Pericarditis has different classification types, depending on the pattern of symptoms and how long symptoms last. Acute pericarditis usually lasts less than three weeks. Incessant pericarditis lasts about four to six weeks but less than three months and is continuous.

Pericarditis is described as recurrent if it occurs about four to six weeks after an episode of acute pericarditis with a symptom-free interval in between. Pericarditis is considered chronic if symptoms last longer than three months.

If you have acute pericarditis, the most common symptom is sharp, stabbing chest pain behind the breastbone or in the left side of your chest. However, some people with acute pericarditis describe their chest pain as dull, achy or pressure-like instead, and of varying intensity.

The pain of acute pericarditis may travel into your left shoulder and neck. It often intensifies when you cough, lie down or inhale deeply. Sitting up and leaning forward can often ease the pain. At times, it may be difficult to distinguish pericardial pain from the pain that occurs with a heart attack.

Chronic pericarditis is usually associated with chronic inflammation and may result in fluid around the heart (pericardial effusion). The most common symptom of chronic pericarditis is chest pain.

Depending on the type, signs and symptoms of pericarditis may include some or all of the following:

• Sharp, piercing chest pain over the center or left side of the chest, which is generally more intense when breathing in
• Shortness of breath when reclining
• Heart palpitations
• Low-grade fever
• An overall sense of weakness, fatigue or feeling sick
• Cough
• Abdominal or leg swelling

Under normal circumstances, the two-layered pericardial sac that surrounds your heart contains a small amount of lubricating fluid. In pericarditis, the sac becomes inflamed and the resulting friction from the inflamed sac leads to chest pain.

The cause of pericarditis is often hard to determine. In most cases, doctors either are unable to determine a cause (idiopathic) or suspect a viral infection.

Pericarditis can also develop shortly after a major heart attack, due to the irritation of the underlying damaged heart muscle. In addition, a delayed form of pericarditis may occur weeks after a heart attack or heart surgery.

This delayed pericarditis is known as Dressler's syndrome. Dressler's syndrome may also be called postpericardiotomy syndrome, post-myocardial infarction syndrome and post-cardiac injury syndrome.

Other causes of pericarditis include:

• Systemic inflammatory disorders. These may include lupus and rheumatoid arthritis.
• Trauma. Injury to your heart or chest may occur as a result of a motor vehicle or other accident.
• Other health disorders. These may include kidney failure, AIDS, tuberculosis and cancer.
• Certain medications. Some medications can cause pericarditis, although this is unusual.

Complications of pericarditis may include:

• Constrictive pericarditis. Although uncommon, some people with pericarditis, particularly those with long-term inflammation and chronic recurrences, can develop permanent thickening, scarring and contraction of the pericardium.

In these people, the pericardium loses much of its elasticity and resembles a rigid case that's tight around the heart, which keeps the heart from working properly. This condition is called constrictive pericarditis and often leads to severe swelling of the legs and abdomen, as well as shortness of breath.

• Cardiac tamponade. When too much fluid collects in the pericardium, a dangerous condition called cardiac tamponade can develop.

Excess fluid puts pressure on the heart and doesn't allow it to fill properly. That means less blood leaves the heart, which causes a dramatic drop in blood pressure. Cardiac tamponade can be fatal if it isn't promptly treated.