Pericarditis and myocarditis

Viral

Bacterial

Fungal

Parasitic

Radiation induced

Drug induced

Neoplastic

Systemic inflammatory disease

Myocardial infarction/Dressler syndrome (pericarditis)

Traumatic (pericarditis)

Metabolic (pericarditis)

Peripartum (myocarditis)

Myocarditis

Myocarditis is an inflammatory disorder of the cardiac muscle characterized by infiltration of the myocardium by immune cells, and myocyte necrosis.
The inflammation may be focal or diffuse.
- Any or all cardiac chambers may be involved.
- It may result in regional or global contractile impairment, chamber stiffening, or conduction system disease.
- Clinical manifestation are highly variable depending upon the region of involvement, and include chest pain, acute heart failure, or cardiac arrhythmias.
Viral illnesses (coxsackievirus, parvovirus, and human herpes virus 6) are the most common causes of myocarditis in the United States.
Diphtheria is the most common bacterial cause worldwide.

Presentation

Pericarditis

Classic presentation

Chest pain: sharp, pleuritic, and worse with recumbency (95%).
Pericardial friction rub heard over the left sternal border (15–30%).
ECG changes: diffuse ST elevations, PR depression in the lateral leads.
Pericardial effusion.

Critical presentation

Hemodynamic instability secondary to cardiac tamponade.
Patients may complain of chest pain and dyspnea.
Heart sounds may be muffled.
Jugular venous distension.
ECG demonstrating electrical alternans.
Large effusion with diastolic right ventricular collapse on bedside echocardiogram.

Myocarditis

Classic presentation

Chest pain that may mimic cardiac ischemia.
Heart failure: dyspnea, fatigue, orthopnea, exercise intolerance.

Critical presentation

Fulminant decompensated heart failure.
Dysrhythmias, including complete heart block.
Syncope and sudden cardiac death.

Diagnosis and evaluation

Pericarditis

Acute pericarditis is largely a clinical diagnosis.
Two of the following four criteria should be met:
- Classic chest pain (sharp, pleuritic, and worse with recumbency).
- Pericardial friction rub.
- ECG changes with new diffuse ST elevation or PR depression in the lateral leads (Table 26.2; Figure 26.1).
  - The ST elevations associated with pericarditis can be differentiated from those seen with ST elevation myocardial infarction.
    - ST elevations in pericarditis rarely exceed 5 mm.
    - ST elevations are diffuse rather than in a vascular distribution.
    - Reciprocal ST depression and PR elevation should only be seen in leads aVR and V1.
    - Associated temporal changes, such as hyperacute T-waves or Q-waves, are not typically seen in pericarditis.
- Pericardial effusion (Figure 26.2):
  - Presence of effusion confirms the diagnosis, though absence does not exclude it.
Chest radiograph: enlarged cardiac silhouette if effusion is present.
Inflammatory markers: leukocytes may be normal or elevated, ESR is usually elevated although it is not specific.
Cardiac markers: may be elevated in myocarditis or postinfarction pericarditis.
Echocardiogram:
- Normal wall motion.
- Evaluate for coexisting effusion; effusion size can be estimated by the distance between the epicardium and the pericardium (<0.5 cm = small effusion; 0.5–2 cm = moderate effusion; >2 cm = large effusion).
- Presence of a large effusion on a bedside echocardiogram with RV collapse during diastole should prompt consideration of impending tamponade.