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4. Pediatrics MCQs

Practice Set 42 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 821

Topic: Pediatric Hip

A 12-year-old obese boy presents with a 3-week history of groin pain and a limp. Examination reveals obligatory external rotation with hip flexion. Radiographs confirm a stable slipped capital femoral epiphysis (SCFE). What is the most appropriate standard surgical management?

. Spica casting
. In situ pinning with a single cannulated screw
. Open reduction and internal fixation
. Prophylactic pinning of the contralateral hip only
. Proximal femoral osteotomy

Correct Answer & Explanation

. In situ pinning with a single cannulated screw

Explanation

The gold standard treatment for a stable SCFE is in situ percutaneous pinning using a single partially threaded cannulated screw. This prevents further slippage while minimizing the risk of avascular necrosis and chondrolysis.

Question 822

Topic: Pediatric Upper Extremity & Spine
A 6-year-old boy falls off monkey bars and sustains a significantly displaced supracondylar humerus fracture (Gartland Type III). He has an absent radial pulse but a well-perfused, "pink, and warm" hand. What is the most appropriate initial management in the operating room?
. Emergent brachial artery exploration
. Closed reduction and percutaneous pinning followed by reassessment of the pulse
. Open reduction via an anterior approach
. Angiography to localize the arterial injury
. Application of a splint and observation for 24 hours

Correct Answer & Explanation

. Closed reduction and percutaneous pinning followed by reassessment of the pulse

Explanation

For a "pink, pulseless" hand in the setting of a displaced supracondylar humerus fracture, the initial step is urgent closed reduction and percutaneous pinning. The pulse frequently returns after fracture realignment; vascular exploration is reserved for cases where the hand remains dysvascular (white and pulseless) after reduction.

Question 823

Topic: 4. Pediatrics
All of the following may be present in a child with type IIIA hypoplasia except:
. Metacarpophalangeal (MP) joint laxity
. Web space contracture
. Lack of extensor pollicis longus
. Unstable carpometacarpal (CMC) joint
. Thenar muscle atrophy

Correct Answer & Explanation

. Unstable carpometacarpal (CMC) joint

Explanation

Type IIIA hypoplasia includes web space narrowing, thenar atrophy, MP joint laxity, and extrinsic tendon abnormalities. Type IIIA is distinguished from a type IIIB by the fact that a stable CMC joint exists. Because a stable CMC joint exists, a reconstruction is the treatment of choice. When the CMC joint is unstable, as in type IIIB hypoplasia, a pollicization is necessary to restore thumb stability.

Question 824

Topic: Pediatric Hip

A 13-year-old obese boy presents with an insidious onset of knee pain and a limp. A pelvic radiograph is obtained.

Which of the following radiographic lines is most appropriate to evaluate for Slipped Capital Femoral Epiphysis (SCFE)?

. Shenton's line
. Klein's line
. Hilgenreiner's line
. Perkin's line
. Skinner's line

Correct Answer & Explanation

. Klein's line

Explanation

Klein's line is drawn along the superior margin of the femoral neck on an AP and frog-leg lateral radiograph. In a normal hip, it intersects the lateral portion of the femoral epiphysis; in SCFE, the epiphysis falls below this line.

Question 825

Topic: 4. Pediatrics

A 4-month-old infant is being treated with a Pavlik harness for Developmental Dysplasia of the Hip (DDH). The mother notes that the child has stopped kicking the affected leg. On exam, the child lacks active knee extension. Which nerve is most likely compressed due to hyperflexion?

. Sciatic nerve
. Femoral nerve
. Obturator nerve
. Lateral femoral cutaneous nerve
. Superior gluteal nerve

Correct Answer & Explanation

. Femoral nerve

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment when the hip is placed in excessive flexion. The harness should be temporarily discontinued, and function almost always recovers spontaneously.

