Pericardial effusion, often referred to as “fluid on the heart,” is a condition where excess fluid accumulates in the pericardium, the sac-like structure surrounding the heart. This sac normally contains a small amount of fluid, typically between 15 to 50 milliliters, which acts as lubrication for the heart’s movement. However, when fluid builds up abnormally, it can exert pressure on the heart, potentially hindering its ability to pump blood effectively.
Infections and Inflammation
Infections represent a common cause of pericardial effusion by triggering pericarditis, an inflammation of the pericardium. This inflammation leads to increased permeability of the capillaries within the pericardium, allowing fluid to leak into the space around the heart. Viral infections are frequently implicated, including coxsackievirus, hepatitis viruses, HIV, and parvovirus B19. Bacterial infections, such as tuberculosis, as well as fungal and parasitic infections, can also cause pericarditis and subsequent fluid accumulation.
Other inflammatory conditions can also result in pericardial effusion. One notable example is Dressler’s syndrome, an inflammatory response that can occur following a heart attack. This syndrome involves inflammation of the pericardium, leading to fluid buildup as part of the body’s post-injury reaction.
Autoimmune Conditions
Autoimmune diseases are another category of conditions that can lead to pericardial effusion. In these disorders, the body’s immune system mistakenly attacks its own healthy tissues, including the pericardium. This misdirected immune response triggers chronic inflammation, which then causes fluid to accumulate in the pericardial sac. The ongoing inflammatory process damages the pericardial lining, leading to increased fluid production.
Common autoimmune conditions associated with pericardial effusion include Systemic Lupus Erythematosus (SLE), a chronic inflammatory disease. Rheumatoid Arthritis, an inflammatory disorder primarily affecting joints, can also extend its inflammatory effects to the pericardium. Sjogren’s Syndrome, characterized by dry eyes and mouth, has also been documented to cause pericardial effusions.
Injury and Trauma
Physical damage or medical procedures can directly contribute to fluid accumulation around the heart. Direct blunt trauma to the chest, such as from car accidents or falls, can cause bleeding into the pericardial sac. Penetrating injuries, like stab wounds, can also introduce blood or other fluids into this space, leading to an effusion.
Pericardial effusion can also arise from iatrogenic causes. Complications from heart surgery, such as post-pericardiotomy syndrome, are known to cause fluid buildup. Cardiac catheterization procedures or the insertion of pacemakers can also inadvertently damage the pericardium.
Cancer and Tumors
The presence of cancer can significantly contribute to the development of fluid on the heart. Malignant cells commonly spread to the pericardium from primary tumors located elsewhere in the body, a process known as metastasis. Less frequently, a tumor may originate directly within the pericardium. Common primary cancers that frequently metastasize to the pericardium include lung cancer, breast cancer, lymphoma, and leukemia.
Cancer causes pericardial effusion through several mechanisms. Direct irritation of the pericardium by cancerous cells can trigger an inflammatory response, leading to fluid production. Tumors can also obstruct the lymphatic drainage pathways around the heart, impeding the normal removal of fluid and causing its accumulation. Additionally, increased permeability of blood vessels near the tumor can lead to fluid leakage into the pericardial space.
Systemic Diseases and Other Factors
Various other medical conditions and systemic factors can lead to pericardial effusion. Kidney failure, particularly uremia, can cause the buildup of toxins in the body, which then irritate the pericardium and trigger an inflammatory response.
Hypothyroidism, a condition where the thyroid gland is underactive, is another systemic cause of pericardial effusion. This can lead to a slow accumulation of fluid due to increased permeability of pericardial capillaries and decreased lymphatic drainage of albumin. Fluid buildup in hypothyroidism is often gradual, meaning symptoms may not be immediately apparent. Radiation therapy to the chest area, particularly for cancers like mediastinal lymphoma or breast cancer, can also cause pericardial inflammation and effusion. In some instances, despite thorough investigation, a specific cause for pericardial effusion cannot be identified; these cases are termed idiopathic pericardial effusion.