Pericarditis, Acute

Introduction
Background

The pericardium is composed of the parietal pericardium (an outer fibrous layer) and the visceral pericardium (an inner serous membrane made of a single layer of mesothelial cells). The visceral pericardium is attached to the epicardial fat and reflects back on itself to form the parietal pericardium. The pericardium normally contains as much as 50 mL of an ultrafiltrate of plasma. Drainage occurs via the thoracic duct and the right lymphatic duct into the right pleural space.

Pericardial physiology includes 3 main functions. First, through its mechanical function, the pericardium promotes cardiac efficiency by limiting acute dilation, maintaining ventricular compliance with preservation of the Starling curve, and distributing hydrostatic forces. The pericardium also creates a closed chamber with subatmospheric pressure that aids atrial filling and lowers transmural cardiac pressures. Second, through its membranous function, the pericardium shields the heart by reducing external friction and acting as a barrier against extension of infection and malignancy. Third, through its ligamentous function, the pericardium anatomically fixes the heart.

Acute pericarditis is an inflammation of the pericardium characterized by chest pain, pericardial friction rub, and serial electrocardiographic changes, as demonstrated in the following images.

Stage 1 ECG changes in patient with acute pericar...
Stage 1 ECG changes in patient with acute pericarditis.

[ CLOSE WINDOW ]

Stage 1 ECG changes in patient with acute pericar...

Stage 1 ECG changes in patient with acute pericarditis.

Stage 2 ECG changes in patient with acute pericar...
Stage 2 ECG changes in patient with acute pericarditis obtained 3 days into clinical course.

[ CLOSE WINDOW ]

Stage 2 ECG changes in patient with acute pericar...

Stage 2 ECG changes in patient with acute pericarditis obtained 3 days into clinical course.

Stage 3 ECG changes of acute pericarditis obtaine...
Stage 3 ECG changes of acute pericarditis obtained 18 days into the clinical course. The patient had resolution of symptoms.

[ CLOSE WINDOW ]

Stage 3 ECG changes of acute pericarditis obtaine...

Stage 3 ECG changes of acute pericarditis obtained 18 days into the clinical course. The patient had resolution of symptoms.

Stage 4 ECG changes in the same patient as in the...
Stage 4 ECG changes in the same patient as in the above images, taken approximately 3 months after acute pericardial illness. The patient remained symptom free despite continued T-wave inversion.

[ CLOSE WINDOW ]

Stage 4 ECG changes in the same patient as in the...

Stage 4 ECG changes in the same patient as in the above images, taken approximately 3 months after acute pericardial illness. The patient remained symptom free despite continued T-wave inversion.

Pathophysiology

In most cases of acute pericarditis, the pericardium is acutely inflamed and has an infiltration of polymorphonuclear (PMN) leukocytes and pericardial vascularization. Often, the pericardium manifests a fibrinous reaction with exudates and adhesions. The pericardium may develop a serous or hemorrhagic effusion. A granulomatous pericarditis occurs with tuberculosis, fungal infections, rheumatoid arthritis (RA), and sarcoidosis.
Frequency
United States

Epidemiological data on incidence are lacking, likely because acute pericarditis is frequently inapparent clinically, despite its presence in numerous disorders. Lorell notes a diagnosis of acute pericarditis in approximately 1 per 1000 hospital admissions.1 Acute pericarditis comprises 1% of emergency room visits in patients with ST-segment elevation.2

Mortality/Morbidity

* Mortality varies greatly depending on etiology. The mortality rate approaches 100% in untreated purulent pericarditis, whereas mortality is virtually nonexistent in acute viral or idiopathic pericarditis.3
* Morbidity also depends on the etiology and development of complications.

Sex

* Acute pericarditis is more common in men than in women.

Age

* Acute pericarditis is more common in adults than in children.

Clinical
History

* Chest pain is the cardinal symptom.
o The quality of the pain may be sharp, dull, aching, burning, or pressing.
o Intensity varies from barely perceptible to severe.
o Pain is usually precordial with referral to the trapezius ridge.
o It is worse during inspiration, when lying flat, or during swallowing and with body motion.
* Dyspnea may be present, especially with tamponade.
* Fever may be present.
* Abdominal pain occurs infrequently in children.

