Pericardial Effusion
Excess fluid collecting in the sac around the heart
Quick Facts
- Type: Cardiovascular condition
- Affected area: Pericardium (sac around the heart)
- Common causes: Infection, inflammation, cancer, kidney failure
- Seek urgent care: Severe shortness of breath, chest pressure, fainting
Overview
Pericardial effusion is the abnormal accumulation of fluid in the pericardium, the protective two-layered sac that surrounds the heart. A small amount of fluid normally sits between these layers to let the heart move smoothly as it beats. When too much fluid collects, it can press on the heart and limit how well it fills and pumps blood.
The effusion may build up slowly over weeks or appear suddenly. A slow, gradual collection can become surprisingly large before causing symptoms because the sac stretches to accommodate it. A rapid buildup, even a smaller one, can be dangerous because the sac cannot stretch quickly. The most serious complication is cardiac tamponade, in which pressure on the heart becomes life-threatening.
The amount of fluid and the speed at which it accumulates matter more than any single measurement. A large but slowly forming effusion may cause only mild symptoms, while a smaller but rapid one can be an emergency. For this reason, doctors assess not only how much fluid is present but also whether it is straining the heart.
Symptoms
Small effusions often cause no symptoms and are found by chance during imaging done for another reason. Larger or rapidly forming effusions can cause:
- Shortness of breath, especially when lying flat
- Chest pressure, fullness, or discomfort
- A sense that the heart is pounding or racing
- Lightheadedness or fainting
- Cough or trouble swallowing from pressure on nearby structures
- Swelling in the legs or abdomen
Severe shortness of breath, chest pain, a feeling of impending collapse, or fainting may signal tamponade and require emergency care.
Causes
Pericardial effusion has many possible causes, and sometimes no cause is found. Common ones include:
- Inflammation (pericarditis): Often from viral infection, this is one of the most frequent causes.
- Infection: Bacterial, tuberculous, or fungal infections can produce fluid.
- Cancer: Tumors that spread to the pericardium can cause effusions.
- Kidney failure: Buildup of waste products (uremia) can irritate the pericardium.
- Autoimmune disease: Conditions such as lupus and rheumatoid arthritis.
- Injury, surgery, or radiation: Trauma or treatment near the chest.
- Underactive thyroid (hypothyroidism).
Risk Factors
- Recent viral illness or pericarditis
- Cancer, especially lung, breast, or blood cancers
- Chronic kidney disease or dialysis
- Autoimmune and inflammatory conditions
- Recent heart surgery, chest injury, or chest radiation
- Tuberculosis or other serious infections
Diagnosis
Doctors confirm and assess pericardial effusion using:
- Echocardiogram: An ultrasound of the heart, the main test, showing the amount of fluid and whether it is pressing on the heart.
- Chest X-ray: May show an enlarged heart shadow with a large effusion.
- Electrocardiogram (ECG): Can show changes suggesting pericarditis or tamponade.
- CT or MRI: Detailed imaging when more information is needed.
- Fluid analysis: If fluid is drained, laboratory testing helps identify infection, cancer, or inflammation.
Treatment
Treatment depends on the size of the effusion, how fast it formed, whether it is straining the heart, and the underlying cause.
- Treating the cause: For example, anti-inflammatory medicines for pericarditis, antibiotics for infection, or dialysis adjustments for kidney-related fluid.
- Monitoring: Small, symptom-free effusions are often watched with repeat echocardiograms.
- Drainage (pericardiocentesis): A needle or catheter removes fluid when the effusion is large, causing symptoms, or threatening tamponade.
- Surgery: A pericardial window or other procedure may be needed for recurrent or persistent effusions.
When tamponade is present, urgent drainage of the fluid is the priority and can be lifesaving.
Prevention
Many effusions cannot be prevented, but you can reduce risk and catch problems early by:
- Treating infections and inflammatory conditions promptly
- Managing chronic conditions such as kidney disease, thyroid disorders, and autoimmune disease
- Attending follow-up after pericarditis, heart surgery, or chest radiation
- Reporting new shortness of breath or chest discomfort to your doctor
When to See a Doctor
Contact a doctor for unexplained shortness of breath, chest discomfort, or swelling. Call emergency services or go to the nearest emergency department right away if you have:
- Severe or sudden shortness of breath
- Chest pain or pressure that does not ease
- Fainting or feeling as if you might pass out
- A racing heartbeat with weakness, cold sweats, or confusion
These can be signs of cardiac tamponade, a medical emergency.
Frequently Asked Questions
Is pericardial effusion dangerous?
It depends on how much fluid there is and how fast it formed. Small, slow effusions are often harmless, but a rapid or large buildup can compress the heart and cause cardiac tamponade, which is life-threatening and needs emergency treatment.
How is fluid around the heart removed?
Fluid is removed with a procedure called pericardiocentesis, where a thin needle or catheter is guided into the sac, usually using ultrasound. For recurring effusions, a surgeon may create a small opening (pericardial window) to allow fluid to drain continuously.
Can pericardial effusion go away on its own?
Yes. Small effusions, especially those caused by a viral infection or mild inflammation, often clear up as the underlying cause is treated or resolves. These are typically monitored with repeat echocardiograms rather than drained.
What does a pericardial effusion feel like?
Many people feel nothing. When symptoms occur, they often include shortness of breath that worsens lying down, chest pressure or fullness, a pounding heartbeat, and lightheadedness. Severe symptoms or fainting need emergency evaluation.
How is pericardial effusion diagnosed?
An echocardiogram, an ultrasound of the heart, is the main test and shows how much fluid is present and whether it is straining the heart. A chest X-ray, ECG, and sometimes CT or MRI add further detail.
References
- Mayo Clinic. Pericardial effusion — Symptoms and causes.
- National Heart, Lung, and Blood Institute (NHLBI). Pericarditis.
- MedlinePlus, U.S. National Library of Medicine. Pericardial effusion.
- American Heart Association. What Is Pericarditis?