct Answer & Explanation

. Avascular necrosis of the femoral head

Explanation

Unrecognized intra-articular hardware penetration during SCFE pinning is the leading iatrogenic cause of chondrolysis. While avascular necrosis (AVN) is a devastating complication, it is more often associated with the initial severity/instability of the slip or aggressive attempted reduction rather than isolated pin penetration.

Question 4800

Topic: 4. Pediatrics

The Ponseti method for the conservative management of congenital talipes equinovarus (clubfoot) emphasizes a specific sequence of deformity correction during serial casting. What is the correct sequence of correction?

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

Correct Answer & Explanation

. Adductus, Varus, Cavus, Equinus

Explanation

The correct sequence of correction in the Ponseti method follows the acronym CAVE: Cavus (corrected by supinating the forefoot and elevating the first ray), Adductus, Varus (corrected together by abducting the midfoot with counter-pressure on the talar head), and finally Equinus (which often requires a percutaneous Achilles tenotomy).

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