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4. Pediatrics MCQs

Practice Set 103 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 2041

Topic: Pediatric Hip

A 13-year-old obese male presents with a 3-week history of left knee pain and an antalgic gait. Exam shows obligatory external rotation of the left hip upon flexion. Radiographs confirm a severe left slipped capital femoral epiphysis (SCFE). Which of the following parameters is the strongest indication for prophylactic pinning of the asymptomatic contralateral hip?

. Age under 10 or open triradiate cartilage
. Male gender
. Severity of the symptomatic slip
. BMI greater than 95th percentile
. Endocrine disorder such as hypothyroidism

Correct Answer & Explanation

. Endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip is strongly indicated in patients with underlying endocrinopathies, such as hypothyroidism or renal osteodystrophy. Other relative indications include open triradiate cartilage and age less than 10 years, but endocrine disorders carry the highest risk of bilateral involvement.

Question 2042

Topic: Pediatric Hip
A 6-week-old female infant born breech undergoes a screening hip ultrasound. The Graf classification reveals an alpha angle of 45 degrees and a beta angle of 80 degrees. What does this indicate, and what is the most appropriate management?
. Normal hip; reassurance
. Physiologic immaturity; repeat ultrasound in 4 weeks
. Subluxated hip (Graf Type III); Pavlik harness
. Dislocated hip (Graf Type IV); closed reduction and spica cast
. Septic hip; urgent aspiration

Correct Answer & Explanation

. Subluxated hip (Graf Type III); Pavlik harness

Explanation

An alpha angle less than 60 degrees indicates acetabular dysplasia. Specifically, an alpha angle < 50 degrees and beta angle > 77 degrees denotes a Graf Type III hip (subluxated). The first-line treatment for a reducible dysplastic hip at this age is a Pavlik harness.

Question 2043

Topic: 4. Pediatrics

A 12-year-old child with cerebral palsy (GMFCS level V) develops a progressive thoracolumbar scoliosis exceeding 60 degrees, leading to significant sitting imbalance, worsening pain, and recurrent respiratory infections. The patient has severe spasticity and a history of gastric reflux. Surgical correction is planned. What is the MOST critical consideration in the preoperative evaluation and planning for this patient, beyond standard scoliosis workup?

. Cardiopulmonary function assessment and optimization
. Preoperative halo traction for curve correction
. Assessment for tethered spinal cord syndrome
. Dual energy X-ray absorptiometry (DEXA) scan for bone density
. Gastrointestinal evaluation for dysphagia and reflux management

Correct Answer & Explanation

. Cardiopulmonary function assessment and optimization

Explanation

In patients with neuromuscular scoliosis, especially those with severe cerebral palsy (GMFCS V), cardiopulmonary complications are the leading cause of morbidity and mortality. These patients often have restrictive lung disease, aspiration risk, and impaired cough reflex, making a thorough preoperative cardiopulmonary assessment and optimization paramount. While gastrointestinal issues like reflux (option E) are common and require management, and bone density (option D) is important for fixation, the immediate surgical risks and long-term prognosis are most significantly impacted by pulmonary status. Halo traction (option B) is used for very rigid curves, and tethered cord (option C) is more relevant for myelomeningocele or rapidly progressive curves, not typically the primary concern in cerebral palsy scoliosis without specific neurological changes.

Question 2044

Topic: Pediatric Hip

A 12-year-old obese boy presents with right hip pain and a limp. Radiographs confirm a stable severe right slipped capital femoral epiphysis (SCFE) with a Southwick slip angle of 65 degrees.

What is the strongest primary indication for prophylactic in situ pinning of the contralateral, asymptomatic hip?

. Southwick angle greater than 50 degrees on the symptomatic side
. Age less than 10 years or open triradiate cartilage
. Presence of an underlying endocrine disorder such as hypothyroidism
. Male gender and BMI greater than the 95th percentile
. Family history of early onset hip osteoarthritis

Correct Answer & Explanation

. Presence of an underlying endocrine disorder such as hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is universally recommended in patients with underlying endocrine or metabolic disorders (e.g., hypothyroidism, renal osteodystrophy). These patients have an exceptionally high risk of developing bilateral disease.

