Pericarditis overview

# Overview
Pericarditis is a condition in which the sac-like covering surrounding the heart (the pericardium) becomes inflamed.  Symptoms of pericarditis include chest pain which increases with deep breathing and lying flat.

# Historical Perspective
The pericardium is a double-walled sac that contains the heart and the roots of the great vessels. Morphologically, it is a conical-shaped, double-walled fibro-serous membrane. It rests posteriorly to the sternum at the level of second to sixth costal cartilages and T5-T8 vertebrae.

# Classification
Pericarditis may be classified according to duration of the disease and recurrence into acute, Incessant, recurrent and chronic.  Moreover, pericarditis can be classified based on the etiology in two groups of infectious and non-infectious causes.

# Pathophysiology
Pericarditis is inflammation of the pericardium, which is the double-walled sac that contains the heart and the roots of the great vessels. There can be an accompanying accumulation of fluid that can be either serous (free flowing fluid) or fibrinous (an exudate, which is a thick fluid composed of proteins, fibrin strands, inflammatory cells, cell breakdown products, and sometimes bacteria). Vascular congestion of the pericardium is also present. The underlying myocardium may or may not be inflamed as well. If the myocardium is involved in the inflammatory process, it is called myopericarditis, and CK and troponin levels may be elevated. Cardiotropic viruses usually spread to the myocardium and pericardium hematogenously and cause acute inflammation with infiltration of polymorphonuclear (PMN) leukocytes and pericardial vascularization. Most patients with viral pericarditis recover completely with few developing recurrences. Some patients develop constrictive pericarditis which could be disabling. Bacterial pericarditis results from contiguous spread of infection within the chest, either de novo or after surgery or trauma, spread from infective endocarditis, hematogenous, or direct inoculation as a result of penetrating injury or cardiothoracic surgery.

# Causes
The causes of pericarditis can be divided into infectious and non-infectious ones. Infectious causes include bacterial, viral, fungal and, parasitic. While, non-infectious causes include autoimmune, neoplastic, metabolic, traumatic and iatrogenic, and drug-related. Acute myocardial infarction, Addisonian crisis, aortic dissection and rupture, blunt or penetrating chest trauma, esophageal perforation, gastric perforation, and myocardial rupture are life threatening causes of pericarditis. Common causes of pericarditis include viral, bacterial organisms, neoplasms, autoimmune and renal failure.

# Differentiating Pericarditis from other Diseases
Pericarditis must be differentiated from diseases presenting with chest pain, shortness of breath and tachypnea which include myocardial infarction, pulmonary embolism, congestive heart failure, pneumonia, vasculitis, and chronic obstructive pulmonary disease (COPD). Manifestation of the pericarditis can help in differentiation from myocardial infarction. Moreover, other differential diagnosis include aortic stenosis, coronary artery vasospasm, esophageal rupture, esophageal spasm, esophagitis,acute gastritis, gastroesophageal reflux disease, and peptic ulcer disease should be considered.

# Epidemiology and Demographics
The incidence of acute pericarditis is approximately 27.7 per 100,000 individuals annually. The recurrence of disease is seen in almost 30% of patients after first episode. The mortality rate of acute pericarditis is approximately 1.1% in developed countries. Patients of all age groups may develop acute pericarditis. Although it commonly affects men in 20 to 50 years of age. Pericarditis in developed countries is most commonly due to malignancy or viral infection. It usually follows respiratory infections, most commonly echovirus or coxsackie virus. In children, it is most commonly caused by adenovirus or coxsackie virus. In developing countries pericarditis is usually secondary to tuberculosis or HIV infection. Tuberculous pericarditis, caused by Mycobacterium tuberculosis, is found in approximately 1% of all autopsied cases of TB and in 1% to 2% of instances of pulmonary TB.

# Risk Factors

# Screening
There is insufficient evidence to recommend routine screening for pericarditis.

# Natural History, Complications and Prognosis
Pericarditis is often self-limited and most people recover in 2 weeks to 3 months. However, the condition can be complicated by significant fluid buildup around the heart (a pericardial effusion or cardiac tamponade) and may require urgent intervention including pericardiocentesis.  If scarring of the sac around the heart (the pericardium) occurs, then this is called constrictive pericarditis which may require surgical stripping of the scar.

# Diagnosis

## Diagnostic Study of Choice

## History and Symptoms
Patients with pericarditis commonly present with chest pain that changes with position, cough, fever, breathlessness, and fatigue are the other common symptoms. Less common symptoms include palpitations, hiccup, odynophagia, faint, dizziness, and abdominal pain which is seen mostly in children.

## Physical Examination
A careful physical examination must be performed to exclude the presence of cardiac tamponade, a dangerous complication of pericarditis.  If cardiac tamponade is present, then pulsus paradoxus, hypotension, an elevated jugular venous pressure and peripheral edema may be present.

## Laboratory Findings
Non-specific markers of inflammation are generally elevated in pericarditis. These include the leukocyte count, C-reactive protein, and ESR. The cardiac troponin is elevated if there is an injury to the underlying myocardium, a condition termed as myopericarditis. Diagnostic pericardiocentesis and biopsy help in identifying an underlying infectious or malignant process.Non-specific markers of inflammation are generally elevated in pericarditis. These include the leukocyte count, C-reactive protein, and ESR. The cardiac troponin is elevated if there is an injury to the underlying myocardium, a condition termed as myopericarditis. Diagnostic pericardiocentesis and biopsy help in identifying an underlying infectious or malignant process.