Physical

* A pericardial friction rub is pathognomonic for acute pericarditis.
o The rub has a scratching, grating sound similar to leather rubbing against leather.
o Auscultation with the diaphragm of the stethoscope over the left lower sternal edge allows the best detection of the rub.
o Auscultation during end expiration with the patient sitting up and leaning forward increases the likelihood of observing this physical finding.
o Serial examinations may be necessary for detection.
o More than 50% of rubs are triphasic. They are composed of (1) an atrial systolic rub that precedes S1, (2) a ventricular systolic rub between S1 and S2 and coincident with the peak carotid pulse, and (3) an early diastolic rub after S2 (usually the faintest).
o The biphasic to-and-fro rub is less common (24%). It can occur with tachycardia and is due to summation of the atrial and early diastolic rub.
o Monophasic rubs (the ventricular systolic) are the least common but may occur in patients with atrial fibrillation.
o Especially when it is monophasic, the pericardial friction rub can be mistaken for a systolic murmur. Pericardial rubs may be differentiated if the rub does not change with usual respiratory or positional maneuvers, if 3 components are present, and if the findings on the ECG are typical.
* Tachypnea may be present.
* Tachycardia may be present.
* Patients may have fever.
* The Beck triad (ie, hypotension; elevated systemic venous pressure, often with jugular venous distention; muffled heart sounds) may occur in patients with cardiac tamponade, especially from sudden intrapericardial hemorrhage.
* Pulsus paradoxus is defined as a > 10 mm Hg decrease in arterial systolic pressure with inspiration. This decrease is important in patients with more slowly developing tamponade because they may lack findings of the Beck triad.

