The human heart has a sac-like structure that surrounds it, which is called the pericardium. The major purpose of this sac is to protect the heart and it contains a fluid that is spread over a thin layer around the whole heart. This fluid in the heart is called the pericardial fluid, which acts as a lubricant and helps the heart to pump and return with some minimum friction.

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Role of Fluid

A small amount of fluid is always found in the heart, known as the small effusion of the pericarditis (the pericardial fluid). This fluid is produced by the sac and it is important for maintaining the functions of the heart. The excess production of this fluid is called pericardial effusion. If the heart gets affected by inflammation, the extra fluid is released and gets collected in the sac, causing pericarditis.

The blood surrounding the heart is called hemopericardium. The blood gets filled in the sac post or during surgery, trauma, and injury. The level of fluid remains constant as it is constantly produced and drained. The high pressure in the body or heart failure can cause the fluid to drain improperly. Hence, the body’s continuous production of the fluid leads to an excess of fluid in the heart.

Causes

The cause of pericarditis could be viral infection or bacterial infection or fungal infection. Pericarditis caused by bacteria is less common and that caused by fungi is rare.

Pericarditis Caused by Virus

Pericarditis is defined as a condition that disturbs the heart function and rhythm and sometimes even leads to death. Pericarditis falls under two categories—acute and chronic pericarditis. Acute pericarditis is a minor condition and lasts for a few minutes, whereas chronic pericarditis develops gradually and becomes severe. This type of pericarditis needs prolonged treatment.

There is one more subcategory called recurring pericarditis, where a person experiences repeated and frequent chest pain (two to three times a day).

In 90% of pericarditis cases, the primary cause has not been found. This fails to prove why the pericardium is getting inflamed. It is commonly understood that viral infections play a vital role in causing pericarditis.

The following viral infections cause pericarditis:

• Usual viral and cold meningitis caused by a group of viruses (enteroviruses)
• Glandular fever
• Pneumonia and bronchitis caused by adenoviruses  
• Infections caused by cytomegalovirus
• Infection caused by the herpes simplex virus (genital herpes and cold sores)
• The deadly viral infection “flu”
• AIDS and HIV
• Hepatitis C

Pericarditis Caused by Bacteria

Another important factor that causes pericarditis is bacterial infections. The inflammation caused by bacterial infection creates more severe pain. The common bacteria that cause pericarditis are Streptococci, Haemophilus influenzae, Pneumococci, Staphylococci, and Meningococci.

Pericarditis occurs more frequently in men than in women, with men between the age of 20 and 50 most likely to get affected by this condition. In studies it has been found that common pericarditis usually occurs after the onset of some kind of respiratory infections.

Other Conditions that Cause Pericarditis

• Pericardial tuberculosis: Pericardial tuberculosis is often found to be difficult to diagnose. Missing or failing to identify pericardial tuberculosis can lead to constrictive pericarditis.
• Cardiac infarction: Cardiac infraction, which is also known as a heart attack, plays a major role in causing pericarditis.  Pericarditis caused by cardiac infraction is divided into two categories—early and late pericarditis.
• Renal failure: The end-stage renal disease has the capability to cause pericarditis. If left untreated, this can even lead to chronic pericarditis. Pericarditis due to renal failure falls under two categories—uremic pericarditis and dialysis-related pericarditis.
• Heart-related surgeries: Not all heart surgeries cause pericarditis. But cases prove that people who have had heart surgeries are identified with frequent recurring pericarditis.
• Cancer: Cancer cells spread from one part of the body to the other through blood vessels and affect the pericardium.  Cancers that cause pericarditis are Hodgkin’s or non-Hodgkin’s cancer, lung cancer, breast cancer, and lymphoma.

Other Triggering Factors

• Immune system tends to attack healthy tissues; this is known as an autoimmune condition (e.g., lupus and rheumatoid arthritis).
• People who undergo radiotherapy can get affected as the radiation from the therapy has the capability to affect the pericardium tissues.
• Hypothyroidism caused because of the underactive thyroid gland has the possibilities of causing pericarditis.
• Irritation in the tissues of pericardium has a major role in causing pericarditis.
• Being involved in an accident and having injury in the chest can also cause damage to the tissue and result in swelling or inflammation in the pericardium.
• Certain medications are also known to trigger pericarditis. The medicines which are prone to cause the condition are those that are related to chemotherapy and penicillin.