The heart wall is made up of three layers:

The endocardium, the innermost layer that lines the inside of the heart chambersThe myocardium, the muscle layer that contracts, causing blood to be pumpedThe epicardium, the protective outer layer that is also the innermost layer of the sac containing the heart (pericardium)

In more severe cases, symptoms can vary, depending on what’s causing the condition.

Fever and chillsFatigueHeadacheMuscle achesJoint painSore throatDiarrheaChest painCoughShortness of breathFast or abnormal heart rhythmsFast breathingSwollen ankles and feet

In other cases, the cause can be identified. Some known causes of myocarditis include:

Viruses, including those that cause flu-like illnesses, colds, rubella (German measles), gastroenteritis, mononucleosis (mono), and HIV and AIDSBacteria, including those that cause strep throat, staph infections, diphtheria, and Lyme diseaseParasites, such as toxoplasma and Trypanosoma cruzi, which is transmitted by insects and can cause Chagas diseaseFungi, such as yeast infections, molds, and fungal infections that are passed through bird droppingsDrugs, including antibiotics (such as penicillin, sulfa drugs, and azithromycin); diuretics (such as furosemide and hydrochlorothiazide); drugs for epilepsy; and cocaineAutoimmune disorders, such as lupus, Crohn’s disease, rheumatoid arthritis, and celiac diseaseExposure to certain toxic substances, such as arsenic, radiation, or carbon monoxide

While anyone can get myocarditis, you’re at greater risk if you:

Have a weak or compromised immune systemAre exposed to agents known to cause myocarditis (such as cocaine)Have previously had myocarditis

Myocarditis caused by a viral infection in an otherwise healthy adult, for example, may begin to clear in a couple of weeks.

Antibiotics to treat bacterial infectionAntiviral drugs to treat viral infectionIntravenous immunoglobulin (IVIG), in which a blood product is injected to help boost the immune systemSteroids to reduce inflammation

If your heart muscle has become weakened, you might be prescribed one of the following medications to help reduce its workload:

Angiotensin-converting enzyme (ACE) inhibitors can decrease blood pressure, allowing blood to flow through the body more easily. They can also help the heart function recover better when it is weak.Angiotensin II receptor blockers have many of the same benefits as ACE inhibitors and are often prescribed as an alternative for patients who cannot tolerate ACE inhibitors.Beta-blockers slow the heart rate down and decrease the effects of adrenaline on the heart, lowering blood pressure so the heart has to do less work.Diuretics to remove excess water and sodium from the body.

Severe cases of myocarditis may need to be treated with medical procedures, including:

Ventricular assist devices (VADs) are mechanical pumps implanted into the abdomen or chest and attached to the weakened heart. The devices help pump blood from the lower heart chambers to the rest of your body.Intra-aortic balloon pump is a procedure in which a doctor inserts a catheter into a blood vessel in the leg and, with the help of X-ray imaging, guides it to the heart. A balloon is attached to the end of the catheter in the main artery and is inflated and deflated, helping to increase blood flow and lessen the heart’s workload.Extracorporeal membrane oxygenation (ECMO) is a device that provides oxygen to the body during severe heart failure. Blood is removed from the body and passes through the ECMO machine where carbon dioxide is removed and oxygen is added before being returned to the body.

Prevention of Myocarditis

There is no specific way to prevent myocarditis, but there are steps you can take to prevent infections that might lead to the condition. These include:

Practicing good hygiene, including frequent hand washing and using a hand sanitizer when soap and water is not availableKeeping away from people who are sick with the flu or other viral illnessStaying up to date on your vaccines, including those that protect against the flu and rubella, diseases that can lead to myocarditisAvoiding risky behavior, such as unprotected sex and using illicit drugsMinimizing exposure to ticks by wearing long sleeve shirts and long pants and using insect repellents containing DEET when spending time in tick-infested areas

Cardiomyopathy is a condition in which the heart muscle becomes weakened, stretched, or structurally damaged. It often affects the heart’s ability to pump and function properly and can lead to heart failure.A heart attack or stroke can occur when the heart muscle is damaged and can’t pump blood, causing the blood to pool in the heart. If the blood clots and blocks an artery supplying blood to the heart, this could lead to a heart attack. If a clot travels to an artery leading to your brain, this can result in a stroke.Heart failure is a condition in which the heart is no longer able to pump blood efficiently to the rest of the body. In more serious cases, myocarditis-related heart failure may require a heart transplant.Arrhythmias are rapid or irregular heartbeats.Sudden cardiac death occurs when the heart suddenly stops beating. If not treated immediately, it becomes fatal.

Systemic lupus erythematosus, which is an inflammatory disease that occurs when the immune system attacks its own tissues. It can affect many areas of the body, including the joints, skin, kidneys, lungs, and heart.Crohn’s disease, which is a chronic inflammatory bowel disease causing inflammation to the digestive tract, which leads to symptoms of severe diarrhea, abdominal pain, weight loss, fatigue, and malnutrition.Rheumatoid arthritis, which is a chronic inflammatory disorder mainly affecting the joints.Celiac disease, which is an immune disease in which those affected have an immune reaction to eating gluten, a protein found in wheat, barley, and rye. Over time, this immune reaction leads to inflammation that damages the small intestine.

Founded in 2005, the Myocarditis Foundation is a nonprofit organization dedicated to raising global awareness of myocarditis. The foundation provides resources for patients, families, and healthcare providers and supports research for the scientific advancement of myocarditis treatments. American Heart Association (AHA) The AHA is the nation’s oldest and largest nonprofit organization dedicated to heart health. Find resources for heart-healthy living and connect with other patients also dealing with heart-related problems through AHA’s Support Network. National Organization for Rare Disorders (NORD) NORD is a patient advocacy organization dedicated to individuals with rare disorders and conditions, including myocarditis. Get the essential facts about myocarditis symptoms, causes, and therapies on NORD’s website. Additional reporting by Rosalyn Carson-DeWitt, MD.