Acute pericarditis is defined as signs and/or symptoms consistent with pericardial inflammation of less than three weeks' duration. The true incidence of pericarditis is difficult to quantify since many cases go undiagnosed. Pericarditis may account for up to 1% of cases of ST elevations on ECG, and account for 5% of emergency room visits. Eighty percent to 90% of cases of pericarditis are idiopathic.
Pericarditis can be an acute, subacute, or chronic process. The etiology of acute pericarditis is often idiopathic or viral, though the pericardium can be affected by numerous other disease processes including infectious, neoplastic, autoimmune, and traumatic causes (Table 132-1).
Table 132-1 Causes of Pericardial Heart Disease ||Download (.pdf)
Table 132-1 Causes of Pericardial Heart Disease
- Bacterial (Pneumococcus, Streptococcus, Staphylococcus, Haemophilus influenzae, gram-negative rods, Brucella melitensis, Francisella tularensis, Legionella pneumophila, Neisseria gonorrhoeae, Neisseria meningitidis, Borrelia burgdorferi [Lyme disease], Mycoplasma)
- Viral (Coxsackievirus, echovirus, adenovirus, varicella, influenza, cytomegalovirus, HIV, hepatitis B, mumps, infectious mononucleosis)
- Mycobacterial (Mycobacterium tuberculosis, Mycobacterium avium-intracellulare)
- Fungal (Histoplasma, Coccidioidomycosis, Blastomyces, Candida albicans, Nocardia, Actinomyces)
- Protozoal (Toxoplasma, Echinococcus, amebae)
- AIDS associated
- Primary (mesothelioma, fibrosarcoma)
- Secondary (breast, lung, melanoma, lymphoma, leukemia)
- Connective tissue diseases (rheumatoid arthritis, systemic lupus erythematosus, scleroderma, acute rheumatic fever, dermatomyositis, mixed connective tissue disease, Wegener granulomatosis)
- Arteritis (temporal arteritis, polyarteritis nodosa, Takayasu's arteritis)
- Acute myocardial infarction and post myocardial infarction (Dressler syndrome)
- Postcardiotomy, posttraumatic
- Nephrogenic, myxedema, amyloidosis, aortic dissection
- Blunt trauma, surgical trauma, penetrating trauma, instrument/device trauma (implantable defibrillators, pacemakers, catheters)
- Pericardial cysts, congenital absence of pericardium, Mulibrey nanism
Although the pericardium is not required to maintain life, it serves many functions within the thorax. The pericardium is composed of two layers. An inner layer, the visceral pericardium, adheres to the epicardial surface of the heart and consists of a layer of mesothelial cells. The outer layer is an avascular, fibrous parietal layer and consists of elastin fibers embedded within compact layers of collagen. The visceral pericardium reflects back near the great vessels and forms the inner layer of the parietal pericardium. The pericardial space is formed from these two layers and normally contains up to 50 mL of an ultrafiltrate of plasma. In the pericardium, villi and cilia enhance the resorption of fluid. The capacity of the pericardium to accept increased fluid volume depends on the rate of accumulation. A rapid addition of 50 to 200 mL will dramatically increase pressure and affect cardiac function, whereas a very slow accumulation of large amounts of fluid as in myxedema will have little effect on pressure or hemodynamics.
The collagen matrix of the parietal pericardium gives the pericardium its unique mechanical properties. Functionally, the pericardium facilitates contraction and relaxation of the ventricles and atria, allowing pressure changes on one side of the heart to be transmitted to the other side. Additionally, the pericardium's mechanical properties may determine cardiac output during exercise via the pericardium's direct limitation of the cardiac filling volumes.
Acute pericarditis presents with chest pain of abrupt onset as the most common complaint. The pain can be quite severe, sharp in character, and nearly always pleuritic in nature. The sharp pain of acute pericarditis differs from the pressure-like discomfort of myocardial ischemia. The pain may be located substernally or located in the anterior chest, and radiation to the neck, arms and shoulders can also occur (Figure 132-1).
Clinical features of acute pericarditis. A prodrome of fever, malaise, and myalgia may herald the chief complaint of chest pain. (Modified, with permission, from Fuster V, O'Rourke RA, Walsh RA, et al. Hurst's the Heart. 12th ed. New York: McGraw-Hill; 2008. Fig. 84-3.)
The phrenic nerve, which innervates the trapezius muscles, traverses the pericardium; therefore, radiation to the either trapezius ridge of the left shoulder is very specific for pericardial pain. Classically, the pain associated with pericarditis will improve with sitting up and leaning forward and is exacerbated by lying flat or with slight changes in position. Associated symptoms include dyspnea from splinting due to pain, cough, myalgia, arthralgias, and occasionally hiccoughs.
