Carditis

Background

Carditis refers to inflammation of the heart, including the endocardium, myocardium, and/or pericardium. In the emergency department, carditis may present subtly or with life-threatening complications. Causes range from infectious (viral, bacterial, rheumatic) to autoimmune (SLE, vasculitis) or drug-induced. It is one of the major Jones criteria for acute rheumatic fever and can present in children or adolescents following a streptococcal infection. Prompt recognition is critical due to risk of valvular damage, heart failure, and arrhythmias.

Clinical Features

Presentation depends on which layer(s) of the heart are involved:

Endocarditis: Fever, new murmur, petechiae, Osler nodes, Janeway lesions May present with embolic phenomena (e.g., stroke, hematuria)

Myocarditis: Fatigue, chest pain, palpitations May mimic ACS or present with heart failure symptoms

Pericarditis: Sharp, pleuritic chest pain improved by sitting up Pericardial friction rub May show diffuse ST elevation and PR depression on ECG

In rheumatic carditis, signs may include: Tachycardia out of proportion to fever New or changing murmur (e.g., mitral regurgitation) Signs of heart failure in a previously healthy child

Differential Diagnosis

Infective endocarditis

Acute coronary syndrome

Pericarditis (viral, autoimmune, uremic)

Myocarditis (viral, toxic, autoimmune)

Sepsis-induced cardiac dysfunction

Valvular disease (e.g., mitral valve prolapse, aortic stenosis)

Rheumatic fever

Systemic lupus erythematosus (SLE)

COVID-19 or post-viral inflammatory syndrome

Evaluation

Workup

Vitals + ECG (look for arrhythmias, PR prolongation, ST changes)

Cardiac biomarkers (troponin, BNP)

CXR (look for cardiomegaly, pulmonary edema)

Echocardiogram (TTE or TEE if endocarditis suspected)

Labs:

CBC, CMP

ESR/CRP (inflammatory markers)

Blood cultures x2–3 (if endocarditis suspected)

ASO or anti-DNase B titers (if rheumatic fever suspected)

Throat culture or rapid strep test

Consider:

ANA, rheumatoid factor (autoimmune causes)

COVID-19 or viral panel

Pericardial fluid studies if effusion and pericardiocentesis performed

Diagnosis

Myocarditis/pericarditis: clinical history, ECG findings, elevated troponin, and/or imaging

Endocarditis: Modified Duke criteria (positive blood cultures + evidence on echo or vascular/immunologic findings)

Rheumatic carditis: Based on Jones Criteria (carditis + supporting evidence of recent group A strep infection)

Management

Infectious Endocarditis

• Start broad-spectrum antibiotics after cultures (e.g., vancomycin + ceftriaxone)
• Consult infectious disease and cardiology

Myocarditis

• Supportive care (oxygen, fluids cautiously, inotropes if shock)
• Avoid NSAIDs unless pericarditis predominant
• Cardiology consult and hospital admission

Pericarditis

• NSAIDs + colchicine if viral/idiopathic
• Avoid steroids unless autoimmune etiology
• Monitor for tamponade (Beck's triad, pulsus paradoxus)

Rheumatic Carditis

• Penicillin (to eradicate strep infection)
• Aspirin or NSAIDs for arthritis/carditis
• Steroids for severe carditis or heart failure symptoms
• Bed rest and cardiology consultation

Disposition

Admit if:

• Evidence of heart failure, hypotension, or hemodynamic instability
• Troponin elevation or suspected myocarditis
• Signs of tamponade or large pericardial effusion
• Suspected or confirmed infective endocarditis
• Suspected acute rheumatic fever with carditis

Discharge may be appropriate if:

• Stable, low-risk pericarditis with no effusion
• Mild, resolving symptoms and normal cardiac studies
• Reliable follow-up with cardiology and primary care is available
• All patients with suspected carditis should have follow-up within days and cardiology consultation arranged from the ED if not admitted.