The normal pericardium

• Limit distension of the heart
• Protect the heart from infection / damage
• Aids the filling of the ventricles

Acute Pericarditis

Causes

Infection (most commonly viral, but often not identified). The most common causatory factors are coxsackie B virus and echovirus. 
Acute MI – post MI pericarditis occurs in about 20% of MI patients. It occurs most commonly with anterior MI’s and MI’s with massive ST elevation.

• The incidence is actually reduced by 5-6% with thrombolysis
• It can be difficult to differentiate this pain from angina pain within the first couple of days after an MI
• Dressler’s syndrome is pericarditis that occurs secondary to myocardial or pericardial damage, and occurs at least 2 weeks after the MI. this makes it different from the normal post MI pericarditis described above. Dressler’s occurs in about 7% of MI patients.The symptoms can arise anywhere between a few weeks and 2 years after an MI, and will usually subside within a few days. Typical time of onset is 1 to 4 weeks after the MI.
  • It is an auto-immune condition whereby the body auto-reacts against damaged myocardial tissue. Antimyocardial antibodies are often found.
  • Recurrence is common
  • May also occur after episodes of unstable angina
  • Presents with massively raised ESR

Less common causes

• Autoimmune reaction
• Trauma
• Neoplasm
• Idiopathic
• Bacterial infection
• TB
• Rheumatic fever
• HIV – these patient may get staphylococcal pericarditis – which is often fatal

Pericarditis and myocarditis often co-exist

Signs and Symptoms

Sharp pain – this can vary in site and severity, however is usually retrosternal. It often radiates to the shoulders and neck, and is aggravated by deep breathing (pleuritic), movement, change of position, exercise and swallowing.

• The pain is typically relieved by leaning forwards
• The differentials for this type of pain are basically pleurisy and pericarditis

Fever – a low grade fever may be present
Pericardial effusion – this is present whatever the cause. However, it can be a result of different factors (depending on the cause); e.g. serous, purulent, haemorrhagic, fibrinous

• Fibrinous exudates – can eventually lead to adhesion
• Serous – this produces a large amount of straw-coloured fluid, with a very high protein content
• Haemorrhagic – usually due to malignant disease, most commonly carcinoma of the breast, bronchus, and lymphoma.
• Purulent – this is rare, and may be a complication of septicaemia.
• Pericardial effusion may press on the surrounding tissues, particularly the bronchi, resulting in dyspnoea

Pericardial friction rub – this is a high pitched superficial scratching or crunching sound, that is produced by movement of the pericardium. It is diagnostic for pericarditis. Usually heard in systole but may also be heard in diastole.

• It is classically heard in three, or two (‘to and fro’ rub) phases – i.e. this means it is heard 3 times or twice during one cardiac cycle
• The rubs are typically heard best with the diaphragm at the left lower sternal edge at full expiration

Investigations

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