Question 2045

Topic: Pediatric Hip

A 12-year-old obese male presents with 3 weeks of left groin pain and a limp. Exam shows obligate external rotation with hip flexion. Radiographs confirm a stable left slipped capital femoral epiphysis (SCFE). Which of the following is the most appropriate absolute indication for prophylactic pinning of the contralateral asymptomatic hip?

. Moderate slip angle on affected side
. Female gender
. Endocrine disorder (e.g., hypothyroidism)
. Age > 14 years
. BMI > 95th percentile

Correct Answer & Explanation

. Endocrine disorder (e.g., hypothyroidism)

Explanation

Prophylactic pinning of the contralateral hip is strongly recommended in patients with endocrine disorders (e.g., hypothyroidism, renal osteodystrophy) or prior radiation therapy, as their risk of bilateral SCFE approaches 100%. Age < 10 is also a significant risk factor, whereas older age and simple obesity are not absolute indications.

Question 2046

Topic: 4. Pediatrics

A 6-year-old boy sustains a severe supracondylar humerus fracture resulting in a pink, pulseless hand. Closed reduction and percutaneous pinning are performed expeditiously. Postoperatively, the hand remains pink and capillary refill is less than 2 seconds, but the radial pulse remains completely absent. What is the most appropriate next step in management?

. Immediate open vascular exploration of the brachial artery
. Observe and admit the patient for close serial vascular examinations
. Remove the pins and partially extend the elbow to relieve tension
. Perform a stellate ganglion sympathetic block
. Order a CT angiogram immediately to locate the exact site of occlusion

Correct Answer & Explanation

. Observe and admit the patient for close serial vascular examinations

Explanation

In a pink, pulseless hand following adequate reduction and stabilization of a pediatric supracondylar fracture, the standard of care is careful observation. Vascular exploration is strictly indicated if the hand becomes persistently white and pulseless despite adequate fracture reduction.

Question 2047

Topic: 4. Pediatrics
A 6-year-old child presents with a pulseless, pink hand following a fall from monkey bars. Radiographs show a Garland III posterolaterally displaced supracondylar humerus fracture. What is the most likely concomitant neurologic deficit?
. Inability to extend the wrist against resistance
. Inability to cross the middle finger over the index finger
. Inability to flex the interphalangeal joint of the thumb
. Numbness over the dorsal first web space
. Numbness over the volar aspect of the little finger

Correct Answer & Explanation

. Inability to flex the interphalangeal joint of the thumb

Explanation

Posterolateral displacement of a supracondylar humerus fracture places the anterior interosseous nerve (AIN) at highest risk due to stretch over the proximal fracture fragment. AIN palsy presents as the inability to flex the thumb IP joint and index finger DIP joint (loss of the "OK" sign).

Question 2048

Topic: Pediatric Hip

A 12-year-old boy with a BMI of 32 presents with right knee pain and an obligate external rotation of the hip during passive flexion. Radiographs confirm a severe, stable slipped capital femoral epiphysis (SCFE). Prophylactic pinning of the contralateral, asymptomatic hip is most strongly indicated if the patient has a history of which of the following?

. Type 1 Diabetes Mellitus
. Hypothyroidism
. Down syndrome
. Asthma requiring intermittent corticosteroids
. Attention deficit hyperactivity disorder

Correct Answer & Explanation

. Hypothyroidism

Explanation

Prophylactic pinning of the contralateral hip in SCFE is highly recommended in patients with underlying endocrine disorders such as hypothyroidism, growth hormone deficiency, or renal osteodystrophy. These systemic factors significantly increase the risk of a subsequent contralateral slip.