Vital signs in patients with pericarditis may be normal or show low-grade fever and tachycardia. High fever may indicate a bacterial cause, and these patients should undergo echocardiographic evaluation. There may be associated tachypnea from the dyspnea or pain. The most specific, and pathognomonic, finding associated with pericarditis is the pericardial friction rub. This scratchy, superficial sound likely results from inflamed visceral and parietal pericardium rubbing against each other. Classically, there are three components correlating with ventricular systole, ventricular diastole, and atrial systole. All components, two components, one component, or none may be present, as the finding is not sensitive. Two components would be expected in atrial fibrillation due to loss of the atrial component; rapid heart rates may only produce two components due to summation of the early diastolic rub and presystolic rub. The rub may be composed solely of the ventricular component, which is the last to leave over the course of illness. These rubs, described as triphasic, biphasic, or monophasic, may be confused with other cardiac abnormalities, especially in patients with a monophasic rub, which may be mistaken for a murmur.
The pericardial friction rub is best heard at the left sternal border, often in a well-localized spot but may be heard only at the apex. Therefore, the examiner needs to take a systematic approach to auscultation; position the patient forward or even on his hands and knees with the chest down or lying on his abdomen propped up on his elbows; use the diaphragm of the stethoscope against the chest wall with forced expiration; and listen over the entire left precordium. Frequent examinations may be required to hear the friction rub given its fleeting nature. The sound has been described as the sound produced when walking through snow, or pulling apart two pieces of Velcro. The rub of pericarditis may sound very similar to the harsh sound of Hamman crunch (heard in some patients with pneumomediastinum); care should be taken to differentiate these two auscultatory findings. In uncomplicated pericarditis, the jugular venous waveforms remain unchanged.
The initial approach to the patient with suspected pericarditis is based on a thorough history, physical examination and testing—ECG, cardiac enzymes, basic chemistry, complete blood count, erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP), and chest radiograph. ECG demonstrates valuable findings for the diagnosis of acute pericarditis (Figure 132-2). Abnormalities are found in approximately 90% of the cases. The most sensitive ECG change of acute pericarditis is ST-segment elevation due to abnormal repolarization secondary to pericardial inflammation. Classically, the ECG of acute pericarditis shows ST elevation in the hexaxial and precordial leads with the exception of AVR and V1 which may have ST-segment depression. The ST elevations have concave shape and are not accompanied by reciprocal changes. In ischemia, on the other hand, the slope of ST elevation is more often convex in shape and accompanied by reciprocal changes on the ECG. These two differences help to distinguish the ST elevation of pericarditis from that of ischemia. In addition, ST-segment elevation, which typically occurs during the first few days of pericardial inflammation, may last up to two weeks. T-wave inversion does not occur at the time of ST-segment elevation nor are there associated Q-waves. PR depression is very specific of acute pericarditis and is attributed to subepicardial atrial injury. In fact, PR depression found in all leads except AVR and V1, which may show PR elevation. This finding may be very useful when the patient has no friction rub and equivocal ST elevation. Electrical alternans, the presence of alternating QRS amplitudes may suggest the presence of a significant pericardial effusion. Serial ECGs at presentation are especially useful because of how the changes evolve in contrast to acute myocardial ischemia or J-point elevation.
Twelve-lead electrocardiogram of patient with acute pericarditis. (Modified, with permission, from Fuster V, O'Rourke RA, Walsh RA, et al. Hurst's the Heart. 12th ed. New York: McGraw-Hill; 2008. Fig. 84-4.)
- Pericarditis account for up to 1% of cases of ST elevations on ECG, and account for 5% of emergency room visits. Eighty percent to 90% of cases of pericarditis are idiopathic.
Creatinine kinase MB fraction and/or troponin I values may be elevated in 8% to 22% of patients presenting with acute pericarditis. Evidence of elevated troponin or CK-MB laboratory values correlate with ST elevation on the electrocardiogram. The elevation of cardiac enzymes may represent silent myocarditis in addition to pericarditis, or the epicardial inflammation that can accompany acute pericarditis. Acute pericarditis may accompany endocardial ischemia, such that coronary disease may need to be ruled out in patients presenting with pericarditis who have concomitant significant elevations in cardiac biomarkers.
Acute pericarditis may be associated with mild elevations in the total white blood cell count, usually with a lymphocytic predominance. The differential of the white blood cell count may reflect the underlying etiology; viral or idiopathic pericarditis may present with a lymphocytic predominance, whereas bacterial pericarditis may have a neutrophilic predominance.
