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4. Pediatrics MCQs

Practice Set 309 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 6161

Topic: Pediatric Upper Extremity & Spine

A 5-year-old boy falls from monkey bars and sustains a significantly displaced extension-type supracondylar humerus fracture. On evaluation in the emergency department, his hand is warm and pink, but the radial pulse is absent. What is the most appropriate next step in management?

. Immediate CT angiography of the upper extremity
. Open exploration of the brachial artery
. Observation and elevation with cast application
. Urgent closed reduction and percutaneous pinning
. Immediate volar fasciotomy of the forearm

Correct Answer & Explanation

. Urgent closed reduction and percutaneous pinning

Explanation

In a "pink, pulseless" hand associated with a supracondylar humerus fracture, the collateral circulation is intact. The most appropriate next step is urgent closed reduction and percutaneous pinning, which frequently restores the radial pulse by relieving arterial kinking.

Question 6162

Topic: 4. Pediatrics

A 6-year-old child presents with severe kyphoscoliosis, knock-knees, and normal intelligence. Radiographs show anterior central beaking of the vertebral bodies and severe atlantoaxial instability. Urinalysis reveals excess keratan sulfate. This patient's condition is due to a deficiency of which of the following enzymes?

. Alpha-L-iduronidase
. Iduronate-2-sulfatase
. N-acetylgalactosamine-6-sulfatase
. Arylsulfatase B
. Acid alpha-glucosidase

Correct Answer & Explanation

. N-acetylgalactosamine-6-sulfatase

Explanation

Morquio syndrome (Mucopolysaccharidosis Type IV) is characterized by normal intelligence, severe skeletal deformities, atlantoaxial instability, and keratan sulfate in the urine. It is caused by a deficiency in N-acetylgalactosamine-6-sulfatase (Type IVA) or beta-galactosidase (Type IVB).

Question 6163

Topic: 4. Pediatrics
A 13-year-old boy sustains an ankle injury while skateboarding. Radiographs show a Salter-Harris III fracture of the anterolateral aspect of the distal tibial epiphysis. The mechanism of injury for this specific fracture is most commonly related to which of the following forces?
. Supination-inversion
. Pronation-abduction
. External rotation
. Axial loading with plantar flexion
. Direct anterior trauma

Correct Answer & Explanation

. External rotation

Explanation

A Juvenile Tillaux fracture is a Salter-Harris III fracture of the anterolateral distal tibial epiphysis. It is caused by an external rotation force that pulls on the anterior inferior tibiofibular ligament (AITFL) as the medial and central physes close earlier than the lateral portion.

Question 6164

Topic: 4. Pediatrics

Which of the following descriptions best outlines the classical radiographic presentation of a chondroblastoma?

. Diaphyseal permeative lytic lesion with an 'onion-skin' periosteal reaction
. Metaphyseal eccentric lytic lesion extending into the epiphysis after physeal closure
. Epiphyseal well-circumscribed lytic lesion with a sclerotic rim in a skeletally immature patient
. Metaphyseal heavily calcified, ring-and-arc lesion causing endosteal scalloping
. Cortical-based blister-like lytic lesion in the tibial diaphysis

Correct Answer & Explanation

. Epiphyseal well-circumscribed lytic lesion with a sclerotic rim in a skeletally immature patient

Explanation

Chondroblastoma is one of the few bone tumors that characteristically arises in the epiphysis (or apophysis) of long bones in skeletally immature individuals. It presents radiographically as a well-defined, eccentric, lytic lesion often with a thin sclerotic margin.

Question 6165

Topic: 4. Pediatrics
During the curettage of a proximal tibial chondroblastoma in a 13-year-old with open physes, the surgeon must balance thorough tumor removal with physeal preservation. Which of the following adjuvants carries the highest risk of irreversible physeal damage if applied directly to the physeal border?
. Phenol
. Liquid nitrogen (cryotherapy)
. High-speed burring
. Hydrogen peroxide
. Pulsed lavage

Correct Answer & Explanation

. Liquid nitrogen (cryotherapy)

Explanation

Liquid nitrogen (cryotherapy) causes severe, deep tissue necrosis and has a very high risk of destroying the adjacent open physis, leading to premature closure and growth arrest. Chemical adjuvants and burring are generally more controllable near the growth plate.

Question 6166

Topic: 4. Pediatrics

The imaging below demonstrates a protruding bone mass in the posterior aspect of the knee in a 10-year-old child. Based on the typical behavior of this disease, which of the following statements regarding its anatomical distribution is most accurate?



. It typically involves the entire epiphysis symmetrically
. It most commonly affects the upper extremities
. It characteristically involves either the medial or lateral half of the epiphysis
. It originates from the diaphyseal medullary canal
. It crosses the open physis to involve the metaphysis primarily

Correct Answer & Explanation

. It characteristically involves either the medial or lateral half of the epiphysis

Explanation

Correct Answer: It characteristically involves either the medial or lateral half of the epiphysisThe images show DEH of the distal femur. The term 'hemimelica' refers to the characteristic involvement of only one half (either medial or lateral) of the affected epiphysis. It rarely affects the upper extremities and does not typically involve the entire epiphysis symmetrically.