Question 2049

Topic: 4. Pediatrics
A 6-year-old boy sustains a supracondylar humerus fracture with complete posterior displacement. Initially, he has an absent radial pulse but the hand is warm and pink. Closed reduction and percutaneous pinning are performed. Post-reduction, the radial pulse remains non-palpable, but capillary refill in the fingers remains brisk (<2 seconds). What is the most appropriate next step in management?
. Immediate open exploration of the brachial artery
. Removal of the pins and conversion to open reduction
. Bedside prophylactic forearm fasciotomy
. Observation and splinting with the elbow in 60-70 degrees of flexion
. Immediate CT angiogram of the upper extremity

Correct Answer & Explanation

. Observation and splinting with the elbow in 60-70 degrees of flexion

Explanation

In the setting of a 'pulseless, pink' hand following successful, anatomically aligned reduction and pinning of a pediatric supracondylar humerus fracture, the standard of care is close clinical observation. Vascular exploration is strictly indicated only if the hand is cold, poorly perfused, and pulseless (white hand) after reduction.

Question 2050

Topic: 4. Pediatrics

A 15-year-old baseball pitcher presents with chronic medial elbow pain, especially during the acceleration phase of throwing. Examination reveals tenderness over the medial epicondyle and a positive valgus stress test. Radiographs show physeal widening of the medial epicondyle. Which of the following is the MOST appropriate initial management strategy?

. Surgical reconstruction of the ulnar collateral ligament (UCL)
. Medial epicondyle excision
. Complete rest from throwing for several months, followed by a gradual return to activity program
. Corticosteroid injection into the medial epicondyle
. Ulnar nerve transposition

Correct Answer & Explanation

. Complete rest from throwing for several months, followed by a gradual return to activity program

Explanation

This presentation is classic for 'Little League Elbow', an overuse injury in adolescent throwing athletes, involving stress on the medial epicondylar physis. Physeal widening indicates apophysitis or avulsion. The initial management is non-operative and involves complete rest from throwing to allow the physis to heal, followed by a structured rehabilitation program focusing on strengthening and proper throwing mechanics. Surgical reconstruction of the UCL is reserved for chronic UCL insufficiency in skeletally mature athletes who have failed extensive non-operative management. Medial epicondyle excision is rarely indicated in this age group. Corticosteroid injections are generally contraindicated in growing physes and tendons. Ulnar nerve transposition may be needed if there is symptomatic ulnar nerve compression, but it's not the primary treatment for the bony pathology.

Question 2051

Topic: 4. Pediatrics

A 14-year-old female presents with a progressive, painless deformity of her right shoulder, characterized by elevation and medial rotation of the scapula, and a short, thick neck. She has limited abduction of the shoulder. What is the MOST likely diagnosis?

. Sprengel's deformity
. Klippel-Feil syndrome
. Poland syndrome
. Congenital pseudoarthrosis of the clavicle
. Congenital muscular torticollis

Correct Answer & Explanation

. Sprengel's deformity

Explanation

This clinical description is classic for Sprengel's deformity, which is congenital elevation and hypoplasia of the scapula. It is characterized by a high-riding scapula that is medially rotated, often associated with a short, thick neck, and limited shoulder abduction due to the abnormal position of the scapula and potential omovertebral bone. Klippel-Feil syndrome is congenital fusion of cervical vertebrae. Poland syndrome involves absence of the pectoralis major and often hand abnormalities. Congenital pseudoarthrosis of the clavicle is a distinct clavicular anomaly. Congenital muscular torticollis involves sternocleidomastoid contracture.

Question 2052

Topic: Pediatric Upper Extremity & Spine

A 7-year-old boy presents with left elbow pain and swelling following a fall from a monkey bar. Radiographs reveal a Gartland Type II supracondylar humerus fracture. His radial pulse is palpable and strong, and he has no neurological deficits. What is the MOST appropriate initial management?

. Open reduction and internal fixation (ORIF)
. Closed reduction and long arm cast immobilization in hyperflexion
. Closed reduction and percutaneous pinning
. Sling immobilization alone
. Observe for 24 hours

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

A Gartland Type II supracondylar humerus fracture is displaced posteriorly with an intact posterior cortex, making it inherently unstable. Given the displacement, closed reduction and percutaneous pinning (CRPP) is the treatment of choice. This provides stable fixation while preserving the biology and allows for early mobilization to prevent stiffness. Closed reduction and casting in hyperflexion is an older technique with risks of neurovascular compromise and redisplacement. ORIF is reserved for irreducible fractures or those with open wounds. Sling immobilization is for non-displaced fractures (Type I). Observation is inappropriate for a displaced fracture.

