“Water around the heart” is a common way to describe Pericardial Effusion, the accumulation of excess fluid within the sac that surrounds the heart. While a small amount of fluid in this sac is normal, an abnormal buildup is a serious concern that requires immediate medical attention. This excess fluid can compress the heart, impairing its ability to pump blood.
The Role of the Heart Sac and Fluid
The heart is encased in the pericardium, a tough, double-layered sac that holds the heart in place. The outer layer, the fibrous pericardium, prevents the heart from over-expanding with blood. The inner layer, the serous pericardium, is divided into two membranes that form the small pericardial cavity.
This cavity normally contains a thin film of serous fluid, typically between 15 and 50 milliliters, which acts as a lubricant. This lubrication allows the heart to beat continuously without creating friction against the surrounding tissues. Pericardial effusion occurs when fluid production exceeds the rate of reabsorption, causing it to accumulate and exert pressure on the heart muscle.
Sources of Pericardial Fluid Build-up
The accumulation of fluid is not a disease in itself but rather a sign of an underlying medical condition affecting the pericardium. The causes of pericardial effusion are broadly categorized into those involving inflammation, systemic illness, injury, or cancer.
Infectious and Inflammatory Causes
A primary source of fluid buildup is inflammation of the sac, known as pericarditis, often triggered by infections. Viral infections, such as coxsackievirus, are the most common infectious cause. Bacterial infections, including tuberculosis, are significant contributors, and fungal or parasitic infections can also provoke an inflammatory response.
Systemic and Autoimmune Conditions
Systemic conditions, where the body’s immune system or metabolic processes are at fault, represent another major category. Autoimmune disorders like Systemic Lupus Erythematosus (Lupus) and Rheumatoid Arthritis can cause the immune system to attack the pericardium, resulting in inflammation and effusion. Severe kidney failure (uremia) also irritates the pericardium due to waste product buildup, causing fluid accumulation.
Trauma and Malignancy
Direct injury to the chest or certain medical procedures can also lead to effusion. Heart surgery may be followed by post-pericardiotomy syndrome, an inflammatory reaction that generates excess fluid. Malignancy is a serious cause, where primary tumors or metastatic cancer (often from lung or breast) spread to the pericardium and stimulate fluid production. Endocrine disorders, such as hypothyroidism, can also lead to fluid buildup.
The Critical Danger of Heart Compression
The most severe complication of a pericardial effusion is cardiac tamponade. This occurs when the accumulated fluid increases the pressure inside the pericardial sac, squeezing the heart. The rising pressure prevents the heart chambers, especially the thinner-walled right side, from fully expanding and filling with blood.
When the heart cannot fill properly, the amount of blood it can pump out drops sharply, leading to low cardiac output and blood pressure. The speed of fluid accumulation is a more significant factor than the total volume; a rapid collection of as little as 100 to 150 milliliters can cause tamponade. Symptoms of cardiac tamponade include a rapid heart rate, fainting or dizziness, and extreme shortness of breath. This condition requires immediate intervention to relieve the pressure and restore proper heart function.
Identifying and Treating the Condition
When a pericardial effusion is suspected, the primary diagnostic tool is the echocardiogram, an ultrasound of the heart that shows the amount of fluid and its effect on heart chamber function. This imaging is used to categorize the effusion by size (small, moderate, or large) and to look for signs of heart compression. Other tests, such as an electrocardiogram or chest X-ray, may also be used.
Treatment is determined by the size of the effusion, the rate of fluid buildup, and the underlying cause. For small, slowly developing effusions that are not causing symptoms, monitoring and treating the root cause with medications may be sufficient. This often involves anti-inflammatory drugs for pericarditis or antibiotics for an infection.
If cardiac tamponade is present or imminent, the excess fluid must be drained immediately through a procedure called pericardiocentesis. This procedure involves inserting a needle, often guided by ultrasound, into the pericardial sac to withdraw the fluid, which rapidly relieves the pressure on the heart.