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4. Pediatrics MCQs

Practice Set 109 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 2161

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a Gartland type III supracondylar humerus fracture. On initial presentation, his hand is 'pink and pulseless', with brisk capillary refill but an absent radial pulse. He is taken immediately to the operating room for closed reduction and percutaneous pinning. Post-operatively in the recovery room, his hand remains pink with brisk capillary refill, but the radial pulse remains absent. What is the most appropriate next step in management?
. Immediate removal of the pins and open reduction
. Perform a CT angiogram of the upper extremity
. Vascular exploration of the brachial artery
. Admission, elevation, and close clinical observation
. Prophylactic fasciotomies of the forearm

Correct Answer & Explanation

. Admission, elevation, and close clinical observation

Explanation

The management of a 'pink, pulseless' hand following a well-reduced and pinned pediatric supracondylar humerus fracture is admission and close clinical observation. Studies show that perfusion is adequate due to collateral circulation, and the radial pulse often returns within a few days as vasospasm resolves. Vascular exploration is strictly indicated if the hand becomes 'white and pulseless' (ischemic) after reduction.

Question 2162

Topic: Pediatric Upper Extremity & Spine

A 14-year-old girl is undergoing a posterior spinal fusion for a Lenke type 1A adolescent idiopathic scoliosis. During the rod rotation maneuver, motor evoked potentials (MEPs) drop by 80% bilaterally in the lower extremities, while somatosensory evoked potentials (SSEPs) remain at baseline. The anesthesiologist confirms that the mean arterial pressure (MAP) is currently 90 mmHg and no paralytics have been administered. What is the most appropriate immediate surgical step?

. Administer high-dose intravenous methylprednisolone
. Release all corrective forces and remove the rods
. Perform an immediate Stagnara wake-up test
. Wait 15 minutes to allow for neurological accommodation
. Perform a rapid multi-level laminectomy for decompression

Correct Answer & Explanation

. Release all corrective forces and remove the rods

Explanation

An isolated drop in MEPs indicates anterior spinal cord (motor tract) compromise. The standard protocol for intraoperative neuromonitoring changes is to first rule out anesthetic causes and optimize hemodynamics (maintaining MAP > 85 mmHg). Since the MAP is already optimized and no paralytics were given, the most appropriate immediate surgical step is to undo the mechanical maneuver that caused the deficit, which involves releasing corrective forces and removing the rods.

Question 2163

Topic: 4. Pediatrics

A 3-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At the two-week follow-up, the mother reports the infant has stopped kicking her left leg. Examination reveals absent active hip and knee flexion on the left, but ankle and toe movements remain completely intact. What is the most likely iatrogenic cause of this presentation?

. Ischemic necrosis of the proximal femoral epiphysis
. Superior gluteal nerve palsy due to hyperabduction
. Femoral nerve palsy due to hyperflexion of the hip in the harness
. Sciatic nerve stretch injury
. Development of a septic hip joint

Correct Answer & Explanation

. Femoral nerve palsy due to hyperflexion of the hip in the harness

Explanation

Femoral nerve palsy is a known, reversible complication of Pavlik harness treatment. It is caused by extreme hyperflexion of the hip, compressing the femoral nerve against the inguinal ligament or the rim of the pelvis. The child will present with absent active knee extension and hip flexion, but preserved distal function. Treatment consists of adjusting the harness to decrease flexion or temporarily discontinuing it until function returns.

Question 2164

Topic: Pediatric Hip

A 9-year-old girl presents with left groin pain and a limp. Examination reveals obligate external rotation of the left hip during passive flexion. Radiographs confirm a severe left slipped capital femoral epiphysis (SCFE). Which of the following patient factors represents the strongest recognized indication for prophylactic in-situ pinning of her contralateral, asymptomatic right hip?

. Body Mass Index >95th percentile
. Female gender
. Underlying endocrine disorder (e.g., hypothyroidism)
. Age older than 12 years
. Presence of a positive Drehmann sign

Correct Answer & Explanation

. Underlying endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly indicated in patients with underlying endocrine or systemic disorders (e.g., hypothyroidism, growth hormone deficiency, renal osteodystrophy) because they have an exceedingly high risk (up to 100%) of developing bilateral disease. Other strong indications include prior therapeutic pelvic radiation and distinctly young age at presentation (males < 10, females < 8).

Question 2165

Topic: Pediatric Hip

In a 7-year-old boy diagnosed with Legg-Calve-Perthes disease, radiographs demonstrate that the lateral pillar of the femoral head maintains 65% of its original height. According to the Herring Lateral Pillar Classification, which group does this represent?