Question 2053

Topic: 4. Pediatrics

Which of the following is considered an absolute indication for replantation following an amputation?

. Single digit amputation in Zone II in a 45-year-old manual laborer
. Avulsion amputation of the ring finger in an adult
. Thumb amputation at the metacarpophalangeal joint
. Crush amputation of the index finger
. Amputation in an adult patient with severe psychiatric illness

Correct Answer & Explanation

. Thumb amputation at the metacarpophalangeal joint

Explanation

Absolute indications for replantation include amputations of the thumb, multiple digits, any amputation in a child, and amputations through the palm or wrist. Single digit amputations in Zone II for adults are generally relative contraindications depending on patient factors.

Question 2054

Topic: Pediatric Upper Extremity & Spine
A 10-year-old boy falls off a bicycle, sustaining a completely displaced supracondylar humerus fracture (Gartland Type III). He has a palpable radial pulse, but is unable to extend his fingers and has numbness in the distribution of the median nerve. Which of the following is the most urgent next step?
. Obtain an orthopedic consultation for closed reduction and percutaneous pinning.
. Perform an urgent nerve conduction study.
. Administer corticosteroids to reduce swelling.
. Observe for 24 hours to see if neurological symptoms improve.
. Order an MRI to assess nerve injury.

Correct Answer & Explanation

. Obtain an orthopedic consultation for closed reduction and percutaneous pinning.

Explanation

A completely displaced supracondylar humerus fracture (Gartland Type III) requires urgent reduction and fixation due to the high risk of neurovascular compromise and development of Volkmann's ischaemic contracture. The presence of median nerve palsy, even with a palpable radial pulse, indicates significant injury and potential for further compromise. Urgent closed reduction and percutaneous pinning (CRPP) is the treatment of choice. Restoration of anatomical alignment often resolves or improves nerve deficits and protects the vascular supply. Delay can lead to irreversible damage. Nerve conduction studies or MRI are not needed urgently and would delay critical intervention. Corticosteroids are not indicated. Observation is dangerous and inappropriate.

Question 2055

Topic: 4. Pediatrics

A 12-year-old boy sustains a physeal injury to his distal tibia (Salter-Harris Type II) after a sports injury. The fracture is minimally displaced. What is the most important factor to counsel the parents about regarding potential long-term complications?

. Risk of infection.
. Development of avascular necrosis.
. Growth arrest and angular deformity.
. Post-traumatic arthritis.
. Recurrent sprains.

Correct Answer & Explanation

. Growth arrest and angular deformity.

Explanation

Salter-Harris fractures involve the physis (growth plate) and, therefore, carry a risk of growth disturbance. For a Salter-Harris Type II fracture, the fracture line extends through the physis and into the metaphysis, but spares the epiphysis. While generally having a good prognosis, any physeal injury has the potential for premature physeal closure, leading to growth arrest and subsequent angular deformity (e.g., limb length discrepancy or malalignment). The risk increases with the severity of the Salter-Harris type (Type V being the highest risk) and the extent of growth plate damage. Infection, avascular necrosis, and post-traumatic arthritis are less common or primary concerns for this specific injury type. Recurrent sprains are not a direct complication of a physeal fracture.

Question 2056

Topic: 4. Pediatrics

A 14-year-old male sustains a displaced epiphyseal fracture of the medial epicondyle of the humerus. Radiographs show the fragment is incarcerated in the elbow joint. Which of the following is the most appropriate management?

. Closed reduction and long arm cast.
. Open reduction and internal fixation (ORIF).
. Excision of the incarcerated fragment.
. Observation with repeat radiographs in 1 week.
. Elbow traction for 3 weeks.

Correct Answer & Explanation

. Open reduction and internal fixation (ORIF).

Explanation

A displaced medial epicondyle fracture, especially if incarcerated within the elbow joint, requires open reduction and internal fixation (ORIF). The fragment needs to be anatomically reduced and fixed (typically with a screw or K-wires) to restore elbow stability and prevent ongoing mechanical blockage or ulnar nerve irritation. Attempting closed reduction is unlikely to succeed if the fragment is truly incarcerated. Excision is generally avoided in a growing child to preserve the physis. Observation or traction are inappropriate for an incarcerated fragment.

