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4. Pediatrics MCQs

Practice Set 13 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 241

Topic: 4. Pediatrics

A 4-year-old child with achondroplasia presents with progressively declining motor milestones, hyperreflexia, and sleep apnea. What is the most critical next step in evaluation?

. MRI of the cervical spine and foramen magnum
. Radiographs of the thoracolumbar spine
. Sleep study to assess for adenotonsillar hypertrophy
. Genetic testing for FGFR3 mutation
. Referral for growth hormone therapy

Correct Answer & Explanation

. MRI of the cervical spine and foramen magnum

Explanation

Infants and young children with achondroplasia are at risk for foramen magnum stenosis. This can cause cervicomedullary compression leading to sleep apnea, hyperreflexia, and sudden death, necessitating urgent MRI evaluation for potential decompression.

Question 242

Topic: 4. Pediatrics

A 5-year-old child presents with disproportionate short stature, a waddling gait, and ligamentous laxity. The facial features are completely normal. Radiographs reveal delayed ossification of the epiphyses and irregular metaphyses. A mutation in which gene is most likely responsible?

. FGFR3
. COMP
. COL2A1
. FLNB
. DTDST

Correct Answer & Explanation

. COMP

Explanation

Pseudoachondroplasia is caused by a mutation in the Cartilage Oligomeric Matrix Protein (COMP) gene. Unlike achondroplasia, patients have normal facial features and head circumference, but present with severe dwarfism, joint laxity, and early-onset osteoarthritis.

Question 243

Topic: 4. Pediatrics
A 4-year-old child with multiple café-au-lait spots and axillary freckling presents with progressive anterolateral bowing of the tibia. Radiographs show a narrowing of the tibial diaphysis with a cystic lesion. Which of the following treatments has the highest success rate if a pseudarthrosis develops?
. Casting and observation
. Excision of the pseudarthrosis and intramedullary rodding with bone grafting
. Electrical bone stimulation
. Vascularized fibular graft
. Syme amputation

Correct Answer & Explanation

. Excision of the pseudarthrosis and intramedullary rodding with bone grafting

Explanation

Congenital pseudarthrosis of the tibia is highly associated with neurofibromatosis type 1. The standard surgical treatment with the highest union rate involves complete excision of the hamartomatous tissue, intramedullary rodding, and robust autogenous bone grafting.

Question 244

Topic: Pediatric Hip

A 13-year-old obese boy presents with thigh pain and obligatory external rotation with hip flexion. He is diagnosed with a slipped capital femoral epiphysis (SCFE). Which of the following is an absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

. Age greater than 14 years
. Underlying endocrine disorder
. Body mass index above the 95th percentile
. Female gender
. Severe initial slip angle

Correct Answer & Explanation

. Underlying endocrine disorder

Explanation

Prophylactic pinning of the contralateral hip in SCFE is strongly recommended for patients with an underlying endocrine disorder (e.g., hypothyroidism, renal osteodystrophy) due to the very high risk of bilateral involvement. Age less than 10 or open triradiate cartilage are also considered risk factors for bilateral slips.

Question 245

Topic: 4. Pediatrics
A 3-year-old child presents with progressive bilateral genu varum. Radiographs demonstrate changes consistent with Langenskiöld stage III Blount's disease. The primary pathophysiology of infantile Blount's disease involves which of the following?
. Dysfunction and growth suppression of the posteromedial proximal tibial physis
. Overgrowth of the lateral tibial physis
. Premature closure of the distal femoral physis
. Pathologic laxity of the lateral collateral ligament
. Primary fibular overgrowth

Correct Answer & Explanation

. Dysfunction and growth suppression of the posteromedial proximal tibial physis

Explanation

Infantile tibia vara (Blount's disease) is characterized by a growth disturbance of the posteromedial aspect of the proximal tibial physis, leading to progressive varus, flexion, and internal rotation deformities. This is largely secondary to excessive mechanical compressive forces (Heuter-Volkmann principle).

Question 246

Topic: 4. Pediatrics
A 6-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following radiographic findings is recognized as a 'head-at-risk' sign indicating a poorer prognosis and risk for hinge abduction?
. Medial subluxation of the femoral head
. Gage sign
. Intact lateral pillar
. Medial metaphyseal cysts
. Delayed bone age

Correct Answer & Explanation

. Gage sign

Explanation

Catterall's 'head-at-risk' signs include the Gage sign (a V-shaped radiolucency in the lateral portion of the epiphysis and adjacent metaphysis), lateral calcification, lateral subluxation, horizontal physis, and metaphyseal cysts. These imply a poorer prognosis and risk of deformity.

Question 247

Topic: 4. Pediatrics

A 2-week-old infant is being evaluated for developmental dysplasia of the hip (DDH). In which of the following clinical scenarios is the use of a Pavlik harness strictly contraindicated?

