McGraw-Hill Specialty Board Review Pediatrics, 2nd Edition

Chapter 1. CARDIOLOGY

CASE 1: A NEONATE WITH A HEART MURMUR

A full-term newborn delivered without complications is noted to have a heart murmur at 1 day of age. The murmur is described as a grade 2/6 systolic ejection-type murmur heard best at the upper left sternal border. The heart sounds are normal. The blood pressure is normal. The peripheral pulses are normal. The oxygen saturation is 100% in room air. On day of life 3, the murmur has changed from a systolic murmur to a continuous murmur again heard best at the upper left sternal border. The baby appears well and is tolerating feeds without difficulties.

SELECT THE ONE BEST ANSWER

1. What is the likely cause of this heart murmur?

(A) patent ductus arteriosus

(B) atrial septal defect

(C) ventricular septal defect

(D) peripheral pulmonary stenosis

(E) aortic stenosis

2. This continuous murmur persists for more than 72 hours. What is the most appropriate test to evaluate the etiology of this murmur?

(A) chest radiograph

(B) electrocardiogram (ECG)

(C) complete blood count

(D) echocardiogram

(E) cardiac catheterization

3. The echocardiogram demonstrates a small patent ductus arteriosus with no associated cardiac lesions and no evidence of left heart volume overload. What advice would you give to the family regarding further follow-up?

(A) no further cardiology follow-up is needed

(B) there is a lifelong ongoing risk for endarteritis and antibiotic prophylaxis should be given as needed

(C) immediate surgical repair is required

(D) there is minimal risk for endarteritis and no antibiotic prophylaxis is needed

(E) B and C

4. At day of life 7, the neonate described develops increased shortness of breath, decreased feeding, and a chest radiograph shows pulmonary edema. What is the best first-line course of action?

(A) prostaglandin Einfusion

(B) a course of indomethacin

(C) supplemental oxygen

(D) nitric oxide

(E) phenylephrine

5. A full-term newborn delivered via normal spontaneous vaginal delivery with Apgars of 9 at 1 minute and 9 at 5 minutes is noted to have a grade 2/6 systolic murmur at the left sternal border on day 1 of life. Upon reexamination on day 4 of life, the neonate is found to have poor perfusion, poor pulses, hypotension, and shock. What is the least likely cause of shock in this neonate?

(A) perinatal asphyxia

(B) sepsis

(C) hypoglycemia

(D) cardiogenic shock

(E) myocarditis

6. Which of the following congenital heart lesions may result in cardiogenic shock following spontaneous closure of the ductus arteriosus?

(A) atrial septal defect

(B) hypoplastic left heart syndrome

(C) mitral valve prolapse

(D) ventricular septal defect

(E) tetralogy of Fallot

7. What test would be most helpful to diagnose the cause of shock in this neonate?

(A) chest radiograph

(B) arterial blood gas

(C) blood glucose level

(D) echocardiogram

(E) a blood culture

8. What is the most appropriate acute treatment for cardiogenic shock as a result of left heart obstructive lesions?

(A) prostaglandin Einfusion

(B) indomethacin administration

(C) supplemental oxygen administration

(D) nitric oxide

(E) intravenous (IV) furosemide

9. What are other courses of action to be taken for patients with cardiogenic shock?

(A) inotropic medications such as epinephrine and dopamine

(B) ventilatory support

(C) oxygen supplementation

(D) correct any metabolic abnormalities

(E) all of the above

10. A neonate with a heart murmur on examination is noted to have a bluish tinge to the lips. The baby is smiling and eating well in no apparent distress. The baby is warm with good pulses. An oxygen saturation monitor was placed on the baby’s finger and the oxygen saturation in room air is 80%. Which of the following is (are) likely to account for this patient’s finding of cyanosis?

(A) cyanotic congenital heart disease

(B) hemoglobinopathy

(C) respiratory disease

(D) anemia

(E) A, B, and C

11. Which test would most likely help differentiate a cardiac versus pulmonary cause for cyanosis?

(A) hyperoxia test

(B) blood gas on room air

(C) chest radiograph

(D) complete blood count

(E) chest computed tomography (CT)

12. What is the most common cyanotic heart lesion in the neonate?

(A) transposition of the great arteries

(B) total anomalous pulmonary venous return

(C) tricuspid atresia

(D) tetralogy of Fallot

(E) Ebstein anomaly

13. What would be an appropriate first-line treatment for the management of cyanosis as a result of heart disease?

(A) prostaglandin Einfusion

(B) indomethacin administration

(C) nitric oxide

(D) surfactant

(E) dopamine

14. A 4-year-old with a known diagnosis of unrepaired tetralogy of Fallot becomes severely cyanotic while crying. Which of the following is not indicated for acute management of this situation?

(A) administering of oxygen

(B) placing the child in the knee-chest position

(C) administering morphine sulfate

(D) rectal stimulation

(E) administration of phenylephrine

15. Which of the following is not a complication of chronic cyanosis?

(A) polycythemia

(B) stroke

(C) brain abscess

(D) cognitive abnormalities

(E) cerebral aneurysms

ANSWERS

1. (A) The most likely cause of this murmur is a patent ductus arteriosus (Figure 1-1). Atrial septal defects are unlikely to cause a heart murmur at this early age, and ventricular septal defects cause a holosystolic murmur that does not evolve into a continuous murmur. Peripheral pulmonary stenosis is associated with a systolic ejection murmur that radiates to the back and to both axillae. Aortic stenosis causes a systolic murmur that does not evolve into a continuous murmur. The ductus arteriosus is required for fetal circulation; however, the structure usually closes within hours after delivery secondary to changes in oxygen tension as well as other circulating factors such as prostaglandin. Persistence of the ductus arteriosus occurs in approximately 0.8 per 1000 live births but is much more common in premature newborns with an incidence as high as 20% in neonates weighing less than 1750 g. In patients with low oxygen tension, pulmonary hypertension, or congenital heart disease, there is delayed closure of the ductus arteriosus.

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FIGURE 1-1Patent ductus arteriosus (PDA). (1) Superior vena cava, (2) inferior vena cava, (3) right atrium, (4) right ventricle, (5) main pulmonary trunk, (6) aorta, (7) left pulmonary artery, (8) left atrium, (9) left ventricle.


2. (D) The ductus arteriosus in this neonate remains patent after 72 hours. The most appropriate test to confirm this is the echocardiogram. This test will not only confirm the diagnosis of the patent ductus arteriosus but will also assess any associated cardiac lesions. It is critical to check for pulmonary artery hypertension or ductal-dependent cardiac lesions when planning for closure of the patent ductus arteriosus.

3. (D) The presence of a small patent ductus arteriosus is unlikely to lead to significant left-to-right shunting or volume overloading and therefore does not place the child at risk for development of heart failure. There is about a 5% incidence of spontaneous closure of a small patent ductus arteriosus, and thus immediate surgery is usually not required in that situation. Recent review of subacute bacterial endocarditis has suggested that the lifelong risk for bacterial endarteritis with the presence of a patent ductus arteriosus is extremely low. Therefore, current guidelines do not recommend antibiotic prophylaxis for this condition.

4. (B) In this situation, a large patent ductus arteriosus has allowed significant left-to-right shunting resulting in pulmonary edema, shortness of breath, and left ventricular volume overload. The treatment options at this point include administration of indomethacin in an attempt to close the patent ductus arteriosus. Indomethacin is effective in approximately 80% of cases; however, its effectiveness decreases if administered after 2 weeks of age. Other treatment options for closure of a hemodynamically significant ductus arteriosus include surgery or transcatheter device closure. Both can be performed safely and effectively with minimal morbidity and mortality. Administration of oxygen to the patient with congestive heart failure because of a large leftto-right shunt would be detrimental in that it may decrease pulmonary vascular resistance and increase the degree of left-to-right shunting, exacerbating the symptoms of heart failure. The same is true for administration of nitric oxide in this situation. Administration of phenylephrine would cause an increase in systemic vascular resistance and result in a greater degree of left-to-right shunting.

5. (A) The etiology of shock in the neonate includes the following:

• hypoglycemia

• asphyxia

• sepsis

• intracranial bleeding

• arrhythmias including tachyarrhythmias and bradycardias

• cardiogenic shock because of left-sided obstructive lesions

• myocarditis

The least likely explanation of shock in this baby is asphyxia because there is no history of perinatal asphyxia or distress based on the birth history.

6. (B) Cardiogenic shock may be the first presentation in the neonate with congenital heart disease. Specific heart lesions causing left ventricular outflow tract obstruction may present in this manner. These lesions include critical aortic stenosis, hypoplastic left heart syndrome, and coarctation of the aorta. A patent ductus arteriosus allows for blood to bypass left-sided obstructions thus maintaining adequate cardiac output. With closure of the ductus, cardiac output is diminished. The neonate with cardiogenic shock from ductal-dependent lesions often presents at 1-2 weeks of age with shock related to the spontaneous closure of the ductus arteriosus.

7. (D) An echocardiogram would be the most useful test in this situation to determine if there is a ductaldependent cardiac lesion. It is also useful to detect primary myocardial dysfunction related to other causes of shock.

8. (A) The acute therapy for shock as a result of ductal-dependent cardiac lesions is infusion of prostaglandin Ein hopes of reestablishing patency of the ductus arteriosus.

9. (E) The other acute management strategies for shock in the neonate include inotropic support with dopamine or epinephrine, ventilatory support in cases of respiratory compromise, oxygen supplementation, and correction of metabolic abnormalities such as acidosis, hypokalemia, and hypocalcemia.

10. (E) Cyanosis can be divided into 2 clinical categories: central or peripheral. Central cyanosis is a result of a decrease in the oxygen saturation of blood supplying the body. Peripheral cyanosis is a benign finding caused by increased oxygen extraction in distal capillary beds and is commonly seen in normal neonates. The clinical detection of cyanosis occurs when approximately 3-5 g/dL of desaturated hemoglobin is present in the systemic circulation. The most common causes of central cyanosis in the neonate include cyanotic heart disease, hemoglobinopathies, and respiratory distress.