Causes

* Idiopathic
o Between 26% and 86% of cases are idiopathic in nature.4
o No clinical features distinguish idiopathic cases from viral pericarditis.
o Most likely, most idiopathic cases are undiagnosed viral infections.
o Seasonal peaks occur in spring and fall.
* Infection
o Viral
+ This is the most common cause of acute pericarditis and accounts for 1-10% of cases.
+ Causative viruses include coxsackievirus B, echovirus, adenoviruses, influenza A and B viruses, Enterovirus, mumps virus, Epstein-Barr virus, human immunodeficiency virus (HIV), herpes simplex virus type 1, varicella-zoster virus, measles virus, parainfluenza virus type 2, and respiratory syncytial virus, cytomegalovirus, hepatitis A, hepatitis B, and hepatitis C.
+ Viruses, especially coxsackievirus B and influenza, can occur as seasonal epidemics.
+ It is usually a short self-limited disease that lasts 1-3 weeks.
+ Patients may have associated myocarditis.
+ The treatment is based on the symptoms present, with observation for the development of tamponade.
+ Pericardial involvement is frequent in persons with HIV, but is usually an asymptomatic pericardial effusion of small volume. Persons with advanced HIV infection develop pericardial involvement more frequently, with one study noting right atrial diastolic compression in 5% of cases involving advanced HIV infection.5 Symptomatic pericarditis occurs in less than 1% of cases involving HIV, and its etiology can include the usual causes, opportunistic infection, Kaposi sarcoma, and HIV.
o Bacterial
+ This accounts for 1-8% of cases and causes purulent pericarditis.
+ Bacterial pericarditis develops from direct pulmonary extension, hematogenous spread, myocardial abscess or endocarditis, penetrating injury to chest wall from either trauma or surgery, or a subdiaphragmatic suppurative lesion.
+ Organisms isolated include gram-positive species such as Streptococcus pneumoniae and other Streptococcus species and Staphylococcus.6 Isolated gram-negative species include Proteus, Escherichia coli, Pseudomonas, Klebsiella, Salmonella, Shigella, Neisseria meningitidis, and Haemophilus influenzae.
+ Less common organisms include Legionella, Nocardia, Actinobacillus, Rickettsia, Borrelia burgdorferi (Lyme borreliosis), Listeria, Leptospira, Chlamydophila psittaci, and Treponema pallidum (syphilis).
+ Anaerobes also have been isolated in 40% of patients in reviews of the pediatric population.
+ Previously, Pneumococcus was the predominant organism. However, in the antibiotic era, staphylococcal and gram-negative species have become more common. Most cases are now associated with thoracic surgery, renal disease, and immunosuppression.
+ Purulent pericarditis can develop from previous aseptic pericarditis and is associated with a poorer prognosis, with a mortality rate nearing 100% for untreated persons and a mortality rate of 12-40% for treated patients.
+ A high percentage of patients develop constrictive pericarditis.
+ Treatment includes appropriate antibiotics for at least 4 weeks and drainage of pericardial fluid.
+ Intrapericardial fibrinolysis can be a useful treatment to assist with drainage of thick, loculated fluid, but open surgical drainage is preferred.
+ Occasionally, patients require partial to total pericardiectomy.
o Tubercular
+ Tuberculosis accounts for 4% of cases.
+ It should be considered in all instances of pericarditis without a rapid course, especially in high-risk groups, such as elderly patients in nursing homes.
+ The diagnostic yield for acid-fast bacilli in pericardial fluid is fairly low (between 30% and 76%).
+ Pericardial biopsy has a much better yield (approximately 100%).
+ Elevated adenosine deaminase in pericardial fluid is useful for diagnosing tuberculosis. Studies note greater than 90% sensitivity and specificity with levels higher than 50-70 U/L.
+ High adenosine deaminase values may indicate a poorer prognosis.
+ Approximately half the patients develop constrictive pericarditis.
+ Treatment is with the usual antituberculous chemotherapy.
+ The mortality rate approaches 50%.
o Other infectious agents
+ Fungal organisms include Histoplasma, Blastomyces, Coccidioides, Aspergillus, and Candida.
+ Parasitic organisms include Entamoeba, Echinococcus, and Toxoplasma.
* Inflammatory disorders
o Rheumatoid arthritis
+ Autopsy studies show a prevalence of 11-50% in patients with RA.
+ Echocardiography studies note pericardial effusions in 50% of patients with RA with nodules and in only 15% of patients with RA without nodules.
+ Pericardial involvement is usually clinically silent. Diagnosis is made in only 2% of adults and 6% of juveniles.
+ Pericarditis occurs predominantly in males with severely destructive and nodular RA.
+ Rarely, pericarditis precedes the onset of RA.
+ ECG almost never demonstrates typical findings of pericarditis, possibly secondary to masking from RA medications.
+ Diagnosis is suggested by serous or hemorrhagic pericardial fluid with a glucose level of less than 45 mg/dL, a white blood cell count higher than 15,000/µL with cytoplasmic inclusion bodies, a protein level higher than 5 g/dL, a low total serum hemolytic complement (CH50), a high immunoglobulin G (IgG) level, and a high rheumatoid factor. Cholesterol levels may be high in the fluid of patients with RA who have nodules.
+ Only symptomatic RA pericarditis should be treated.
+ Interestingly, symptomatic disease tends to occur in patients with arthritis, pleuritis, and other complications who are already being treated with anti-inflammatory agents such as corticosteroids, gold, and antimalarial drugs.
o Systemic lupus erythematosus
+ Clinically evident pericarditis has been reported in 25% of patients with lupus. Autopsy series reveal pericardial involvement in 62%.
+ Pericarditis usually occurs in flare-ups, but it may be the presenting manifestation. In contrast to RA, ECG findings usually demonstrate typical changes of pericarditis.
