Inflammatory diseases of the heart may categorized anatomically. The pericardium, myocardium, or endocardium may be involved. Pancarditis describes inflammation involving all layers of the heart. Inflammatory cardiac disorders are caused by a number of etiologies and are a consideration in children presenting with symptoms ranging from nonspecific to cardiovascular collapse.

This chapter discusses the presentation, diagnosis, and management of children presenting to the emergency department with inflammatory or infectious disease of the heart.

Pericarditis may be categorized as infectious, noninfectious, or idiopathic. The underlying etiologies overlap with those of myocarditis. Recurrent cases of pericarditis are usually idiopathic or viral.¹ Causes overlap with those of myocarditis (Table 42-1).

The diagnosis of pericarditis in a pediatric patient is a clinical challenge. In patients without a history of cardiac surgery or a condition that would predispose them to pericarditis, chest pain is the most common presenting symptom. Chest pain is often worsened with deep inspiration, and alleviated by leaning forward. Younger children may not be able to describe chest pain. While chest pain is present in more than 90% of patients, it is rarely the sole presenting symptom.² Fever, vomiting, cough, shortness of breath, and fatigue are the most common other symptoms and are most often accompanied by chest pain.²

Physical examination findings include tachycardia and a pericardial friction rub, although the identification of a rub may be uncommon.² With a large enough pericardial effusion, one may not hear a friction rub because the visceral and parietal pleura are not opposed. As effusions increase in volume, dyspnea or shock may develop. In the presence of pericardial tamponade, jugular venous distention and hepatomegaly may be noted on physical examination. Cardiac output decreases secondary to decreased cardiac stroke volume. Delayed capillary refill, decreased urine output, hypotension, and pulsus paradoxus, an exaggerated decrease in systolic blood pressure during inspiration may develop.³

The electrocardiogram (ECG) may be diagnostic. Classic findings include diffuse ST and T wave changes. PR interval may occur. In patients with little or no effusion, the chest radiograph may be normal. Cardiomegaly is noted on chest radiography when moderate or large pleural effusions are present. Echocardiography will rapidly demonstrate the presence, size, and location of a pericardial effusion and can rapidly identify cardiac tamponade (Fig. 42-1).

Creatinine kinase and troponin levels are often elevated. Of the common inflammatory markers (complete blood count [CBC] and erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]), the CRP is most likely to be abnormal.²

The presence and extent of a pericardial effusion determines the management of pericarditis. In patients with a small or no effusion, the treatment is generally supportive and includes anti-inflammatory medication and cardiology consultation. Children with large effusions merit urgent cardiology and critical care consultation.

Children with pericarditis and large pericardial effusion exhibiting signs of hemodynamic instability secondary to cardiac tamponade require emergent pericardiocentesis. Although pericardiocentesis can be lifesaving in cases of tamponade, there are a number of serious complications, including cardiac arrest, arrhythmia, thrombus formation, and pneumothorax. While several studies document the high overall success rate and low rate of complications of echocardiographic-guided pericardiocentesis, it is important to note that the procedures in these studies were performed by clinicians with considerable experience and expertise (Fig. 42-2).^4,5

Acute myocarditis is an inflammatory process of the myocardium that results in cardiac dysfunction. The exact incidence of this disease is unknown. While myocarditis may lead to cardiovascular collapse and death, some patients may have a more indolent disease course and present later with dilated cardiomyopathy. However, there are also subclinical cases, and these often resolve without ever presenting for medical care.

ETIOLOGY

In cases of suspected myocarditis, an etiologic agent is identified infrequently.⁶ Viral etiologies, particularly enteroviruses, predominate; however, bacteria, rickettsia, fungi, and parasites are known agents.

CLINICAL PRESENTATION

Myocarditis often presents with nonspecific symptoms of variable severity, making the diagnosis clinically challenging. The signs and symptoms of myocarditis may mimic other very common disorders. In particular, children under 10 years of age will present with respiratory or gastrointestinal complaints.⁷ Frequently, it is not until later in the clinical course that these symptoms are noted to be of cardiac origin and patients are often admitted with a different diagnosis. The clinical presentation can be divided into specific symptom complexes based on presentation (Table 42-2).

Respiratory complaints may include cough, wheeze, congestion, fever, or tachypnea. In the case of a child who is tachypneic but lacks symptoms of wheezing or supporting evidence for the diagnosis of pneumonia, one should consider the possibility of myocarditis. Myocarditis should also be considered in any child who deteriorates despite aggressive treatment for bronchospasm or reactive airway disease.⁷ Other signs and symptoms include those associated with congestive heart failure—poor feeding, cyanosis, and grunting. Murmur, gallop rhythm, rales, or organomegaly may confirm the diagnosis (Table 42-3) but are unlikely findings at presentation.