## Electrocardiogram
In the presence of a large effusion or tamponade, there may be diminished voltage and electrical alternans (alternation of QRS complex amplitude or axis between beats).

## X-ray
A flask-shaped, enlarged cardiac silhouette will be observed on chest x-ray in pericarditis complicated with pericardial effusion or tamponade. A mass may also be seen when malignancy is the cause. Calcification of pericardium may be noted in constrictive pericarditis.

## Echocardiography and Ultrasound
Echocardiography is generally performed to assess for the presence of a pericardial effusion and to assess and monitor its size. Echocardiography is critical in confirming the clinical suspicion cardiac tamponade.

## CT scan
On CT, pericardial fluid adds to the thickness of pericardium as both have the similar signal intensities. In pericarditis, pericardium can generate an intermediate signal intensity and may enhance after gadolinium administration. In pericardial effusion, hemorrhagic effusions can be differentiated from a transudate or an exudate based on signal characteristics (high signal on T1-weighted images) or density (high-density clot on CT). CT is superior to MRI in the visualization of pericardial calcification which is often seen in the patient with pericardial constriction. CT imaging also helps in detecting the presence of tumors and the extent of metastasis of the neoplasm.

## MRI
On MRI, normal pericardium appears as a thin dark band that is bordered by a bright band on both sides on T1 weighted spin imaging. These surrounding bright bands are associated with the surrounding epicardial and pericardial fat. Following the administration of gadolinium, pericardium may appear thick and inflamed in the setting of pericarditis. Lower intensity signal is observed in constrictive pericarditis than in acute pericarditis. Comprehensive visualization of the LV endocardium and the physiologic consequences of abnormal pericardial thickening can also be obtained without exposure to ionizing radiation.

## Other Imaging Findings

## Other diagnostic studies
Echocardiography guided pericardiocentesis may be helpful in the diagnosis of the pericarditis etiology. Pericardial fluid aspiration for cytology and immunohistochemistry analysis should be done in pericarditis with effusion. Pericardiocentesis should be done in patients with high susceptibility of neoplastic pericarditis which cytology analysis for malignancy was negative.

# Treatment

## Medical Therapy
The management of pericarditis depends on whether the patient has an uncomplicated vs. complicated disease course. Uncomplicated pericarditis is generally treated with non-steroidal anti-inflammatory drugs, such as Ibuprofen in cases of either viral or idiopathic pericarditis, and Aspirin in cases of post-MI pericarditis. Pericarditis complicated with either effusion or cardiac tamponade is generally treated with urgent pericardiocentesis in the case of cardiac tamponade, antibiotics in the case of purulent pericardial effusion, and either steroids or colchicine among patients with recurrent or refractory disease.

## Interventions

## Surgery

### Pericardiocentesis
Percutaneous pericardiocentesis is a procedure where fluid is aspirated from the pericardium (the sac enveloping the heart) using a needle via a percutaneous approach. Pericardiocentesis can provide a diagnostic sampling of pericardial fluid and can be used as a therapeutic maneuver to evacuate pericardial fluid and lower the pericardial pressure.

### Pericardial Window
Creation of a pericardial window is a cardiac surgical procedure in which an opening is made in the pericardium to drain fluid that has accumulated around the heart by creating a fistula or "window" from the pericardial space to the peritoneal cavity. Flow of fluid into the peritoneal cavity prevents the accumulation of fluid around the heart (a pericardial effusion), which might cause compression and impaired filling of the heart (cardiac tamponade), a dangerous complication. The procedure is performed for both diagnostic and therapeutic purposes. The creation of a pericardial window is usually performed by a cardiac surgeon or thoracic surgeon who makes an incision, commonly sub-xiphoid, and cuts a small hole in the pericardium. This surgery is performed with local anesthesia. An incision is made either below the sternum, or alternately between the ribs of the left chest. The resection can be with scissors, cautery, a stapling device, or a harmonic scalpel, with no one technique demonstrably better than another. It is best to have a combination of techniques available to resect the pericardium adequately. The surgeon may place a catheter in the pericardial window so that fluid can continue to drain for a short period of time after the surgery. Chest tubes are removed in 2-3 days once the drainage is less than 200cc/24hrs.

### Pericardial Stripping
Pericardiectomy is the surgical removal of part or most of the pericardium. This operation is performed  to relieve constrictive pericarditis or to remove a pericardium that is calcified and fibrous. Constrictive pericarditis is a progressive disease without spontaneous reversal of pericardial thickening. Some patients can be medically managed for several years. Edema can be controlled with diuretics and slowing the heart rate can maximize the diastolic filling time. Many patients eventually develop significant debility from impaired cardiac output and elevated right and left sided filling pressures. The definitive treatment for constrictive pericarditis is pericardiectomy which is also known as pericardial stripping. This is a surgical procedure where the entire pericardium is peeled away from the heart. Due to the significant risks involved with pericardial stripping, many patients are treated medically, with judicious use of diuretics.

## Primary Prevention

## Secondary Prevention