11. (A) The test most likely to help differentiate cyanotic heart disease from respiratory disease is the hyperoxia test. In this test, 100% oxygen is administered to the patient and the partial pressure of oxygen is measured. In patients with cyanotic heart disease, the partial pressure of oxygen rarely increases above the level of 100 mm Hg, whereas in lung disease there is usually some change from the baseline POwith administration of oxygen. The lack of response to oxygen in cyanotic heart disease is a result of fixed right-to-left shunting of desaturated blood to the systemic circulation. Although the other tests mentioned may be helpful in the evaluation of the cyanotic neonate, they are not as sensitive in differentiating cardiac from respiratory etiologies.

12. (A) Cardiac lesions associated with cyanosis include

• transposition of the great arteries (the most common)

• tetralogy of Fallot

• truncus arteriosus

• tricuspid atresia

• pulmonary atresia

• total anomalous pulmonary venous return

Other lesions include single-ventricle physiology such as hypoplastic left heart syndrome, or Ebstein anomaly of the tricuspid valve with right-to-left shunting across an atrial septal defect.

13. (A) In patients with cyanosis because of heart disease, there is either obligate mixing of saturated and desaturated blood reaching the systemic circulation (eg, truncus arteriosus) or decreased effective pulmonary blood flow. In either situation, promotion of increased pulmonary blood flow or improved mixing of desaturated and saturated blood would increase the systemic oxygen saturation. This is acutely achieved by infusion of prostaglandin Eto reestablish (or maintain) patency of the ductus arteriosus. Therefore, in situations where cyanosis because of heart disease is suspected, infusion of prostaglandin Eshould be instituted as soon as possible.

14. (D) Patients with tetralogy of Fallot are at risk for a hypercyanotic “tet” spell. This usually occurs in patients older than 2 years of age, although it has been reported at younger ages. The mechanism of a hypercyanotic spell is acute and progressive pulmonary stenosis, with increased right-to-left shunting of desaturated blood to the systemic circulation. This is precipitated by an increase in circulating catecholamines, anxiety, hypoxia, or dehydration. Interventions to break this cycle include administration of oxygen, morphine, propranolol, or phenylephrine, placing the child in a knee-chest position. In extreme cases, muscle relaxation and intubation are required. Rectal stimulation would serve to worsen the crisis by increasing the catecholamine levels (Figure 1-2).

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FIGURE 1-2. Tetralogy of Fallot. There are infundibular and pulmonary stenoses. There is also right-to-left shunting at the atrial level. (1) Superior vena cava, (2) inferior vena cava, (3) right atrium, (4) right ventricle, (5) right pulmonary vein, (6) left atrium, (7) left ventricle, (8) aorta.


15. (E) Complications in patients with chronic cyanosis include polycythemia (compensation for decreased systemic oxygen tension), and risk of strokes because of an increased propensity for forming blood clots and increased blood viscosity. This is particularly concerning when the hematocrit is higher than 70%. A relative anemia may be seen in patients with cyanosis with low hemoglobin indexes. Some have suggested that this increases the risk of stroke because of increased blood viscosity. Another complication is brain abscess formation because of poor venous blood flow and increased susceptibility to infection. Impaired cognitive function is associated with long-standing cyanosis. The degree of impairment is related to both the degree and duration of cyanosis.


S
UGGESTED READING

Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, eds. Moss and Adams Heart Disease in Infants, Children and Adolescents. 7th ed. Philadelphia, PA: Williams and Wilkins; 2007.

Braunwald E, Zipes DP, Libbey P, eds. Braunwald: Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia, PA: WB Saunders; 2004.

Keane JF, Fyler DC, Lock JE, eds. Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia, PA: Hanley and Belfus; 2006.

Park M, ed. Pediatric Cardiology for Practitioners. 5th ed. St. Louis, MO: Mosby; 2007.

CASE 2: A 10-YEAR-OLD BOY WITH PALPITATIONS

A 10-year-old boy presents to the clinic with a history of intermittent episodes of palpitations occurring 1 time per month. The episodes are not associated with exercise or activity, last for several minutes, and resolve spontaneously. There is no significant past medical history, no new medications, and no dizziness or syncope. A 12-lead ECG, performed while he is asymptomatic, is normal.

SELECT THE ONE BEST ANSWER

1. Which test would best help to evaluate the etiology of this patient’s palpitations?

(A) echocardiogram

(B) chest radiograph

(C) event recorder monitor

(D) exercise stress test

(E) tilt table test

Match the ECG rhythm strips in questions 2 through 5 to one of the findings below.

(A) premature atrial contractions

(B) premature ventricular contractions

(C) sinus tachycardia

(D) sinus arrhythmia

2. Figure 2-1 shown below

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FIGURE 2-1.


3. Figure 2-2 shown below

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FIGURE 2-2.


4. Figure 2-3 shown below

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FIGURE 2-3.


5. Figure 2-4 shown below

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FIGURE 2-4.


6. What is the most likely cause of supraventricular tachycardia in the patient whose history was presented above?

(A) a concealed accessory bypass tract causing orthodromic, reciprocating tachycardia

(B) AV node reentry tachycardia

(C) ectopic atrial tachycardia

(D) atrial flutter

(E) atrial fibrillation

7. What is an appropriate acute therapy for symptomatic orthodromic, reciprocating tachycardia?

(A) DC cardioversion

(B) IV adenosine

(C) vagal maneuvers

(D) all of the above

(E) none of the above

8. Which of the following agents is considered firstline therapy for chronic control of orthodromic, reciprocating tachycardia?

(A) propafenone

(B) atenolol

(C) sotalol

(D) amiodarone

(E) flecainide

9. What would be the most appropriate acute therapy for symptomatic ectopic atrial tachycardia?

(A) DC cardioversion

(B) IV adenosine

(C) vagal maneuvers

(D) IV esmolol

(E) none of the above

10. A child with supraventricular tachycardia (SVT) is found to have a resting ECG rhythm strip shown in Figure 2-5. What is the diagnosis?

(A) sinus tachycardia

(B) ventricular preexcitation

(C) ventricular tachycardia

(D) sinus rhythm

(E) sinus arrhythmia

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FIGURE 2-5.


11. Which statement is true regarding the diagnosis of Wolff-Parkinson-White (WPW) syndrome?

(A) there is an increased risk of sudden cardiac death

(B) there is an increased risk of ectopic atrial tachycardia

(C) there is an increased risk of tachycardiainduced cardiomyopathy

(D) there is no risk of atrial fibrillation

(E) there is no increased risk for associated structural heart disease

12. Which of the following agents is considered firstline therapy for chronic control of orthodromically, reciprocating tachycardia associated with ventricular preexcitation (WPW syndrome)?

(A) digoxin

(B) verapamil

(C) propranolol

(D) amiodarone

(E) flecainide

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FIGURE 2-6.


13. A 10-year-old child experiences palpitations associated with dizziness when standing. He has had one episode of syncope following standing in school. What is the most common etiology of syncope in this age group?

(A) seizures

(B) cardiac disease

(C) hypoglycemia

(D) neurocardiogenic (vasovagal)

(E) cardiac arrhythmia

14. Which of the following features would suggest neurocardiogenic syncope?

(A) urinary incontinence during episodes of syncope

(B) auditory aura preceding episode of syncope

(C) transient right arm paralysis following episode of syncope

(D) symptoms of dizziness, blurred vision, diaphoresis preceding syncope

(E) prolonged episode of unconsciousness

15. Which of the following is true regarding tilt table testing for syncope?

(A) tilt table testing should be performed for every patient with syncope

(B) the results of tilt table testing are highly reproducible for an individual

(C) tilt table testing is reserved for complicated cases where the diagnosis of syncope is uncertain

(D) tilt table testing is useful for predicting response to medications

(E) tilt table testing should be performed before initiation of medical therapy

16. A newborn baby presents with a heart rate of 45 beats per minute (bpm), a normal blood pressure, and good perfusion. The ECG rhythm strip is shown in Figure 2-6. What is the diagnosis?

(A) first-degree AV block

(B) second-degree AV block (type 1)

(C) second-degree AV block (type 2)

(D) third-degree AV block

(E) sinus bradycardia

17. What is the most likely cause of congenital AV block in newborns?

(A) maternal lupus

(B) maternal rubella

(C) maternal use of lithium

(D) maternal diabetes mellitus

(E) maternal use of alcohol

18. The patient from Question 16 subsequently develops signs of heart failure with poor perfusion and tachypnea. What is the most appropriate long-term therapy for this patient?

(A) pacemaker implantation

(B) digoxin

(C) theophylline

(D) atropine

(E) caffeine

19. A 10-year-old patient with history of palpitations is found to have the ECG rhythm strip shown in Figure 2-7. What is the most likely diagnosis of the palpitations?

(A) myocardial ischemia

(B) orthodromic reentry tachycardia

(C) ventricular arrhythmias

(D) premature atrial beat

(E) premature junctional beats

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FIGURE 2-7.


20. What are the known modes of inheritance for congenital long QT syndrome?

(A) autosomal recessive inheritance

(B) autosomal dominant inheritance

(C) spontaneous mutation

(D) all of the above

(E) it is not known

21. Which of the following medications is associated with drug-induced long QT syndrome?

(A) propranolol

(B) amitriptyline

(C) metoclopramide

(D) amoxicillin

(E) ibuprofen

ANSWERS

1. (C) Palpitations are a common complaint in young patients reported by 16% of patients in a survey at a large primary care clinic. Palpitations are associated with acute arrhythmias in less than 5% of cases when evaluated with long-term monitoring. Palpitations associated with symptoms of dizziness or syncope or in the setting of a family history of arrhythmias or sudden cardiac death would increase the suspicion of an underlying cardiac disorder. Although the echocardiogram, stress test, and chest radiograph are often used to exclude significant cardiac disease, they are unlikely to determine the specific etiology of the palpitations. In this situation, an event recorder could be used to record an ECG rhythm strip during symptoms. An event recorder is a long-term monitoring device used for patients with symptoms that occur infrequently.

