Congenital Heart Disease in Pediatric Patients: Recognizing the Undiagnosed and Managing Complications in the Emergency Department (Pharmacology CME)

Table of Contents

 

1. Abstract
2. Case Presentations
3. Introduction
   1. Epidemiology
   2. Presentations Of Congenital Heart Disease
4. Critical Appraisal of the Literature
5. Etiology And Pathophysiology
   1. Transition From Fetal To Neonatal Circulation
   2. Pathophysiology Of Clinical Presentations Of Shock
   3. Pathophysiology Of Clinical Presentations Of Cyanosis
   4. Pathophysiology Of Clinical Presentations Of Congestive Heart Failure
6. Differential Diagnosis
7. Prehospital Care
8. Emergency Department Evaluation
   1. Initial Evaluation And Stabilization
   2. History
   3. Physical Examination
9. Diagnostic Studies
   1. Laboratory Studies
   2. Electrocardiography
   3. Chest Radiography
   4. Echocardiography
10. Treatment
    1. Shock And Congenital Heart Disease
    2. Cyanosis And Congenital Heart Disease
    3. Congestive Heart Failure And Congenital Heart Disease
       1. Medications
11. Special Populations
    1. Complications Of Surgically Repaired/ Palliated Congenital Heart Disease
       1. Emergency Management Of Surgically Repaired/ Palliated Congenital Heart Disease Presenting With Acute Decompensation
    2. Anomalous Origin Of The Left Coronary Artery From The Pulmonary Artery
    3. Heterotaxy Syndromes
    4. Aortic Arch Abnormalities And Pulmonary Slings
    5. Pulmonary Hypertension
    6. Dysrhythmias
12. Controversies And Cutting Edge
    1. Oxygen In Congenital Heart Disease
    2. Intubation And Positive-Pressure Ventilation
    3. Prostaglandin E1
    4. Subacute Bacterial Endocarditis And Antibiotic Prophylaxis
13. Disposition
14. Summary
15. Abbreviations
16. Risk Management Pitfalls In Pediatric Congenital Heart Disease
17. Time- And Cost-Effective Strategies
18. Case Conclusions
19. Clinical Pathway For Management Of Congenital Heart Disease In The Neonate Presenting With Shock
20. Clinical Pathway For Management Of Hypercyanotic Episode In Pediatric Patients With Tetralogy Of Fallot
21. Clinical Pathway For Management Of Congenital Heart Disease In The Pediatric Patient Presenting With Congestive Heart Failure
22. Tables and Figures
    1. Table 1. Absolute And Relative Frequency Of The Most Common Cardiac Defects
    2. Table 2. Clinical Presentations Of Congenital Heart Disease In Children
    3. Table 3. Genetic Defects And Syndromes Associated With Congenital Heart Disease
    4. Table 4. Risk Factors For Congenital Heart Disease
    5. Table 5. Cardiovascular Examination Findings In Specific Congenital Heart Disease
    6. Table 6. Possible Chest X-Ray And Electrocardiogram Findings In Congenital Heart Disease
    7. Table 7. Common Surgical Procedures And Their Complications In Complex Congenital Heart Disease
    8. Table 8. Indications And Antibiotics For Endocarditis Prophylaxis In Congenital Heart Disease
    9. Figure 1. Timing And Presentation Of Congenital Heart Defects
    10. Figure 2. Electrocardiogram Of 1-Week-Old Patient With Hypoplastic Left Heart Syndrome, Showing Right Ventricular Hypertrophy And Strain
    11. Figure 3. Electrocardiogram Of 6-Week-Old Patient, With Ventricular Septal Defect, Showing Left Ventricular Hypertrophy And Left Axis Deviation
    12. Figure 4. Total Anomalous Pulmonary Venous Return Initially Complicated By Multilobar Pneumonia
    13. Figure 5. Anteroposterior And Lateral Chest X-Ray Of An Infant With Anomalous Left Coronary Artery From The Pulmonary Artery
    14. Figure 6. Normal Infant Thymus May Be Mistaken For Cardiomegaly
    15. Figure 7. Electrocardiogram Of 5-Month-Old Patient With Anomalous Origin Of The Left Coronary Artery From The Pulmonary Artery
    16. Figure 8. Right-Sided Aortic Arch And Vascular Ring
23. References

Abstract

Congenital heart disease is the most common form of all congenital malformations and, despite advances in prenatal and newborn screening, it may present undiagnosed to the emergency department. Signs and symptoms of congenital heart disease are variable and often nonspecific, making recognition and treatment challenging. Patient presentations can range from life-threatening shock or cyanosis in a neonate to respiratory distress or failure to thrive in infants. Advances in surgical techniques have improved short- and long-term survival of infants and children with congenital heart disease, but these children are at risk for a variety of complications related to the underlying or surgical anatomy and physiology. This review focuses on the recognition and initial management of patients with undiagnosed congenital heart disease presenting to the ED and touches on considerations for postoperative infants and children with complex congenital heart disease.