. Typical DDH in a 4-week-old infant
. Teratologic hip dislocation in a child with arthrogryposis multiplex congenita
. A bilaterally Barlow-positive examination
. An Ortolani-positive hip in an otherwise healthy newborn
. A dislocated hip that reduces easily with gentle abduction

Correct Answer & Explanation

. Teratologic hip dislocation in a child with arthrogryposis multiplex congenita

Explanation

The Pavlik harness relies on active hip motion and normal muscle tone to achieve and maintain reduction. It is contraindicated in rigid teratologic dislocations, such as those associated with arthrogryposis or spina bifida, which typically require surgical intervention.

Question 248

Topic: Pediatric Lower Extremity

A newborn is noted to have a shortened leg, anterior bowing of the tibia, and an absent lateral ray of the foot.

Radiographs confirm fibular hemimelia. Which of the following knee conditions is most commonly associated with this anomaly?

. Absent anterior cruciate ligament
. Patella alta
. Medial collateral ligament deficiency
. Congenital patellar dislocation
. Bipartite patella

Correct Answer & Explanation

. Absent anterior cruciate ligament

Explanation

Fibular hemimelia is frequently associated with knee instability, most notably an absent or hypoplastic anterior cruciate ligament (ACL). Other associations include ball-and-socket ankle joint and tarsal coalitions.

Question 249

Topic: 4. Pediatrics

A 7-year-old boy with spastic diplegic cerebral palsy has progressive hip pain. AP pelvis radiograph demonstrates a migration percentage of 55%. What is the most appropriate definitive management?

. Observation and repeat radiographs in 6 months
. Bilateral adductor tenotomies
. Varus derotational osteotomy (VDRO) and pelvic osteotomy
. Proximal femoral resection
. Total hip arthroplasty

Correct Answer & Explanation

. Varus derotational osteotomy (VDRO) and pelvic osteotomy

Explanation

In a child with cerebral palsy, a migration percentage >50% generally represents a true dislocation or severe subluxation that will not respond to soft tissue release alone. Bony reconstruction with a varus derotational osteotomy (VDRO) and concurrent pelvic osteotomy (e.g., Dega or San Diego) is required.

Question 250

Topic: 4. Pediatrics

A 9-year-old girl is diagnosed with Klippel-Feil syndrome based on a short neck, low posterior hairline, and limited cervical range of motion. Screening of which of the following organ systems is mandatory due to a high association with this syndrome?

. Hepatic
. Genitourinary
. Gastrointestinal
. Pulmonary
. Endocrine

Correct Answer & Explanation

. Genitourinary

Explanation

Klippel-Feil syndrome is associated with several systemic anomalies, most notably genitourinary abnormalities (seen in over 30% of patients), such as unilateral renal agenesis. Congenital heart defects and hearing loss are also highly prevalent and require screening.

Question 251

Topic: 4. Pediatrics

Congenital pseudarthrosis of the tibia (CPT) presents with anterolateral bowing of the tibia and is notoriously difficult to treat. It is most strongly associated with which of the following systemic conditions?

. Marfan syndrome
. Ehlers-Danlos syndrome
. Neurofibromatosis type 1
. Tuberous sclerosis
. Osteogenesis imperfecta

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Approximately 50% of patients with congenital pseudarthrosis of the tibia (CPT) have Neurofibromatosis type 1 (NF1). The pathology involves a thickened periosteum containing hamartomatous fibrous tissue that impedes normal bone healing.

Question 252

Topic: 4. Pediatrics

A 2-month-old boy is brought to the clinic for congenital muscular torticollis. His head is tilted to the right and rotated to the left. A firm mass is palpated in the right sternocleidomastoid muscle. Which of the following screening evaluations is highly recommended?

. Ultrasound of the cervical spine
. Ultrasound of the hips
. Echocardiogram
. Renal ultrasound
. MRI of the brain

Correct Answer & Explanation

. Ultrasound of the hips

Explanation

There is a known association between congenital muscular torticollis and developmental dysplasia of the hip (DDH), occurring in up to 20% of cases. Screening with a clinical hip exam and an ultrasound of the hips is standard practice.

Question 253

Topic: Pediatric Upper Extremity & Spine

A 6-year-old boy sustains a severely displaced extension-type supracondylar humerus fracture. On examination, he has a completely absent radial pulse, but his hand is warm, pink, and has a capillary refill of less than 2 seconds. What is the most appropriate next step in management?

. Immediate open exploration of the brachial artery
. Preoperative CT angiogram of the upper extremity
. Urgent closed reduction and percutaneous pinning
. Observation in a splint for 24 hours
. Doppler ultrasound of the radial artery

Correct Answer & Explanation

. Urgent closed reduction and percutaneous pinning

Explanation

A pulseless but well-perfused (pink and warm) hand following a supracondylar humerus fracture is usually due to brachial artery kinking or spasm. The immediate treatment of choice is urgent closed reduction and percutaneous pinning, after which perfusion is reassessed.

Question 254

Topic: Pediatric Lower Extremity

According to the Aitken classification for Proximal Focal Femoral Deficiency (PFFD), Class A is defined by which of the following characteristics?