+ Fluid analysis reveals increased leukocytes of PMN predominance with a high protein level, low-to-normal glucose level, low complement, and, possibly, a pH level of less than 7. In addition, fluid analysis reveals positive autoantibodies, such as the antinuclear antibody or anti–double-stranded DNA.
+ Treat with anti-inflammatory agents and optimization of systemic lupus erythematosus (SLE) treatment.
+ Development of tamponade and constrictive pericarditis is rare.
o Scleroderma
+ Pericarditis is recognized in 5-10% of patients with scleroderma. Autopsy prevalence rate is 70%.
+ Pericardial effusions occur in 40% of patients with scleroderma and can be due to scleroderma, myocardial failure (restrictive cardiomyopathy), and renal failure.
+ Restrictive cardiomyopathy and pericardial constriction can coexist. Usually, pulmonary hypertension, right heart failure, and systolic dysfunction occur.
+ Pericardial fluid has a protein value greater than 5 g/dL, has a low cell count, and does not demonstrate the antibodies found in RA and SLE.
+ These patients have a poor prognosis.
o Rheumatic fever
+ This occurs more commonly in lower socioeconomic groups and in children.
+ It often accompanies endocarditis and myocarditis, with a worse prognosis.
+ Consider this etiology in any child with pericarditis.
+ In adults, pericarditis may not occur with myocardial or valvular involvement, and it is associated with a better prognosis. It usually appears 7-10 days after onset of fever and arthritis. Often, stage 1 ECG findings are absent.
+ Antistreptolysin O titer is usually greater than 400.
+ Rarely is a large effusion present.
+ This is not a demonstrated cause of constrictive pericarditis.
+ Pericarditis resolves with anti-inflammatory treatment.
o Sarcoidosis
o
+ Echocardiography shows that pericardial involvement is present in 20% of cases.
+ Patients may not have significant myocardial infiltration.
+ It rarely causes cardiac tamponade or constrictive pericarditis.
o Other inflammatory conditions
+ Sjögren syndrome
+ Mixed connective-tissue disease
+ Reiter syndrome
+ Ankylosing spondylitis
+ Inflammatory bowel disease
+ Wegener granulomatosis
+ Vasculitis (eg, giant cell arteritis, polyarteritis)
+ Polymyositis
+ Behçet syndrome
+ Whipple disease
+ Familial Mediterranean fever
+ Serum sickness
* Metabolic disorders
o Renal failure
+ Renal failure accounts for approximately 12% of cases.
+ In the predialysis era, pericarditis developed in 35-50% of patients with uremia who had chronic renal failure and less commonly in those with acute renal failure. Death often followed in several weeks.
+ With dialysis, the incidence rate is less than 10%.
+ Pericarditis occurs after the onset of dialysis in 8-12% of cases.
+ ECG commonly does not show the typical ST-T segment changes due to lack of inflammation.
+ In uremic patients, heart rates may be deceptively slow with tamponade, fever, and hypotension due to autonomic impairment.
+ Some authors suggest that uremic pericarditis is a different entity from dialysis-associated pericarditis.
+ Asymptomatic pericardial effusions can occur in 36-62% of patients with uremia who require dialysis. They are often small to moderate in size, and they can occur secondary to volume overload. They can lead to significant hemodynamic complications during routine dialysis. The presence of a large pericardial effusion that persists for longer than 10 days after intensive dialysis has a high likelihood of causing tamponade.
+ Treatment is intensive dialysis.
+ If no improvement is noted after 7-10 days or if the patient has hemodynamic instability, proceed with pericardiocentesis or pericardiectomy.
+ Intensive dialysis is beneficial to most patients with uremia who develop pericarditis prior to dialysis. Dialysis-induced pericarditis fails to respond to more intensive dialysis in 25-33% of patients.
o Hypothyroidism
+ This accounts for as many as 4% of cases.
+ Pericardial involvement usually occurs with severe hypothyroidism.
+ Patients may develop large pericardial effusions, but they rarely develop tamponade.
+ Pericardial fluid is often clear with high protein and cholesterol levels and with few cells.
+ Low ECG voltage is often observed.
+ Myocardial involvement is common.
+ Treatment is hormone replacement.
o Cholesterol pericarditis
+ Cholesterol pericarditis is also called gold-paint pericarditis.
+ Granulomatous pericarditis has been implicated in some cases.
+ Cholesterol pericarditis is a complication of a chronic pericardial effusion exacerbated by cholesterol crystals.
+ It usually presents with large effusions that are not hemodynamically important.
+ Development of constriction is rare.
* Cardiovascular diseases
o Myocardial infarction7,8
+ After a transmural infarction, a fibrinous pericardial exudate appears within 24 hours. It begins to organize at 4-8 days, and it completes organization at 4 weeks.
+ If pericardial involvement is confined to the infarct zone, stage 1 ECG findings are often not seen.
+ Positive T waves that last longer than 48 hours after an acute myocardial infarction (AMI) or premature reversal of inverted T waves may indicate pericardial involvement.
+ The pericardial pain occurs less frequently than the friction rub. The rub often is detected on the second or third day after an AMI but may be heard within 24 hours and as late as 10 days.
+ Prior to thrombolytic therapy, infarct-associated pericarditis ranges from 7-23% of cases. At autopsy, almost all patients were noted to have localized fibrinous pericarditis overlying the area of infarction.
+ With thrombolytic therapy and direct infarct angioplasty, the incidence of infarct-associated pericarditis has decreased to 5-8%.
+ Overall, pericardial involvement indicates larger infarction, greater incidence of left ventricular dysfunction, and greater mortality.
+ Pericarditis usually heals without consequence.
