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Pediatric Emergency Medicine

Pediatric Cardiology Answer Sheet- 6/11

Cardiology answer sheet- June 2011

American College of Emergency Physicians Section of Pediatric Emergency Medicine

Rajender Gattu, MD, Assistant Professor of Pediatrics, Division of Pediatric Emergency Medicine, University of Maryland School of Medicine

John S. Kim, MD, Department of Pediatrics, University of Maryland Hospital for Children, Baltimore, MD

Pediatric Quizzes

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1. Answer:  a.

Explanation: The case scenario is consistent with hypoplastic left heart syndrome presenting as a cardiogenic shock.  Single ventricle physiologies are ductal dependent lesions, therefore, PGE2 infusion will show an immediate clinical improvement as the ductus arteriosus remains open.  Although septic shock from infection is a differential diagnosis, treating with antibiotics alone is not immediately life saving.  Routine treatment of shock with IV fluids and oxygen may aggravate the symptoms in this patient.  [Mastropietro, et al. Emergency Presentation of Congenital Heart Disease in Children. Pediatric Emergency Medicine Practice. 2008; 5(5):1-32.]

2.  Answer:  a

Explanation: Congenital heart disease occurs in 0.5–0.8% of live births. This overall incidence does not include mitral valve prolapse, PDA of preterm infants, and bicuspid aortic valves.  A ventricular septal defect (VSD) is involved in approximately one third of all children with a congenital heart defect.  VSD, however, commonly occurs in association with a myriad of other defects and syndromes.  Bicuspid aortic valve is identified in approximately 2% of adults and is one of the most common isolated congenital heart lesions.  Bicuspid aortic valve, which is usually asymptomatic in children, is part of a spectrum of heart defects that includes congenital aortic stenosis which accounts for about 5% of cardiac defects.  [Kliegman, et al. Nelson Textbook of Pediatrics. 18th ed. Philadelphia: Saunders Elsevier; 2007.]

3.   Answer: c 

Explanation: The patient in the vignette is presenting with signs and symptoms of sympathetic overdrive including tachycardia, tachypnea, diaphoresis etc are consistent with myocardial ischemia as a complication of coronary artery aneurysms secondary to prior Kawasaki disease (KD). Immediate step in the management will be MONA (Morphine, Oxygen, Nitroglycerin and Aspirin). If diagnosed treatment for KD with IVIG, although controversial, is intended to decrease the inflammatory response in an effort to prevent coronary artery aneurysms (primary complication of KD).  Without treatment, coronary artery aneurysms develop in one of every four to five children with Kawasaki disease.  Coronary artery aneurysms can be associated with subsequent thrombosis and/or stenosis, thus presenting as myocardial ischemia or infarction.  [New burger, et al. Kawasaki Disease. Curr Opin Pediatr. 2004 Oct; 16(5):508-14.]

4. Answer: d

Explanation: The patient in the above vignette is presenting to the pediatric emergency department with congestive heart failure and cardiogenic shock.  Ductal dependent lesions usually present with CHF and cardiogenic shock in the first week of life. Heart failure outside of the immediate neonatal period can be associated with a number of cardiac etiologies, including: (1) pulmonary over circulation caused by left-to-right shunting due to ventricular septal defect (VSD), (2) cardiomyopathy and depressed myocardial function associated with coronary artery abnormalities such as ALCAPA or myocarditis.  [Sharieff, et al. Pediatric Cardiac Disorders. J Emer Med. 2004, 26(1):65-79.]

  

 5.  Answer:  a 

Explanation: Bacterial endocarditis has been most-commonly associated with complex congenital heart disease (CHD) and the use of indwelling central venous catheters.  The incidence of IE in association with CHD has risen in recent decades secondary to the advanced surgical techniques and an associated increase in survival.  In addition, patients who have undergone complex surgeries that utilize prosthetic materials (e.g. conduits, shunts, or patches) are at a greater risk of IE.  Tetralogy of Fallot is among one of the most common cardiac defects associated with IE, however, bacteria can seed in patients with and without valvular disease.  The patient in the vignette presents as a complication of aortic stenosis.  Staphylococcus Aureus is the most common bacteria associated with infective endocarditis (57%), followed by Viridans Streptococci (20%), coagulase-negative Staphylococci (14%), and Group A Streptococcus (3%).  [Day, et al. Characteristics of Children Hospitalized with Infective Endocarditis. Circulation. 2009 Feb;119:865-870.]

6. Answer: b

Explanation: Congenital complete heart block (CCHB) is most commonly associated with neonatal lupus caused by maternal lupus antibodies crossing the placenta.  Pediatric patients with symptomatic complete heart block may present with bradycardia.  Management of acutely symptomatic bradycardia always starts with airway and breathing; heart rate and circulation should be supported with CPR with epinephrine or atropine in accordance with the American Heart Association Pediatric Advanced Life Support guidelines.  In the subacute and/or stable phase of CCHB, heart rate can be supported with medications such as isoproterenol.  The definitive treatment, however, is pacing in the neonatal period if heart rate is less than 55.  Complete heart block is not a shockable rhythm via cardioversion.  However, cardioversion may eventually become applicable if bradycardia progresses to pulseless electrical activity (PEA).  [Dolara, et al. Controversies in the therapy of isolated congenital complete heart block. J Cardiovasc Med. 2010 Jun; 11(6):426-430.]

7. Answer: e

Explanation: Pacemakers are used in pediatric patients most commonly for varying degrees of heart block and/or poor cardiac output (caused by, for example, heart failure associated with cardiomyopathy).  Pacemakers produce an electrical stimulus to induce depolarization of the heart and subsequent ventricular contraction.  When pacers fail to produce an adequate electrical stimulus to depolarize the heart it is called non-capture or loss of capture.  This pacemaker dysfunction can be caused by a number of problems; including, lead failure or break, decreased electrode conductance caused by fibrosis around the lead, low pacemaker output or battery depletion, or if the capture threshold is set too high.  Pacemaker capture is set on the pacer and is the lowest threshold at which the depolarizing output current causes myocardial contraction. [Skippen, et al. Pacemaker therapy of postoperative arrhythmias after pediatric cardiac surgery. 2010 Jan; 11(1):133-8.]  

 8. Answer: c

Explanation: The patient in this vignette presents with headache and hypertensive urgency secondary to hypertension associated with her renal disease.  Her presentation is consistent with hypertensive urgency, rather than hypertensive emergency.  Hypertension in children is defined as systolic or diastolic blood pressure greater than the 95th percentile according to the National Heart Lung and Blood Institute (NHLBI) guidelines based on height percentile and blood pressure data from the 2000 NHANES study.  Hypertensive emergency is defined as elevated blood pressure with evidence of end-organ damage (brain, kidneys, eyes, or heart).  Hypertensive emergencies in children usually present with hypertensive encephalopathy associated with neurologic symptoms such as lethargy, seizures, and even coma.  Oral agents should be the first line of therapy for hypertensive urgency. Management of hypertensive urgency should focus on the initiation of long-term therapy for hypertension and blood pressure should be lowered gradually, particularly in patients with chronic disease (such as chronic kidney disease). [Constantine, et al. Assessment and management of hypertensive emergencies and urgencies in children. Pediatr Emer Care. 2005 Jun;21(6):391-396.]

 Copyright 2011 American College of Emergency Physicians. Pediatric Emergency Medicine Section quizzes may be reproduced for educational purposes only. To obtain permission to reprint for any other purpose, please submit your written request to: Deputy Executive Director, American College of Emergency Physicians, PO Box 619911, Dallas, TX 75261.

 

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