2. (B) The ECG in Figure 2-1 shows normal sinus rhythm with a premature ventricular contraction. Premature ventricular contractions are a less common finding in young patients occurring with an incidence of approximately 5-10%. They are usually benign; however, they may rarely be associated with significant heart disease. Therefore, the evaluation often includes an echocardiogram or stress test to assess for associated cardiac disease. Premature ventricular contractions that are not associated with significant heart disease do not require therapy unless they are associated with significant symptoms of discomfort or palpitations.

3. (C) The ECG in Figure 2-2 shows sinus tachycardia. The more common etiologies of sinus tachycardia at this age include anxiety or emotion, hyperthyroidism, anemia, postural orthostatic tachycardia syndrome, and dehydration. It is the most common cause of palpitations in young patients.

4. (D) The ECG in Figure 2-3 shows sinus arrhythmia. This is a benign finding associated with an irregular heart rhythm heard during auscultation. It may vary with respiration and can be pronounced in children. There is no association with significant heart disease.

5. (A) The ECG in Figure 2-4 demonstrates normal sinus rhythm with a single premature atrial contraction. Premature atrial contractions are a common benign finding in young patients occurring with an incidence of approximately 17-25%. They are usually not associated with significant cardiac disease. Because of the benign nature of the premature atrial contractions, they do not require further investigation.

6. (A) The most likely cause of supraventricular tachycardia at this age is orthodromic, reciprocating tachycardia because of an accessory bypass tract (“concealed” in this case based on the normal resting ECG). AV node reentry tachycardia is less common at this age; however, this becomes the predominant mechanism of tachycardia in young adults. Ectopic atrial tachycardia and atrial flutter occur with a low incidence throughout childhood. Atrial flutter is more commonly seen in patients who have congenital heart disease.

7. (D) Acceptable therapy for orthodromic, reciprocating tachycardia that occurs because of a concealed bypass tract includes DC cardioversion, IV adenosine, or vagal maneuvers. Other antiarrhythmic drugs such as calcium channel blockers can also be used. The determination of which therapy is used is based on the patient’s clinical status at the time of presentation. In patients with stable tachycardia and vital signs, vagal maneuvers or IV adenosine may be first-line treatment. In patients with unstable tachycardia, DC cardioversion may be the first-line therapy. Of note, IV calcium channel blockers are not recommended for use in infants younger than 1 year of age secondary to an increased risk for hypotension.

8. (B) First-line medical therapy for chronic treatment of supraventricular tachycardia includes digoxin, calcium channel blockers, and beta-blockers (eg, atenolol). Amiodarone, flecainide, and sotalol are all effective drugs for treatment of SVT but have a higher incidence of side effects (proarrhythmia). Thus they are usually reserved for cases that are resistant to first-line medications.

9. (D) Ectopic atrial tachycardia is a rare tachycardia occurring with an incidence of approximately 10% throughout childhood. In some cases of automatic atrial tachycardia, the heart rate is only slightly higher than sinus rhythm; thus the tachycardia may go undetected for months to years. Patients with ectopic tachycardia are at risk for ventricular dysfunction and heart failure. Unlike orthodromic, reciprocating tachycardia and AV node reentry tachycardia, ectopic atrial tachycardia arises from a single atrial focus that does not depend on the AV node. Therefore, adenosine, vagal maneuvers, and DC cardioversion are ineffective. Appropriate acute therapy includes IV beta-blockers, calcium channel blockers, or amiodarone.

10. (B) The ECG in Figure 2-5 demonstrates ventricular preexcitation (short PR interval and slurred upstroke of the QRS or delta wave) because of an accessory bypass tract. When associated with tachycardia, this is known as the Wolff-Parkinson-White (WPW) syndrome. The incidence of WPW syndrome is approximately 0.3%. The mechanism of tachycardia is orthodromic, reciprocating tachycardia similar to that in patients with concealed bypass tracts.

11. (A) There is an increased risk of sudden cardiac death (approximately 1 in 1000 patient-years) in WPW syndrome. Sudden cardiac death occurs because of rapid conduction over the accessory bypass tract during atrial tachycardia resulting in ventricular compromise. Patients with WPW syndrome are not at increased risk for ectopic atrial tachycardia or tachycardia-induced cardiomyopathy, but there is an increased incidence of atrial fibrillation in this population.

12. (C) First-line chronic medical therapy for patients with WPW syndrome includes beta-blockers or other antiarrhythmic medications such as flecainide or amiodarone. The use of digoxin and/or verapamil is contraindicated in these patients because these agents may potentiate rapid antegrade conduction over the accessory pathway and may increase the risk for sudden death.

13. (D) The most common etiology of syncope in young patients is neurocardiogenic or vasovagal syncope. This occurs in up to 20% of the population. Other possibilities include neurologic (eg, seizures), metabolic (eg, anemia, dehydration), or cardiac (eg, arrhythmia) causes.

14. (D) Typical features of neurocardiogenic syncope include preceding symptoms of nausea, dizziness, diaphoresis, or blurred vision. The episodes are related to position and usually occur when sitting or standing. Loss of consciousness is brief and resolves spontaneously. The other features mentioned are suggestive of syncope because of a seizure.

15. (C) Tilt table testing (Figure 2-8) is a simple test used to reproduce neurocardiogenic syncope. However, the low sensitivity and specificity as well as the lack of reproducibility of the test limit its usefulness. It is usually reserved for difficult situations where the etiology of syncope is uncertain. It is not recommended for all patients with syncope and is not useful for predicting response to medications.

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FIGURE 2-8. Tilt table with footboard support. (Reproduced, with permission, from Prystowsky EN, Klein GT. Cardiac Arrhythmias: An Integrated Approach for the Clinician. New York: McGraw-Hill; 1994:353.)


16. (D) The ECG rhythm strip in Figure 2-6 demonstrates third-degree AV block. This is defined as complete dissociation of the atrial and ventricular electrical activity.

17. (A) The most common cause of congenital complete AV block is maternal lupus. The pathogenesis is thought to be a result of maternal transfer of lupus antibodies (anti-Ro or anti-La) to the fetus and subsequent damage of the developing conduction system. In patients with congenital AV block, the chances of their mother having anti-Ro or anti-La antibodies are approximately 60-70%. For mothers with lupus, there is a 5% incidence of having a child with complete AV block. Other causes of AV block in the neonate include structural heart disease, myocarditis, and metabolic disease.

18. (A) In patients with congenital AV block and symptomatic bradycardia, the treatment of choice is pacemaker implantation. No other therapy has been shown to affect long-term outcome in these patients. Medications are not consistently effective for prevention of bradycardia and therefore are not recommended for chronic therapy. Other indications for pacemaker implantation in patients with complete heart block include a wide QRS escape rhythm, a prolonged QT interval, an asymptomatic infant with a heart rate less than 55 bpm, an asymptomatic child with a heart rate less than 50 bpm, and asymptomatic complete heart block with a heart rate less than 75 bpm associated with congenital heart disease.

19. (C) The ECG in Figure 2-7 demonstrates a prolonged QT interval. The QT interval is usually corrected for heart rate (QTc) and normal limits vary with age and gender. Palpitations associated with this ECG would most likely be a result of a polymorphic ventricular tachycardia known as torsades de pointes. The ventricular arrhythmia may be selflimited or result in symptoms of dizziness, syncope, or death. The occurrence of torsades de pointes is associated with exercise or activity; however, in some cases it may occur at rest.

20. (D) Congenital long QT syndrome is most commonly inherited in an autosomal dominant manner (Romano-Ward). It is a result of a defect in 1 of 5 known genes that affect potassium and sodium ion channels in the heart. A specific gene defect has been identified in 50% of patients with clinical long QT syndrome. A less common mode of inheritance is autosomal recessive (Jervell and Lange-Nielsen syndrome). In these patients, there is often associated conductive hearing loss and a higher risk for ventricular arrhythmias and sudden death. Finally, some cases of congenital long QT syndrome occur because of spontaneous mutations. The risk for sudden death in patients with long QT syndrome who present with symptoms of dizziness or syncope is approximately 20% in 1 year, if untreated. The use of beta-blockers decreases the risk of sudden death to < 5%. Therefore, beta-blockers have become the mainstay of therapy as well as avoidance of strenuous activities, especially swimming. Pacemaker implantation is occasionally required for patients with either baseline bradycardia or those who develop bradycardia following treatment with betablockers. Implantable cardioverter defibrillators are now used more frequently in patients who continue to become symptomatic despite medical therapy with a beta-blocker or for those in whom there is a strong family history of sudden death.

21. (B) Acquired long QT syndrome can occur with head trauma, myocardial infarction, cardiomyopathy, or as a result of drugs or medications. This list of drugs/medications associated with the acquired prolonged QT syndrome is extensive and updated regularly. Some of the more common medications on this list include amitriptyline or other tricyclic antidepressants, erythromycin, and cisapride.


S
UGGESTED READING

Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, eds. Moss and Adams Heart Disease in Infants, Children and Adolescents. 7th ed. Philadelphia, PA: Williams and Wilkins; 2007.

Braunwald E, Zipes DP, Libbey P, eds. Braunwald: Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia, PA: WB Saunders; 2004.

Keane JF, Fyler DC, Lock JE, eds. Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia, PA: Hanley and Belfus; 2006.

Park M, ed. Pediatric Cardiology for Practitioners. 5th ed. St. Louis, MO: Mosby; 2007.

CASE 3: A 7-YEAR-OLD WITH A HEART MURMUR

A 7-year-old boy with no significant past medical history is noted to have a heart murmur heard for the first time during a routine physical evaluation by his lifelong pediatrician. The physical examination is significant for a grade 2/6 vibratory systolic murmur heard best at the lower left sternal border with no radiation. The remainder of the physical examination is normal.