+ Effusions may occur, but they rarely lead to tamponade.
+ Pericarditis does not contraindicate thrombolytic or anticoagulant therapy.
+ Anticoagulation should be discontinued if pericardial effusion develops or effusion size increases.
+ Treatment is aspirin.
o Dressler syndrome
+ Pericarditis associated with Dressler syndrome is usually observed 2-3 weeks after a myocardial infarction.
+ Initially, the syndrome was described in as many as 4% of patients post-AMI. Later studies suggested a much lower incidence.
+ Dressler syndrome is rarely described with pulmonary embolism.
+ It may be a unique autoimmune-mediated phenomenon to myocardial antigens, or it may merely be an unrecognized postmyocardial infarction pericarditis.
+ ECG findings may demonstrate diagnostic changes of acute pericarditis, especially if the ECG findings normalize after the infarction.
+ Patients may develop pulmonary infiltrates and large pericardial effusions.
+ Because of the risk of hemorrhagic pericarditis, anticoagulant therapy should be stopped.
+ Treatment is with nonsteroidal anti-inflammatory drugs (NSAIDs).
o Aortic dissection
+ This accounts for 1% of cases.
+ This accounts especially for cases with hemorrhage into the pericardium.
o Takotsubo cardiomyopathy
o Neoplasm
+ This accounts for 5-17% of cases.
+ In patients presenting with acute pericarditis or pericardial effusion, 4-7% have an unsuspected malignancy.
+ Neoplastic disease, particularly advanced, is the most frequent cause of tamponade in the hospital.
+ Symptoms develop over days to weeks. Dyspnea is common and is the most significant symptom.
+ Occasionally, the tumor encases the heart and causes constrictive pericarditis rather than tamponade.
+ Primary neoplasm of the heart and pericardium is rare. Pericardial mesothelioma and angiosarcoma are lethal malignancies with aggressive local spread that respond poorly to treatment. Infants and children can present with a teratoma in the pericardial space. These can often be successfully removed.
+ Most cases are a result of metastatic disease. Autopsy studies have noted that approximately 10% of patients with cancer develop cardiac involvement, and, often, it is clinically silent. The neoplastic cells reach the pericardium through the bloodstream, through the lymphatic system, or via local growth.
+ Lung cancer, including adenocarcinoma and squamous and small cell carcinoma, accounts for approximately 33% of cases. Breast cancer accounts for 25%. Leukemia and lymphoma, including Hodgkin and non-Hodgkin, account for 15% of cases. Malignant melanoma represents another 5%. Almost all other malignancies, except primary brain, comprise the rest of the cases. Kaposi sarcoma also has become a more prominent cause of neoplastic disease with the AIDS epidemic.
+ The pericardial carcinoembryonic antigen (CEA) level is often elevated.
+ Cytology findings are positive in 80-90% of breast and lung cancer cases, but the percentage is lower in other malignancies. Obstruction of the lymphatic drainage can cause the pericardial effusion to be more significant than the tumor mass.
+ Initial treatment includes relief of tamponade, confirmation of the diagnosis, and systemic treatment of the neoplasm.
+ Further treatment options include sclerosis of the pericardial space, instillation of chemotherapeutic agents into the pericardial space, local radiation, or pericardiectomy.
* Miscellaneous causes, including iatrogenic
o Drugs
+ Some medications, including penicillin and cromolyn sodium, induce pericarditis through a hypersensitivity reaction.
+ The anthracycline antineoplastic agents, such as doxorubicin and cyclophosphamide, have direct cardiac toxicity and can cause acute pericarditis and myocarditis.
+ Pericarditis can develop from a drug-induced SLE syndrome caused by medications including procainamide, hydralazine, methyldopa, isoniazid, mesalazine, and reserpine.
+ Smallpox vaccination infrequently leads to myocarditis. In a review of a large vaccination program in the US military, approximately 12 per 100,000 vaccinated troops developed myopericarditis within 14 days of vaccination.9 Whether this is due to a direct viral cytopathic effect or an immune-mediated phenomenon is unclear.
+ Methysergide causes constrictive pericarditis through mediastinal fibrosis.
+ Dantrolene, phenytoin, and minoxidil produce pericarditis through an unknown mechanism.
+ Treatment includes stopping the administration of the offending agent and anti-inflammatory therapy as needed.
o Irradiation10
+ Pericardial disease is the most common cardiac toxicity. Others are coronary artery disease, conduction disturbance, and myocardial and valvular disease.
+ High incidence occurs with high doses, especially those greater than 4000 rad.
+ It can present as acute pericarditis, with or without effusion; chronic constrictive pericarditis; or effusive-constrictive pericarditis.
o Postpericardiotomy syndrome
+ This is similar to Dressler syndrome, except that postpericardiotomy syndrome occurs after cardiac surgery.
+ Several series note an incidence rate of 10-40%. Approximately 1% develop tamponade.
+ Pericardial effusions can occur in the absence of typical features of postpericardiotomy syndrome.
+ In one study, 56% developed pericardial effusions early after cardiac surgery, without correlation to pericarditis or tamponade. The effusions were more common after heavy postoperative bleeding.
+ Pericarditis may develop with other cardiac instrumentation, including percutaneous transluminal coronary angioplasty (PTCA) and pacemaker implantation. Usually, it is associated with epicardial or pericardial hematoma formation.
+ Treatment is with aspirin or NSAIDs.
o Trauma
+ This accounts for approximately 1% of cases.
+ Pericarditis can develop from penetrating and nonpenetrating cardiac trauma, esophageal rupture or perforation, and pancreatitis.

http://emedicine.medscape.com/article/156951-overview