. Group A
. Group B
. Group B/C
. Group C
. Group D

Correct Answer & Explanation

. Group B

Explanation

According to the Herring Lateral Pillar Classification: Group A has no loss of lateral pillar height. Group B maintains >50% lateral pillar height. Group B/C is a border group at exactly or near 50%. Group C maintains <50% lateral pillar height. 65% falls squarely into Group B.

Question 2166

Topic: 4. Pediatrics

Congenital pseudarthrosis of the tibia (CPT) classically presents with anterolateral bowing of the tibia and subsequent fracture. Which systemic condition is most strongly associated with CPT?

. Marfan syndrome
. Ehlers-Danlos syndrome
. Neurofibromatosis type 1
. Osteogenesis imperfecta
. Achondroplasia

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Over 50% of patients with Congenital Pseudarthrosis of the Tibia (CPT) have Neurofibromatosis type 1 (NF-1). The classic deformity is anterolateral bowing, which differs from the posteromedial bowing often seen with calcaneovalgus foot deformities, or the anterolateral bowing in osteogenesis imperfecta.

Question 2167

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents to the emergency department after falling off monkey bars. Radiographs demonstrate a completely displaced, extension-type supracondylar humerus fracture with no bony contact between the proximal and distal fragments. Upon closed reduction in the operating room, the surgeon notes the medial periosteal hinge is intact. According to the Gartland classification, what type of fracture is this?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type III

Explanation

Gartland Classification: Type I = non-displaced. Type II = displaced with intact posterior cortex. Type III = completely displaced with no cortical contact (though a medial or lateral periosteal hinge may remain intact, dictating displacement direction). Type IV = complete multidirectional instability due to complete periosteal disruption (diagnosed intraoperatively).

Question 2168

Topic: 4. Pediatrics
A 14-year-old boy presents with an ankle injury after falling while skateboarding. Radiographs show a Salter-Harris III fracture of the anterolateral distal tibia. What is the mechanism of injury and the deforming force acting on this fracture fragment?
. External rotation; Anterior inferior tibiofibular ligament (AITFL)
. Internal rotation; Posterior inferior tibiofibular ligament (PITFL)
. Inversion; Calcaneofibular ligament (CFL)
. External rotation; Deltoid ligament
. Plantarflexion; Anterior talofibular ligament (ATFL)

Correct Answer & Explanation

. External rotation; Anterior inferior tibiofibular ligament (AITFL)

Explanation

A juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibia. It occurs due to an external rotation force. The fragment is avulsed by the anterior inferior tibiofibular ligament (AITFL). This happens because the distal tibial physis closes central, then medial, and finally lateral, leaving the lateral portion susceptible in adolescence.

Question 2169

Topic: Pediatric Hip

A 6-week-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). The parents report that the child has stopped kicking the affected leg. On examination, the knee lacks active extension, but ankle motion is intact. What is the most likely cause?

. Obturator nerve palsy due to excessive abduction
. Femoral nerve palsy due to excessive hyperflexion
. Sciatic nerve palsy due to excessive extension
. Common peroneal nerve palsy due to strap compression
. Avascular necrosis of the femoral head

Correct Answer & Explanation

. Femoral nerve palsy due to excessive hyperflexion

Explanation

Femoral nerve palsy is a known complication of the Pavlik harness, typically caused by excessive hyperflexion of the hips, which compresses the femoral nerve against the inguinal ligament. It presents with absent active knee extension. The harness should be adjusted or temporarily discontinued.

Question 2170

Topic: Pediatric Hip

A 12-year-old boy presents with a left-sided Slipped Capital Femoral Epiphysis (SCFE) and undergoes in situ pinning. Prophylactic pinning of the contralateral right hip is most strongly indicated in which of the following scenarios?

. The patient has an underlying endocrine disorder, such as hypothyroidism.
. The patient is classified as having a severe slip (>50 degrees) on the left.
. The patient is an obese male with no other comorbidities.
. The patient is older than 14 years of age at presentation.
. The slip is acute rather than chronic.

Correct Answer & Explanation

. The patient has an underlying endocrine disorder, such as hypothyroidism.

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly controversial but is strongly indicated in patients with a high risk of bilateral disease. The highest risk group includes patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy, growth hormone deficiency) or those undergoing prior radiation therapy, as the risk of contralateral slip can approach 100%. Age < 10 or > 16 is also higher risk, but endocrine disorder is the strongest absolute indication.

