Menu

4. Pediatrics MCQs

Practice Set 226 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 4501

Topic: Pediatric Hip

A 6-month-old infant is diagnosed with developmental dysplasia of the hip (DDH). The Ortolani and Barlow tests are negative, but there is asymmetry of the thigh folds and limited hip abduction. What is the most appropriate initial treatment?

. Observation with close follow-up
. Pavlik harness
. Spica cast
. Open reduction and internal fixation
. Traction followed by casting

Correct Answer & Explanation

. Pavlik harness

Explanation

For an infant diagnosed with DDH between birth and 6-9 months, especially with reducible instability or limited abduction (even if Ortolani/Barlow are negative at this age due to soft tissue contracture), a Pavlik harness is the gold standard initial treatment. It maintains the hips in flexion and abduction, promoting proper acetabular development. Observation is insufficient for true DDH. Spica cast or open reduction are used for older infants, failed harness treatment, or irreducible hips.

Question 4502

Topic: Pediatric Lower Extremity

A 16-year-old male presents with chronic anterior knee pain, worsening with prolonged sitting, ascending/descending stairs, and squatting. There is tenderness along the medial facet of the patella. Patellar apprehension test is negative. What is the most likely diagnosis?

. Patellar tendinopathy
. Osgood-Schlatter disease
. Patellofemoral pain syndrome (PFPS)
. Osteochondritis dissecans of the medial femoral condyle
. Medial plica syndrome

Correct Answer & Explanation

. Patellofemoral pain syndrome (PFPS)

Explanation

The classic symptoms of anterior knee pain, exacerbated by prolonged sitting (theater sign), stairs, and squatting, with tenderness around the patella, are highly characteristic of patellofemoral pain syndrome (PFPS). This is a diagnosis of exclusion. Patellar tendinopathy causes pain specifically at the inferior pole of the patella. Osgood-Schlatter affects the tibial tuberosity in younger adolescents. Osteochondritis dissecans would typically cause mechanical symptoms and localized pain in the condyle, not primarily patellofemoral. Medial plica syndrome can mimic PFPS but usually has a palpable painful plica and is less common.

Question 4503

Topic: 4. Pediatrics

Which of the following conditions is most commonly associated with a 'double bubble' sign on prenatal ultrasound?

. Clubfoot
. Developmental dysplasia of the hip
. Amniotic band syndrome
. Duodenal atresia
. Spina bifida

Correct Answer & Explanation

. Duodenal atresia

Explanation

The 'double bubble' sign on prenatal ultrasound, characterized by two adjacent fluid-filled structures (stomach and dilated duodenum), is pathognomonic for duodenal atresia. This is a common anomaly in infants with Down syndrome. The other conditions listed are unrelated to this specific gastrointestinal finding.

Question 4504

Topic: Pediatric Upper Extremity & Spine

A 4-year-old boy falls from a height and sustains a supracondylar humerus fracture. He presents with a pulseless but warm and pink hand. What is the immediate next step in management after initial stabilization and pain control?

. Observation and repeat pulse check in 30 minutes
. Immediate surgical exploration of the brachial artery
. Closed reduction and percutaneous pinning
. Angiography to assess vascular injury
. Application of a coaptation splint

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

In a supracondylar humerus fracture with a pulseless but perfused (warm, pink, good capillary refill) hand, the immediate priority after initial stabilization is gentle closed reduction and percutaneous pinning. Often, the pulse will return with reduction of the fracture and relief of mechanical obstruction/kinking of the brachial artery. If the pulse does not return after successful reduction, then further vascular workup (angiography) or surgical exploration is indicated. Immediate exploration without attempting reduction is usually not necessary unless there are signs of overt ischemia (cold, pale hand) or a hard sign of vascular injury. Observation is inappropriate for a pulseless extremity.

Question 4505

Topic: Pediatric Hip

Which of the following is the hallmark radiological sign for a slipped capital femoral epiphysis (SCFE)?

