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4. Pediatrics MCQs

Practice Set 7 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 121

Topic: 4. Pediatrics

A 6-year-old child presents with a 4-day history of right thigh pain and high fever. Plain radiographs are unremarkable. An MRI is obtained.

Blood cultures are pending. Which of the following strictly dictates the need for urgent surgical debridement in this patient's condition?

. Elevated CRP > 50 mg/L
. Presence of a subperiosteal abscess > 2 cm
. Positive blood cultures
. Duration of symptoms > 48 hours
. Bone marrow edema alone on MRI

Correct Answer & Explanation

. Presence of a subperiosteal abscess > 2 cm

Explanation

Urgent surgical debridement in acute pediatric osteomyelitis is primarily indicated if there is a drainable fluid collection, such as a large subperiosteal abscess, or if the patient fails to improve after 48-72 hours of IV antibiotics.

Question 122

Topic: 4. Pediatrics

The 9-year-old patient presented in the radiographs (Slide 1, Slide 2) should be diagnosed with:

. C ongenital dislocation of the radial head
. Unrecognized traumatic dislocation of the radial head
. Osteogenesis imperfecta
. Fibrous dysplasia
. Multiple exostoses

Correct Answer & Explanation

. Osteogenesis imperfecta

Explanation

This patient has type V osteogenesis imperfecta, which is characterized by hereditary radial head dislocation in 86% of patients (this patients motherand brother also have the condition bilaterally) as well as heterotopic calcification, osseous fragility, and scoliosis. Dislocation of the radial head occurs less often (0%-29%) in the other types of osteogenesis imperfecta and is linked to angular deformation of the long bones. The signs of osteogenesis imperfecta in this patient include thin long bones, several healed fractures, and angular deformations.

Question 123

Topic: Pediatric Upper Extremity & Spine

A 3-year-old boy falls on his upper extremity and shows sign of pain. His radiograph only shows a posterior fat pad sign of the elbow. What is the most likely diagnosis:

. Nursemaid elbow
. Elbow sprain
. Supracondylar humerus fracture
. Proximal ulna fracture
. Lateral condyle fracture

Correct Answer & Explanation

. Supracondylar humerus fracture

Explanation

A positive posterior fat pad sign is more suspicious for occult fracture than an anterior fat pad sign because flexing the elbow normally may elevate the anterior but not the posterior fat pad. A positive posterior fat pad sign is most likely to represent an undisplaced supracondylar fracture of the distal humerus, followed by proximal ulna, lateral conydle, and radial neck fracture. A nursemaid elbow is a diagnosis of exclusion and should be used only when the mechanism is one of traction rather than compression.

Question 124

Topic: Pediatric Upper Extremity & Spine

Which of the following is not an indication to urgently treat a supracondylar humerus fracture:

. Antecubital ecchymosis
. Firm compartments
. Associated forearm fracture
. Poor perfusion
. Medial comminution

Correct Answer & Explanation

. Medial comminution

Explanation

Medial comminution is an indication of potential bony instability but does not convey any increased vascular risk. All of the other indications convey a vascular risk, and treatment should not be delayed.

Question 125

Topic: Pediatric Hip
A 5-year-old patient with Legg-Calvé-Perthes disease has lateral pillar B involvement. He has 15% epiphyseal extrusion. Treatment should consist of:
. Observation
. Femoral osteotomy
. Iliac osteotomy
. Combined femoral and iliac osteotomy
. External fixation

Correct Answer & Explanation

. Observation

Explanation

Patients who have Legg-Calvé-Perthes disease with onset before 6 years of age have a good prognosis unless they have lateral pillar involvement in the B/C border or C categories.

Question 126

Topic: Pediatric Hip
Which of the following characteristics is more commonly found in patients with Meyer dysplasia than in patients with Legg-Calvé-Perthes disease?
. Bilateral involvement
. Asynchronous onset
. Metaphyseal widening
. Epiphyseal extrusion
. Later degenerative change

Correct Answer & Explanation

. Bilateral involvement

Explanation

Meyer dysplasia is a rare condition that affects children before age 4. A characteristic of the condition includes delayed ossification of the epiphyses, which eventually develop normal ossification. Meyer dysplasia is synchronous, meaning that both heads have symmetrical involvement unlike Legg-Calvé-Perthes disease. Meyer dysplasia is usually bilateral, in contrast to Legg-Calvé-Perthes disease, which is bilateral in fewer than 10% of patients. There is no metaphyseal widening and no treatment is indicated.