Question 6167

Topic: 4. Pediatrics
A 9-year-old male presents with aching pain, deformity, and limited range of motion in his right knee. Radiographs show asymmetric epiphyseal enlargement of the distal femur with multiple ossification centers. What is the most likely diagnosis?
. Multiple Hereditary Exostoses
. Dysplasia Epiphysealis Hemimelica
. Blount's Disease
. Legg-Calvรฉ-Perthes Disease
. Slipped Capital Femoral Epiphysis

Correct Answer & Explanation

. Dysplasia Epiphysealis Hemimelica

Explanation

The clinical presentation of aching pain, deformity, and limited range of motion combined with the hallmark radiographic finding of asymmetric epiphyseal enlargement with multiple ossification centers is classic for Dysplasia Epiphysealis Hemimelica (DEH).

Question 6168

Topic: 4. Pediatrics

Which of the following radiographic findings is considered the hallmark of Dysplasia Epiphysealis Hemimelica in a growing child?

. Symmetrical widening of the physis
. Central lytic lesion with a sclerotic rim in the metaphysis
. Asymmetric epiphyseal enlargement with multiple ossification centers
. Sunburst periosteal reaction along the diaphysis
. Onion-skin periosteal reaction in the metadiaphysis

Correct Answer & Explanation

. Asymmetric epiphyseal enlargement with multiple ossification centers

Explanation

Correct Answer: Asymmetric epiphyseal enlargement with multiple ossification centersThe characteristic radiographic appearance of DEH is asymmetric epiphyseal enlargement (hemimelic involvement) accompanied by multiple ossification centers within the affected area.

Question 6169

Topic: 4. Pediatrics

Dysplasia epiphysealis hemimelica (DEH) is a rare skeletal developmental disorder. Which of the following demographic profiles is most consistent with the typical presentation of DEH?

. A 4-year-old male
. A 4-year-old female
. A 25-year-old male
. A 45-year-old female
. A 60-year-old male

Correct Answer & Explanation

. A 4-year-old male

Explanation

Correct Answer: A 4-year-old maleThe age of onset for DEH is usually between 2 and 14 years. Furthermore, males are affected twice as frequently as females, making a young male child the most typical demographic presentation.

Question 6170

Topic: 4. Pediatrics

A 7-year-old child presents with a painless, bone-hard swelling at the lateral side of the left ankle, as shown below. What is the estimated incidence of the suspected condition?


. 1 in 10,000
. 1 in 50,000
. 1 in 100,000
. 1 in 500,000
. 1 in 1,000,000

Correct Answer & Explanation

. 1 in 1,000,000

Explanation

Correct Answer: 1 in 1,000,000The clinical image shows a typical presentation of Dysplasia Epiphysealis Hemimelica (DEH). DEH is a very rare skeletal developmental disorder with an estimated incidence of 1 in 1,000,000.

Question 6171

Topic: 4. Pediatrics

A 12-year-old boy presents with a deformity and limited range of motion in his right ankle. Imaging reveals an asymmetric epiphyseal enlargement with multiple ossification centers on the medial side of the distal tibia. Which of the following is the most likely diagnosis?

. Multiple Hereditary Exostoses
. Dysplasia Epiphysealis Hemimelica
. Blount's Disease
. Slipped Capital Femoral Epiphysis
. Osgood-Schlatter Disease

Correct Answer & Explanation

. Dysplasia Epiphysealis Hemimelica

Explanation

Correct Answer: Dysplasia Epiphysealis HemimelicaThe clinical presentation of a young male with limited ROM, deformity, and radiographic findings of asymmetric epiphyseal enlargement with multiple ossification centers on one side (hemimelic) of the distal tibia is the classic description of Dysplasia Epiphysealis Hemimelica (DEH).

Question 6172

Topic: 4. Pediatrics
When evaluating a pediatric patient suspected of having Dysplasia Epiphysealis Hemimelica (DEH), what is the hallmark radiographic feature typically observed?
. Symmetrical epiphyseal enlargement with a single central ossification center
. Asymmetric epiphyseal enlargement with multiple ossification centers
. Metaphyseal flaring with a 'celery stalk' appearance
. Diaphyseal cortical thickening with a radiolucent nidus
. Epiphyseal collapse and fragmentation resembling Legg-Calvรฉ-Perthes disease

Correct Answer & Explanation

. Asymmetric epiphyseal enlargement with multiple ossification centers

Explanation

Characteristically, DEH lesions show on radiographs as asymmetric epiphyseal enlargement with multiple ossification centers. The involvement is typically hemimelic, meaning it affects either the medial or lateral side of the epiphysis, leading to this asymmetric appearance.

Question 6173

Topic: 4. Pediatrics

A pediatric orthopedic surgeon is counseling the parents of a child recently diagnosed with Dysplasia Epiphysealis Hemimelica (DEH). When discussing the rarity of the condition, what is the accepted estimated incidence?

