Carditis is a general medical term that describes inflammation within the heart or the tissues directly surrounding it. This inflammation is the body’s immune response to injury or infection, which can impair the heart’s normal function. The condition is not a single disease but rather a family of related issues, each defined by which specific layer of the heart is affected.
The Three Primary Forms of Carditis
The heart is composed of three distinct layers, and the name of the carditis corresponds to the layer that is inflamed. The outermost layer is the pericardium, a protective, fluid-filled sac. Inflammation of this sac is known as pericarditis, which can cause fluid to accumulate and create friction between the layers as the heart beats.
Myocarditis is the inflammation of the myocardium, the thick, muscular middle layer responsible for the heart’s pumping action. Inflammation here directly weakens the heart’s ability to circulate blood efficiently. The innermost layer is the endocardium, which lines the heart chambers and covers the heart valves.
Inflammation of this lining and the heart valves is called endocarditis, often leading to damage that disrupts the valves’ ability to close properly. While these three conditions are distinct, inflammation can affect all three layers simultaneously, a rare and severe condition termed pancarditis.
Common Causes and Risk Factors
The triggers for carditis are separated into infectious agents and non-infectious conditions, with the cause often suggesting which layer of the heart is involved. Viral infections are the most frequent cause of myocarditis and pericarditis, often stemming from common illnesses like the flu, common cold, or COVID-19.
Endocarditis is most commonly caused by bacterial infections, particularly when bacteria enter the bloodstream and colonize the heart valves. Group A Streptococcus is a serious bacterial cause that can lead to rheumatic fever and rheumatic carditis. Other infectious culprits include fungi, parasites, and spirochetes, such as those causing Lyme disease.
Non-infectious causes typically involve the immune system mistakenly targeting the heart tissue. Autoimmune diseases like systemic lupus erythematosus and rheumatoid arthritis can lead to carditis. Additionally, certain medications, toxins, or radiation therapy can provoke an inflammatory reaction.
Recognizing the Symptoms
The signs of carditis vary widely, sometimes mimicking other conditions, requiring medical evaluation for an accurate diagnosis. General symptoms common to any form of carditis include fever, fatigue, and shortness of breath, reflecting impaired heart function. However, some symptoms are more specific to the location of the inflammation.
Pericarditis often presents with a distinctive, sharp chest pain that worsens when taking a deep breath or lying flat. This pain frequently lessens when the person sits up and leans forward, a positional change that reduces friction. Myocarditis and endocarditis are more likely to cause symptoms related to compromised pumping ability.
These symptoms include a rapid or irregular heartbeat. Swelling in the legs, ankles, and feet, known as edema, is also a sign of potential heart failure, as the heart struggles to move fluid through the body. Endocarditis can also present with night sweats, joint pain, or small red spots on the skin.
Medical Approaches to Diagnosis and Management
Diagnosing carditis begins with blood tests that look for elevated inflammatory markers and cardiac enzymes, such as troponin, which indicate damage to the heart muscle. These initial tests are followed by non-invasive imaging to visualize the heart’s structure and function. An electrocardiogram (EKG) detects abnormalities in the heart’s electrical activity, while a chest X-ray can show signs of fluid around the heart or enlargement.
The most definitive non-invasive tool is an echocardiogram, which uses sound waves to create a moving image of the heart, allowing doctors to assess pumping action, fluid buildup, or valve damage. In complex cases, a cardiac magnetic resonance imaging (MRI) provides detailed images of the heart tissue. In rare instances, an endomyocardial biopsy—a small tissue sample—may be taken to confirm the diagnosis and identify the exact cause.
Management focuses on treating the underlying cause and controlling inflammation and associated symptoms. Bacterial infections are treated with targeted antibiotics. Viral causes are usually managed with supportive care, allowing the immune system to clear the infection. Non-infectious causes, particularly those linked to autoimmune conditions, may require anti-inflammatory medications or immunosuppressive drugs.
Medications are also used to manage resulting symptoms. Anti-inflammatory drugs reduce pain and swelling, and diuretics help the body shed excess fluid caused by impaired heart function. In severe cases involving heart failure, medications like ACE inhibitors or beta blockers may be prescribed to help the heart muscle recover. Supportive care and monitoring are typically provided in a hospital setting until the inflammation subsides.