Pericarditis refers to inflammation of the pericardium,
the double-walled, fluid-filled sac that encloses the heart. The pericardial
cavity contains a fluid which serves as lubricant and allows the heart to contract
and relax with minimum friction. It also protects the heart from infection and over-distension.
The most common form is acute pericarditis, meaning symptoms develop suddenly
but do not last long. Subacute and chronic forms develop more slowly and last longer.
Recurrent pericarditis is when there are symptom-free intervals in between episodes.
A typical symptom of acute pericarditis is chest pain, which can be sharp or dull. The
pain may radiate to the left shoulder or arm, similar to that of a heart attack, or ischemia.
Unlike ischemic pain, however, pericardial pain is worsened with deep breathing,
coughing, swallowing, or lying flat; and improved with sitting up or leaning forward.
Inflammation of the pericardium can cause fluid to accumulate in the pericardial cavity.
This is called pericardial effusion. The increased fluid volume may limit cardiac filling,
leading to low cardiac output and sometimes life-threatening circulatory shock,
known as cardiac tamponade. The rate at which fluid accumulates is often more critical
than the volume of fluid. Slow accumulation of a large volume may not cause tamponade,
but a relatively small effusion can do so if it builds up too rapidly, because the pericardium
cannot stretch quickly enough to accommodate it. Less commonly, chronic inflammation may also
result in a thickened and stiffened pericardium, a condition known as constrictive pericarditis.
As the stiff pericardium reduces cardiac filling, blood backs up in the body’s veins and the lungs,
where it came from. A peripheral venous congestion leads to swelling of legs and abdominal organs,
while an elevated pulmonary pressure results in difficulty breathing.
The cause of pericarditis is often difficult to determine. Possible causes include:
viral infection, bacterial infection, injury to the chest, inflammatory disorders, other health
problems, and some medications. Pericarditis may also develop following a heart attack
or cardiac surgery. It can happen immediately after, or as a delayed form several weeks later.
Diagnosis can usually be made based on evaluation of chest pain,
and presence of pericardial rub, a characteristic sound produced when pericardial layers rub against
each other; but tests are commonly performed to confirm, and to exclude heart attack.
In about half of patients, electrocardiograms show changes that go through a characteristic sequence
of four stages. Pericardial effusion, if present, can be seen with echocardiography or chest x-ray.
Treatment depends on the cause
and disease severity. Mild cases may get better on their own without treatment.
Pain and inflammation can be relieved with anti-inflammatories.
Corticosteroids may be used for non-infectious cases that do not respond to other medicines.
Bacterial infections are treated with antibiotics, and possibly drainage.
If cardiac tamponade is present, a procedure called pericardiocentesis
is performed to remove the excess fluid from the pericardial cavity. Severe constrictive
pericarditis may require surgical removal of the pericardium, as a last resort.