It is not always clear what causes pericarditis, although a viral infection is usually suspected.

In around 90% of acute pericarditis cases, no obvious cause can be found to explain why the pericardium has become inflamed. Many cases are thought to be the result of viral infections, which current diagnostic technology is generally unable to detect.

Viral infections

Viral infections associated with acute pericarditis include:

• infections such as the common cold or viral meningitis, which are caused by a group of viruses known as enteroviruses
• infections caused by adenoviruses, such as pneumonia or bronchitis
• glandular fever 
• infections caused by the cytomegalovirus
• herpes simplex viral infections (cold sores or genital herpes)
• flu (influenza)
  
• hepatitis C   
• HIV and AIDS 

Other causes

Other less common causes of acute pericarditis include:

• bacterial infection, particularly tuberculosis
• autoimmune conditions such as rheumatoid arthritis or lupus, where the immune system attacks healthy tissues
• radiotherapy – the radiation used in radiotherapy can damage the tissue of the pericardium, and breast or lung cancer patients may be at particular risk
• kidney failure – exactly why kidney failure causes acute pericarditis is unclear
• underactive thyroid gland (hypothyroidism) – exactly why hypothyroidism causes acute pericarditis is unclear
• cancer – cancer that spreads from other parts of the body to the pericardium can damage tissue
• heart attacks – pericarditis can sometimes develop after a heart attack, as damaged heart muscles can irritate the pericardium
• injury or irritation to the tissue of the pericardium that occurs during heart surgery
• severe injury to the chest, for example following a car accident
• some medications, such as penicillin or some chemotherapy medicines, have been known to trigger acute pericarditis as a side effect in some people

Recurring pericarditis

Despite being a relatively common condition, recurring pericarditis remains poorly understood with little known about its causes.

One theory is that your immune system may be responsible. The theory suggests that something goes wrong with your immune system many months or years after the initial infection that caused your first episode of acute pericarditis. It starts to produce infection-fighting antibodies that are meant to be used to fight the virus, but instead are sent to the heart, leading to inflammation of the pericardium. Exactly why the immune system would behave in this way is unclear.

Another theory is that fragments of the virus may lay dormant (inactive) in the tissue of the pericardium and then suddenly reactivate, triggering the process of inflammation.

What is known, is that people treated with corticosteroids during their first episode of acute pericarditis are six times more likely to go on to develop recurring pericarditis than people who do not receive this treatment. Because of this, corticosteroids are used as a last resort, if you fail to respond to other medications. 

Read more about treating pericarditis.

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 – where the tissue of the pericardium becomes hardened through scarring

Chronic effusive pericarditis

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

In cases where symptoms are present, they may include:

• 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, in many cases no obvious cause can found.

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

If medication fails to be effective, 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 will be passed through the chest and guided into the pericardium. Imaging technology, such as an echocardiogram, may be used to guide the catheter accurately. 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 one 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, in most cases no obvious cause can be found.

Unlike the acute form of pericarditis, chronic constrictive pericarditis tends not to respond well to medication and usually the only realistic option for a complete cure is to surgically remove the pericardium (pericardiectomy).

However, this type of surgery carries a one 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 it 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.

The first stage in the diagnosis of pericarditis is to ask about your symptoms and recent medical history, such as whether you have recently had a chest infection or been in an accident.

The next stage is to listen to your heart with a stethoscope. Pericarditis can change the sound of your heartbeat to a distinctive rasping or grating sound, which is clearly detected by the stethoscope.

You may have blood tests to check for infections, and to check how organs such as your liver and kidneys are functioning.

In some cases, a needle may be used to drain any fluid from around your heart so it can be tested.

A diagnosis is usually confirmed by electrocardiogram (ECG). During an ECG, electrodes are placed on your skin to measure the electrical activity of your heart.

People with pericarditis usually experience a distinctive change in the electrical activity of the heart, which can be detected with an ECG.

Further testing

Further testing is only usually required if the test described above proves negative or you have additional symptoms not normally associated with pericarditis, such as swelling of the arms and legs or extreme tiredness.

