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4. Pediatrics MCQs

Practice Set 81 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 1601

Topic: Pediatric Upper Extremity & Spine

A 12-year-old girl who is 3 months postmenarchal undergoes full-time brace treatment for scoliosis. The posteroanterior radiograph (Figure A ) taken at that time reveals a right thoracic curve measures 28 degrees, and the left lumbar curve measures 23 degrees. At age 15, after 3 years of bracing, a repeat posteroanterior radiograph is obtained, now revealing a right thoracic curve measuring 11 degrees and the left lumbar curve measuring 19 degree, and Risser 4. Which statement best represents the indicated course of action in this patient? Review Topic

. Discontinuation of bracing as she has reached skeletal maturity.
. Continue full-time bracing until skeletal maturity.
. Continue nocturnal bracing until skeletal maturity.
. Posterior spinal fusion.
. MRI of the cervical, thoracic and lumbar spine.

Correct Answer & Explanation

. Discontinuation of bracing as she has reached skeletal maturity.

Explanation

This patient has adolescent idiopathic scoliosis (AIS) and has reached skeletal maturity. Bracing was successful and discontinuation of bracing is appropriate.Curves <25° can be treated with observation, while flexible curves from 25° to 45° in skeletally immature patients (Risser 0, 1, 2) should be treated with bracing. Bracing success is most commonly defined as <5° curve progression and failure is 6° or more curve progression at orthotic discontinuation (skeletal maturity), absolute progression to >45° either before or at skeletal maturity, or discontinuation in favor of surgery. Skeletal maturity is defined Risser sign 4, <1cm change in height over 2 visits 6 months apart, 2 years postmenarchal.Richards et al. attempted to define parameters for future AIS bracing studies. Outcome measures should include patients with (1) <5° curve progression vs >6° progression at maturity, (2) curves exceeding 45° at maturity, or those who have had surgery recommendation/undergone.Negrini et al. performed a Cochrane systematic review. Basing conclusions on 2studies, they found that (1) a brace treated curve progression (74% success) better than observation (34% success) and electrical stimulation (33% success), and (2) a rigid brace is more successful than an elastic one (SpineCor) at curbing curve progression.AisastandingPAradiographshowing.Incorrect

Question 1602

Topic: 4. Pediatrics
A 6-month-old child is seen in the emergency department with a spiral fracture of the tibia. The parents are vague about the etiology of the injury. There is no family history of a bone disease. In addition to casting of the fracture, initial management should include
. a skeletal survey to rule out other fractures.
. a punch biopsy of the skin for collagen analysis to rule out osteogenesis imperfecta.
. DNA testing for osteogenesis imperfecta.
. blood studies for calcium, phosphorus, and alkaline phosphate levels.
. blood studies for parathyroid hormone levels.

Correct Answer & Explanation

. a skeletal survey to rule out other fractures.

Explanation

DISCUSSION: Unwitnessed spiral fractures should raise the possibility of child abuse, especially prior to walking age. With nonaccidental trauma being considered in the differential diagnosis, a skeletal survey is indicated to determine if there are other fractures in various stages of healing.

Question 1603

Topic: 4. Pediatrics

A 7-year-old sustains the isolated injury shown in Figures A and B. On physical examination there is no evidence of soft tissue compromise and he is able to make an okay sign, give a thumbs up sign and cross his fingers. Which treatment will minimize complications? Review Topic

. Observation alone
. Closed reduction with casting in > 90 degrees of flexion
. Closed reduction with casting at 90 degrees of flexion
. Closed reduction and a percutaneous pinning construct using laterally based pins
. Closed reduction and a percutaneous pinning construct using crossed pins

Correct Answer & Explanation

. Observation alone

Explanation

This patient has sustained an extension type supracondylar fracture (Gartland Type 3). The optimal treatment is closed reduction and a percutaneous pinning construct using laterally based pins.Supracondylar fractures are common pediatric elbow injuries. Extension type injuries account for 95-98% of all cases. Non-displaced injuries may be treated conservatively. Displaced fractures are treated with closed reduction and percutaneous pinning. Use of laterally divergent pin constructs avoids risk of ulnar nerve injury, while maintaining satisfactory fracture alignment.Slobogean et al. retrospectively reviewed pediatric supracondylar fractures to identify if there was an increased risk of ulnar nerve injury with crossed pin configurations. They found a higher incidence of ulnar nerve injury with crossed pinning constructs. For every 28 crossed pin constructs, there was one ulnar nerve injury identified.Woratanarat et al. retrospectively reviewed supracondylar fractures to identify differences in the outcomes between lateral pinning versus crossed pinning constructs. No difference was found for loss of fixation or development of late deformity between the two groups. Crossed pin constructs were associated with a 4.3 times higher risk of iatrogenic ulnar nerve injury.Omid et al. review pediatric supracondaylar humerus fractures. They note that lateral pinning is as stable as crossed pinning when appropriately spread-out at the fracture line. This also avoids the risk of ulnar nerve injury.Figures A and B show AP and lateral radiographs of a pediatric supracondylar fracture. This would be classified as a Gartland Type 3.Incorrect Answers:

