Pericarditis - Infectious Diseases of the Heart

PERICARDITIS

Pericarditis refers to an inflammation of the pericardium, the membranous sac enveloping the heart. It may be a primary ill-ness, or it may develop in the course of a variety of medical and surgical disorders. The incidence of pericarditis varies with the cause. For example, pericarditis occurs after pericardectomy (opening of the pericardium) in 5% to 30% of patients after car-diac surgery (Beers et al., 1999). Pericarditis that occurs within 10 days to 2 months after acute myocardial infarction (Dressler’s syndrome) causes 1% to 3% of all cases of pericarditis (Beers et al., 1999). Pericarditis may be acute or chronic. It may be classified by the layers of the pericardium becoming attached to each other (adhesive) or by what accumulates in the pericardial sac: serum (serous), pus (purulent), calcium deposits (calcific), clotting proteins (fibrinous), or blood (sanguinous).

Pathophysiology

The following are some of the causes underlying or associated with pericarditis:

·      Idiopathic or nonspecific causes

·      Infection: usually viral (eg, Coxsackie, influenza); rarely bacterial (eg, streptococci, staphylococci, meningococci, gonococci); and mycotic (fungal)

·       Disorders of connective tissue: systemic lupus erythemato-sus, rheumatic fever, rheumatoid arthritis, polyarteritis

·      Hypersensitivity states: immune reactions, medication re-actions, serum sickness

·      Disorders of adjacent structures: myocardial infarction, dissecting aneurysm, pleural and pulmonary disease (pneumonia)

·      Neoplastic disease: caused by metastasis from lung cancer or breast cancer, leukemia, and primary (mesothelioma) neoplasms

·      Radiation therapy

·      Trauma: chest injury, cardiac surgery, cardiac catheterization, pacemaker implantation

·      Renal failure and uremia

·       Tuberculosis

Pericarditis can lead to an accumulation of fluid in the peri-cardial sac (pericardial effusion) and increased pressure on the heart, leading to cardiac tamponade . Frequent or prolonged episodes of pericarditis may also lead to thickening and decreased elasticity that restrict the heart’s ability to fill properly with blood (constrictive pericarditis). The pericardium may be-come calcified, further restricting ventricular expansion during ventricular filling (diastole). With less filling, the ventricles pump out less blood, leading to decreased cardiac output and signs and symptoms of heart failure. Restricted diastolic filling may result in increased systemic venous pressure, causing peripheral edema and hepatic failure.

Clinical Manifestations

The most characteristic symptom of pericarditis is chest pain, al-though pain also may be located beneath the clavicle, in the neck, or in the left scapula region. The pain or discomfort usually re-mains fairly constant, but it may worsen with deep inspiration and when lying down or turning. It may be relieved with a forward-leaning or sitting position. The most characteristic sign of peri-carditis is a friction rub. Other signs may include mild fever,increased white blood cell count, and increased erythrocyte sedi-mentation rate (ESR). Dyspnea and other signs and symptoms of heart failure may occur as the result of pericardial compression due to constrictive pericarditis or cardiac tamponade.

Assessment and Diagnostic Findings

Diagnosis is most often made on the basis of the patient’s history, signs, and symptoms. An echocardiogram may detect inflamma-tion and fluid build-up, as well as indications of heart failure, and help to confirm the diagnosis. Because the pericardial sac sur-rounds the heart, a 12-lead ECG detects ST changes in many, if not all, leads.

Medical Management

The objectives of management are to determine the cause, ad-minister therapy, and be alert for cardiac tamponade. When car-diac output is impaired, the patient is placed on bed rest until the fever, chest pain, and friction rub have subsided.

Analgesics and NSAIDs such as aspirin or ibuprofen may be prescribed for pain relief during the acute phase. They also hasten the reabsorption of fluid in the patient with rheumatic pericarditis. Corticosteroids (eg, prednisone) may be prescribed if the pericarditis is severe or if the patient does not respond to NSAIDs. Colchicine may also be used as an alternative medication.

Pericardiocentesis, a procedure in which some of the pericar-dial fluid is removed, may be performed to assist in the identifi-cation of the causative agent. It may also relieve symptoms, especially if there are signs and symptoms of heart failure. A peri-cardial window, a small opening made in the pericardium, may be performed to allow continuous drainage into the chest cavity. Surgical removal of the tough encasing pericardium (pericar-diectomy) may be necessary to release both ventricles from the constrictive and restrictive inflammation.

Nursing Management

The nurse caring for the patient with pericarditis must be alert to the possibility of cardiac tamponade.

Patients with acute pericarditis require pain management with analgesics, positioning, and psychological support. Patients experiencing chest pain often benefit from education and reas-surance that the pain is not a heart attack. To minimize compli-cations, the nurse educates and assists the patient with activity restrictions until the pain and fever subside. As the patient’s con-dition improves, the nurse encourages gradual increases of activity. If pain, fever, or friction rub reappear, however, activity restric-tions must be resumed. The nurse educates the patient and family about a healthy lifestyle to enhance the patient’s immune system.

The nurse monitors the patient for heart failure. A patient who is hemodynamically unstable or experiencing congestion is treated the same as a patient with acute heart failure .