These tests may include:

• a chest X-ray
• a magnetic resonance imaging (MRI) scan
• a computer tomography (CT) scan
• an echocardiogram – this test is similar to an ultrasound scan, as it uses sound waves to build up a detailed picture of your heart and pericardium

Pericarditis is inflammation (swelling) of the pericardium, which is the fluid-filled sac surrounding your heart.

The main sign of pericarditis is chest pain. This can be a sudden, sharp and stabbing pain behind your breastbone or more of a dull ache. The pain usually worsens when lying down.

Pericarditis is not usually a serious condition and can often be treated on an outpatient basis, so you do not have to be admitted to hospital.

Read more about the symptoms of pericarditis.

Types of pericarditis

There are three main types of pericarditis:

• acute pericarditis – where the symptoms last less than three months (with treatment, symptoms normally resolve within a week)
• recurring pericarditis – where someone has repeated episodes of acute pericarditis
• chronic pericarditis – a complication of pericarditis, where the symptoms last longer than three months

Why does pericarditis happen?

In most cases of pericarditis, no cause is identified. However, it is usually suspected that an infection, either viral or bacterial, is responsible.

Other things that may cause pericarditis include chest injury, some cancers and some treatments, such as radiotherapy or chemotherapy.

Problems with the body’s natural defence system (the immune system) may also have a role in recurring and chronic pericarditis.

Read more about the causes of pericarditis.

How is pericarditis treated?

Acute pericarditis can usually be treated with medication such as non-steroidal anti-inflammatory drugs (NSAIDs), although antibiotics may be used if there is a bacterial infection.

A medication called colchicine is often used for recurring pericarditis, as it can prevent symptoms returning.

Treatment for chronic pericarditis will depend on the underlying cause. Some cases respond well to medication, while others may require surgery.

Read more about treating pericarditis.

Who is affected?

Pericarditis is a relatively common heart condition. Around 5% of all admissions to accident and emergency (A&E) departments for severe chest pain are diagnosed as pericarditis.

Pericarditis tends to be more common in men than women. It can affect people of all ages, but mostly occurs in adults.

The Map of Medicine is used by doctors throughout the NHS to determine the best treatment options for their patients. NHS Choices offers everyone in England exclusive and free access to this cutting-edge internet resource, which lets you see exactly what your doctor sees.

The information in the Map has been approved by the UK’s leading clinical experts, is based on the best available clinical evidence, and is continually updated. To take advantage of this unique resource go to:

Map of Medicine: pericardial disease

The most common sign of all types of pericarditis is chest pain.

Most people who have had pericarditis describe experiencing a sudden sharp pain, usually behind their breastbone, on the left side of their body. Some people describe the pain as more like a dull ache or feeling of pressure.

The pain may also radiate up from your chest into your left shoulder and neck.

It is usually worse when coughing, eating and lying down. Sitting up or leaning forward will usually help relieve the pain.

Additional symptoms

Depending on the underlying cause of your pericarditis, you may also experience:

• a high temperature (fever) 
• shortness of breath
• fatigue
• nausea
• dry cough
• swelling of the legs or abdomen

In some cases, pericarditis occurs along with myocarditis, which is an infection of the heart muscle.

If these symptoms only occur for a short time or a one-off episode, it is called ‘acute pericarditis’. However, if they last three months or more, it is known as ‘chronic pericarditis’.

Read about the complications of pericarditis for more information on chronic pericarditis.

Recurring pericarditis

Recurring pericarditis is when you experience frequent episodes of acute pericarditis.

There are two main types of recurring pericarditis:

• Incessant pericarditis is where the symptoms of acute pericarditis develop once medications such as non-steroidal anti-inflammatory drugs (NSAIDs) are withdrawn. Symptoms usually begin within six weeks of the treatment being withdrawn.
• Intermittent pericarditis is where you will go for long periods without any symptoms (often many months or sometimes years) before symptoms return without warning.