SELECT THE ONE BEST ANSWER

1. What is the most likely diagnosis of this heart murmur?

(A) Still murmur

(B) ventricular septal defect

(C) atrial septal defect

(D) peripheral pulmonary stenosis

(E) venous hum

2. What supporting evidence would help to confirm the diagnosis of an innocent Still murmur?

(A) a fixed, split second heart sound

(B) the murmur is louder in the supine position compared to the sitting or standing position

(C) a diastolic rumble

(D) the murmur is associated with a precordial thrill (grade IV)

(E) radiation to the back and axilla

3. Which test would not be indicated for this patient at this time?

(A) ECG

(B) echocardiogram

(C) chest radiograph

(D) cardiac catheterization

(E) four extremity blood pressure determination

4. What would be the appropriate advice to give the family regarding a child with this murmur?

(A) endocarditis prophylaxis is needed

(B) rigorous sports should be avoided

(C) sports participation is allowable

(D) annual echocardiograms are required

(E) other family members should be screened for heart disease

5. A 6-week-old infant presents with a heart murmur and a history of poor feeding, diaphoresis, and tachypnea. On examination, he is playful but tachypneic with a grade 2/6 systolic regurgitant murmur heard best in the mid left sternal border, with hepatomegaly, rales, intermittent wheezes, cool extremities with normal distal pulses, and an active precordium. What is the likely diagnosis of this patient?

(A) chronic lung disease

(B) acute upper respiratory infection

(C) congestive heart failure

(D) dehydration

(E) hyperthyroidism

6. Which test would not be helpful in evaluating this patient?

(A) an echocardiogram

(B) an ECG

(C) a chest radiograph

(D) a throat culture

(E) a physical examination

7. What heart lesion is least likely to present with congestive heart failure symptoms and signs at age 6 weeks?

(A) ventricular septal defect

(B) patent ductus arteriosus

(C) atrial septal defect

(D) aortopulmonary window

(E) large coronary artery fistula

8. Which feature may help to distinguish heart failure from an anomalous left coronary artery arising from the pulmonary artery versus heart failure secondary to a ventricular septal defect?

(A) extreme irritability and crying at the onset of feeding

(B) diaphoresis

(C) weight loss

(D) decreased frequency of wet diapers

(E) tachypnea

9. Which therapy would not be indicated for the acute management of congestive heart failure because of a left-to-right shunting lesion?

(A) digoxin

(B) oxygen supplementation

(C) dobutamine

(D) furosemide

(E) enalapril

10. A 2-year-old patient presents with symptoms of heart failure. An echocardiogram demonstrates no intracardiac lesion but a dilated, poorly functioning left ventricle. What is the least likely cause of the dilated cardiomyopathy in this patient?

(A) myocarditis

(B) metabolic disease

(C) idiopathic

(D) myocardial ischemia

(E) tachycardia-induced cardiomyopathy

11. Which of the following would be supportive evidence of the diagnosis of myocarditis?

(A) an endomyocardial biopsy showing fibrosis

(B) an endomyocardial biopsy showing fibrosis and inflammation

(C) systolic flow murmur

(D) an S3 gallop on cardiac examination

(E) hepatomegaly

12. What is the most common cause of myocarditis?

(A) Staphylococcus aureus (B) streptococcus infection

(C) Epstein-Barr virus

(D) enterovirus

(E) influenza A virus

13. Which of the following should be avoided for the treatment of acute myocarditis?

(A) dopamine

(B) IV immunoglobulin

(C) supportive therapy with diuretics

(D) IV digoxin

(E) dobutamine

14. Which therapy would not be considered standard management for patients with chronic congestive heart failure?

(A) beta-blockers

(B) diuretics

(C) angiotensin-converting enzyme (ACE) inhibitors

(D) calcium channel blockers

(E) digoxin

15. A 7-year-old patient presents with heart murmur, chest pain, and shortness of breath. The murmur is a continuous type that varies in quality with position changes. The patient seems to have relief when sitting and leaning forward. The heart sounds are distant. What is the likely diagnosis for this patient?

(A) pulmonary embolus

(B) pericarditis

(C) myocardial infarction

(D) gastroesophageal (GE) reflux

(E) pleural effusion

16. What is the most common cause of this 7-year-old’s diagnosis among young patients in the United States?

(A) viral infection

(B) acute rheumatic fever

(C) bacterial infection

(D) collagen vascular disease

(E) drug induced

17. While in the office, the 7-year-old patient becomes lethargic with poor perfusion and hypotension. What is the most likely explanation?

(A) pulmonary embolus

(B) myocardial infarction

(C) stroke

(D) cardiac tamponade

(E) arrhythmia

ANSWERS

1. (A) The patient most likely has a Still murmur. This is described as a vibratory or musical systolic ejection murmur occurring at the left sternal border with no other associated cardiac findings. It is the most common innocent heart murmur in children and usually presents at 2-7 years of age. Other innocent murmurs include pulmonary outflow tract murmur, the peripheral pulmonary stenosis murmur of the newborn, and a venous hum. The incidence of innocent heart murmurs in young patients after infancy is approximately 17-66%.

2. (B) Features of innocent heart murmurs include not only the quality and location of the heart murmur but also the fact that the first and second heart sounds are normal. The murmurs are usually welllocalized without much radiation and are usually graded between 1 and 3 with no associated precordial thrill. The murmurs are usually described as vibratory, musical, or blowing, and they are louder in the supine position compared with the sitting or standing position. This is not the case with the innocent venous hum that is often louder in the sitting position. A venous hum can be distinguished by the great amount of variability in quality with position changes and with turning the head. Innocent murmurs do not typically have a diastolic component. A split, fixed second heart sound is associated with an atrial septal defect.

3. (D) Common tests performed in evaluation of innocent heart murmurs include 12-lead ECGs, chest radiographs, 4-extremity blood pressure (to rule out coarctation of the aorta) and echocardiograms. The use of these tests is at the discretion of the examining physician and depends on the findings on physical examination as well as the past medical and family history. An invasive procedure such as a cardiac catheterization is usually not recommended for evaluation of an innocent heart murmur if the tests just listed have been normal.

4. (C) Innocent heart murmurs are not associated with any increased risk for bacterial endocarditis; thus prophylaxis is not needed. Sports participation is not restricted because there is not an increase in cardiac events associated with innocent heart murmurs. Innocent murmurs, by definition, are not associated with structural heart disease, so yearly echocardiograms are usually not recommended. There is no familial association with structural heart disease. Depending on the age at time of diagnosis, a followup visit is occasionally recommended for younger patients.

5. (C) The child presents with evidence of congestive heart failure. In addition to the clinical findings described, other findings associated with congestive heart failure include edema, usually of the eyelids or in dependent areas, jugular venous distention, an S3 or S4 gallop on examination, and cardiomegaly or pulmonary edema demonstrable on chest radiograph.

6. (D) Evaluation of a young patient with congestive heart failure requires a physical examination to assess for edema, hepatomegaly, pulmonary congestion, and cardiac gallop. An echocardiogram is used to assess cardiac function and any associated cardiac structural abnormalities. A 12-lead ECG is used to assess for any ischemic changes, arrhythmias, or bradycardia. A chest radiograph is helpful to assess for cardiomegaly or pulmonary edema as well as to assess for any obvious primary pulmonary disorders. A throat culture would not be useful at this age for evaluation of heart failure.

7. (C) Cardiac lesions that present with heart failure at this age are usually a result of an increase in the amount of left-to-right shunting secondary to the natural decrease in the pulmonary vascular resistance. Common left-to-right shunting lesions include a ventricular septal defect, a patent ductus arteriosus, a large coronary artery fistula, and an aortopulmonary window. Atrial septal defects do not usually present with heart failure at this age mainly because the amount of left-to-right shunting depends on the compliance of the right ventricle rather than the drop in pulmonary vascular resistance.

8. (A) An anomalous left coronary artery arising from the pulmonary artery is a rare congenital heart defect. The right coronary artery arises normally from the aorta. A number of collateral vessels develop between the right and left coronary arteries, and thus, when there is a drop of pulmonary vascular resistance, a “steal phenomenon” occurs with coronary blood essentially flowing from the aorta to the right coronary artery across the collaterals to the left coronary artery and into the pulmonary artery. Because of this, certain areas of the myocardium are at risk for ischemia. Patients with this lesion often present at 6-8 weeks of age with extreme irritability (especially at the onset of feeding) that is a result of angina. Other symptoms such as diaphoresis, weight loss, hepatomegaly, and decreased frequency of wet diapers occur at a similar frequency to other conditions associated with heart failure.

9. (B) Acute management of heart failure because of left-to-right shunting lesions include inotropic support with digoxin, dopamine, dobutamine, or epinephrine. Diuretics are also used to relieve symptoms of edema. Milrinone is an inotrope and afterload-reducing agent that is commonly employed for the treatment of heart failure. Use of oxygen may exacerbate symptoms of heart failure in the presence of left-to-right shunting lesions by decreasing pulmonary vascular resistance and increasing the degree of left-to-right shunting. The ultimate long-term therapy is to eliminate the left-to-right shunting lesion either with surgery or interventional cardiac catheterization.

10. (D) Myocardial dysfunction resulting in dilated cardiomyopathy is uncommon in the pediatric population. The causes include myocarditis, metabolic diseases, idiopathic, familial dilated cardiomyopathy, or tachycardia-induced cardiomyopathy. Ischemic heart disease is a rare cause of dilated cardiomyopathy at this age but is the most common cause in the adult population.

11. (B) Myocarditis is defined as inflammation of the myocardium thought to occur because of a cellmediated immunologic reaction. The diagnosis is confirmed by endomyocardial biopsy showing fibrosis and inflammation. A biopsy showing fibrosis alone may be seen with any form of cardiomyopathy and is not specific for acute myocarditis. Other features suggestive of myocarditis include tachycardia out of proportion to the symptoms of heart failure, cardiac dysfunction, a pericardial effusion, and a preceding history of upper respiratory illness. A systolic flow murmur, hepatomegaly, and S3 gallop may occur with myocarditis but are nonspecific findings for this diagnosis.