Question 826

Topic: Pediatric Hip

An obese 13-year-old boy presents with left knee pain and an obligate external rotation of the hip during flexion. The radiograph is shown below.

When treating this condition with in situ percutaneous pinning, what is the most significant iatrogenic risk factor for the development of chondrolysis?

. Prophylactic pinning of the contralateral hip
. In situ fixation using a single fully-threaded screw
. Unrecognized intra-articular hardware penetration
. Delayed surgical intervention beyond 4 weeks
. Starting the screw on the anterior aspect of the femoral neck

Correct Answer & Explanation

. Unrecognized intra-articular hardware penetration

Explanation

In Slipped Capital Femoral Epiphysis (SCFE), unrecognized intra-articular screw penetration is a major risk factor for chondrolysis. Surgeons must use the "approach-withdraw" fluoroscopic technique to confirm the screw tip is entirely within the femoral head.

Question 827

Topic: Pediatric Hip

A 6-month-old infant with developmental dysplasia of the hip (DDH) failed Pavlik harness treatment and is scheduled for a closed reduction and spica casting. During the procedure, the surgeon assesses the "safe zone" of Ramsey. How is this zone defined?

. The arc of motion between maximum adduction and maximum internal rotation
. The arc of motion between maximum abduction and the angle of re-dislocation in adduction
. The arc between maximum hip flexion and full extension
. The degree of coverage of the femoral head by the acetabulum measured fluoroscopically
. The alpha angle measured dynamically on intraoperative ultrasound

Correct Answer & Explanation

. The arc of motion between maximum abduction and the angle of re-dislocation in adduction

Explanation

Ramsey's safe zone is the arc of motion between maximum abduction (limited by the adductors) and the angle at which the hip re-dislocates as it is adducted. Immobilization within this zone prevents both avascular necrosis (from excessive abduction) and re-dislocation.

Question 828

Topic: 4. Pediatrics

Congenital thumb duplication:

. Should be treated after 2 years of age
. Usually presents bilaterally
. Usually presents in association with other systemic abnormalities
. Often presents with a hypoplastic radial thumb and a dominant-appearing ulnar thumb
. Occurs in approximately 1 out of every 5,000 births

Correct Answer & Explanation

. Often presents with a hypoplastic radial thumb and a dominant-appearing ulnar thumb

Explanation

Experts recommend treating congenital thumb duplication before the age of 6 months, when the potential for growth and remodeling is greatest. The condition usually presents unilaterally, lacking association with other systemic abnormalities, and usually presents with a hypoplastic radial duplicate and dominant ulnar duplicate.

Question 829

Topic: 4. Pediatrics

One of the more common complications of congenital thumb duplication reconstruction is:

. Weakness of resulting digit
. Paresthesias in resulting digit
. Ulnar deviation at metacarpophalangeal joint and radial deviation at interphalangeal joint
. Nonhealing wound
. Nail splitting

Correct Answer & Explanation

. Ulnar deviation at metacarpophalangeal joint and radial deviation at interphalangeal joint

Explanation

A Z-deformity, with ulnar deviation at the MC P joint and radial deviation at the IP joint, is one of the most common complications after reconstruction. Weakness, paresthesias, and wound complications are uncommon possible complications.

Question 830

Topic: 4. Pediatrics

A 6-year-old child sustains an extension-type supracondylar fracture of the humerus. On examination, the child is unable to form an "A-OK" sign with the thumb and index finger. Which nerve is most likely injured?

. Median nerve main trunk
. Anterior interosseous nerve (AIN)
. Radial nerve
. Ulnar nerve
. Musculocutaneous nerve

Correct Answer & Explanation

. Anterior interosseous nerve (AIN)

Explanation

The anterior interosseous nerve (AIN) is the most commonly injured nerve in extension-type pediatric supracondylar humerus fractures. Injury to the AIN results in weakness of the flexor pollicis longus and flexor digitorum profundus to the index finger, preventing the "A-OK" sign.

