What is pericarditis?

Pericarditis is an inflammation of the pericardium, which is the thin, double-layered sac which surrounds the heart and holds it in place within the chest. The pericardium consists of two layers: the outer layer (fibrous pericardium) and the inner layer (serous pericardium).

When the pericardium becomes inflamed, the layers can rub against each other, causing chest pain. Pericarditis can be acute or chronic.

Typical symptoms of pericarditis include chest pain och hög temperatur (feber).

The pain:

• Is usually in the middle of the chest or slightly left of centre.

• May feel sharp and stabbing but may be a persistent steady pain.

• May spread to the neck and/or shoulders.

• Typically gets worse on taking a deep breath, swallowing, coughing, or lying down.

• May ease on sitting up or leaning forward.

Breathlessness may also be a symptom, especially if cardiac tamponade develops (see under 'Complications' below).

Other symptoms depend on the underlying cause of pericarditis.

Infection with a virus is the most common cause of pericarditis. Several different viruses can cause pericarditis, including coxsackieviruses, echoviruses, influenza viruses, adenoviruses, the mumps virus, human immunodeficiency virus (HIV) and viruses that cause hepatitis.

Other causes are uncommon and include:

• Infection with a bacteria. This often causes pus to form between the inner and outer layers of the pericardium. The infection has usually spread from nearby tissues (such as an infection of the heart itself) or from a wound infection following heart surgery. Rarely, syphilis or fungi can infect the pericardium.

• Tuberculosis (TB) infection. This is usually as part of a more widespread TB infection in the lungs and other parts of the body.

• Uraemic pericarditis. This is inflammation caused by waste products building up in the bloodstream in people with untreated kidney failure.

• Heart attack (myocardial infarction). Inflammation of the pericardium may occur if there is damage to nearby heart tissue, caused by a heart attack.

• Following heart surgery. Inflammation can occur a few days to a few weeks after open heart surgery.

• Following injury. For example, pericarditis can develop following a stab wound or a severe blow to the chest (for example, following a road traffic accident).

• Inflammatory diseases which can affect various parts of the body may include inflammation of the pericardium - for example, reumatoid artrit, scleroderma, polyarteritis nodosa and systemic lupus erythematosus (SLE).

• Radiotherapy to treat cancers in the chest.

• Cancer which has spread to the pericardium from another part of the body (this is very rare).

In many cases, no cause is found. This is called idiopathic pericarditis. Many of these cases are probably caused by a viral infection which cannot be identified.

The diagnosis is initially suspected in someone with the symptoms listed above. On listening to the chest with a stethoscope, there may be a "pericardial friction rub". This sounds like a grating noise. Not all cases of pericarditis have this rub.

Pericarditis can cause similar symptoms to a variety of medical conditions. Tests are usually needed to clarify the diagnosis. These will usually take place in the emergency department of a hospital although some may then be carried out as an outpatient following assessment by a cardiologist.

• A chest X-ray may show a change in the shape of the heart (a flask-shaped heart) or fluid in the lung cavity.

• Blood tests may show an underlying cause for the pericarditis.

• An electrocardiogram (ECG). This is a tracing of the electrical activity of the heart. It often shows a typical pattern in someone with pericarditis.

• An echocardiogram. This is an ultrasound scan of the heart. It shows the structure of the heart and surrounding tissues. It can detect if any fluid has built up between the layers of pericardium, which is typical of pericarditis.

• Other tests such as a magnetic resonance imaging (MRI) scan or computerised tomography (CT) scan may be needed to look for changes in the pericardium. These tests tend to be done if a cause other than a viral infection is suspected.

• If a large pericardial effusion develops, a sample of the fluid may be taken with a needle and syringe and analysed for infections such as TB.

Treatment for viral or idiopathic pericarditis

Nonsteroidal bnti-inflammatory drugs (NSAIDS)such as ibuprofen are usually given to ease the pain and reduce inflammation. Colchicine, alongside typical NSAIDs, is also now recommended as a first-line treatment for pericarditis (although it is not licensed for this) and has been shown to help to improve the outcome and reduce the chances of the inflammation coming back. People treated with colchicine had a 30% lower chance of the pericarditis recurring.

If the pain is severe and not settling with the standard treatments above, steroid medicines may be used to reduce the inflammation. These are very successful but can have more side effects. The pain and inflammation usually settle within a few weeks.

Treatment for other causes

The treatment depends on the cause. For example, it may involve antituberculosis medication for TB, antibiotic medicines for bacterial infections or dialysis (filtering of the blood) for uraemic pericarditis.

Complications are uncommon. They include:

Pericardial effusion

Fluid may build up between the two layers of the pericardium. A small amount of fluid is not usually a problem and tends to go when the inflammation settles. However a lot of fluid may prevent the heart chambers from filling normally and prevent the heart muscle from pumping blood properly. Blood pressure can drop suddenly. This is called cardiac tamponade and is a life-threatening emergency unless the excess fluid is quickly drained using a needle and syringe.

Constrictive pericarditis

This is an uncommon condition that may develop if the pericardium has been inflamed for a long time. The pericardium thickens and contracts around the heart. This is serious, as it can interfere with the function of the heart. The thickened pericardium can be removed by an operation called a pericardiectomy.

Both of the these complications may cause heart failure. The symptoms may include shortness of breath, swollen legs and ankles and tiredness.

Most people with viral or idiopathic pericarditis recover fully within a few weeks, without any complications or longer-term effects. In some cases the symptoms return 'on and off' for several months. These repeated episodes are usually less severe than the first one.

Pericarditis caused by heart attack or injury usually settles over one to two weeks.

The outlook for other causes of pericarditis as outlined above (eg, uraemic, bacterial, TB) can vary depending on the severity of the underlying cause.