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4. Pediatrics MCQs

Practice Set 6 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 101

Topic: Pediatric Hip

A 13-year-old obese boy presents with 3 weeks of vague left knee pain and a limp. Examination reveals an obligate external rotation of the hip during active flexion.

What is the most devastating potential complication of the underlying condition?

. Chondrolysis
. Avascular necrosis
. Early-onset osteoarthritis
. Femoral neck nonunion
. Septic arthritis

Correct Answer & Explanation

. Avascular necrosis

Explanation

Avascular necrosis (AVN) is the most devastating complication of Slipped Capital Femoral Epiphysis (SCFE), often secondary to unstable slips or overly aggressive reduction attempts. Chondrolysis is another severe complication but generally has a more predictable, albeit stiff, long-term outcome compared to segmental collapse from AVN.

Question 102

Topic: Pediatric Hip

In a 7-year-old boy diagnosed with Legg-Calve-Perthes disease, which of the following radiographic findings is considered a 'head at risk' sign according to Catterall?

. Gage sign
. Waldenstrom sign
. Crescent sign
. Metaphyseal blanch sign
. Klein's line disruption

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/metaphysis), lateral calcification, lateral subluxation, horizontal growth plate, and metaphyseal cysts. These indicate a poorer prognosis.

Question 103

Topic: 4. Pediatrics

According to the Ponseti method for the treatment of idiopathic congenital talipes equinovarus (clubfoot), what is the correct sequence of deformity correction?

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

Correct Answer & Explanation

. Cavus, Adductus, Varus, Equinus

Explanation

The Ponseti method corrects the deformities in a specific order remembered by the acronym CAVE: Cavus (by elevating the first ray), Adductus, Varus, and finally Equinus (usually requiring a percutaneous Achilles tenotomy).

Question 104

Topic: Pediatric Hip

A 6-month-old girl is diagnosed with developmental dysplasia of the hip (DDH) and has failed a proper 3-week trial of a Pavlik harness, with the hip remaining dislocated. What is the most appropriate next step in management?

. Continue Pavlik harness for an additional 4 weeks
. Switch to a rigid abduction orthosis (e.g., Ilfeld splint)
. Closed reduction and spica casting
. Immediate open reduction and capsulorrhaphy
. Pelvic osteotomy

Correct Answer & Explanation

. Closed reduction and spica casting

Explanation

If a Pavlik harness fails to achieve reduction within 3 to 4 weeks, it should be abandoned to prevent 'Pavlik harness disease' (damage to the posterior acetabular wall). The next appropriate step is closed reduction and spica casting under general anesthesia.

Question 105

Topic: Pediatric Upper Extremity & Spine

A 6-year-old girl sustains a severely displaced extension-type supracondylar humerus fracture. On presentation, her hand is well-perfused and pink, but the radial pulse is absent. What is the most appropriate initial management?

. Immediate open exploration of the brachial artery
. Observation and admission for 24 hours
. Urgent closed reduction and percutaneous pinning
. CT angiography of the upper extremity
. Prophylactic forearm fasciotomy

Correct Answer & Explanation

. Urgent closed reduction and percutaneous pinning

Explanation

In a 'pulseless, pink' hand following a supracondylar fracture, the collateral circulation is intact. The standard of care is urgent closed reduction and percutaneous pinning, which often restores the palpable pulse.

Question 106

Topic: 4. Pediatrics

A 7-year-old child with spastic quadriplegic cerebral palsy is undergoing routine hip surveillance.

What radiographic measurement is most critical for monitoring lateral hip subluxation in this patient?

. Alpha angle
. Center-edge angle of Wiberg
. Reimers migration percentage
. Acetabular index
. Tonnis angle

Correct Answer & Explanation

. Reimers migration percentage

Explanation

The Reimers migration percentage (or index) measures the proportion of the ossified femoral head outside the lateral margin of the acetabulum (Perkin's line). It is the standard metric used in cerebral palsy hip surveillance.

Question 107

Topic: 4. Pediatrics

A 2-year-old girl presents with bilateral genu varum. Radiographs reveal a metaphyseal-diaphyseal angle (Drennan's angle) of 18 degrees. What is the most likely diagnosis?

. Physiologic bowing
. Infantile Blount's disease
. Nutritional rickets
. Achondroplasia
. Osteogenesis imperfecta

Correct Answer & Explanation

. Infantile Blount's disease

Explanation

A metaphyseal-diaphyseal angle (Drennan's angle) greater than 16 degrees on standing AP radiographs is highly predictive of infantile Blount's disease (tibia vara) rather than physiologic bowing.

Question 108

Topic: Pediatric Hip

In which of the following patients presenting with a unilateral slipped capital femoral epiphysis (SCFE) is prophylactic pinning of the contralateral hip most strongly indicated?