The erythrocyte sedimentation rate may have mild elevation, but significant elevations in the ESR may suggest an autoimmune etiology, uremia, bacterial processes, or tuberculosis. Patients presenting with uremia may have a pericardial friction rub on exam.
The chest radiograph may be completely normal in viral or idiopathic acute pericarditis. Pericardial effusion should be suspected in the setting of an abnormal cardiac silhouette. An accumulation of more than 200 mL of pericardial effusion will enlarge the cardiac silhouette, indistinguishable from other causes of cardiomegaly. As more fluid accumulates, however, a “water bottle” configuration may develop. In the absence of pulmonary venous congestion, considerable cardiomegaly may be a clue that a pericardial effusion is present. Fluid between the two pericardial layers may show separation of the epicardial fat pad from the outer border of the cardiac silhouette. An abnormal chest radiograph may suggest the etiology for the pericarditis, or a different diagnosis. An infiltrate on chest X-ray may suggest bacterial pericarditis as the etiology. An upper lobe infiltrate, or a completely normal chest X-ray may accompany tuberculosis pericarditis. Pulmonary congestion may suggest ischemia or myocarditis.
Echocardiography is the imaging modality of choice in acute pericarditis because of its availability, lack of radiation exposure, and ability to rule out potentially fatal complications such as tamponade. An echocardiogram is recommended for most patients with pericarditis, especially patients with fever, currently on anticoagulation therapy, in an immunocompromised state, a recent history of trauma, or if there is suspected myocardial involvement. Echocardiography in patients with uncomplicated acute pericarditis may be completely normal. A small effusion may be present which does not necessitate intervention. Large pericardial effusions are uncommon in acute pericarditis and should trigger the clinician to pursue other diagnoses. Focal wall motion abnormalities may suggest that myocarditis may be present.
CT and MRI are emerging as valuable methods for detecting complicated pericarditis. The inflamed pericardium in both acute and chronic pericarditis can be visualized by MRI. The ability to assess fluid attenuation on both CT and MRI allows a noninvasive assessment of the etiology. The thickened pericardial layers and any pericardial effusion can be effectively visualized on cardiac MRI. Furthermore, MRI may be the noninvasive imaging modality of choice for the diagnosis of myocarditis, which can accompany pericarditis.
Patients with a history, physical examination, and testing consistent with pericarditis should receive nonsteroidal anti-inflammatory drugs (NSAIDs) as the initial treatment. Aspirin is preferred over NSAIDs if acute myocardial infarction is the cause of acute pericarditis, as NSAIDs may promote ventricular rupture. Therapeutic options include: aspirin (2–4 g daily), ibuprofen (1600–3200 mg daily), or other NSAIDs at high therapeutic dosing for 2 to 4 weeks' duration. If there is no large effusion and cardiac enzymes are normal, the patient can be discharged and followed up within two to four weeks to ensure resolution. If the pain has resolved, therapy can be discontinued at that time.
Patients that do not have an adequate response to NSAIDs may require narcotic analgesics for pain control. Colchicine in combination with aspirin is an alternative regimen in the treatment of acute pericarditis, and reduces recurrences of pericarditis in comparison to aspirin alone. Colchicine alone is an alternative agent when aspirin or an NSAID is contraindicated. Colchicine should be initiated at a 2 mg loading dose, then 1 mg daily for 2 weeks, but may require maintenance therapy for up to 3 months.
Alternately, a prednisone taper over the course of a week, starting at 60 mg orally can be used. However, patients receiving steroid therapy for acute pericarditis have a higher relapse rate than with other medications. Corticosteroids are indicated in acute pericarditis due to systemic inflammatory diseases or uremia. Corticosteroids also should be considered in patients who are refractory to or have contraindications to aspirin, NSAIDs, and colchicine. However, corticosteroids may promote the development of recurrent pericarditis and should not be used in patients with acute pericarditis due to bacterial infection or tuberculosis. They should also be avoided in patients with postinfarction pericarditis due to the risk of ventricular aneurysm formation.
The most common complication of acute pericarditis is recurrent pericarditis, occurring in 15% to 30% of patients presenting with acute pericarditis. Colchicine is the treatment of choice for recurrent acute pericarditis and can prevent recurrences. In patients with a first episode of pericarditis, patients treated with colchicine therapy (1.0–2.0 mg/d for the first day, then 0.5–1.0 mg/d for 6 months) decreases recurrence (24% vs 51%) over standard therapy plus aspirin.