12. (D) The most common cause of myocarditis is infection due to enterovirus (eg, coxsackievirus and echovirus) as demonstrated by polymerase chain reaction (PCR) of endomyocardial biopsies. Other agents include other viruses (such as adenovirus and Epstein-Barr virus), bacteria, rickettsia, fungi, protozoa, and parasites. Other etiologies include immunemediated diseases, toxic myocarditis, and collagen vascular diseases.

13. (D) The acute management of myocarditis includes the use of steroids, IV immunoglobulins, diuretics, and inotropic support. Use of IV digoxin during the acute phase of myocarditis is associated with increased occurrence of arrhythmias and is thus typically not recommended. There are conflicting data regarding the efficacy of these therapies, and no single therapy has shown to significantly improve the long-term outcome in patients with myocarditis. Generally, most patients improve and have complete recovery, although the acute mortality rate may be as high as 75% in neonates.

14. (D) In patients with ventricular dysfunction and chronic congestive heart failure, therapy includes the use of diuretics and digoxin. The use of afterloadreducing agents such as ACE inhibitors has been shown to reduce morbidity and mortality. The recent use of beta-blockers has been shown to decrease myocardial oxygen demand and also decreases morbidity and mortality among adults with ventricular dysfunction. The use of calcium channel blockers is not recommended because of the significant negative inotropic effect. The long-term management for patients with ventricular dysfunction and heart failure includes medical therapy and routine monitoring with exercises tests to obtain objective data regarding cardiac performance.

15. (B) The most likely diagnosis of this patient is acute pericarditis. This is defined as inflammation of the parietal and visceral pericardium and results in serous hemorrhagic or purulent pericardial effusion. The clinical manifestations include a pericardial friction rub and the presence of a dull substernal chest pain that improves when leaning forward. There may be a history of upper respiratory tract infection and fever.

16. (A) The most common agents causing pericarditis in the United States are viruses. Acute rheumatic fever is a common cause in certain parts of the world. Other causes include bacterial infection, collagen vascular disease, tuberculosis, oncologic disease, and uremia.

17. (D) Cardiac tamponade is the most likely cause of this patient’s acute decompensation. The clinical features of cardiac tamponade include distant heart sounds, tachycardia, pulsus paradoxus, hepatomegaly, venous distention, and hypotension. The diagnosis can be confirmed with an echocardiogram. Acute management would include pericardiocentesis or surgical drainage of the pericardial fluid. Long-term management is directed at the cause of the pericarditis.

Pulsus paradoxus is defined as a drop of 10 mm Hg or more in the systolic blood pressure with breathing. The normal variability of systolic blood pressure with breathing (<10 mm Hg) results from fluctuation of left ventricular filling because intrapulmonary pressures vary with respiration. This phenomenon is exaggerated with cardiac tamponade and may also occur with pulmonary embolism, obstructive respiratory disease, or hypotension.


S
UGGESTED READING

Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, eds. Moss and Adams Heart Disease in Infants, Children and Adolescents. 7th ed. Philadelphia, PA: Williams and Wilkins; 2007.

Braunwald E, Zipes DP, Libbey P, eds. Braunwald: Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia, PA: WB Saunders; 2004.

Keane JF, Fyler DC, Lock JE, eds. Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia: Hanley and Belfus; 2006.

Park M, ed. Pediatric Cardiology for Practitioners. 5th ed. St. Louis, MO: Mosby; 2007.

CASE 4: A 5-YEAR-OLD WITH A HEART MURMUR AND FEVER

A 5-year-old child presents to the clinic with a history of fever, rash, a swollen knee and ankle, shortness of breath, and fatigue. His past medical history is significant for the fact that he had a streptococcal throat infection 3 weeks prior to this visit but did not take the amoxicillin that was prescribed. On physical examination, he has a temperature of 38.9°C. He has a grade 2/6 systolic regurgitant murmur heard best at the apex and an S3 gallop. He has hepatomegaly and good peripheral pulses.

SELECT THE ONE BEST ANSWER

1. What is the most likely diagnosis in this child?

(A) acute rheumatic fever

(B) infective endocarditis

(C) Kawasaki disease

(D) sickle cell disease

(E) sepsis

2. What is the most common cause of this disease?

(A) group A beta-hemolytic streptococcal pharyngitis

(B) group A beta-hemolytic streptococcal impetigo

(C) Staphylococcus aureus skin infection

(D) enterococcus infection

(E) influenza A infection

3. What is the incidence of acute rheumatic fever following untreated streptococcal pharyngitis?

(A) 0.001%

(B) 0.3-3%

(C) 13-15%

(D) 25-33%

(E) 35-50%

4. Which heart valve(s) is/are the most commonly affected with acute rheumatic fever?

(A) mitral valve

(B) aortic valve

(C) tricuspid valve

(D) pulmonary valve

(E) B and D

5. Which of the following is not a major criterion for the diagnosis of acute rheumatic fever?

(A) erythema marginatum

(B) carditis

(C) chorea

(D) arthralgias

(E) arthritis

6. Which statement is true regarding antibiotic therapy for acute rheumatic fever?

(A) eradication of streptococci from the pharynx is the goal

(B) penicillin prophylaxis for 1 year is required but then can be stopped earlier if the patient is well

(C) penicillin prophylaxis can be given either twice daily by mouth or once monthly by intramuscular (IM) injection

(D) oral sulfadiazine or tetracycline can be substituted for penicillin in patients who are penicillin allergic

(E) oral cephalosporins can be substituted for penicillin in patients who are penicillin allergic

7. The heart murmur in this patient is most likely a result of which of the following?

(A) mitral valve regurgitation

(B) mitral valve stenosis

(C) tricuspid valve regurgitation

(D) pulmonary valve regurgitation

(E) aortic valve stenosis

8. A 2-year-old child presents with a 10-day history of fever, a heart murmur, bilateral nonexudative conjunctivitis, swollen and erythematous lips and strawberry tongue with erythematous and edematous hands and feet, and a polymorphous rash on the face, trunks, and extremities. The most likely diagnosis in this patient is

(A) Kawasaki disease

(B) measles

(C) viral upper respiratory tract infection

(D) group A beta-hemolytic streptococcal pharyngitis

(E) Hodgkin lymphoma

9. What acute finding would not be expected to be associated with this 2-year-old’s diagnosis?

(A) sterile pyuria

(B) hydrops of the gallbladder

(C) cervical adenopathy with at least one node longer than 1.5 cm

(D) thrombocytosis

(E) A and B

10. Which of the following statements is true regarding coronary artery involvement with this 2-year-old’s disease?

(A) there is a 50% incidence of coronary artery aneurysms if untreated

(B) the peak incidence for coronary artery aneurysms is 6-12 months following the onset of fever

(C) patients with giant coronary artery aneurysms (>8 mm in diameter) are at highest risk for late stenosis and myocardial infarction

(D) coronary artery rupture is the most common cause of mortality within the first 7 days of the onset of fever

(E) coronary artery aneurysms are not at risk for development of thrombus

11. The 2 drugs most commonly used for the acute management of this disease are

(A) aspirin and intravenous immunoglobulin (IVIG)

(B) penicillin and IVIG

(C) steroids and aspirin

(D) steroids and penicillin

(E) penicillin and aspirin

12. A 5-year-old boy presents with a fever of 10 days, weight loss, night sweats, a new heart murmur, splenomegaly, joint pains, and a history of having had his teeth cleaned by the dentist 1 month prior to this visit. On examination, he was found to have a grade 2/4 diastolic murmur heard best at the midleft sternal border radiating to the apex. There is an S3 gallop rhythm. What is the most likely diagnosis for this patient?

(A) infective endocarditis

(B) juvenile rheumatoid arthritis

(C) Kawasaki disease

(D) acute rheumatic fever

(E) mononucleosis

13. Which of the following laboratory evidence most likely supports the diagnosis of infective endocarditis?

(A) two positive blood cultures with the same organism and no other source other than the heart

(B) increased white blood cell count

(C) increased C-reactive protein (CRP)

(D) throat culture positive for group A betahemolytic streptococcus

(E) increased erythrocyte sedimentation rate (ESR)

14. Which bacterial species would be the most common cause of infective endocarditis in this 5-year-old child?

(A) alpha-hemolytic streptococcus

(B) Staphylococcus aureus

(C) Staphylococcus epidermidis

(D) Enterococcus faecalis

(E) Bacteroides fragilis or other anaerobe

15. What percent of cases of infective endocarditis have negative blood cultures?

(A) 10%

(B) 20%

(C) 30%

(D) 40%

(E) 50%

16. Which of the following heart lesions would not be considered an increased risk for the development of infective endocarditis?

(A) mitral regurgitation

(B) aortic insufficiency

(C) aortic stenosis

(D) atrial septal defect

(E) ventricular septal defect

17. What is the most common antibiotic regimen that should be started in cases of suspected infective endocarditis before knowing the results of the blood culture?

(A) vancomycin or oxacillin and gentamicin

(B) ampicillin and gentamicin

(C) ampicillin and ceftriaxone

(D) vancomycin alone

(E) none of the above

18. Which of the following procedures does not require endocarditis prophylaxis in patients who are susceptible to endocarditis?

(A) tonsillectomy

(B) urinary tract surgery

(C) professional dental cleaning

(D) endotracheal intubation

(E) cardiac surgery

ANSWERS

1. (A) The most common cause of this constellation of symptoms is acute rheumatic fever, a multisystem inflammatory disease. The disease occurs among children 5 to 15 years of age with a peak incidence at 8 years and is rarely seen in children younger than 2 years of age.

