Myocarditis Health Article

Definition

Myocarditis is inflammation of the heart muscle.

See also: Pediatric myocarditis

Alternative Names

Inflammation - heart muscle

Causes, incidence, and risk factors

Myocarditis is an uncommon disorder that is usually caused by viral, bacterial, or fungal infections that reach the heart.

Viral infections:

• Coxsackie
• Cytomegalovirus
• Hepatitis C
• Herpes
• HIV
• Parvovirus

Bacterial infections:

• Chlamydia
• Mycoplasma
• Streptococcus
• Treponema

Fungal infections:

• Aspergillus
• Candida
• Coccidioides
• Cryptococcus
• Histoplasma
• Schistosomiasis

When you have an infection, your immune system produces special cells that release chemicals to fight off disease. If the infection affects your heart, the disease-fighting cells enter the heart. However, the chemicals produced by an immune response can damage the heart muscle. As a result, the heart can become thick, swollen, and weak. This leads to symptoms of heart failure.

Other causes of myocarditis may include:

• Allergic reactions to certain medications or toxins (alcohol, cocaine, certain chemotherapy drugs, heavy metals, and catecholamines)
• Being around certain chemicals
• Certain diseases that cause inflammation throughout the body (rheumatoid arthritis, sarcoidosis)

Symptoms

There may be no symptoms. If symptoms occur, they may include:

• Abnormal heartbeat
• Chest pain that may resemble a heart attack
• Fatigue
• Fever and other signs of infection including headache, muscle aches, sore throat, diarrhea, or rashes
• Joint pain or swelling
• Leg swelling
• Shortness of breath

Other symptoms that may occur with this disease:

• Fainting, often related to irregular heart rhythms
• Low urine output

Signs and tests

A physical examination may reveal the following:

• Abnormal heartbeat or heart sounds (murmurs, extra heart sounds)
• Fluid in the lungs
• Rapid heartbeat (tachycardia)
• Swelling (edema) in the legs

Tests used to diagnosis myocarditis include:

• Blood cultures for infection
• Blood tests for antibodies against the heart muscle and the body itself
• Chest x-ray
• Electrocardiogram (ECG)
• Heart muscle biopsy (endomyocardial biopsy)
• Red blood cell count
• Ultrasound of the heart (echocardiogram)
• White blood cell count