Pericardial Effusion

The heart is wrapped in the pericardium, a thin sac with two layers. Normally there is a small amount of fluid between the two layers, about 10 to 50 mL, which acts as a lubricant. Pericardial effusion means the fluid inside this sac increases beyond normal. Depending on the cause, the fluid may be clear fluid, blood, pus, or fluid containing cancer cells.

Part of the Pericardial Disease Family

An effusion often accompanies inflammation of the heart lining, covered on the Pericarditis page along with its subtypes. However, an effusion can also occur without inflammation, for example in heart failure, severe kidney disease, or an underactive thyroid gland. In countries with many TB cases, such as Indonesia, TB should always be considered as a possible cause, especially when the effusion comes with fever, night sweats, and weight loss. When the fluid presses on the heart and disrupts its pumping, the situation becomes an emergency, covered on the Cardiac Tamponade page.

How Quickly the Fluid Builds Up

The pericardial sac can stretch slowly. Fluid that builds up over weeks to months can reach a large volume before causing symptoms. In contrast, fluid that builds up over hours, for example from bleeding after a heart procedure, can press on the heart even when the amount is relatively small. For this reason, doctors assess the amount of fluid, how quickly it is increasing, and its effect on the filling of the heart.

Size and Duration

With echocardiography, doctors measure the thickness of the fluid layer. An effusion is called small if it is less than 10 mm, moderate if it is 10 to 20 mm, and large if it is more than 20 mm. An effusion that lasts more than three months is called chronic. A small effusion without symptoms is generally not dangerous, while a large effusion that persists needs monitoring because some can progress to tamponade.

Treatment Follows the Cause

The 2015 ESC guidelines for pericardial diseases recommend treatment based on the cause and on whether the heart is being compressed. If there are signs of inflammation, the effusion is treated like pericarditis with anti-inflammatory medication. If there is an underlying disease, that disease is treated. The fluid is drained with a needle (pericardiocentesis) if it is pressing on the heart, if a bacterial infection or cancer is suspected, or if it is large and persistent without a clear cause. The course of the condition depends more on its cause than on the amount of fluid.

Pericardial effusion is often found by chance, for example during a chest X-ray or echocardiography done for another reason. Echocardiography is the main test: the doctor can see the fluid, measure the thickness of the layer, and assess whether the fluid is starting to press on the heart chambers. When there is a lot of fluid, an ECG may show smaller electrical waves or waves that alternate in size. A chest X-ray may show an enlarged heart shadow.

The next step is to find the cause. Blood tests assess inflammation (CRP), thyroid function, kidney function, and troponin, depending on your symptoms. CT or cardiac MRI helps show trapped (loculated) fluid, a thickened lining, or a mass. If fluid is drained, a sample is examined in the laboratory to look for germs, TB, or cancer cells.

See a doctor if you have shortness of breath that gets worse when lying down, a feeling of fullness in the chest, or tire easily for no clear reason, especially if you have cancer, an autoimmune disease, or kidney disease, or have recently had heart surgery. If an effusion was found by chance, follow-up is still needed to find the cause and monitor the amount of fluid. Go to the emergency room right away if you have:

• Severe shortness of breath or breathing that gets worse over a few hours
• Severe dizziness, nearly fainting, or fainting
• Pale, cold skin with a very fast heartbeat
• Unusual restlessness or confusion