. Increased femoral neck-shaft angle
. Decreased epiphyseal height
. Absence of Klein's line crossing the lateral part of the femoral epiphysis
. Widening of the physis with metaphyseal sclerosis
. Bone fragmentation and collapse of the femoral head

Correct Answer & Explanation

. Absence of Klein's line crossing the lateral part of the femoral epiphysis

Explanation

The hallmark radiological sign for SCFE is a failure of Klein's line (a line drawn along the superior border of the femoral neck) to intersect the lateral portion of the femoral epiphysis on an AP pelvic radiograph. Normally, Klein's line should cross at least a portion of the epiphysis. Widening of the physis with metaphyseal sclerosis can be seen, but the relationship with Klein's line is more definitive. Increased neck-shaft angle is not specific, and bone fragmentation/collapse suggests AVN, not acute SCFE.

Question 4506

Topic: 4. Pediatrics
A 5-year-old child presents with a painful, swollen knee after a fall. Radiographs show a fracture involving the physis and epiphysis of the distal femur, without metaphyseal involvement. Which Salter-Harris classification type describes this injury?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type III

Explanation

A fracture involving the physis and epiphysis but sparing the metaphysis is a Salter-Harris Type III injury. Type I is a purely physeal slip. Type II involves physis and metaphysis. Type IV involves epiphysis, physis, and metaphysis. Type V is a crush injury to the physis.

Question 4507

Topic: 4. Pediatrics
Which type of osteogenesis imperfecta (OI) is generally considered the most severe, often lethal in the perinatal period?
. Type I
. Type II
. Type III
. Type IV
. Type V

Correct Answer & Explanation

. Type II

Explanation

Osteogenesis Imperfecta Type II is the most severe form, typically lethal in the perinatal period due to severe skeletal deformity, multiple intrauterine fractures, and pulmonary hypoplasia. Type I is the most common and mildest, Type III is severe but not usually lethal perinatally, and Type IV and V are intermediate in severity.

Question 4508

Topic: 4. Pediatrics

Which anatomical structure is most commonly entrapped in a Salter-Harris Type II fracture of the distal tibia, potentially preventing successful closed reduction?

. Posterior tibial nerve
. Tibialis anterior tendon
. Flexor hallucis longus tendon
. Periosteum
. Deltoid ligament

Correct Answer & Explanation

. Periosteum

Explanation

In a Salter-Harris Type II fracture, particularly of the distal tibia, the metaphysis fractures and the periosteum is typically torn on the convex side and often remains intact on the concave side. This intact periosteal sleeve can become invaginated into the fracture site, preventing a concentric reduction of the epiphysis and metaphysis. This is often referred to as a 'periosteal hinge.' The tendons and nerve are less likely to be directly entrapped in a way that prevents reduction of this specific fracture pattern.

Question 4509

Topic: Pediatric Hip
Which of the following conditions is characterized by a gradual onset of hip pain in an obese adolescent, often presenting with a painful limp and limited internal rotation and abduction?
. Legg-Calvé-Perthes disease
. Transient synovitis of the hip
. Septic arthritis
. Slipped capital femoral epiphysis (SCFE)
. Juvenile idiopathic arthritis

Correct Answer & Explanation

. Slipped capital femoral epiphysis (SCFE)

Explanation

Slipped capital femoral epiphysis (SCFE) classically presents in obese adolescents (typically 10-16 years old) with a gradual onset of hip or knee pain, a painful limp, and characteristic limited internal rotation and abduction of the hip. Legg-Calvé-Perthes disease occurs in younger children (4-8 years). Transient synovitis is acute and resolves. Septic arthritis is acute with systemic signs. Juvenile idiopathic arthritis has a more chronic inflammatory presentation.

Question 4510

Topic: 4. Pediatrics

What is the most common type of congenital clubfoot (talipes equinovarus)?