. 1 in 10,000
. 1 in 50,000
. 1 in 100,000
. 1 in 500,000
. 1 in 1,000,000

Correct Answer & Explanation

. 1 in 1,000,000

Explanation

Correct Answer: EDysplasia Epiphysealis Hemimelica (DEH) is an exceptionally rare skeletal developmental disorder. The reported incidence in the literature is approximately 1 in 1,000,000.

Question 6174

Topic: 4. Pediatrics

A 4-year-old boy is brought to the orthopedic clinic with a painless, bony prominence on the medial aspect of his right knee. Radiographs reveal an irregular, multi-centric ossification center arising from the medial distal femoral epiphysis. Which of the following is true regarding the genetic etiology of this condition?

. It is inherited in an autosomal dominant pattern linked to EXT1 mutations.
. It is associated with a mutation in the FGFR3 gene.
. It is inherited in an autosomal recessive pattern linked to diastrophic dysplasia.
. It is a sporadic, non-hereditary developmental anomaly.
. It is associated with an underlying GNAS gene mutation.

Correct Answer & Explanation

. It is a sporadic, non-hereditary developmental anomaly.

Explanation

Dysplasia Epiphysealis Hemimelica (DEH), or Trevor's disease, is a sporadic, non-hereditary developmental disorder. Unlike multiple hereditary exostoses, DEH is not associated with EXT1 or EXT2 gene mutations.

Question 6175

Topic: 4. Pediatrics

A 10-year-old male with a known diagnosis of Trevor's disease presents with increasing varus deformity of the knee. The lesion originates from the medial femoral epiphysis. When does this mass typically cease its active growth?

. At 5 years of age
. At 10 years of age
. At skeletal maturity
. It continues to grow indefinitely
. After spontaneous ossification at age 18

Correct Answer & Explanation

. At skeletal maturity

Explanation

The growth of a DEH lesion is commensurate with the physiological growth of the child. It typically ceases to enlarge once the physes close and skeletal maturity is reached.

Question 6176

Topic: 4. Pediatrics

Which of the following epidemiological profiles best fits the typical presentation of Dysplasia Epiphysealis Hemimelica?

. Female infant, bilateral upper extremity involvement
. Male child, unilateral lower extremity involvement
. Female adolescent, bilateral lower extremity involvement
. Male adult, unilateral upper extremity involvement
. Female child, unilateral axial skeleton involvement

Correct Answer & Explanation

. Male child, unilateral lower extremity involvement

Explanation

DEH predominantly affects young males (male-to-female ratio of 3:1) and usually presents in early childhood. It classically involves a single lower extremity.

Question 6177

Topic: 4. Pediatrics

A 12-year-old boy undergoes surgical excision of a DEH mass from his medial proximal tibia. Postoperatively, what secondary deformity must the surgeon closely monitor for during his remaining growing years?

. Progressive valgus deformity
. Progressive varus deformity
. Recurvatum deformity
. Profound limb lengthening of the affected side
. Anterior tibial bowing

Correct Answer & Explanation

. Progressive varus deformity

Explanation

Surgical excision of a medial epiphyseal lesion can inadvertently damage the medial physis or articular cartilage, leading to growth arrest on the medial side and a subsequent progressive varus deformity.

Question 6178

Topic: 4. Pediatrics

A pediatric orthopedic surgeon reviews a plain radiograph of a 6-year-old ankle showing a multi-lobulated, stippled ossification center distinct from, but adjacent to, the main talar ossification center. Over time, what is the expected natural radiographic progression of this lesion?

. It will become completely radiolucent and cystic.
. It will eventually merge and ankylose with the adjacent metaphysis.
. It will enlarge and merge with the main epiphyseal ossification center.
. It will undergo spontaneous regression and disappear before puberty.
. It will migrate into the joint space as a loose body.

Correct Answer & Explanation

. It will enlarge and merge with the main epiphyseal ossification center.

Explanation

In early stages, DEH appears as separate, irregular ossification centers adjacent to the epiphysis. As the child grows, these secondary centers typically enlarge and merge with the main epiphyseal ossification center.

Question 6179

Topic: 4. Pediatrics

When surgical intervention is performed for a symptomatic DEH lesion of the distal femur, what is the most significant potential iatrogenic complication?

. Massive hemorrhage from the popliteal vessels
. Damage to normal articular cartilage and premature physeal closure
. Recurrence with rapid malignant transformation
. Systemic dissemination of chondrocytes
. Pathological fracture of the diaphysis

Correct Answer & Explanation

. Damage to normal articular cartilage and premature physeal closure

Explanation

Surgical excision of DEH risks iatrogenic damage to the normal parent articular cartilage and the adjacent growth plate, potentially leading to premature physeal closure and early-onset osteoarthritis.

Question 6180

Topic: 4. Pediatrics

An 8-year-old male child has established Trevor disease involving the medial aspect of the distal femur. If left untreated, what resulting limb deformity is most likely to develop as the child grows?

. Genu recurvatum
. Genu varum
. Genu valgum
. Coxa vara
. Equinovarus

Correct Answer & Explanation

. Genu varum

Explanation

Overgrowth of the medial epiphysis of the distal femur or proximal tibia typically results in an asymmetric increase in medial joint height, subsequently pushing the knee into a varus deformity (genu varum).

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