Question 1604

Topic: 4. Pediatrics

A child with an idiopathic clubfoot is successfully treated by the Ponseti method. The risk of recurrence of the deformity is most dependent on which of the following factors? Review Topic

. Maternal age
. Positive family history
. Family's compliance with bracing
. The child's age at walking
. The child's body mass index

Correct Answer & Explanation

. Maternal age

Explanation

The recurrence rate of clubfoot deformity after successful correction by the Ponseti method has been shown to inversely correlate with reported brace compliance. Maternal age, walking age, and body mass index have not been correlated to recurrence. A positive family history increases the risk of a child being born with a clubfoot but does not influence the recurrence rate.

Question 1605

Topic: 4. Pediatrics
Figures 9a and 9b show the spinal radiographs of a 3-year-old child with short limb dwarfism. The lateral radiograph is obtained with maximal lumbar extension. Management should consist of:
. Close clinical follow-up
. A thoracolumbosacral orthosis
. Anterior spinal fusion
. Posterior spinal fusion
. Fibroblast growth factor replacement

Correct Answer & Explanation

. Close clinical follow-up

Explanation

The patient has kyphosis in association with achondroplasia. The AP radiograph shows decreased interpedicular distance at the lower lumbar vertebrae, a feature considered to be a distinctive sign of achondroplasia. Most patients with achondroplasia have kyphosis, and this usually resolves spontaneously. When the fixed component is greater than 30°, however, brace treatment is recommended. Spinal fusion is seldom required.

Question 1606

Topic: Pediatric Hip
Figures 8a and 8b show the current radiographs of a 10-year-old boy with a hip disorder who was treated with an abduction orthosis 3 years ago. If no further remodeling occurs, what is the most likely prognosis?
. The patient is at risk for repeated episodes of ischemic necrosis.
. The patient is at high risk for deep venous thrombosis.
. No further problems will develop on the involved side.
. Accelerated onset of degenerative arthritis will develop on the involved side in the fifth or sixth decade of life.
. Epiphyseodesis will be required on the involved side.

Correct Answer & Explanation

. Accelerated onset of degenerative arthritis will develop on the involved side in the fifth or sixth decade of life.

Explanation

DISCUSSION: The radiographs show a child with Legg-Calve-Perthes disease (LCPD) that has healed. Deformity (asphericity) of the femoral head is evident, but the femoral head and acetabulum are congruous. Stulberg and associates found that hips with aspherical congruity at skeletal maturity functioned well until the fifth or sixth decade of life. Similarly, another study found that degenerative arthritis caused deteriorating hip function after age 40 years in patients with this degree of residual deformity. Repeated episodes of ischemic necrosis are unlikely. Although some studies suggested coagulation abnormalities such as protein C and S deficiencies in children with LCPD, other studies failed to show any evidence of inherited thrombophilia in most children with this disorder. There are no studies to suggest growth acceleration occurs following LCPD. REFERENCES: Stulberg SD, Cooperman DR, Wallenstein R: The natural history of Legg-Calve-Perthes disease. J Bone Joint Surg Am 1984;66:479-489. McAndrew MP, Weinstein SL: A long-term follow-up of Legg-Calve-Perthes disease. J Bone Joint Surg Am 1984;66:860-869.

Question 1607

Topic: 4. Pediatrics

A radiograph of a 27 month old child with bilateral genu valgum and internal tibial torsion shows the metaphyseal-diaphyseal angle of Levine and Drennen is 12 degrees on the right and 13 degrees on the left. Based on this finding, management should consist of

. a corrective osteotomy
. application of braces
. medial physeal stapling until the varus corrects
. observation
. application of corrective casts

Correct Answer & Explanation

. a corrective osteotomy

Explanation

This paper showed that the older the child was at the time of presentation the more likely it was that the angle would be smaller in a child who had physiological bowing and larger in a child who had Blount disease. Physiologic bowing is common in children who are less than 3 years old whereas Blount disease is reported to be less than 1% at this age. Corrective bracing is initiated for presumed early Blount disease only is the metaphyseal-diaphyseal angle is more than 16 degrees. If the angle is less than 9 degrees the patient is observed. Between 9 and 16 degrees, bracing is considered only if there is instability on walking. The patient is then evaluated on 4 month intervals.