Case Presentations

An 8-day-old boy is brought to the ED by his mother for lethargy and “fast breathing.” She states that he has not been feeding well for the past couple of days and his breathing has become faster and more labored over the past 24 hours. This morning he became lethargic and looked pale. She denies any fever, cough, vomiting, or diarrhea. The baby was born at term and delivered at home by a midwife, and there was little prenatal care. He has been exclusively breastfed, but feeds have become progressively shorter over the preceding 48 hours. At triage, the infant appeared ashen gray and limp, with the following vital signs: temperature, 36°C; heart rate, 194 beats/min; respiratory rate, 76 breaths/min; and initial oxygen saturation, 92% on room air. He was rushed back to the resuscitation room. As you enter the room to evaluate this critically ill neonate, you consider sepsis, metabolic disease, and congenital heart disease, and wonder how you can distinguish among these potential causes of critical illness in the first weeks of life. Given the clinical picture of this neonate, you administer broad-spectrum antibiotics, begin fluid resuscitation, and consider whether to initiate empiric prostaglandin, but you are not sure if this is necessary or safe without a clear diagnosis.

A 3-month-old girl is brought to the ED by her parents in January for difficulty breathing. Her mother has noticed a gradual increase in her work of breathing over the past few days, along with poor feeding. She has a slight runny nose but no fever or cough and no vomiting or diarrhea. Her 2-year-old sibling has had a cold for the past few days. The infant was born at 37 weeks after an uncomplicated pregnancy and spontaneous vaginal delivery, and discharged at 24 hours of life. Her pediatrician noted a heart murmur at her 2-month visit and referred her to a cardiologist for further evaluation, but the appointment is not until the next week. Upon further questioning, the mother says that she has been a difficult feeder, but that she seems to be getting worse, with shorter feeds and falling asleep at the breast, and she seems sweaty during feeds. She also noted that the infant is not gaining weight. At triage, her vital signs are: temperature, 37.6°C; heart rate, 180 beats/min; respiratory rate, 60 breaths/min; and oxygen saturation, 90% on room air. She is noted to have moderate respiratory distress. On examination, you note labored breathing with scattered rales, rhonchi, and mild wheezing, making it difficult to appreciate the heart sounds. You consider bronchiolitis, but decide to obtain a chest x-ray, given her history. The x-ray revealed a large heart, patchy perihilar opacities, and some fluid in the fissures. You suspect congestive heart failure and wonder if additional tests may be helpful and what medical therapies are indicated.

Introduction

Congenital heart disease (CHD) includes a spectrum of anatomic malformations of the heart and great vessels that occur during embryologic development of the fetus and can cause a wide range of physiologic perturbations and physical signs and symptoms. While many defects are identified prenatally through fetal ultrasound (including approximately 33% of all CHD and 57%-83% of critical lesions)¹ or diagnosed in the newborn period prior to discharge from the hospital, some CHD may go unrecognized and present without previous diagnosis to the emergency department (ED). The emergency clinician must maintain a high index of suspicion in these rare cases, as the clinical picture of undiagnosed CHD can be nonspecific, can mimic other common and benign childhood disease, or can present with a child in extremis. Infants and children with partially or fully corrected or palliated CHD may also present to the ED with complications related to the structural heart disease, the surgical repair, or as a result of concurrent illness in the setting of limited physiologic reserves. This review focuses primarily on the presentation, evaluation, and stabilization of undiagnosed CHD presenting to the ED, but will also touch on common emergencies in the patient with known heart defects.