Question 2171

Topic: Pediatric Hip

An infant with developmental dysplasia of the hip (DDH) is placed in a Pavlik harness. Hyperflexion of the hips beyond 120 degrees in the harness is most commonly associated with which of the following complications?

. Avascular necrosis of the femoral head
. Inferior dislocation of the hip
. Femoral nerve palsy
. Obturator nerve palsy
. Sciatic nerve palsy

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Hyperflexion of the hip in a Pavlik harness risks compression of the femoral nerve against the inguinal ligament, leading to femoral nerve palsy. Excessive abduction, on the other hand, significantly increases the risk of avascular necrosis of the femoral head.

Question 2172

Topic: Pediatric Hip

Prophylactic pinning of the contralateral asymptomatic hip in a patient with a unilateral Slipped Capital Femoral Epiphysis (SCFE) is most strongly indicated in which of the following scenarios?

. A 13-year-old obese male with an acute-on-chronic slip
. A 12-year-old female with a mild idiopathic slip
. A 14-year-old male with a history of minor hip trauma
. A 9-year-old male with panhypopituitarism and a slip angle of 40 degrees
. A 15-year-old athlete with a stable unilateral slip

Correct Answer & Explanation

. A 9-year-old male with panhypopituitarism and a slip angle of 40 degrees

Explanation

Prophylactic pinning of the contralateral hip is indicated in patients at high risk for a subsequent contralateral slip. Risk factors include underlying endocrine disorders (e.g., panhypopituitarism, hypothyroidism, renal osteodystrophy), prior radiation therapy, and atypical age of presentation (younger than 10 or older than 16 years).

Question 2173

Topic: 4. Pediatrics

In the Ponseti method for the treatment of congenital idiopathic clubfoot, the sequence of correction of the deformities is strictly protocolized. Which deformity is corrected last, and how is it typically addressed?

. Cavus, treated by elevating the first ray
. Varus, treated by lateral pressure on the cuboid
. Adductus, treated by external rotation of the foot
. Equinus, treated by a percutaneous Achilles tenotomy
. Supination, treated by pronation of the forefoot

Correct Answer & Explanation

. Equinus, treated by a percutaneous Achilles tenotomy

Explanation

The acronym CAVE dictates the specific order of correction in the Ponseti method: Cavus, Adductus, Varus, and Equinus. Equinus is the final deformity to be corrected. Because the Achilles tendon is typically very tight and thick, correction usually requires a percutaneous Achilles tenotomy before the final cast is applied.

Question 2174

Topic: Pediatric Hip

An 11-year-old girl with renal osteodystrophy presents with a symptomatic left slipped capital femoral epiphysis (SCFE). Radiographs confirm a moderate slipped epiphysis on the left. The right hip is currently asymptomatic and radiographically normal. What is the most appropriate management of the right hip?

. Observation with clinical follow-up every 6 months
. Prophylactic in situ pinning
. Bilateral spica cast application
. MRI of the right hip to rule out pre-slip
. Wait for closure of the triradiate cartilage before intervening

Correct Answer & Explanation

. Prophylactic in situ pinning

Explanation

Prophylactic pinning of the contralateral asymptomatic hip is highly recommended in patients with endocrine or metabolic disorders (e.g., hypothyroidism, renal osteodystrophy) and those who have undergone previous pelvic radiation, due to an exceedingly high risk (approaching 50-100%) of developing a subsequent slip.

Question 2175

Topic: Pediatric Hip

An 18-month-old girl presents with a painless limp. Examination reveals a positive Galeazzi sign and asymmetric thigh folds. Radiographs confirm a completely dislocated left hip with an acetabular index of 38 degrees. What is the most appropriate next step in management?

. Pavlik harness application
. Closed reduction and spica casting
. Open reduction, pelvic osteotomy, and spica casting
. Observation until age 3, then varus derotational osteotomy
. Abduction bracing for 6 months

Correct Answer & Explanation

. Open reduction, pelvic osteotomy, and spica casting

Explanation

In a child aged 18 months or older with Developmental Dysplasia of the Hip (DDH), conservative measures usually fail. Because there is significant acetabular dysplasia (acetabular index of 38 degrees), open reduction combined with a pelvic osteotomy (e.g., Salter or Pemberton) is necessary to improve anterolateral coverage, followed by spica casting.