. Flexible
. Positional
. Neuropathic
. Idiopathic
. Syndromic

Correct Answer & Explanation

. Idiopathic

Explanation

Idiopathic clubfoot (talipes equinovarus) is the most common type, meaning it occurs without an identifiable underlying cause or associated syndrome. Positional clubfoot is a mild, flexible deformity that often resolves with stretching. Flexible and rigid refer to the clinical presentation, not the etiology. Neuropathic and syndromic clubfoot are associated with specific neurological conditions or syndromes, making them less common than the idiopathic form.

Question 4511

Topic: 4. Pediatrics

An 18-year-old male rugby player presents with anterior chest pain, dysphagia, and a sensation of choking after a direct blow to the anteromedial shoulder. Clinical examination reveals the arm is held in an adducted and flexed position, and there is a palpable void adjacent to the sternum. Based on the patient's age and clinical presentation, what is the most likely true anatomical pathology?

. Acromioclavicular joint dislocation
. True posterior sternoclavicular joint dislocation
. Posterior physeal fracture of the medial clavicle
. Anterior sternoclavicular joint dislocation
. First rib fracture with subclavian vessel entrapment

Correct Answer & Explanation

. Posterior physeal fracture of the medial clavicle

Explanation

The medial clavicular physis is the last physis in the body to fuse, typically closing between the ages of 20 and 25. Therefore, injuries in patients under age 25 that clinically appear to be sternoclavicular dislocations are almost always Salter-Harris fractures through the medial physis. Posterior displacement is a medical emergency due to the proximity of the trachea, esophagus, and great vessels, requiring reduction in the operating room with thoracic surgery standby.

Question 4512

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy presents with a displaced Gartland Type III supracondylar humerus fracture. On initial presentation, his hand is pink, but the radial pulse is absent. The patient is taken emergently to the OR. After anatomic closed reduction and percutaneous pinning, the hand remains pink, warm, and well-perfused (capillary refill < 2 seconds), but the radial pulse remains absent by Doppler. What is the most appropriate next step in management?
. Immediate open exploration of the brachial artery
. Intraoperative CT angiogram
. Observation with close clinical monitoring and admission
. Removal of the pins and conversion to open reduction
. Emergent fasciotomy of the forearm compartments

Correct Answer & Explanation

. Observation with close clinical monitoring and admission

Explanation

A 'pulseless, pink' hand following reduction and pinning of a pediatric supracondylar humerus fracture suggests adequate collateral circulation despite probable brachial artery spasm, kinking, or intimal injury. Current guidelines recommend close observation and hospital admission for a pulseless but well-perfused (pink) hand after definitive fracture stabilization. Routine vascular exploration is not indicated unless the hand becomes poorly perfused (white, cool, capillary refill > 3 seconds), in which case open exploration of the artery would be warranted.

Question 4513

Topic: 4. Pediatrics

A 6-year-old boy presents with a displaced extension-type supracondylar humerus fracture. Upon initial presentation, his radial pulse is absent, but his hand is warm, pink, and well-perfused. Following successful closed reduction and percutaneous pinning in the operating room, his hand remains pink with brisk capillary refill, but the radial pulse remains absent. What is the most appropriate management?

. Immediate open vascular exploration
. Immediate open reduction of the fracture
. Admit for close observation and limb elevation
. CT angiography of the upper extremity
. Remove the pins and hyperflex the elbow

Correct Answer & Explanation

. Admit for close observation and limb elevation

Explanation

In a 'pulseless but pink' hand following reduction and pinning of a pediatric supracondylar fracture, observation is the recommended management. Excellent collateral circulation maintains perfusion, and the pulse typically returns within days.

Question 4514

Topic: Pediatric Hip

A 12-year-old obese male presents with a slipped capital femoral epiphysis (SCFE). Which of the following best describes the typical anatomical direction of epiphyseal displacement relative to the femoral neck?

. Anterior and superior
. Anterior and inferior
. Posterior and superior
. Posterior and inferior
. Directly posterior

Correct Answer & Explanation

. Posterior and inferior

Explanation

In a slipped capital femoral epiphysis, the epiphysis typically displaces posteriorly and inferiorly relative to the femoral neck metaphysis. Conversely, the metaphysis translates anteriorly and superiorly.