2. (A) Acute rheumatic fever is triggered by group A beta-hemolytic streptococcal infection of the upper respiratory tract. Acute rheumatic fever does not occur following streptococcal skin infections, staphylococcal infections, or enterococcal infections. The pathogenesis of rheumatic fever is thought to be secondary to an immune response to antigens in the M protein of the capsule of the group A beta-hemolytic streptococcus, which occurs in susceptible hosts and cross-reacts with similar epitopes in human joint tissue, heart, and brain tissue. Pathologic findings include inflammatory lesions that include perivascular granulomas consisting of infiltrates of cells and fibrin that are also known as Aschoff bodies.

3. (B) The incidence of acute rheumatic fever is approximately 0.3-3% in untreated patients with Streptococcus pyogenes pharyngitis. The onset of disease occurs 1-5 weeks later with a mean of 18 days following the onset of pharyngitis. The typical course includes pharyngitis with improvement of symptoms. Two weeks later the patient begins to develop a low-grade fever and the inflammatory response of rheumatic fever.

4. (A)

5. (D) Although there is no specific diagnostic laboratory test for rheumatic fever, the diagnosis is based on the Jones criteria. These are separated into major and minor manifestations. Major criteria include polyarthritis, carditis, erythema marginatum, subcutaneous nodules, and chorea. The most common manifestation is polyarthritis occurring in up to 70% of patients, typically a migratory arthritis involving the large joints (knees, hips, ankles, elbows), which characteristically responds dramatically to salicylate therapy. Carditis occurs in approximately 50% of cases and includes myocarditis, pericardial effusions, arrhythmias, and valvular heart disease. Erythema marginatum (Figure 4-1) occurs in less than 10% of patients and is a nonpruritic serpiginous rash that occurs on the torso and is almost never seen on the face. The rash is evanescent and becomes more apparent following hot baths or being wrapped in warm blankets. Subcutaneous nodules are nontender, freely mobile nodules occurring usually over the bony surfaces of the elbows, wrists, shins, knees, ankles, and spine. They occur in 2-10% of cases. Chorea occurs in up to 15% of cases and is a neuropsychiatric disorder that may include choreiform movements, hypotonia, emotional lability, anxiety, and an obsessive-compulsive disorder. Chorea usually occurs late, after the initial pharyngitis with the average time to onset of about 6-7 months. It may last as long as 18 months. Recent evidence suggests that chorea is associated with the presence of antineuronal antibodies. Minor manifestations include fever, arthralgias (when polyarthritis is not present), increased acute phase reactants such as CRP, and a prolonged PR interval on ECG (in the absence of other evidence of carditis). The diagnosis of acute rheumatic fever is made with either 2 major manifestations or with a single major manifestation and 2 minor manifestations. If made by 1 major manifestation and 2 minors, the diagnosis should be supported by evidence of a preceding streptococcal infection either by a positive throat culture or by rising streptococcal antibody titers (eg, antistreptolysin O). There are 3 exceptions to the Jones criteria for diagnosis of acute rheumatic fever:

1. Chorea may be the only manifestation of rheumatic fever.

2. Indolent carditis may be the only manifestation in patients following the initial infection.

3. Recurrences often do not strictly fulfill the Jones criteria. Therefore, a presumptive diagnosis of recurrent rheumatic fever may be made with fewer than the usual number of criteria. Recurrent disease should only be diagnosed if there is supporting evidence of a recent streptococcal infection.

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FIGURE 4-1. Erythema marginatum on the trunk of an 8-year old caucasian boy. The pen mark shows the location of the rash approximately 60 minutes previously. (Reproduced, with permission, from Fuster V, O’Rourke RA, Walsh RA, et al. Hurst’s the Heart. 12th ed. New York: McGraw-Hill; 2008:1694.)


6. (C) Treatment for acute rheumatic fever includes therapy directed at the streptococcal infection with penicillin followed by prevention of recurrences with either twice-daily oral penicillin or oncemonthly IM benzathine penicillin injections. Although some advocate prophylaxis to be continued at least until the patient is 21 years of age, others recommend that prophylaxis be lifelong. In patients who are penicillin allergic, prophylaxis can be substituted with either oral sulfadiazine or erythromycin. Recurrences of acute rheumatic fever usually occur within the first 5 years after the initial diagnosis and are characterized by more severe cardiac valve involvement. It is estimated that approximately 10-25% of patients with heart valve involvement will have complete resolution by 10 years.

7. (A) The mitral valve is the most commonly affected followed by the aortic valve and, rarely, the tricuspid or pulmonary valves. Initially, the affected valves develop regurgitation as a result of inflammation and valve dysfunction. However, with healing of the inflammation, long-term development of mitral valve stenosis can occur. This may be seen as early as 2-3 years following the acute episode but usually occurs 10-20 years later.

8. (A) The child described most likely has Kawasaki disease, an acute vasculitis of unknown etiology. Kawasaki disease is the leading cause of acquired heart disease in children in the United States. The incidence ranges from 2-6/100,000 children and is highest in Asian American children. The peak incidence is at 1-2 years of age with 85% of the cases occurring in children younger than 5 years of age. The disease is uncommon in patients older than 8 years of age or younger than 3 months of age. The clinical manifestations include the presence of fever for at least 5 days, no other reasonable etiology, and 4 of 5 of the following:

1. A nonexudative conjunctivitis that is usually bilateral

2. Erythema of the lips, oral mucosa, and pharynx, including a strawberry tongue and cracking or peeling of the lips later into the disease

3. A polymorphous rash of the face, trunk, and extremities that later can involve the perineal area and is characterized by desquamation at 5-7 days (Figure 4-2)

4. Cervical adenopathy greater than 1.5 cm in diameter that is usually unilateral

5. Changes in the extremities, including edema and erythema of the hands and feet followed by periungual desquamation at 11-25 days into the disease

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FIGURE 4-2. Kawasaki disease. Desquamation of the tissue of the palm. (Reproduced, with permission, from Wolff K, Johnson RA. Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology, 6th ed. New York: McGraw-Hill; 2009: Fig. 14-45.)


Incomplete Kawasaki disease can be diagnosed when fever is present for 5 or longer days in the presence of 2 to 3 of the preceding criteria when the CRP is 3.0 mg/dL or more and/or the ESR is 40 mm/hour or more. In this instance, certain laboratory criteria should be met including hypoalbuminemia, anemia, increased serum alanine aminotransferase, thrombocytosis, leukocytosis, and sterile pyuria.

9. (D) Other supportive findings of the acute phase of Kawasaki disease include urethritis with sterile pyuria, aseptic meningitis, abdominal pain, hydrops of the gallbladder, and arthritis that usually involves the small joints but may involve the large joints 2-3 weeks into the disease. Also, mild carditis and arrhythmias may occur. The subacute phase occurs 11-25 days following the onset of fever and is characterized by a decrease in the rash and fever with the onset of desquamation of the fingers and toes. Thrombocytosis peaks at 2-4 weeks into the course of the disease. It is during this phase that coronary artery aneurysms usually become evident.

10. (C) Coronary artery aneurysms are the most feared complication of Kawasaki disease and occur in up to 15-25% of untreated patients (Figure 4-3). They are a result of the panvasculitis resulting in aneurysmal transformation of the coronary arteries and may be seen as early as 7 days after the onset of the fever. Their incidence peaks at 3-4 weeks and they are seldom found after 8 weeks into the course of the disease. Giant aneurysms are described as having a diameter greater than 8 mm and are associated with increased mortality and morbidity. Patients with aneurysms also have a higher incidence of developing stenoses leading to myocardial ischemia and infarction with long-term follow-up. Coronary artery rupture is the most common cause of mortality in the subacute phase; myocarditis, heart failure, and arrhythmias are the most common causes of mortality in the acute phase within the first 10 days after the onset of fever. Risk factors for the development of coronary artery aneurysms include male gender, age younger than 1 year, hemoglobin less than 10 g/dL, white blood cell count greater than 30,000/mm3, ESR greater than 101 mm/hour, and prolonged fever. Echocardiography is recommended for assessment of coronary artery involvement with Kawasaki disease. The most recent recommendations suggest that an echocardiogram is obtained at diagnosis, and if no coronary disease is seen, then it should be repeated in 6-8 weeks. If coronary artery involvement is documented, then follow-up should be more frequent based on the extent of disease.

11. (A) The management of Kawasaki disease includes high-dose aspirin, which is given during the acute phase, followed by low-dose aspirin for 6-8 weeks. This is given for antithrombotic effect while thrombocytosis is present. IVIG is administered within the first 10 days of the disease at a dose of 2 g/kg and may be repeated if fever persists following this therapy. The use of IVIG decreases the incidence of coronary artery aneurysms to less than 5%. If aneurysms persist past 2 months, then aspirin or other anticlotting agents should be continued. The use of steroids is not indicated for uncomplicated Kawasaki disease.

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FIGURE 4-3. Parasternal short-axis images of coronary artery aneurysms associated with Kawasaki disease. A. The proximal left coronary artery (LCA) is diffusely dilated and aneurysmal. B. A proximal right coronary artery aneurysm (arrow) is shown. Ao, aorta, LA, left atrium. (Reproduced, with permission, from Fuster V, O’Rourke RA, Walsh RA, et al. Hurst's the Heart, 12th ed. New York: McGraw-Hill, Fig. 16-140.)


12. (A) The most likely diagnosis in this situation is infective endocarditis. This is an inflammatory disorder of the heart resulting from an infection. The signs and symptoms of infective endocarditis include acute findings of fever, anorexia, weight loss, pallor, night sweats, myalgias, and new onset of a heart murmur, usually as a result of valve disease from infection. Later findings result from embolic phenomena and include splinter hemorrhages, Roth spots (retinal hemorrhages), Janeway lesions, Osler nodes, splenomegaly, clubbing, arthralgias, arthritis, glomerulonephritis, and aseptic meningitis (Figure 4-4). The pathogenesis of infective endocarditis results from the initial setting of a jet of blood or turbulence within the heart leading to endothelial damage and formation of a sterile clot or vegetation. This serves as a nidus for bacterial infection.