Question 2176

Topic: Pediatric Hip

A 12-year-old girl is diagnosed with a unilateral slipped capital femoral epiphysis (SCFE) of the left hip. The parents inquire about the risk to the contralateral, currently asymptomatic right hip. Which of the following patient factors is the strongest predictor of a future contralateral slip and represents the best indication for prophylactic in-situ pinning?

. Female gender
. Open triradiate cartilage
. Presentation with acute-on-chronic SCFE
. Obesity (BMI > 95th percentile)
. Patient age older than 14 years

Correct Answer & Explanation

. Open triradiate cartilage

Explanation

The risk of developing a contralateral SCFE is closely linked to skeletal immaturity. An open triradiate cartilage is a well-established and powerful radiographic marker of significant remaining skeletal growth and is one of the strongest predictors for the development of a subsequent contralateral slip. A modified Oxford Bone Age score can also be utilized. While obesity is a risk factor for initial SCFE, bone age/skeletal maturity (e.g., open triradiate cartilage) is the specific metric most heavily weighed when deciding on prophylactic pinning.

Question 2177

Topic: Pediatric Lower Extremity

The Ponseti method is the gold standard for the treatment of idiopathic clubfoot (talipes equinovarus). The deformity is corrected through a series of specific manipulations and serial casting. According to the strictly defined Ponseti protocol, what is the very first component of the deformity that must be addressed and corrected during the first cast?

. Cavus
. Adduction
. Varus
. Equinus
. Supination

Correct Answer & Explanation

. Cavus

Explanation

The Ponseti method follows a precise order of correction, often remembered by the acronym CAVE: Cavus, Adduction, Varus, Equinus. The very first step involves correcting the cavus deformity, which is driven by a pronated forefoot relative to the hindfoot. To correct the cavus, the first metatarsal must be elevated (supinating the forefoot) to align it with the midfoot and hindfoot, establishing a normal longitudinal arch before the rest of the deformities are swung outwards.

Question 2178

Topic: Pediatric Hip

Which of the following patients diagnosed with a unilateral slipped capital femoral epiphysis (SCFE) is most strongly indicated for prophylactic in situ pinning of the contralateral asymptomatic hip?

. A 12-year-old boy with a BMI in the 85th percentile
. A 10-year-old boy with primary hypothyroidism
. A 14-year-old boy with a positive family history of SCFE
. A 13-year-old girl with an acute-on-chronic SCFE
. A 15-year-old boy with a posterior sloping angle of 10 degrees

Correct Answer & Explanation

. A 10-year-old boy with primary hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended for patients with underlying endocrine disorders (e.g., hypothyroidism, renal osteodystrophy, growth hormone deficiency) and for patients presenting at a very young age (males <12 years, females <10 years). These patients have a significantly increased risk of developing bilateral disease.

Question 2179

Topic: Pediatric Hip

A 3-month-old female with developmental dysplasia of the hip (DDH) is being treated with a Pavlik harness. During a follow-up, the parents report she has stopped kicking her leg on the treated side. On examination, the hip is hyperflexed beyond 120 degrees in the harness, and active knee extension is absent. Which nerve is most likely affected?

. Sciatic nerve
. Obturator nerve
. Femoral nerve
. Superior gluteal nerve
. Lateral femoral cutaneous nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

Femoral nerve palsy is the most common nerve injury associated with Pavlik harness treatment for DDH. It is typically iatrogenic, caused by hyperflexion of the hip (usually >120 degrees), which dynamically compresses the femoral nerve against the inguinal ligament or the brim of the pelvis. Clinically, it presents with a loss of active knee extension (decreased kicking). Treatment involves immediate temporary removal or adjustment of the harness flexion straps.

Question 2180

Topic: Pediatric Hip

A 12-year-old boy presents with left hip pain and an obligate external rotation during passive hip flexion. Radiographs confirm a left Slipped Capital Femoral Epiphysis (SCFE). Under which of the following conditions is prophylactic pinning of the asymptomatic contralateral hip most strongly indicated?

. Open triradiate cartilage at the time of presentation
. History of an underlying endocrine disorder
. Male gender and age greater than 14 years
. High body mass index (> 95th percentile) as an isolated risk factor
. Presence of a type II physeal configuration on lateral radiograph

Correct Answer & Explanation

. History of an underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended for patients with underlying endocrine disorders (such as hypothyroidism, panhypopituitarism, or renal osteodystrophy) or those who have undergone previous pelvic radiation. These patients have a significantly higher risk of developing bilateral disease compared to idiopathic cases.

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