. Absence of the femoral head and acetabulum
. Severe femoral shortening with no connection between the femur and the acetabulum
. Presence of a normal femoral head with a bony connection to the shaft resulting in a subtrochanteric varus deformity
. Complete absence of the femur
. Absent femoral head with a functional acetabulum

Correct Answer & Explanation

. Presence of a normal femoral head with a bony connection to the shaft resulting in a subtrochanteric varus deformity

Explanation

Aitken Class A PFFD is characterized by the presence of a femoral head and a functional acetabulum. The femoral head is connected to the shaft by a cartilaginous model that eventually ossifies, though there is often a severe subtrochanteric varus deformity and limb shortening.

Question 255

Topic: 4. Pediatrics

An 8-year-old boy presents with progressive deformity. Recommended management includes:

. 3 months
. 6 months
. 9 months
. 12 months
. 24 months

Correct Answer & Explanation

. 24 months

Explanation

This patient has a type II kyphosis (anterior bar). Because he is only 8 years old and the curve has progressed, further increase is likely. Observation is not indicated. Bracing has no influence on congenital curves. The kyphosis is >55° (78°) so a posterior fusion may not effectively halt the growth of these vertebral bodies in a posterior direction. Anterior and posterior fusion is the most likely procedure to control the curve.C orrect Answer: Anterior and posterior fusion 2291 A child with congenital below-elbow amputation is best fit with an active prosthesis at which age: A patient with congenital below-elbow amputation has sensation/proprioception in the limb and is able to perform most activities without assistance. Prostheses may interfere with crawling. Passive devices should not be started until walking begins, and active devices started at 2 to 4 years.

Question 256

Topic: 4. Pediatrics

A 14-year-old boy sustains a hip dislocation in a motor vehicle accident. With closed reduction, he is at risk for all of the following except:

. Physeal separation
. Entrapped osteochondral fragment
. Degenerative joint disease
. Avascular necrosis
. Protrusio acetabulae

Correct Answer & Explanation

. Entrapped osteochondral fragment

Explanation

With a hip dislocation in a young adolescent, occult injury to the physis may occur. Reports of physeal separation during the reduction, as well as entrapped osteochondral fragments appear in the literature. Degenerative joint disease may eventually develop due to the cartilage injury. Avascular necrosis risk is approximately 10%.

Question 257

Topic: Pediatric Hip

Which of the following disease processes is demonstrated in the radiograph (Slide):

. Pigmented villonodular synovitis
. Slipped capital femoral epiphysis
. Developmental dysplasia of the hip
. Legg-C alve-Perthes disease
. Multiple epiphyseal dysplasia

Correct Answer & Explanation

. Legg-C alve-Perthes disease

Explanation

The left femoral epiphysis shows avascular changes characteristic of Legg-C alve-Perthes disease without slippage. Although developmental dysplasia of the hip may also be complicated by avascular changes, the femoral neck and acetabulum would manifest more longstanding growth alterations as well. The contralateral hip would be symmetric in patients with multiple epiphyseal dysplasia.

Question 258

Topic: 4. Pediatrics

Which of the following features is not associated with congenital muscular torticollis:

. Developmental dysplasia of the hip
. Metatarsus adductus
. Flattening of the occiput contralateral to the tight sternomastoid
. Asymmetrical facial features
. Imperforate anus

Correct Answer & Explanation

. Imperforate anus

Explanation

Congenital muscular torticollis is caused by in-utero molding, as are developmental dysplasia of the hip and metatarsus adductus. Contralateral occipital flattening and asymmetrical facial features develop secondarily with torticollis. Imperforate anus is associated with congenital hemivertebrae but not with muscular torticollis.

Question 259

Topic: 4. Pediatrics
A 6-year-old child with spastic diplegic cerebral palsy requires the use of a wheeled walker for mobility indoors and outdoors. They are transported in a manual wheelchair for long distances in the community. What is the appropriate Gross Motor Function Classification System (GMFCS) level?
. Level I
. Level II
. Level III
. Level IV
. Level V

Correct Answer & Explanation

. Level III

Explanation

GMFCS Level III children walk using a hand-held mobility device in most indoor settings and use wheeled mobility for long distances. Level II children walk without devices but have limitations outdoors.

Question 260

Topic: Pediatric Hip

A 7-year-old boy is diagnosed with Legg-Calve-Perthes disease.

Which of the following radiographic findings is considered a "head-at-risk" sign described by Catterall?

. Subchondral fracture line covering >50% of epiphysis
. Central pillar collapse
. Gage sign
. Acetabular dysplasia
. Premature physeal closure

Correct Answer & Explanation

. Gage sign

Explanation

Gage sign is a V-shaped radiolucency in the lateral epiphysis and adjacent metaphysis. It represents a Catterall "head-at-risk" sign in Legg-Calve-Perthes disease, indicating a potential for a poor outcome.

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