Epidemiology

CHD is the most common major congenital anomaly, comprising one-third of all congenital malformations, and is the most common cause of mortality from birth defects in infants.^1,2 Differing definitions of CHD and methodologies make the exact determination of birth prevalence difficult; however, a 2011 systematic review and meta-analysis of 114 articles representing more than 24,000,000 births estimates a worldwide birth prevalence of 9.1/1000.² There is significant geographic variability, with the highest rates of CHD seen in Asia (9.3/1000), followed by Europe (8.2/1000), North America (6.9/1000), and the lowest rate noted in Africa (1.9/1000).² The birth prevalence of CHD appears to have increased worldwide over the past century, and leveled off since the late 1990s. Possible explanations for the increased prevalence include improvements in diagnosis (eg, fetal ultrasound and echocardiography), improved prenatal care with increased survival of preterm infants, or changing social and environmental determinants of disease (eg, delayed age of maternity, medication, or toxic exposures).

The spectrum of anatomic defects associated with CHD is broad, but 8 discrete lesions comprise more than three-quarters of all defects.² (See Table 1.) Complex and critical CHD, such as hypoplastic left heart syndrome (HLHS), total anomalous pulmonary venous return (TAPVR), and anomalous left coronary artery from the pulmonary artery (ALCAPA), are less common but important forms of CHD.

Presentations Of Congenital Heart Disease

While reviews and textbooks often categorize CHD based on the anatomy or physiology of structural lesions, it is more useful to the emergency clinician to consider the clinical presentations of CHD. Undiagnosed CHD can present in several ways, depending on the pathophysiology of the lesion(s), although individual variations may lead to overlapping features. Cardiovascular collapse/shock is typically seen in CHD and is characterized predominantly by left outflow tract obstruction. Cyanosis may be the presenting feature in lesions with limited pulmonary blood flow or right-to-left shunting of deoxygenated blood, or both. Respiratory distress from congestive heart failure (CHF) typically results from left-to-right shunting of blood, resulting in pulmonary overcirculation. Table 2 summarizes the 3 main clinical presentations of CHD, including the symptoms, signs, and potential anatomic lesions associated with each.

Another potentially useful way to identify CHD is by the age of presentation. Lesions that depend on the ductus arteriosus for pulmonary or systemic circulation typically present with cyanosis or shock in the first week or weeks of life as the ductus closes. Lesions that result in pulmonary overcirculation leading to CHF more often develop gradually in the second or third month of life as falling pulmonary vascular resistance increases left-to-right shunting and results in pulmonary edema. Figure 1 depicts the typical age of presentation for various types of CHD.

Critical Appraisal Of The Literature

A literature search was performed in PubMed using combinations of the search terms congenital heart disease or congenital heart defects and emergency department, epidemiology, etiology, embryology, genetics, congestive heart failure, shock, cardiogenic shock, cyanosis, prostaglandin, PGE₁, and vasopressors. Only articles published in English whose subjects included children aged birth to 18 years were reviewed. Within CHD, only 25 clinical trials were available, none were conducted in the ED, and only 1 (on the use of prostaglandin E₁ [PGE₁]) was relevant to the acute management of infants and children with CHD. There was 1 practice guideline and evidence-based review of the management of pediatric heart failure that was not specific to CHD. The lack of high-quality evidence relevant to the ED management of infants and children with CHD is not surprising, given the rarity of ED presentation, the frequently critical nature of acute illness in these children, and the general difficulties related to clinical trials in the pediatric population. In the absence of evidence from clinical trials, the literature review was broadened to include review articles, systematic reviews, and case series related to pediatric CHD in the ED as well as the results of literature searches for specific therapies for pediatric cardiogenic shock, pediatric CHF, and complications of CHD and its surgical palliation and repair. In total, more than 70 peer-reviewed articles comprise the literature that informed this review.

Risk Management Pitfalls In Pediatric Congenital Heart Disease

1. “This neonate had normal prenatal care, including a prenatal ultrasound, so CHD has been ruled out. There must be another cause for his shock.”
   While prenatal ultrasound has advanced significantly over recent decades, only about one-third of all CHD and 57% to 85% of critical CHD are detected before birth. Normal prenatal care and screening ultrasound do not exclude the possibility of significant CHD.


2. “I don’t hear a murmur or a gallop, so this isn’t CHD.”
   The absence of abnormal heart sounds does not preclude underlying structural disease. A murmur requires turbulent blood flow across a defect, usually from a significant pressure gradient. In the first days of life, high pulmonary vascular resistance can minimize left-to-right shunting across a large ASD or VSD, and a murmur may not be detected prior to discharge from the nursery.