Question 2057

Topic: 4. Pediatrics

A 2-month-old infant presents with a transverse femoral shaft fracture after a suspicious mechanism of injury. What is the most critical next step in management beyond fracture care?

. Application of a Pavlik harness.
. Referral to a child protection team.
. Immediate traction and spica cast.
. Skeletal survey to look for other occult fractures.
. MRI of the brain to rule out intracranial injury.

Correct Answer & Explanation

. Referral to a child protection team.

Explanation

In an infant (typically under 1 year, but often up to 2 years), a transverse femoral shaft fracture, especially with a suspicious mechanism, raises high concern for non-accidental injury (child abuse). The most critical next step, beyond stabilizing the fracture, is a referral to a child protection team (social services). A skeletal survey for other occult fractures and an MRI of the brain (for subdural hematomas) are also important investigations to complete the workup for abuse, but the referral ensures the safety of the child. A Pavlik harness is for developmental dysplasia of the hip. Traction and spica cast are for fracture management but not the immediate priority for investigation of abuse.

Question 2058

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls onto an outstretched hand and sustains a Gartland Type III supracondylar humerus fracture. On examination, his hand is pink but pulseless, with brisk capillary refill. What is the most appropriate initial management?
. Immediate CT angiogram of the upper extremity
. Urgent open exploration of the brachial artery
. Closed reduction and percutaneous pinning
. Application of a splint in 90 degrees of flexion
. Observation and elevation for 24 hours

Correct Answer & Explanation

. Closed reduction and percutaneous pinning

Explanation

A pink, pulseless hand in the setting of a displaced supracondylar fracture is typically due to brachial artery kinking or vasospasm. The first step is urgent closed reduction and percutaneous pinning, which relieves the traction on the vessel and frequently restores the palpable pulse.

Question 2059

Topic: 4. Pediatrics

Which zone of the physeal growth plate is characterized by chondrocytes that are metabolically active, rapidly dividing, and responsible for longitudinal bone growth?

. Zone of calcification
. Zone of hypertrophy
. Zone of resting
. Zone of proliferation
. Zone of ossification

Correct Answer & Explanation

. Zone of proliferation

Explanation

The epiphyseal growth plate (physis) is divided into several distinct zones, each with specific cellular activities contributing to longitudinal bone growth. The Zone of Resting (Reserve Zone) contains quiescent chondrocytes. The Zone of Proliferation is where chondrocytes actively divide and arrange into columns, thereby increasing the length of the cartilage model. Following this, cells enter the Zone of Hypertrophy, where they enlarge, accumulate lipids, and prepare for calcification and eventual apoptosis. The Zone of Calcification is where the hypertrophic chondrocytes' matrix becomes calcified. Finally, the Zone of Ossification is where osteoblasts deposit new bone on the calcified cartilage remnants.

Question 2060

Topic: 4. Pediatrics

Achondroplasia, the most common form of short-limbed dwarfism, is caused by a gain-of-function mutation in which receptor?

. Parathyroid hormone receptor 1 (PTHR1)
. Fibroblast growth factor receptor 3 (FGFR3)
. Bone morphogenetic protein receptor 1A (BMPR1A)
. Vitamin D receptor (VDR)
. Collagen Type II alpha 1 (COL2A1)

Correct Answer & Explanation

. Fibroblast growth factor receptor 3 (FGFR3)

Explanation

Achondroplasia is an autosomal dominant genetic disorder caused by a gain-of-function mutation in the Fibroblast Growth Factor Receptor 3 (FGFR3) gene. FGFR3 normally acts as a negative regulator of endochondral ossification. The activating mutation in achondroplasia leads to constitutive (always on) activation of this receptor, resulting in exaggerated inhibition of chondrocyte proliferation and differentiation in the growth plate. This premature cessation of chondrocyte activity severely impairs longitudinal bone growth, leading to the characteristic short-limbed dwarfism.

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