Question 1608

Topic: 4. Pediatrics
The mother of a 24-month-old girl reports that the child cannot rotate her right forearm. She also notes delayed development, with the child first walking at 18 months. The child has a five-word vocabulary and has not begun using simple phrases. Examination reveals that the right forearm is fixed in 80 degrees of pronation. The remainder of the examination of both upper extremities is otherwise normal. A radiograph is shown in Figure 41. Which of the following studies will best aid in diagnosis?
. Renal ultrasound
. Echocardiography
. Chromosome analysis
. Creatine phosphokinase
. MRI of the forearm

Correct Answer & Explanation

. Chromosome analysis

Explanation

DISCUSSION: The patient has classic radioulnar synostosis. Patients with this disorder frequently have duplication of sex chromosomes. Synostosis is often seen in females with 48-XXXX or 49-XXXXX in association with delayed development and mental retardation. In males, it can be associated with 48-XXXY or 49-XXXXY. Radioulnar synostosis is not usually associated with muscle disorders, congenital heart disease, or renal anomalies. MRI of the forearm can reveal other soft-tissue anomalies, but this information is not particularly helpful in planning therapy. Osteotomy is sometimes indicated to improve rotational position of the wrist, but this patient’s rotation is quite functional for everyday tasks, and rotational osteotomy is not indicated.

Question 1609

Topic: 4. Pediatrics
  • A 13-year-old quarterback feels a “pop” in his knee while being tackled. Radiographs of the knee and results of a Lachman’s test are normal. Examination reveals tenderness over the distal femoral physis. To help confirm the diagnosis, management should first include
. an MRI scan
. arthroscopic examination
. AP and frog-lateral radiographs of the pelvis and hips
. varus and valgus stress radiographs of the knee
. physical examination of the knee under anesthesia

Correct Answer & Explanation

. varus and valgus stress radiographs of the knee

Explanation

Injuries involving the distal femoral epiphysis cartilage plate are fairly common. Appropriate management should include a complete knee exam with a standard series of X-rays. Of particular importance is to notice any varus or valgus deformity. Stephens et al. (JBJS 1974:56A) measured varus and valgus deformities clinically and roentgenographically. A varus or valgus deformity greater than 3 degrees as compared with the uninjured side was considered clinically significant. Such deformities are highly suggestive of a physeal injury. A MRI may show the injury, but is expensive as is an arthroscopy or examination under anesthesia.

Question 1610

Topic: Pediatric Hip
Of the following clinical situations, which is most likely to lead to osteonecrosis associated with a slipped capital femoral epiphysis (SCFE)?
. A girl younger than age 15 years
. A boy younger than age 15 years
. An unstable SCFE
. A stable SCFE
. A stable SCFE associated with morbid obesity

Correct Answer & Explanation

. An unstable SCFE

Explanation

DISCUSSION: Osteonecrosis of the femoral head is the most devastating complication of SCFE. There is a 47% incidence of ischemic necrosis associated with an unstable SCFE. By definition, the patient with an unstable SCFE is unable to bear weight even with crutches. Osteonecrosis is most likely associated with the initial femoral head displacement rather than the result of either tamponade from hemarthrosis or from gentle repositioning prior to stabilization. Age, sex, and obesity are not risk factors for osteonecrosis. REFERENCES: Loder RT, Richards BS, Shapiro PS, et al: Acute slipped capital femoral epiphysis: The importance of physeal stability. J Bone Joint Surg Am 1993;75:1134-1140. Herring JA: Tachdjian’s Pediatric Orthopaedics, ed 3. Philadelphia, PA, WB Saunders, 2002, vol 2, pp 711-745.

Question 1611

Topic: 4. Pediatrics
Figures 16a and 16b show the radiographs of an otherwise healthy 3 1/2-year-old boy who has an isolated deformity of the left leg. Definitive primary treatment of this condition should consist of:
. distraction osteogenesis.
. an intramedullary nail and onlay bone graft.
. a short leg cast.
. a vascularized free fibular graft.
. plate fixation and an autogenous bone graft.

Correct Answer & Explanation

. an intramedullary nail and onlay bone graft.

Explanation

Treatment of congenital pseudarthrosis of the tibia is problematic. To achieve union, a resection of the pseudarthrosis, stabilization, and bone grafting must be performed. Simple cast immobilization does not yield union. On the first surgical attempt, retrograde intramedullary nailing offers the best chance for success by transfixing the ankle and subtalar joints with abundant autogenous bone grafting. Distraction osteogenesis and vascularized free fibular graft are reserved as salvage procedures.

