What is the appropriate management for an 18-month-old child with a history of viral upper respiratory infection, presenting with hyperactive precordium, gallop rhythm, mild respiratory distress, and hepatomegaly?

Management of Acute Myocarditis in an 18-Month-Old Child

This 18-month-old child presenting with hyperactive precordium, gallop rhythm, mild respiratory distress, and hepatomegaly following a viral upper respiratory infection has acute myocarditis with heart failure and requires immediate hospitalization for supportive cardiac care, continuous cardiorespiratory monitoring, and consideration for urgent pediatric cardiology consultation. 1, 2, 3

Immediate Recognition and Stabilization

The clinical presentation is classic for acute myocarditis with congestive heart failure:

• Hyperactive precordium, tachycardia, and gallop rhythm are cardinal signs of myocarditis with depressed myocardial contractility in the acute phase 1
• Hepatomegaly indicates systemic venous congestion from right heart failure 1
• Mild respiratory distress reflects pulmonary congestion and increased work of breathing 2, 4
• Recent viral upper respiratory infection is the typical preceding event for viral myocarditis in children 1, 2

Critical pitfall: Do not dismiss these findings as simple pneumonia or bronchiolitis—the combination of cardiac findings (hyperactive precordium, gallop) with hepatomegaly distinguishes myocarditis from isolated respiratory infection 1, 3

Urgent Hospitalization and Monitoring

Admit immediately to a pediatric ward with continuous cardiorespiratory monitoring capability 2, 4:

• Continuous pulse oximetry to detect hypoxemia 2, 4
• Cardiac monitoring for arrhythmias (prolonged PR interval, ST-T wave changes are common) 1
• Vital signs every 2-4 hours including heart rate, respiratory rate, blood pressure 4
• Strict intake/output monitoring and daily weights 4

Transfer to pediatric ICU if any of the following develop 2, 5:

• Oxygen requirement FiO2 ≥0.50 to maintain SpO2 >92% 2
• Signs of low cardiac output syndrome or shock 1, 5
• Development of apnea, grunting, or altered mental status 2
• Sustained tachycardia with inadequate blood pressure 2

Urgent Pediatric Cardiology Consultation

Consult pediatric cardiology immediately—this is not optional 3, 6:

• One-third of infants with congenital or acquired heart disease become critically ill during the first year of life 3
• Infants with congestive heart failure, shock, or arrhythmias require urgent referral for specific diagnosis and potentially life-saving intervention 3
• Pediatric cardiologists make significantly different management decisions than general pediatricians for cardiac disease, including more frequent cardiac medications, additional procedures, and closer follow-up 6

Initial Diagnostic Evaluation

Obtain immediately upon admission 1, 4:

• 12-lead electrocardiogram (look for arrhythmias, prolonged PR interval, ST-T wave changes) 1
• Chest radiograph (assess for cardiomegaly, pulmonary edema) 4
• Echocardiogram (essential to assess myocardial contractility, chamber dimensions, valve function, pericardial effusion) 1, 6
• Blood cultures if fever present 7, 4
• Complete blood count, electrolytes, liver function tests 1

Supportive Medical Management

Oxygen therapy 2, 4:

• Maintain SpO2 >92% at all times 4
• Initiate supplemental oxygen via nasal cannula if SpO2 <92% on room air 2, 4

Fluid management 4, 5:

• Restrict fluids to 80% of maintenance due to risk of fluid overload in heart failure 4
• Monitor serum electrolytes daily 4
• Ensure adequate hydration but avoid volume overload 2

Cardiac medications (initiated by or in consultation with pediatric cardiology) 1, 6, 5:

• Diuretics for pulmonary and systemic congestion
• ACE inhibitors for afterload reduction
• Inotropic support if signs of low cardiac output develop
• Avoid medications that may worsen myocardial function 5

Supportive care 4:

• Antipyretics (acetaminophen) for fever management 4
• Elevate head of bed 30-45 degrees 4
• Minimize exertion and maintain bed rest during acute phase 1

Monitoring for Deterioration

Watch closely for signs requiring ICU escalation 2, 5:

• Worsening respiratory distress despite oxygen therapy 2
• Development of shock (poor perfusion, prolonged capillary refill, hypotension) 1, 5
• New or worsening arrhythmias 1
• Inability to maintain adequate oral intake 2
• Altered mental status or decreased responsiveness 2

Special Considerations

Young age (18 months) is a significant risk factor 2:

• Infants under 12 months have higher attack rates and more severe disease 2
• This child at 18 months remains at elevated risk for rapid deterioration 2

Secondary bacterial infection risk 2, 7:

• Children with viral infections may develop secondary bacterial infections, especially when hospitalized 2
• Monitor for persistent or worsening fever despite supportive care 7
• Consider antibiotics if bacterial superinfection suspected 7

Prognosis with appropriate management 1:

• Most children with myocarditis make complete recovery with appropriate supportive care 1
• Close follow-up after discharge is essential to monitor for any signs of clinical deterioration 2