. A 12-year-old boy with a BMI of 30
. An 11-year-old girl with idiopathic SCFE
. A 10-year-old boy with renal osteodystrophy
. A 14-year-old boy with an acute-on-chronic SCFE
. A 13-year-old girl with an ipsilateral retroverted acetabulum

Correct Answer & Explanation

. A 10-year-old boy with renal osteodystrophy

Explanation

Prophylactic pinning of the contralateral hip is strongly recommended in patients with endocrine or metabolic disorders (e.g., renal osteodystrophy, hypothyroidism) due to a very high rate of subsequent contralateral slips.

Question 109

Topic: 4. Pediatrics

Proximal focal femoral deficiency (PFFD) in a newborn is most frequently associated with which of the following concurrent congenital anomalies?

. Tibial hemimelia
. Fibular hemimelia
. Radial clubhand
. Developmental dysplasia of the hip
. Amniotic band sequence

Correct Answer & Explanation

. Fibular hemimelia

Explanation

Fibular hemimelia is the most common concurrent congenital anomaly associated with proximal focal femoral deficiency (PFFD), occurring in up to 70-80% of these patients.

Question 110

Topic: 4. Pediatrics

A 13-year-old girl sustains a twisting injury to her ankle. A CT scan confirms a classic triplane fracture. In which planes do the fracture lines of a typical triplane fracture occur?

. Sagittal (metaphysis) / Transverse (physis) / Coronal (epiphysis)
. Sagittal (epiphysis) / Transverse (physis) / Coronal (metaphysis)
. Coronal (epiphysis) / Transverse (metaphysis) / Sagittal (physis)
. Transverse (epiphysis) / Coronal (physis) / Sagittal (metaphysis)
. Sagittal (epiphysis) / Coronal (physis) / Transverse (metaphysis)

Correct Answer & Explanation

. Sagittal (metaphysis) / Transverse (physis) / Coronal (epiphysis)

Explanation

A classic triplane fracture consists of three planes: a sagittal fracture through the epiphysis, a transverse fracture through the physis, and a coronal fracture through the posterior metaphysis.

Question 111

Topic: 4. Pediatrics

A 2-year-old boy with anterolateral bowing of the tibia develops a spontaneous fracture. This condition (congenital pseudoarthrosis of the tibia) is most strongly associated with which of the following genetic disorders?

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

Correct Answer & Explanation

. Neurofibromatosis type 1

Explanation

Anterolateral bowing of the tibia progressing to congenital pseudoarthrosis is highly associated with Neurofibromatosis type 1 (NF1). Over 50% of patients with this pseudoarthrosis have NF1.

Question 112

Topic: 4. Pediatrics

A 12-year-old elite baseball pitcher presents with insidious onset of proximal shoulder pain while throwing. Radiographs show widening and irregularity of the proximal humeral physis. What is the most appropriate initial treatment?

. Absolute rest from throwing for 3 months
. Physical therapy focusing only on rotator cuff strengthening while continuing play
. Corticosteroid injection into the subacromial space
. Percutaneous pinning of the physis
. Open reduction and internal fixation

Correct Answer & Explanation

. Absolute rest from throwing for 3 months

Explanation

Little Leaguer's shoulder is a stress injury (Salter-Harris I) of the proximal humeral physis caused by repetitive torsional forces. The mainstay of treatment is absolute rest from throwing, typically for 3 months, followed by a gradual return-to-throw program.

Question 113

Topic: Pediatric Hip
A 7-year-old boy is diagnosed with Legg-Calvé-Perthes disease. Which of the following describes the most critical prognostic factors for long-term hip deformity?
. Age at onset and lateral pillar classification
. Gender and extent of medial pillar collapse
. Body mass index and epiphyseal height
. Initial range of motion and presence of crescent sign

Correct Answer & Explanation

. Age at onset and lateral pillar classification

Explanation

The most important prognostic factors in Legg-Calvé-Perthes disease are the age at clinical presentation (worse outcomes if >8 years) and the Herring lateral pillar classification. Preservation of the lateral pillar height corresponds to better long-term sphericity of the femoral head.

Question 114

Topic: 4. Pediatrics

A nonverbal 12-year-old patient with totally involved cerebral palsy and developmental delay has been in pain for the past week. The source of the pain cannot be localized. Pelvis radiographs and urinalysis are unremarkable. The next recommended study is:

. Ultrasound of the hips
. Magnetic resonance imaging (MRI) of the brain
. Whole-body bone scan
. Computed tomography (C T) of the lumbar spine
. Thermography

Correct Answer & Explanation

. Whole-body bone scan

Explanation

In a nonverbal child with longstanding pain, the whole-body bone scan is the most sensitive and specific test. Whole-body bone scans detected a cause of pain in more than half of such children in one study; most causes of pain were fractures. MRI cannot be focused enough, and C T has the same limitation as well as increased radiation exposure. Thermography is not widely available and has not been studied in children with cerebral palsy.