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FIGURE 4-4. Selected peripheral manifestations of infective endocarditis. A. Splinter hemorrhages are linear hemorrhages under the nails that do not reach the nail margin. They are often red for the first two days and brownish thereafter. B. Conjunctival hemorrhages. C. Osler nodes are tender, erythematous nodules often occurring in the pulp of the fingers. D. Janeway lesions are small, flat, irregular spots found on the palms and soles. They are typically erythematous and nontender. (Reproduced, with permission, from Fuster V, O’Rourke RA, Walsh RA, et al. Hurst’s the Heart, 12th ed. New York: McGraw-Hill, Fig. 85-4.)


13. (A) The diagnosis of infective endocarditis can be determined by

1. Pathologic evidence either by surgery or embolectomy of an infected thrombus within the heart.

2. Two positive blood cultures with the same organism with no other source other than the heart.

3. A clinical course compatible with infective endocarditis.

Supportive evidence of endocarditis includes laboratory findings of anemia, increased white blood cell count, increased ESR or CRP, hematuria, decreased complement component C3, and increased bilirubinemia. The echocardiogram is useful for detecting intracardiac vegetations. The type of echocardiogram performed, whether it be transthoracic or transesophageal, depends on the age of the patient and the ability to achieve good acoustic windows.

14. (A) The most common organism causing infective endocarditis following dental procedures is Streptococcus viridans. However, Staphylococcus aureus and Staphylococcus epidermidis have become important causes of infective endocarditis. Staphylococcus aureus is now, overall, the leading cause. Enterococcus spp. is also a common cause of endocarditis, particularly in adults. Among patients with burns or IV drug abusers, staphylococci are the most common causative organisms. Infants with sepsis are also at higher risk for endocarditis with no underlying cardiac disease.

15. (A) Up to 10% of cases of endocarditis are culture negative. However, in 90% of cases, the causative agent may be identified by obtaining at least 3 blood cultures during the first 24 hours of hospitalization.

16. (D) Valvular heart lesions are most commonly associated with predisposition for the development of infective endocarditis; however, other forms of congenital heart disease, including tetralogy of Fallot, ventricular septal defect, patent ductus arteriosus, coarctation of the aorta, and pulmonary valve stenosis, have also been implicated. Congenital heart defects such as atrial septal defect, peripheral pulmonary stenosis, and mitral valve prolapse without mitral regurgitation are not considered to be highrisk lesions for development of infective endocarditis, and thus bacterial endocarditis prophylaxis is not indicated in these situations.

17. (A) In patients with suspected infective endocarditis, a course of either vancomycin or oxacillin and gentamicin is started because the most likely organisms include streptococci and staphylococci, depending on the rate of methicillin-resistant S aureus in the patient’s geographic area. Once the organism is identified, the antibiotic regimen can be adjusted. Surgical intervention is occasionally required for removal of foreign bodies that are difficult to sterilize with IV antibiotics or repair of valves that have been damaged by infection. Other complications associated with endocarditis include mycotic aneurysms, localized cardiac abscesses, and autoimmune phenomena such as nephritis and arthritis.

18. (D) Procedures in which there is a risk for significant bacteremia would require bacterial endocarditis prophylaxis. These procedures include dental procedures where bleeding is anticipated, tonsillectomy, cardiac surgery, incision of infected sites, urologic surgery, and Foley placement in the presence of a urinary tract infection. Endotracheal intubation is not associated with a high incidence of bacteremia and thus antibiotic prophylaxis is not required.


S
UGGESTED READING

Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, eds. Moss and Adams Heart Disease in Infants, Children and Adolescents. 7th ed. Philadelphia, PA: Williams and Wilkins; 2007.

Braunwald E, Zipes DP, Libbey P, eds. Braunwald: Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia, PA: WB Saunders; 2004.

Keane JF, Fyler DC, Lock JE, eds. Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia, PA: Hanley and Belfus; 2006.

Newburger J, Takahashi M, Gerber M, et al. Diagnosis, treatment and long-term management of Kawasaki disease. A statement for health professionals from the Committee on Rheumatic Fever, Endocarditis, and Kawasaki Disease, Council on Cardiovascular Disease in the Young, American Heart Association. Pediatrics. 2004;114:1708-1733.

Park M, ed. Pediatric Cardiology for Practitioners. 5th ed. St. Louis, MO: Mosby; 2007.

CASE 5: A 10-YEAR-OLD BOY WITH ELEVATED BLOOD PRESSURE ASCERTAINED AT A ROUTINE PHYSICAL EXAMINATION

A 10-year-old boy presents for a preparticipation sports physical examination. He has previously been well with no significant past medical history. His vital signs indicate a heart rate of 101 bpm and a blood pressure of 130/85 mm Hg (greater than the 95th percentile for age). The remainder of his examination is normal.

SELECT THE ONE BEST ANSWER

1. What is the most appropriate next step?

(A) recheck the blood pressure with a smaller blood pressure cuff

(B) recheck the blood pressure on at least 2 other separate occasions before beginning further evaluation

(C) begin medical therapy with antihypertensive medications

(D) order a renal ultrasound

(E) check serum catecholamine levels

2. At this age, what is the most common cause of hypertension?

(A) primary familial or idiopathic hypertension

(B) coarctation of the aorta

(C) renal artery thrombosis

(D) renal parenchymal disease

(E) adrenal hyperplasia

3. Renal parenchymal hypertension is caused by all except which of the following mechanisms?

(A) salt retention

(B) water retention

(C) increased renin levels

(D) excess levels of catecholamines

(E) none of the above cause renal parenchymal hypertension

4. On the third visit, the patient continues to demonstrate evidence of systemic hypertension with elevated blood pressure recordings. Of the following, which is the most appropriate testing at this time?

(A) urinalysis

(B) serum catecholamine levels.

(C) renal CT scan

(D) urine 17-hydroxy steroids or 17-ketosteroids

(E) all of the above

5. Which of the following interventions would not be recommended at this time?

(A) stop all exercise

(B) weight reduction

(C) stop tobacco use

(D) salt reduction

(E) all of the above should be recommended

6. Beta-blockers are useful for treatment of hypertension but are contraindicated in all but which of the following?

(A) patients with asthma

(B) patients with diabetes

(C) hyperthyroidism

(D) bradycardia

(E) severe bee sting allergy

7. The patient returns with a hypertensive crisis with a systolic blood pressure greater than 180 mm Hg and a diastolic blood pressure greater than 110 mm Hg associated with headache, vomiting, and pulmonary edema. What is the most commonly used medication in this setting?

(A) nitroprusside sodium

(B) captopril

(C) phentolamine

(D) Aldactone

(E) clonidine

8. A 10-year-old child presents for a sports physical examination. The examination and blood pressure are completely normal. There is a family history of hypercholesterolemia in his mother. What is the most appropriate advice for this patient?

(A) total serum cholesterol should be evaluated

(B) total serum cholesterol and lipoprotein analysis should be evaluated

(C) exercise stress test should be performed

(D) total serum cholesterol should be evaluated at 21 years of age

(E) none of the above

9. At what serum cholesterol level would lipoprotein analysis be indicated?

(A) 120 mg/100 mL

(B) 140 mg/100 mL

(C) 180 mg/100 mL

(D) 200 mg/100 mL

(E) 220 mg/100 mL

10. Which of the following is not a common cause of secondary hypercholesteremia in children?

(A) obesity

(B) isotretinoin

(C) oral contraceptive pills

(D) hyperthyroidism

(E) anorexia

11. What is the most common form of inherited hyperlipidemia?

(A) familial hypercholesterolemia

(B) familial combined hyperlipidemia

(C) mild hypertriglyceridemia

(D) severe hypertriglyceridemia

(E) none of the above

12. Which of the following is a true statement regarding the treatment for hypercholesterolemia in children?

(A) a Step 1 diet is recommended for children younger than 2 years of age

(B) bile acid sequestrants are recommended for children older than 10 years of age when diet modification alone is not effective

(C) lovastatin may be used in selected cases for children younger than 2 years of age

(D) none of the above

(E) all of the above

13. A 10-year-old child with physical features of tall stature, a long thin face, scoliosis, pectus excavatum with a family history of sudden death at a young age (an uncle who died while playing basketball) presents for a preparticipation sports physical. What is the likely diagnosis in this patient?

(A) Marfan syndrome

(B) hypertrophic cardiomyopathy

(C) Turner syndrome

(D) Down syndrome

(E) homocystinuria

14. What is the most common cardiac lesion associated with this 10-year-old’s diagnosis?

(A) mitral valve prolapse

(B) aortic stenosis

(C) coarctation of the aorta

(D) left ventricular outflow tract obstruction

(E) atrial septal defect

15. An echocardiogram is ordered and demonstrates mild aortic root dilation. What is the recommendation for further management?

(A) participation in sports is unrestricted

(B) follow-up echocardiogram in 10 years

(C) return to clinic only if symptoms of chest pain occur during activities

(D) treatment with beta-blockers may decrease the risk of further aortic root dilatation

(E) aortic root replacement

16. What findings during routine pre-participation physical examination would place a child at risk for sudden death during sports?

(A) a harsh systolic murmur at the upper right sternal border

(B) family history of diabetes

(C) respiratory sinus arrhythmia

(D) a single elevated blood pressure reading that returns to normal on subsequent visits

(E) arm span less than height

ANSWERS

1. (B) Hypertension is defined as a systolic or diastolic blood pressure recording greater than the 95th percentile for age and gender, recorded on 3 separate occasions. Severe hypertension is defined as blood pressure recordings greater than the 95th percentile by 8-10 mm Hg. Accurate blood pressure recordings are crucial for this diagnosis and should be taken in a quiet, nonthreatening manner. The width of the blood pressure cuff should be 40-50% or more of the arm circumference. Smaller blood pressure cuffs result in erroneously high blood pressure recordings. Ideally, blood pressure recordings should be taken in all 4 extremities. Anxiety leading to transient elevations in blood pressure (white coat hypertension) accounts for up to 40% of elevated blood pressure recordings in children. Because the diagnosis of hypertension should not be based on a single reading, medical therapy and testing for secondary causes of hypertension are not appropriate during this first visit.

