Pericarditis is an inflammation of the pericardium, which is the fibrous sac surrounding the heart. It may be acute or a chronic problem. Regardless of the cause, pericarditis has two components:
- effusion (fluid production )
These occur together in varying degrees, so that some cases involve mainly effusion and others mainly inflammation.
There are many possible causes, inflammatory, cancerous, degenerative or unknown, but the major causes include:
- virus infections ( including HIV)
- bacterial infection
- heart attack - recent or long ago
- cardiac surgery
- sharp or blunt trauma, including angiograms
- malignancies (lung, breast, Hodgkins & mesothelioma)
- metabolic disturbances - uraemia, dialysis
- collagen diseases
Symptoms and signs
The classical symptoms are sharp chest pain, which is relieved by sitting up and leaning forwards. The pain is often worse with deep breathing and coughing and patients often hold the front of their chest for some relief of pain. A fever may be present, especially in infective cases, and sometime with malignancies.
On examination, a particular friction rub may be heard as the heart rubs against the inflamed pericardium. Or, if fluid has collected in the pericardium, heart sounds may be muffled or seem distant.
In some patients the description of symptoms may not be very precise, so some tests are needed to make a definite diagnosis. These include:
Serial ECG's done over a few hours can be the most useful test, as there is a specific pattern of evolution in pericarditis, which distinguishes the disorder from a heart attack. This is important because the two conditions may give similar symptoms at first, but require totally different treatment.
This is often normal, but will show in effusion. It is an easy, non-invasive test.
This may be normal, but if significant effusion is present (200ml or more), an enlarged heart shadow will be seen.
CT, MRI or radionuclide scans are only done in cases of difficult diagnosis.
Relevant tests will be done to detect infection or specific disorders
- Full blood count - can detect infection
- Blood culture if septicaemia is suspected
- Analysis of pericardial fluid sample (see later)
- Heart rhythm disturbances are common in percarditis with myocarditis. Atrial fibrillation, tachycardia or heart block can occur and are managed accordingly.
- Tamponade - because the pericardium cannot stretch, continued fluid accumulation will eventually squeeze the heart, preventing proper filling and compromising its function. If the volume if fluid is large or increases rapidly, emergency treatment may be needed.
- Constrictive pericarditis - this is long-term outcome. Inflammation leads to fibrosis and contraction of tissues, leaving the heart encased in a shrunken, rigid pericardium, which further restricts the function o f the heart.
Where the cause is known, specific treatment is given, for example antibiotics or antifungals. Diuretics may be of use to reduce general fluid overload.
Where the cause is unknown or suspected to be viral, treatment is aimed at symptom relief and halting inflammation. Aspirin and non-steroidal anti-inflammatories achieve good results (90%), and some patients respond to colchicine. If the patient does not respond to these medications and no specific cause for the pericarditis is found, cortocisteroids are used; this is of particular benefit in auto-immune conditions.
For patients with acute tamponade, (effusion compromising heart function), or if malignancy or bacterial infection (e.g. tuberculosis) is suspected, some of the fluid may be drained and analysed. This relieves symptoms and can provide a diagnosis. This procedure, (pericardiocentesis) may be done by the cardiologist or surgeon by draining some fluid through a needle and syringe into the pericardium under local anaesthetic. For large volumes a drainage tube can be inserted into the pericardium under general anaesthesia, and the fluid slowly drained out.
For malignant effusions, a small operation can be done to remove a piece of the pericardium, creating a "window" to allow fluid to drain away and not compress the heart.
Pericardiocentesis is only done when absolutely necessary because it can cause problems later if done for the wrong reasons.
Viral pericarditis usually settles in 2-3 months and has an excellent long-term prognosis, with later constrictive pericarditis developing in only about 1% of patients. Those with an infective cause have a higher risk of this complication occurring.
Dr. AG Hall