3. “Although this 1-week-old is in shock, we can’t get an echocardiogram, and I’m not sure what is going on, so I don’t want to start PGE₁ until we have more information. I’ll just fluid resuscitate….”
   In the critically ill neonate presenting with shock, PGE₁ can be life-saving and should be empirically initiated if there is no response to an initial 10-mL/kg bolus of intravenous fluids. Careful monitoring of clinical response is all that is needed and the infusion can be stopped if the clinical condition worsens.


4. “All children with significant hypoxia require 100% FiO₂ to normalize oxygenation.”
   While oxygen can be beneficial and is first-line therapy for many conditions associated with hypoxia or poor perfusion, its potent pulmonary vasodilatory effects must be considered in the context of CHD with significant shunting lesions, as decreased pulmonary vascular resistance can lead to worsening pulmonary edema or decreased systemic perfusion as a result of exacerbation of left-to-right shunting. Baseline oxygen saturations should be targeted in patients with complex CHD, if the baseline is known, and oxygen saturation of 90% to 95% should be targeted if the baseline is unknown. Wean oxygen if clinical deterioration is observed after initiation of therapy.


5. “Although he is breathing on his own, this child with a Fontan procedure and gastroen-teritis is hypoxic and tachypneic, so I should intubate. I don’t expect a difficult airway.”
   While intubation may be required for infants and children with apnea or agonal respirations, the switch to positive-pressure ventilation and the vascular and cardiac effects of preintubation medications must be carefully considered in patients with complex CHD who may be dependent on preload. In addition, airway anomalies may be associated with some CHD. Consultation with anesthesia or cardiology is recommended in all but the most emergent cases in which intubation is considered.


6. “This is the fourth bad case of bronchiolitis I’ve had this shift! She’s getting worse despite intravenous fluids, so I’ll just admit her and try nebulized epinephrine.”
   CHD presenting with CHF can mimic common viral illness such as bronchiolitis, and, during epidemics, it is easy to overlook heart disease as a cause of respiratory distress in an infant. Worsening of clinical condition with usual treatment (such as intravenous fluids for presumed dehydration in bronchiolitis) should alert you to the possibility of CHF, for which diuretics are first-line therapy. A BNP and chest x-ray may help in these circumstances.


7. “I’m going to start PGE₁ on this neonate with suspected CoA and transfer him to a children’s hospital. I'd better intubate prior to transport in case he develops apnea, even though he is breathing well on his own now.”
   Although often recommended in textbooks, prophylactic intubation is likely not necessary in the absence of observed apnea or agonal respirations prior to transport. One study found a higher rate of adverse events among neonates on PGE₁ who were prophylactically intubated compared to those who were not intubated for transport.⁴⁴


8. “The nurse got an ECG at triage for this 6-year-old with chest pain and it looks like ischemia! That’s impossible in a child with no past medical history, so it must be a technical error.”
   Although rare, children can develop myocardial ischemia or infarct from ALCAPA. Though ALCAPA typically presents in early infancy, it can escape detection and present later in life with acute myocardial infarction or progressive CHF from recurrent ischemia.


9. “I need to refer this 2-year-old with TOF to a pediatric dentist for outpatient extraction of multiple carious teeth. Her last surgery was > 6 months ago, so I don’t think she needs antibiotic prophylaxis prior to oral surgery.”
   The 2010 American Heart Association guidelines on antibiotic prophylaxis for bacterial endocarditis eliminated many of the indications for prophylaxis, but children with cyanotic CHD and allografts are at higher risk for SBE and should receive preprocedural antibiotic prophylaxis, with a single dose of oral or parenteral antibiotics 30 to 60 minutes prior to the procedure.


10. “This 5-month-old has a systolic ejection murmur and a slight diastolic rumble, but I think it is an innocent murmur. She doesn't require cardiology referral.”
    A systolic ejection murmur can be benign and a common finding in many children, but a diastolic murmur is usually pathologic and should be referred to a cardiologist for further evaluation.

Tables and Figures

References

Evidence-based medicine requires a critical appraisal of the literature based upon study methodology and number of subjects. Not all references are equally robust. The findings of a large, prospective, randomized, and blinded trial should carry more weight than a case report.

To help the reader judge the strength of each reference, pertinent information about the study, such as the type of study and the number of patients in the study are included in bold type following the references, where available. The most informative references cited in this paper, as determined by the authors, are noted by an asterisk (*) next to the number of the reference.

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