2. (A) Hypertension is classified as either primary (essential or idiopathic) or secondary. Primary hypertension is the most common syndrome in older patients such as this child, whereas secondary hypertension is common in younger patients with more severely elevated blood pressure recordings. Ninety percent of secondary causes are because of renal parenchymal disease, renal artery disease, and coarctation of the aorta.

3. (D) Renal parenchymal hypertension causes salt and water retention and in some cases elevated renin levels leading to increased vascular resistance. Increased serum catecholamine levels causing hypertension are seen with pheochromocytomas or with congenital adrenal hyperplasia (11-hydroxylase deficiency or 17-hydroxylase deficiency). Hypertension is also seen with use of certain drugs or medications and in cases of hypercalcemia.

4. (A) The initial evaluation of hypertension is guided by both the examination and the family history. The important features of the history include a past medical history of urinary tract infections, cardiovascular surgeries, weakness or cramps, medication use, and tobacco use. Important features of the family history include history of hypertension or premature heart disease. The important features of the physical examination include accurate blood pressure recordings in 4 extremities, assessment for heart murmurs or bruits, assessment of peripheral pulses, assessment of renal tenderness, and a thorough eye examination. The usual initial laboratory evaluation includes a urinalysis, serum electrolytes including blood urea nitrogen (BUN) and creatinine, and possibly a 12-lead ECG, chest radiograph, and echocardiogram. A cholesterol level and a lipoprotein analysis are indicated in select cases. If there is severe hypertension and end-organ involvement or hypertension refractory to therapy, then tests evaluating for secondary causes of hypertension can be performed.

5. (A) Additional management in patients with hypertension includes nonpharmacologic interventions such as exercise proscription, weight reduction, avoidance of tobacco or oral contraceptive pills, and reduction of dietary salt intake. In severe hypertension or persistent hypertension despite nonpharmacologic interventions, pharmacologic agents are often used that include diuretics, beta-blockers, and vasodilators.

6. (C) Beta-blockers are often used in conjunction with diuretics or in conditions where hyperthyroidism results in hypertension. However, they are contraindicated for use in patients with asthma (can precipitate bronchospasm), diabetes (prevents manifestation of symptoms of hyperglycemia), and in patients with bradycardia.

7. (A) A hypertensive emergency requires immediate reduction of blood pressure usually within minutes to hours. Hypertensive crises can be associated with neurologic signs or congestive heart failure. Administration of parental medications is important for the acute treatment of hypertensive emergencies. These medications include diazoxide, nitroprusside sodium, diuretics, IV nifedipine, hydralazine, or labetalol. Phentolamine is usually reserved for patients with pheochromocytomas.

8. (A) Hypercholesterolemia is a major risk factor for coronary artery disease. Several long-term prospective studies have shown that lowering serum cholesterol levels decreases the risk for coronary artery disease in the future. This has prompted a more aggressive approach to screening and therapy for hypercholesterolemia in young patients. The current recommendations for serum cholesterol screening include the child of a single parent with a cholesterol level greater than 240 mg/100 mL or if the history is unobtainable but there is a suspicion of hypercholesterolemia. The recommendations to perform a serum cholesterol level and lipoprotein analysis include children with parents or grandparents with a history of coronary angioplasty or coronary artery bypass surgery, men younger than 55 years of age, women younger than 65 years of age, and children with parents or grandparents with a documented myocardial infarction among men younger than 55 years of age or women younger than 65 years of age.

9. (D) Serum cholesterol levels can be measured in the nonfasting state anytime after the age of 2 years. If serum cholesterol levels are higher than 200 mg/dL, lipoprotein analysis is indicated. Lipoprotein analysis requires the patient to be fasting for 12 hours before the testing.

     LDL = (total serum cholesterol) − (HDL)

   − (triglyceride concentration × 0.2)

Low-density lipoprotein (LDL) levels <110 mg/dL, in the presence of elevated cholesterol levels, should be repeated in 5 years. If the LDL level is 110-129 mg/dL, a Step 1 diet is recommended. If the LDL level is higher than 130 mg/dL, then a Step 1 or Step 2 diet is recommended with consideration of medical therapy and further evaluation for secondary causes of hyperlipidemia.

10. (D) Secondary causes of hyperlipidemia include

• exogenous factors such as obesity, isotretinoin use, oral contraceptive use

• endocrine or metabolic diseases including hypothyroidism

• obstructive liver disease

• renal failure

• other factors including anorexia or a high-fat and high-cholesterol diet

11. (B) Familial combined hyperlipidemia is the most common etiology of inherited hyperlipidemias in children. It occurs with an incidence of approximately 1 in 300 individuals and is inherited in an autosomal dominant fashion. Laboratory analysis reveals elevation of cholesterol and/or elevation of triglyceride levels. The etiology of familial combined hyperlipidemia is a result of an increased apoB-100 production by the liver related to multiple genetic factors. The clinical course is characterized by late onset of coronary artery disease and peripheral vascular disease. Familial hypercholesterolemia occurs in approximately 1 in 500 individuals and is inherited in an autosomal codominant fashion. In the heterozygous form, there are elevated serum cholesterol levels and a high risk of premature coronary artery disease. The etiology of the hypercholesterolemia is a result of a decrease in the number of LDL receptors. In the homozygous form, there is severe hypercholesterolemia with increased risk of myocardial infarction. The etiology for hypercholesterolemia is nearly complete absence of LDL receptors. Mild hypertriglyceridemia is associated with obesity, glucose intolerance, hyperuricemia, and increased alcohol intake. Severe hypertriglyceridemia is a result of a deficiency of lipoprotein lipase and is associated with recurrent pancreatitis, hepatosplenomegaly, and xanthomas.

12. (B) In patients with hypercholesterolemia, therapy is not indicated for children younger than 2 years of age. In children older than 2 years of age, initial treatment includes the Step 1 diet recommended for approximately 3 months. If the serum cholesterol level remains elevated, then a Step 2 diet is recommended for 6-12 months. If the level continues to be elevated and the child is older than 10 years of age with an LDL higher than 190 or an LDL higher than 160 and a family history of hypercholesterolemia, then bile acid sequestrants such as cholestyramine are the first-line choice of medical therapy. In selected cases, lovastatin has been reported to be of beneficial use. However, it is currently not recommended for routine use.

13. (A) The patient in this scenario most likely carries the diagnosis of Marfan syndrome, an autosomal dominant genetic disorder due to a mutation in the fibrillin gene on chromosome 15. This leads to defective connective tissue disease. The clinical features include a long thin face, tall stature with the arm span greater than the height, pectus excavatum or carinatum, scoliosis, lens subluxation, and high arched palate (Figure 5-1). There is a family history of Marfan syndrome in 70-85% of cases. Patients with hypertrophic cardiomyopathy do not have the physical stigmata described in this case, but it is an important diagnosis in cases where there is a family history of sudden unexpected death. Patients with Turner syndrome have physical stigmata consistent with short stature and webbed neck; patients with Down syndrome also have short stature with characteristic facial features.

art

FIGURE 5-1. Pectus excavatum. Adolescent with a pectus excavatum deformity. Note that the most pronounced sternal curvature is in the lower half. (Reproduced, with permission, from Doherty G. Current Diagnosis & Treatment: Surgery, 13th ed. New York: McGraw-Hill; 2010: Fig. 43-4.)


14. (A) The most common heart lesions occurring in patients with Marfan syndrome include mitral valve prolapse and dilatation of the aortic root due to abnormalities in the connective tissue as a result of a mutation in the fibrillin gene. Aortic stenosis because of a bicuspid aortic valve and coarctation of the aorta are commonly seen in patients with Turner syndrome, and left ventricular outflow tract obstruction may be seen in patients with severe forms of hypertrophic cardiomyopathy. The typical examination feature in a patient with mitral valve prolapse includes a systolic ejection click that varies in timing when the patient is standing versus when he is squatting. A diastolic murmur of mitral regurgitation may be heard in conjunction with more severe cases of mitral valve prolapse.

15. (D) In patients with Marfan syndrome, participation in activities is limited to mildly aerobic low-impact sports. This is to avoid precipitation of further aortic root dilation or rupture and to avoid retinal detachment. It is recommended that patients with Marfan syndrome undergo routine echocardiographic evaluation to assess aortic root dilation as well as routine ophthalmologic examinations. Betablockers are effective to decrease the progression of aortic root dilation.

16. (A) The American Heart Association recommends that a preparticipation physical examination screening include obtaining a family history for sudden cardiac death and a review of systems looking for a history of dizziness or syncope. Physical findings of Marfan syndrome, hypertension, decreased peripheral pulses, or a pathologic murmur such as the harsh systolic murmur described would indicate the need for further evaluation. The finding of a family history of diabetes, respiratory, sinus arrhythmia, or a single elevated blood pressure returning to normal at subsequent visits would not place this patient at risk for sudden death during sports.


S
UGGESTED READING

Allen HD, Driscoll DJ, Shaddy RE, Feltes TF, eds. Moss and Adams Heart Disease in Infants, Children and Adolescents. 7th ed. Philadelphia, PA: Williams and Wilkins; 2007.

Braunwald E, Zipes DP, Libbey P, eds. Braunwald: Heart Disease: A Textbook of Cardiovascular Medicine. 7th ed. Philadelphia, PA: WB Saunders; 2004.

Keane JF, Fyler DC, Lock JE, eds. Nadas’ Pediatric Cardiology. 2nd ed. Philadelphia, PA: Hanley and Belfus; 2006.

Park M, ed. Pediatric Cardiology for Practitioners. 5th ed. St. Louis, MO: Mosby; 2007.


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