Question 831

Topic: 4. Pediatrics

A 4-month-old infant is treated with a Pavlik harness for developmental dysplasia of the hip. At the 2-week follow-up, the infant is noted to have decreased active knee extension on the affected side. What is the most appropriate next step in management?

. Continue the harness and observe for spontaneous recovery
. Discontinue the harness immediately
. Switch to a rigid hip spica cast
. Perform an immediate open reduction
. Obtain an MRI of the lumbar spine to rule out dysraphism

Correct Answer & Explanation

. Discontinue the harness immediately

Explanation

Decreased active knee extension indicates a femoral nerve palsy, a known complication of Pavlik harness treatment due to excessive hip flexion. The harness must be discontinued immediately to allow the nerve to recover before attempting alternative treatments.

Question 832

Topic: Pediatric Hip

A 13-year-old obese male presents with a 3-week history of right groin pain and a slight limp. On physical examination, as the right hip is passively flexed, it obligatorily deviates into external rotation. What is the eponymous name of this clinical sign?

. Ortolani sign
. Barlow sign
. Galeazzi sign
. Drehmann sign
. Trendelenburg sign

Correct Answer & Explanation

. Drehmann sign

Explanation

The Drehmann sign is the obligatory external rotation of the hip during passive flexion. It is a classic and highly indicative physical examination finding in patients with a slipped capital femoral epiphysis (SCFE).

Question 833

Topic: 4. Pediatrics

A 6-year-old child sustains a severely displaced extension-type supracondylar humerus fracture. On presentation, the hand is pink but the radial pulse is absent. Following urgent closed reduction and percutaneous pinning, the hand remains pink with brisk capillary refill, but the radial pulse is still not palpable. What is the most appropriate next step?

. Immediate exploration of the brachial artery
. Observation and admission for 24-48 hours
. Prophylactic fasciotomy of the forearm
. Removal of the pins and conversion to open reduction
. Emergent CT angiography of the upper extremity

Correct Answer & Explanation

. Observation and admission for 24-48 hours

Explanation

A 'pulseless but pink' hand after reduction and pinning of a pediatric supracondylar humerus fracture indicates adequate collateral perfusion. The standard of care is close observation for 24-48 hours, as the pulse often returns once spasm and edema subside.

Question 834

Topic: Pediatric Upper Extremity & Spine

Which of the following is not usually associated with radial deficiency:

. Thrombocytopenia absent radii
. Fanconi anemia
. Holt-Oram syndrome
. Larsen syndrome
. C ardiac anomalies

Correct Answer & Explanation

. Larsen syndrome

Explanation

Patients with thrombocytopenia absent radii, Fanconi anemia, Holt-Oram syndrome, and cardiac anomolies all are associated with radial deficiency. Larsen syndrome is associated with multiple, larger joint dislocation.

Question 835

Topic: 4. Pediatrics
A 6-year-old boy presents with a Salter-Harris II distal radius fracture 3 weeks after injury. He is nontender and neurologically intact. On radiographs, he has a 35ยฐ dorsal angulation. The appropriate course of treatment is:
. Observe, cast, follow until healed
. Observe, cast, follow with serial radiographs for at least 2 years
. Close reduction and casting
. Close reduction and pins
. Open reduction

Correct Answer & Explanation

. Observe, cast, follow with serial radiographs for at least 2 years

Explanation

For a patient with delayed presentation of a distal radius fracture, appropriate management includes casting and observation for at least 2 years to assess physeal damage and remodeling. The patient may require osteotomy if remodeling does not occur.

Question 836

Topic: 4. Pediatrics

A 24-year-old man presents with a short forearm and a hand deformity. The patient is otherwise healthy with no other congenital defects. The clinical appearance of his forearm is shown (Slide). Your diagnosis is:

. Ulnar club hand
. Preaxial longitudinal deficiency
. Postaxial longitudinal deficiency
. Thumb aplasia
. Hypoplastic hand syndrome

Correct Answer & Explanation

. Preaxial longitudinal deficiency

Explanation

This is a classic appearance of a radial club hand, which is often referred to as preaxial longitudinal deficiency. Ulnar club hand and postaxial longitudinal deficiency are synonymous.

