Pericarditis

Pericarditis is usually secondary to disorders involving the heart, or adjacent mediastinal structures (Eg:  Myocardial infarct, trauma, radiation, tumour or infections).

Rarely, it may be due to systemic abnormalities (uremia, diabetes mellitus, chronic nephritis, severe anemia , autoimmune disease).

HISTOPATHOLOGY REPORTING OF PERICARDIAL SPECIMEN

Acute pericarditis is most often of viral origin.

Chronic pericarditis is seen in tuberculosis and fungal infections, which on healing may lead to damaging adhesion. Terminal pericarditis is seen in chronic debilitating diseases e.g. Uremia,

Acute Pericarditis :  Acute Pericarditis. N Engl J Med 2004; 351:2195-2202, Nov 18, 2004  

It may occur in several forms:

Serous pericarditis :

This form usually consists of 50 to 200 ml of slowly accumulating exudates characteristically produced by nonbacterial involvement, including rheumatic fever, systemic lupus erythematosus, tumours, uremia and primary viral infection (Eg. Coxsackie). Microscopically, there is scant epicardial or pericardial acute and chronic inflammatory infiltrates.

Fibrinous and serofibrinous pericarditis: Image Link

This is the most common clinical form, seen in myocardial infarct with a pericardial friction rub. Exudate may be completely resolved or be organized causing adhesive pericarditis. Image Link

Purulent (suppurative) pericarditis: Image Link

This is due to bacteria, fungus or parasitic infection. Infection reaches by direct extension, by hematogenous or lymphatic route from the neighbouring areas of infection e.g. Pneumonia, empyema, lung abscess, subphrenic abscess, liver abscess etc or during cardiotomy.

Most common causative organisms are Staphylococci, Streptococci, and Pneumococci. 

Purulent pericarditis is composed of 400 to 500 ml of a thin to creamy pus with erythematous, granular serous surfaces.  Image Link

The patient presents with fever, rigor and a friction rub.

It usually organizes and may produce mediastinopericarditis or constrictive pericarditis.

Hemorrhagic pericarditis: Image Link

 This is composed of an exudates of blood admixed with fibrinous to suppurative effusion. Most commonly it follows cardiac surgery or is associated with tuberculosis or malignancy. It usually organizes with or without calcification.

Caseous pericarditis:

This form is due to tuberculosis (by direct extension from neighbouring lymphnodes) or less commonly, mycotic infection. This type most frequently, causes fibrocalcific constrictive pericarditis.

Chronic pericarditis:

Acute pericarditis may heal by resolution or by pericardial fibrosis ranging from a thick, pearly, nonadherent epicardial plaque , to thin delicate adhesion to massive adhesions.  In some cases the cause is unknown.

Accordingly, chronic pericarditis may be of the following types:

1.Adhesive pericarditis :

Chronic pericarditis with adhesion between parietal and visceral pericardium is called adhesive pericarditis. These are mostly seen in rheumatic disease. Less commonly, it may be due to infection by pyogenic bacteria, tuberculosis etc. In some cases, the cause is unknown.

2.Adhesive mediastinopericarditis:

Here, the pericardial sac is obliterated due to adhesion between two layers of pericardium as well as between parietal pericardium and surrounding mediastinal structures, chest wall & diaphragm. The heart thus contracts against all the surrounding attached structures leading to hypertrophy and dilation.

3.Constrictive pericarditis:  Image Link

There is marked thickening of the parietal pericardium with less involvement of visceral pericardium causing constriction of great vessels entering and leaving heart.

The pericardial space is obliterated by a dense fibrous tissue, which is often calcified.                       Image Link

Cardiac hypertrophy and dilation cannot occur because of the dense enclosing scar and the heart becomes smaller. Tuberculosis is the most common cause.  Image Link

Occasionally,  it may be due to pyogenic infection and in some, the cause is unknown but never rheumatic.

The patients of pericarditis may develop ascites and due to long standing ascites, liver & spleen are coated with fibrin.

Later, there is fibrosis of the liver (cardiac cirrhosis).  Pleura may be involved similarly.

This polyserositis is known as Pick’s disease.

A Clearer View of Effusive–Constrictive Pericarditis. N Engl J  Med  2004; 350:435-437, Jan 29, 2004.

Effusive–Constrictive Pericarditis.N Engl J Med 2004; 350:469-475, Jan 29, 2004.

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