Pericardial Effusion

A pericardial effusion is an abnormal accumulation of fluid in the pericardial space.

Causes
The pericardial effusion may be acute or chronic.

There are various causes of acute pericardial effusions, such as a traumatic injury to the chest, post myocardial infarction, or as a complication of pericarditis. In traumatic injury, the fluid that accumulates inside the pericardial space is blood.

Chronic pericardial effusions are usually from another underlying disease, such as a malignant disease, human immunodeficiency virus (HIV) or severe kidney disease.

Signs and Symptoms
There may be varying degrees of shortness of breath and chest discomfort. There may be signs of heart failure depending on the effusion size, and how quickly it progressed. 

The pericardium is able to stretch more if the effusion is slowly developing. Therefore, a chronic pericardial effusion is much beaer tolerated than an acute pericardial effusion. Chronic pericardial effusions can develop to be quite large before any symptoms are apparent, whereas in contrast, a small acute pericardial effusion may cause significant symptoms.

Investigations
The echocardiogram (ECHO) confirms the presence and size of a pleural effusion. There may be various changes on the electrocardiogram (ECG). Chest x-ray may show evidence of an enlarged pericardium, if the effusion is large. Auscultation of the heart may reveal muffled heart sounds.

In situations where the cause is unknown, a thorough patient history and physical examination should be done to identify the presence of another disease known to potentially cause pericardial effusions. However, sometimes an underlying condition cannot be found.

Treatment
Symptomatic pericardial effusions may require drainage. This is commonly done by inserting a catheter through the chest wall and aspirating the fluid (a procedure called pericardiocentesis).

Immediate drainage of the effusion may not be advised for patients who are hemodynamically stable. Instead, identification and treatment of the underlying condition may result in improvement of the effusion.

Complications
A pericardial effusion can develop into cardiac tamponade.

 

Cardiac Tamponade

If the pericardial effusion is large, or if it had an acute onset, then the pericardium may not be able to stretch further. This constricts the heart, and inhibits its filling ability. This is a condition called cardiac tamponade.

Signs and Symptoms
The patient is usually tachycardic, and with bulging neck veins (distended jugular veins). Hypotension can also quickly develop. The patient may have chest pain, shortness of breath, and feel faint, or they may be unconscious. 

Investigations
Cardiac tamponade is a clinical diagnosis, made from the history and physical assessment. An echocardiogram (ECHO) can confirm the pericardial effusion and assess the hearts ability to contract; however there is rarely time to perform this. Delayed treatment may result in cardiac arrest.

Treatment
The treatment is drainage of the effusion, a procedure called pericardiocentesis. Oxygen must be administered. Intravenous fluids and an inotrope infusion (such as dopamine) can also be commenced whilst the doctor prepares for an emergency pericardiocentesis.