Question 4515

Topic: Pediatric Hip

When treating developmental dysplasia of the hip (DDH) in an infant with a Pavlik harness, excessive hyperflexion of the hip (greater than 120 degrees) increases the risk of which iatrogenic complication?

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

Correct Answer & Explanation

. Femoral nerve palsy

Explanation

Excessive flexion (>120 degrees) in a Pavlik harness puts the patient at risk for a femoral nerve palsy due to compression of the nerve against the inguinal ligament. Excessive abduction, on the other hand, risks avascular necrosis.

Question 4516

Topic: Pediatric Hip

A 6-year-old boy is diagnosed with Legg-Calve-Perthes disease (LCPD). According to the Herring lateral pillar classification, which radiographic feature is the most critical determinant of a poor prognosis (Herring Group C)?

. Sclerosis of the anterior pillar
. Greater than 50% loss of lateral pillar height
. Less than 50% loss of lateral pillar height
. Central pillar fragmentation only
. Presence of a subchondral crescent sign

Correct Answer & Explanation

. Greater than 50% loss of lateral pillar height

Explanation

The Herring lateral pillar classification heavily dictates prognosis in LCPD based on AP pelvic radiographs in the fragmentation stage. Group C, defined by >50% loss of lateral pillar height, portends the worst prognosis with the highest risk of permanent femoral head deformity.

Question 4517

Topic: 4. Pediatrics

A 7-year-old boy presents with a waddling gait and joint pain. Radiographs demonstrate small, irregular, and delayed ossification of the epiphyses in the hips and knees, with a radiographically normal spine. Mutations in which of the following genes are most commonly associated with this specific condition?

. COL1A1
. COMP
. FGFR3
. RUNX2
. SOX9

Correct Answer & Explanation

. COMP

Explanation

The clinical and radiographic presentation of irregular epiphyses with a normal spine is classic for Multiple Epiphyseal Dysplasia (MED). Mutations in the COMP gene (Cartilage Oligomeric Matrix Protein) are the most common cause of the autosomal dominant form of MED. FGFR3 mutations cause achondroplasia and hypochondroplasia. COL1A1/COL1A2 cause osteogenesis imperfecta. RUNX2 causes cleidocranial dysplasia.

Question 4518

Topic: 4. Pediatrics

A 10-year-old boy sustains a Salter-Harris type II fracture of the distal radius. The initial fracture cleavage plane mechanically propagates primarily through which specific histologic zone of the physis?

. Zone of resting cells
. Zone of proliferation
. Zone of hypertrophy
. Zone of provisional calcification
. Primary spongiosa

Correct Answer & Explanation

. Zone of hypertrophy

Explanation

Physeal fractures typically fail through the zone of hypertrophy. This layer is mechanically the weakest region of the growth plate because of the large cellular volume of the swollen chondrocytes and the relative lack of extracellular matrix.

Question 4519

Topic: Pediatric Hip

A 4-month-old infant is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). During follow-up, the mother notes the child is no longer actively extending the knee on the treated side. Which of the following harness malpositioning errors is the most likely cause?

. Excessive hip abduction
. Excessive hip adduction
. Excessive hip flexion
. Insufficient hip flexion
. Insufficient hip abduction

Correct Answer & Explanation

. Excessive hip flexion

Explanation

Placing the hip in excessive flexion within a Pavlik harness can compress the femoral nerve against the inguinal ligament. This results in a transient femoral nerve palsy, evident by a lack of active knee extension.

Question 4520

Topic: 4. Pediatrics

In a classic Salter-Harris Type I fracture of the distal radius in a pediatric patient, the fracture line typically propagates through which distinct histologic zone of the physis?

. Resting zone
. Proliferative zone
. Zone of hypertrophy
. Zone of provisional calcification
. Primary spongiosa

Correct Answer & Explanation

. Zone of hypertrophy

Explanation

Salter-Harris fractures most commonly propagate through the zone of hypertrophy. This zone lacks the structural support of abundant extracellular matrix and calcification, making it the weakest point biomechanically.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page