It is estimated that one in four people with a history of acute pericarditis will develop recurring pericarditis.

When to seek medical advice

Always seek immediate medical advice if you experience sudden chest pains. While most cases of pericarditis are not serious, it is important that other more serious conditions are ruled out, such as a heart attack or a blood clot.

Visit your local accident and emergency (A&E) department or telephone NHS Direct on 0845 46 47 or NHS 111 as soon as possible.

Pericarditis is usually treated with medication, although surgery is used in rare cases.

The medical staff involved in your care will first assess whether it is safe to treat you at home, or whether the risk of complications is high enough for you to be admitted to hospital as a precaution.

You will usually be admitted to hospital if:

• you have a high temperature (fever) of 38^oC  (100.4^oF) or above
• you have a high number of white blood cells – this could be the result of a serious infection
• your symptoms develop after a sudden injury to your chest
• you take blood thinning medication
• blood tests show you have high levels of a type of protein called troponin in your blood (this can be the result of damage to the heart muscle)
• there is a risk of you developing cardiac tamponade, a serious complication of pericarditis caused by a build up of fluid around the heart

Hospital admission may also be recommended if you fail to respond to the treatment outlined below.

Non-steroidal anti-inflammatory drugs (NSAIDs)

Most cases of pericarditis can be successfully treated with non-steroidal anti-inflammatory drugs (NSAIDs). NSAIDs work by reducing the inflammation of the pericardium. They also relieve the chest pain.

Ibuprofen is the preferred choice of NSAID. The exception is if you have recently had a heart attack, as ibuprofen can interfere with the healing of your heart. In such circumstances, high-dose aspirin will usually be recommended.

As NSAIDs can occasionally cause stomach ulcers, you will probably be prescribed an additional medication called a proton pump inhibitor that provides protection against stomach ulcer.

Colchicine

Colchicine is an additional medicine that can be used either on its own or in combination with NSAIDs.

It is often used if your symptoms fail to respond to NSAIDs or you are unable to take NSAIDs because of a pre-existing medical condition. 

Colchicine is useful because it kills some of the cells of the immune system that cause inflammation, so can reduce inflammation of the pericardium.

Side effects of colchicine include:

• abdominal pain
• vomiting
• diarrhoea

These side effects usually improve once your body gets used to the medication.

Colchicine does not currently have a licence to be used to treat pericarditis in the UK, which means that it has not undergone clinical trials for this condition. However, studies have shown colchicine can be effective in treating pericarditis, so you may still be prescribed it if the benefits outweigh any potential risks.

Corticosteroids

Corticosteroids are usually only given when the symptoms of pericarditis fail to respond to NSAIDs and colchicine, or there is a build-up of fluid inside the pericardium, which could put the heart at risk.

Corticosteroids block the effects of the immune system, leading to a reduction in inflammation.

Corticosteroids are powerful medicines and can have a range of side effects, especially if used for a long period of time.

Side effects of corticosteroids include:

• weight gain
• mood swings
• increased sweating

Other treatments and measures

Treatment for pericarditis is different if it is not caused by a viral infection. For example, if your pericarditis is caused by a bacterial infection, such as tuberculosis, antibiotics are used.

If your pericarditis occurs along with myocarditis, an infection of the heart muscle, you may be advised not to do any strenuous exercise for a few weeks.

In some cases, the fluid that builds up around the heart may be drained with a needle during a procedure called pericardiocentesis. However, this is usually only used if you develop complications of pericarditis.

Recurring pericarditis

NSAIDs can be used to relieve symptoms of an episode of pericarditis, while a long-term course of colchicine has proved effective in preventing the return of symptoms.

If medications fail to control symptoms then a short-course of steroid medication may be recommended.

If your symptoms are particularly severe and not responding to medication, then a type of surgery known as pericardiectomy may be recommended.

This involves the surgeon making a large incision in your chest and removing some or all of your pericardium.

It should be stressed that a pericardiectomy is usually regarded as a last resort, as the surgery is relatively risky – there is an estimated one in 20 chance of it causing death.