Question 837

Topic: 4. Pediatrics

A 24-year-old man presents with a short forearm and a hand deformity. The patient is otherwise healthy with no other congenital defects. The clinical appearance of his forearm is shown (Slide). The patient has an elbow flexion contracture of 70ยฐ and desires lengthening. Which of the following statements is not true regarding lengthening:

. Nerve palsies may occur during lengthening.
. Lengthening must be done gradually.
. Lengthening usually equalizes limb length.
. Lengthening helps improve function by extending the reach.
. Lengthening leads to recurrence of the deformity.

Correct Answer & Explanation

. Nerve palsies may occur during lengthening.

Explanation

In most cases of radial club hand, excluding a hypoplastic radius, full correction cannot be achieved.

Question 838

Topic: 4. Pediatrics

A 24-year-old man presents with a short forearm and a hand deformity. The patient is otherwise healthy with no other congenital defects. The clinical appearance of his forearm is shown (Slide). Although the patient has a thumb, it is in an abnormal position. Any attempt to make his thumb more functional will be influenced by:

. Index finger camptodactyly
. Presence of a side-to-side finger grip
. Stiff fingers
. Recurrence of radial club hand
. Radial bowing

Correct Answer & Explanation

. Presence of a side-to-side finger grip

Explanation

The pattern of usage of the hand is established in the brain by 2 to 3 years of age. Although pollicization has been performed in adolescents, patients continue to prefer a scissor pinch. At 24 years of age, this pattern will be well established. The patient can be coaxed to use his thumb, but it will not be involuntary and automatic.C orrect Answer: Presence of a side-to-side finger grip

Question 839

Topic: Pediatric Upper Extremity & Spine

A radial club hand is the result of an insult during which phase of the gestation period:

. Weeks 1 to 4
. Weeks 4 to 7
. Weeks 8 to 12
. Weeks 12 to 16
. Anytime during gestation

Correct Answer & Explanation

. Weeks 4 to 7

Explanation

A radial club hand is the result of an insult during weeks 4 to 7 of gestation.

Question 840

Topic: Pediatric Upper Extremity & Spine
A 15-day-old boy presents with deformity of the right hand. The boy was delivered prematurely and underwent an urgent arterial switch for transposition of great vessels. The patient is in stable condition. He has a radial club hand, and because the radial head cannot be palpated, total absence of radius is suspected. The thumb is absent and the index finger has camptodactyly. The forearm is short compared to the left side, and the patient flexes his elbow upon stimulation. Spontaneous finger motion is also present. A thorough physical examination is performed and a set of investigations is ordered. The results are as follows: complete blood count 10,000/ยตL; platelet 254ร—10^3/ยตL; neutrophils 50%; Hb 14.2 g/dL; lymphocytes 40%; Hct 45%; and monocytes 10%. No renal abnormalities were noted on ultrasonogram of the abdomen. A radiograph of the spine is normal. Diagnosis is:
. Vertebral defects, anal atresia, tracheoesophageal fistula with esophageal atresia, and radial and renal anomalies (VATER)
. Abnormalities of vertebrae, anus, cardiovascular tree, trachea, esophagus, renal system, and limb buds (VACTERL)
. Thrombocytopenia absent radii (TAR) syndrome
. Holt-Oram syndrome
. Fanconi's anemia

Correct Answer & Explanation

. Holt-Oram syndrome

Explanation

The patient has a radial club hand with a cardiac defect. Because the spine radiograph is normal, the diagnosis cannot be VATER or VACTERL anomaly as both involve vertebrae. Blood work up is normal, making this diagnosis Holt-Oram syndrome.

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