Question 1612

Topic: 4. Pediatrics

A defect in the gene coding for fibrillin-1 would lead to which diagnosis? Review Topic

. Osteogenesis Imperfecta
. Neurofibromatosis
. Achondroplasia
. Pseudoachondroplasia
. Marfan Syndrome

Correct Answer & Explanation

. Osteogenesis Imperfecta

Explanation

A defect in fibrillin-1 is the underlying cause of Marfan Syndrome.Marfan Syndrome is a genetic disorder of connective tissue typically caused by a mutation in the gene coding for the fibrillin-1 protein. Affected patients are typically very tall with long limbs and thin fingers and toes. Marfan Syndrome patients have many common features including ectopic lens, aortic root dilation, scoliosis, protrusio acetabuli, and ligamentous laxity.Shirley et al. present a review of Marfan Syndrome with emphasis on the musculoskeletal manifestations including ligamentous laxity, protrusio acetabuli, and scoliosis. They note that scoliosis in these patients, when compared to those with idiopathic scoliosis, commonly progresses faster, is more resistant to bracing, and has a higher association with dural ectasia.Dean presents a review of Marfan Syndrome and its underlying genetic cause of a mutation in fibrillin. They state that diagnosis can be made using the Ghent nosology (see Illustration A) which can diagnose or rule out the condition in 86% of patients. They caution using these criteria in young children as some features of Marfan Syndrome may not present until later ages.Illustration A is a summary of the 2010 Revised Ghent nosology for diagnosing Marfan Syndrome.Incorrect Answers:

Question 1613

Topic: 4. Pediatrics
A biopsy of the involved physis in a patient with slipped capital femoral epiphysis (SCFE) would most likely reveal:
. a dense perichondral ring.
. an abnormally thick zone of proliferation.
. increased undulations or irregularity of the growth plate.
. granulation tissue between the columns in the zone of hypertrophy.
. normal proteoglycan content.

Correct Answer & Explanation

. granulation tissue between the columns in the zone of hypertrophy.

Explanation

Vascular invasion, histologically similar to granulation tissue, has been noted between the columns in the zone of hypertrophy, leading to the theory of microtrauma as an etiology. SCFE is also associated with conditions that increase the height of the zone of hypertrophy, including the adolescent growth spurt and endocrinopathies. The perichondral ring has been shown to decrease in thickness with age. Normal undulations in the growth plate also decrease during this time, possibly further destabilizing the physis. Abnormal accumulations of proteoglycan have been reported.

Question 1614

Topic: 4. Pediatrics
A 3-year-old patient with L3 myelomeningocele has bilateral dislocated hips. Management should consist of
. observation.
. bilateral open reduction.
. bilateral open reduction and psoas transfers.
. bilateral open reduction and external oblique transfers.
. bilateral valgus osteotomies.

Correct Answer & Explanation

. observation.

Explanation

In patients with myelomeningocele, the presence of bilateral hip dislocation does not affect ambulation, bracing requirements, sitting ability, degree of scoliosis, or level of comfort. There is little evidence to support active treatment of bilateral hip dislocations in patients with myelomeningocele proximal to L4.

Question 1615

Topic: 4. Pediatrics
What is the most important predictor of functional outcome in patients with myelomeningocele?
. Functional motor level
. Sensory level
. Dysplasia of the hip
. Foot deformity
. Hydrocephalus

Correct Answer & Explanation

. Functional motor level

Explanation

The functional motor level of the patient is of prime importance in determining prognosis and outcome. Patients with thoracic and upper lumbar motor levels will need wheelchairs or hip-knee-ankle-foot orthoses to ambulate at all. Patients with midlumbar motor levels can be household or limited community walkers, whereas children with low lumbar or sacral motor levels are likely to be able to walk in the community.

Question 1616

Topic: 4. Pediatrics
  • An 8-1/2-month-old male infant who has developmental dysplasia of the hip was treated in a Pavlick harness for 3 months. At follow-up, examination of the hip reveals full flexion and extension and abduction to 80 degrees. Figure 41a shows an AP arthrogram and Figure 41b an arthrographic view in flexion and abduction. Management should now consist of
. application of a hip abduction brace for 22 hours per day
. application of a hip spica under anesthesia
. discontinuance of all bracing and repeat radiographs in 3 months
. open reduction of the hip and application of a spica cast
. open reduction, varus osteotomy, and application of a spica cast