Question 115

Topic: 4. Pediatrics

A 23-month-old patient demonstrates intoeing. He walked at 21 months. His height is in the 3rd quantile, and he is cognitively normal. Possible diagnoses include all of the following except:

. Osteogenesis imperfecta
. Rickets
. Internal tibial torsion
. Achondroplasia
. Metaphyseal chondrodysplasia

Correct Answer & Explanation

. Internal tibial torsion

Explanation

The upper limit of normal age for onset of walking is 18 months. All of the diagnoses, except for internal tibial torsion, may explain the delayed walking, short stature, and intoeing.

Question 116

Topic: 4. Pediatrics

Based on the presented radiographs (Slide 1, Slide 2), what is the proper diagnosis of this 12-month-old female patient:

. Normal study
. Avascular necrosis of the femoral head
. Developmental coxa vara of the right femur
. Physeal fracture
. Osteogenesis imperfecta

Correct Answer & Explanation

. Physeal fracture

Explanation

This patient had a physeal fracture of the right proximal femur, which was the result of a non-accidental injury. Notice the displacement of the right femoral metaphysic anteriorly on the frog view despite comparable degrees of rotation. A metaphyseal calcification is apparent posterior to the femoral neck. Treatment involved spica cast application.

Question 117

Topic: 4. Pediatrics
A 13-year-old boy has been experiencing hip pain for 1 month. The pain is worse with activity. The patient has no history of fever or weight loss, and both of his hips flex to 90°. Based on his radiograph (Slide 1) and magnetic resonance image (Slide 2), which of the following is the most likely diagnosis:
. Leukemia
. Pincer-type impingement
. Psoas tendonitis
. Slipped epiphysis
. Avascular necrosis

Correct Answer & Explanation

. Slipped epiphysis

Explanation

This patient has a subtle grade 1 slipped capital femoral epiphysis. He is a male Risser 0 and is overweight. He has decreased internal rotation of the involved hip in flexion. The plain pelvis radiograph shows slightly less epiphyseal height on the left side, slight posterior metaphyseal overlap, and increased irregularity of the physis. MRI confirms a lucent plane in the physis and surrounding edema. A plain film (Slide 3) confirms the diagnosis. In situ fixation was performed on this patient.

Question 118

Topic: 4. Pediatrics

A 13-year-old boy has been experiencing hip pain for 1 month. The pain is worse with activity. The patient has no history of fever or weight loss, and both of his hips flex to 90°. , which of the following is the most likely diagnosis:

. Leukemia
. Pincer-type impingement
. Psoas tendonitis
. Slipped epiphysis
. Avascular necrosis

Correct Answer & Explanation

. Slipped epiphysis

Explanation

This patient has a subtle grade 1 slipped capital femoral epiphysis. He is a male Risser 0 and is overweight. He has decreased internal rotation of the involved hip in flexion. The plain pelvis radiograph shows slightly less epiphyseal height on the left side, slight posterior metaphyseal overlap, and increased irregularity of the physis. MRI confirms a lucent plane in the physis and surrounding edema. A plain film (Slide 3) confirms the diagnosis. In situ fixation was performed on this patient.

Question 119

Topic: 4. Pediatrics

In a child being treated for uncomplicated acute hematogenous osteomyelitis (AHO) with intravenous antibiotics, which of the following criteria is most widely accepted for safely transitioning to oral antibiotics?

. Normalization of the Erythrocyte Sedimentation Rate (ESR)
. A 50% reduction in peak C-reactive protein (CRP) levels along with clinical improvement
. Sterile repeat bone aspirate cultures
. Radiographic resolution of periosteal elevation
. Completion of exactly 14 days of IV therapy

Correct Answer & Explanation

. A 50% reduction in peak C-reactive protein (CRP) levels along with clinical improvement

Explanation

Transition to oral antibiotics in uncomplicated pediatric AHO is guided by clinical improvement, being afebrile for 24-48 hours, and a decreasing CRP trend (often a 50% drop from the peak). ESR normalizes too slowly to guide this transition.

Question 120

Topic: 4. Pediatrics

Kingella kingae is a common cause of pediatric septic arthritis. A thorough history from the parents of an affected child will most likely reveal which of the following antecedent events?

. Recent upper respiratory or oropharyngeal infection
. Recent history of tick bite
. Recent travel to a developing country
. A penetrating injury to the foot
. Contact with farm animals

Correct Answer & Explanation

. Recent upper respiratory or oropharyngeal infection

Explanation

Kingella kingae colonizes the posterior pharynx of young children. Infections are frequently preceded by viral upper respiratory tract infections or stomatitis, which facilitate the organism's entry into the bloodstream.

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