Question 127

Topic: 4. Pediatrics

Which of the following is an accurate mean age for a motor milestone:

. Sit up without assistance at 6 months
. Walk independently at 24 months
. Hop on one foot at 2 years
. Roll from prone to supine position at 2 months
. Able to run at 36 months

Correct Answer & Explanation

. Sit up without assistance at 6 months

Explanation

Motor milestones provide a way of assessing a childs motor development. If they are not met, a physician or parent may be more alert for neurological or connective tissue disorders. Common pediatric milestone include: Sit up without assistance at 6 months Walk independently at 12 months Hop on one foot at 4 years Roll from prone to supine position at 4 months Able to run at 18 months

Question 128

Topic: 4. Pediatrics
In the workup of scoliosis, what is/are the best method(s) to assess skeletal maturity during a patient's peak height velocity (Risser grade 0)?
. Greulich and Pyle atlas (hand/wrist radiographs)
. Modified Sauvegrain method (olecranon radiographs)
. Tanner-Whitehouse-III RUS (radius, ulna, small bones of hand) method
. Triradiate cartilage closure
. B, C, and D

Correct Answer & Explanation

. B, C, and D

Explanation

Precise information about skeletal maturity during peak growth rate is important in deciding treatment options in patients with scoliosis. The modified Sauvegrain method, Tanner-Whitehouse-III RUS method, and triradiate cartilage closure are each accurate and reliable markers of maturity that the orthopedic surgeon can use to quickly assess pediatric patients.

Question 129

Topic: 4. Pediatrics

Which of the following treatments decreases hip subluxation in patients with cerebral palsy who have displaced hips:

. Passive stretching
. Hip abduction bracing
. Hip abduction bracing and botulinum toxin type A
. Electrical stimulation of the hip abductors
. Surgical adductor lengthening

Correct Answer & Explanation

. Surgical adductor lengthening

Explanation

Only hip adductor lengthening has been shown to decrease hip subluxation in patients with displaced hips. Patients treated with botulinum toxin type A and hip abduction still result in progression.

Question 130

Topic: 4. Pediatrics

A 6-year-old child presents with a pink, pulseless hand following a displaced supracondylar humerus fracture. After closed reduction and percutaneous pinning, the hand remains pink and pulseless. What is the next best step in management?

. Explore the brachial artery immediately
. Perform a stellate ganglion sympathetic block
. Admit for observation with the arm slightly extended and elevated
. Remove the pins and cast in 120 degrees of flexion
. Perform prophylactic forearm fasciotomies

Correct Answer & Explanation

. Admit for observation with the arm slightly extended and elevated

Explanation

A pink, pulseless hand after adequate reduction indicates sufficient collateral circulation. Current pediatric guidelines recommend close observation for 24-48 hours with the elbow extended slightly rather than immediate arterial exploration.

Question 131

Topic: 4. Pediatrics

Which of the following pediatric physeal fractures carries the highest rate of premature physeal closure and subsequent growth arrest?

. Proximal humerus Salter-Harris II
. Distal radius Salter-Harris II
. Distal femur Salter-Harris II
. Proximal tibia Salter-Harris I
. Distal fibula Salter-Harris I

Correct Answer & Explanation

. Distal femur Salter-Harris II

Explanation

Distal femur physeal fractures have an exceptionally high incidence of growth arrest (often exceeding 50%), even in minimally displaced Salter-Harris II fractures. Anatomical reduction and close follow-up for limb length discrepancy are essential.

Question 132

Topic: 4. Pediatrics



Based on the typical mechanism for pediatric lateral condyle fractures, which muscle group is responsible for the distraction and rotational displacement of the fracture fragment?

. Flexor-pronator mass
. Extensor-supinator mass
. Biceps brachii
. Triceps brachii
. Brachialis

Correct Answer & Explanation

. Extensor-supinator mass

Explanation

The lateral condyle serves as the origin for the extensor-supinator musculature of the forearm. The continuous pull of this muscle mass acts as a deforming force, frequently leading to significant displacement and rotational deformity.

Question 133

Topic: Pediatric Hip



A 12-year-old boy presents with an altered gait and thigh pain. If the underlying diagnosis is Slipped Capital Femoral Epiphysis (SCFE), what is the anatomical direction of the epiphyseal slip relative to the femoral neck?

. Anterior and superior
. Anterior and inferior
. Posterior and superior
. Posterior and inferior
. Directly medial

Correct Answer & Explanation

. Posterior and inferior

Explanation

In SCFE, the capital femoral epiphysis typically slips posteriorly and inferiorly relative to the metaphysis of the femoral neck. This displacement leads to the characteristic externally rotated and shortened posture of the affected limb.