Correct Answer & Explanation

. application of a hip abduction brace for 22 hours per day

Explanation

The arthrograms (which are actually reversed from the question) reveal a superiorly dislocated hip in both views. The head is lateral to Perkins’ line, superior to Hilgenreiners’ line, and Shenton’s line is broken. Tachdjian gives the following reasons for operative reduction: hip unreducible by closed means, hip requires extreme position to maintain reduction, unstable reduction, non-concentric reduction. Miller gives a little better explanation of treatment options: if under 6 mos. and reducible: Pavlick Harness (confirm the reduction with U/S or x-ray); if under 6 mos. and unreducible: Pavlick harness, and if unsuccessful then traction and closed reduction. A stable reduction must be demonstrated in the harness within 2 to 4 weeks. Abduction bracing may be used for residual dysplasia if the child is ambulating. If 6 to 18 months and unreducible: traction and closed reduction (check reduction with arthrogram; medial dye pool < 5mm is good; if failed closed reduction, then must operatively reduce), then cast for > 4 months followed with nighttime bracing. If 12 to 18 months who fail close reduction, must OR. If >3 years: OR with pelvic osteotomy.

Question 1617

Topic: 4. Pediatrics
The main blood supply to the capital femoral epiphysis in a 10-year-old child is supplied from the
. artery of the ligamentum teres.
. epiphyseal branch of the lateral femoral circumflex artery.
. posterosuperior and posteroinferior retinacular branches of the lateral femoral circumflex artery.
. posterosuperior and posteroinferior retinacular branches of the medial femoral circumflex artery.

Correct Answer & Explanation

. posterosuperior and posteroinferior retinacular branches of the medial femoral circumflex artery.

Explanation

DISCUSSION: Before the age of 4 years, blood to the femoral head is supplied by the medial and lateral femoral circumflex arteries as well as the artery of the ligamentum teres. After the age of 4, the blood supply through the artery of the ligamentum teres diminishes. The lateral femoral circumflex system regresses, and its flow into the physis and epiphysis diminishes significantly so the medial femoral circumflex artery becomes the predominant blood supply to the metaphysis. The medial femoral circumflex artery provides the principal blood supply to the proximal femur via its posterosuperior and posteroinferior retinacular branches.

Question 1618

Topic: 4. Pediatrics
A 7-year-old girl sustains the fracture shown in Figure 29a. Casting results in uneventful healing. Ten months later, the patient has a progressive valgus deformity of the right lower extremity. A radiograph is shown in Figure 29b. Management should now consist of
. observation.
. proximal tibial osteotomy.
. proximal tibial hemiepiphyseodesis.
. a long leg brace with a varus-producing strap.
. MRI to map the extent of the osseous physeal bridge.

Correct Answer & Explanation

. observation.

Explanation

Although fractures of the proximal tibial metaphysis in young children appear innocuous, development of a progressive valgus deformity is possible despite adequate and appropriate treatment. When treating a child with this injury, it is prudent to warn the parents that a valgus deformity of the tibia may develop. The most likely cause is asymmetric growth of the proximal tibial physis. Because spontaneous angular improvement can be expected in most patients, surgery to correct these deformities should be delayed at least 2 to 3 years and should be limited to patients who have symptoms. There are no studies that document the efficacy of bracing for this deformity.

Question 1619

Topic: 4. Pediatrics
Figure 19 shows the radiograph of a 6-month-old infant who has limited hip motion. History reveals no complications during pregnancy or delivery. Examination reveals that hip abduction is 45 degrees in flexion bilaterally. The neurologic examination is normal. What is the best course of action?
. Adductor tenotomy
. Physical therapy
. Observation
. Abduction orthosis
. Neurologic consultation

Correct Answer & Explanation

. Observation

Explanation

Diminished hip abduction can occur in normal children and is not always associated with hip pathology; therefore, initial management should consist of observation.

Question 1620

Topic: 4. Pediatrics

A 2-year-old girl has the fracture shown in Figures 5a and 5b. This fracture is most commonly associated with which of the following entities? Review Topic

. Neurofibromatosis
. Child abuse
. Osteogenesis imperfecta type II
. Osteopetrosis
. Achondroplasia

Correct Answer & Explanation

. Neurofibromatosis

Explanation

The radiographs reveal constriction of the tibial diaphysis in the region of the fracture, which is characteristic of the dysplastic type of pseudarthrosis of the tibia. Neurofibromatosis occurs in approximately 50% of children who have anterolateral bowing with or without pseudarthrosis of the tibia. The appearance of this fracture differentiates it from those resulting from child abuse. Type II osteogenesis imperfecta is usually lethal in the perinatal period. Radiographs in children with osteopetrosis show overly dense bones. Achondroplasia is not associated with fractures of the tibia.

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