In rare cases, pericarditis can develop into further problems, some of which can be life-threatening.

Chronic pericarditis

Chronic pericarditis is defined as pericarditis that persists for more than three months.

There are two main types of chronic pericarditis:

• chronic effusive pericarditis – when an excess of fluid gathers in the space inside the pericardium
• chronic constrictive pericarditis – the tissue of the pericardium becomes hardened through scarring

Chronic effusive pericarditis

It's hard to estimate exactly how widespread chronic effusive pericarditis is, as most cases do not cause any noticeable symptoms. One study estimated that 1 in 20 older adults have some degree of fluid build-up inside their pericardium.

It can cause the following symptoms:

• chest pain
• light-headedness
• shortness of breath

Possible causes of chronic effusive pericarditis include:

• infections – such as hepatitis or tuberculosis
• cancers that spread from other parts of the body to the pericardium
• damage or injury that occurs during surgery

However, no obvious cause can be found in many cases.

Medications such as non-steroidal anti-inflammatory drugs (NSAIDs) are the first treatment tried.

If medication doesn't work, surgery may be recommended. Chronic effusive pericarditis can be treated with a surgical technique called a pericardiocentesis.

During a pericardiocentesis, a thin plastic tube known as a catheter is passed through the chest and guided into the pericardium. The catheter then drains away the excess fluid.

A local anaesthetic is used to numb the skin of your chest so you will not feel any pain during the procedure.

Chronic constrictive pericarditis

It is estimated that 1 in 10 people with a history of acute pericarditis will go on to develop chronic constrictive pericarditis.

The most common symptom of chronic constrictive pericarditis is shortness of breath.

Other symptoms include:

• fatigue
• abdominal pain and swelling
• nausea and vomiting

Possible causes of chronic constrictive pericarditis include:

• infections – most often bacterial infections, such as tuberculosis
• complications of radiotherapy
• damage or injury that occurs during surgery

However, no obvious cause can be found in most cases.

Chronic constrictive pericarditis tends not to respond well to medication, and surgery to remove the pericardium (pericardiectomy) is usually the only cure.

However, this type of surgery carries a 1 in 20 risk of causing death, so surgery would only usually be recommended if your symptoms were having a significant adverse effect on your quality of life.

Cardiac tamponade

In a very small number of cases, inflammation of the pericardium can lead to a large build-up of fluid inside the pericardium. The extra fluid puts the heart under pressure, which makes it unable to pump blood around the body effectively. This is known as cardiac tamponade.

Cardiac tamponade is a potential complication in all cases of pericarditis, but is more common in cases where pericarditis has been caused by tuberculosis or cancer.

If the heart cannot pump blood at the normal level, blood pressure can drop and cause:

• light-headedness
• blurred vision
• palpitations
• confusion
• nausea
• general weakness
• a temporary loss of consciousness

These symptoms can develop very quickly, sometimes within minutes.

Cardiac tamponade is life-threatening and requires emergency treatment. If you have a history of pericarditis and develop the symptoms listed above, call 999 and ask for an ambulance.

Cardiac tamponade is usually treated with a pericardiocentesis.