Question 134

Topic: 4. Pediatrics

A 3-year-old child presents with progressive bowing of the legs. Radiographs demonstrate changes at the proximal medial tibia. Which radiographic measurement is most useful in differentiating infantile Blount disease from physiological bowing?

. Metaphyseal-diaphyseal angle (Drennan angle)
. Tibiofemoral angle
. Epiphyseal-metaphyseal angle
. Hilgenreiner angle
. Southwick angle

Correct Answer & Explanation

. Metaphyseal-diaphyseal angle (Drennan angle)

Explanation

The metaphyseal-diaphyseal angle (Drennan's angle) is crucial for evaluating infantile tibia vara. An angle greater than 16 degrees is highly suggestive of infantile Blount disease, distinguishing it from physiological genu varum.

Question 135

Topic: Pediatric Lower Extremity

During the Ponseti serial casting technique for idiopathic clubfoot, which component of the deformity is corrected last?

. Cavus
. Adductus
. Varus
. Equinus
. Forefoot supination

Correct Answer & Explanation

. Equinus

Explanation

The Ponseti method dictates sequential correction following the CAVE acronym: Cavus, Adductus, Varus, and lastly Equinus. The equinus deformity is often corrected by a percutaneous Achilles tenotomy prior to applying the final cast.

Question 136

Topic: Pediatric Hip

During an open reduction of a Developmentally Dysplastic Hip (DDH) via a medial (Ludloff) approach in an 11-month-old, which structure is directly released to allow access to the joint and facilitate reduction?

. Gluteus medius
. Iliopsoas tendon
. Sartorius
. Tensor fasciae latae
. Rectus femoris

Correct Answer & Explanation

. Iliopsoas tendon

Explanation

The medial approach allows direct access to the medial structures blocking reduction, primarily requiring the release of the iliopsoas tendon. This approach avoids disruption of the abductors but carries a risk of injury to the medial circumflex femoral artery.

Question 137

Topic: Pediatric Hip

A 4-month-old infant in a Pavlik harness for DDH develops an inability to actively extend the knee. This complication is most likely due to:

. Excessive hip abduction
. Inadequate hip abduction
. Excessive hip flexion
. Inadequate hip flexion
. Straps causing direct pressure on the fibular neck

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Hyperflexion of the hip in a Pavlik harness can cause compression of the femoral nerve against the inguinal ligament. This leads to an iatrogenic femoral nerve palsy, manifesting clinically as poor active knee extension.

Question 138

Topic: Pediatric Hip
Which of the following is considered the most significant poor prognostic factor in Legg-Calvé-Perthes disease?
. Male gender
. Bilateral involvement
. Age at onset greater than 8 years
. Presence of a positive Galeazzi sign
. Associated mild obesity

Correct Answer & Explanation

. Age at onset greater than 8 years

Explanation

Older age at presentation (typically > 8 years) is a major poor prognostic factor in Legg-Calvé-Perthes disease. Older patients have less remaining time for femoral head remodeling before physeal closure, increasing the risk of early osteoarthritis.

Question 139

Topic: 4. Pediatrics
A 13-year-old sustains a twisting ankle injury. Radiographs reveal a fracture that appears as a Salter-Harris III on the AP view and a Salter-Harris II on the lateral view. What is the most likely diagnosis?
. Tillaux fracture
. Triplane fracture
. Pilon fracture
. Maisonneuve fracture
. Bosworth fracture

Correct Answer & Explanation

. Triplane fracture

Explanation

A triplane fracture occurs in adolescents during the transitional period of asymmetric physeal closure. It involves the metaphysis, physis, and epiphysis, classically appearing as a Salter-Harris III on AP radiographs and a Salter-Harris II on lateral radiographs.

Question 140

Topic: 4. Pediatrics

A child presenting with frequent fractures, blue sclerae, and dentinogenesis imperfecta is diagnosed with Osteogenesis Imperfecta. This condition is primarily caused by a defect in the synthesis of:

. Type II collagen
. Type I collagen
. Type X collagen
. Chondroitin sulfate
. Fibroblast growth factor

Correct Answer & Explanation

. Type I collagen

Explanation

Osteogenesis Imperfecta is an inherited connective tissue disorder caused predominantly by mutations in the COL1A1 or COL1A2 genes. These mutations result in qualitative or quantitative defects in the production of Type I collagen, the major protein in bone.

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