Infectious-allergic myocarditis: causes and treatment

Author Ольга Кияница


The development of myocarditis is directly related to inflammation, which can occur on the background of immunopathological reactions or infection. In such cases, talking about infectious-allergic myocarditis. It must be treated without fail, since otherwise serious complications can occur.

Myocarditis is a rare type of heart disease that usually causes no symptoms, but can be life-threatening.Myocarditis got its name because the middle layer of the heart is called the myocardium. Therefore, “myo” means muscle, “card” means the heart, and the prefix “it” indicates an inflammatory process.

The causes of myocarditis are different, but in the presence of an infectious factor and an immunopathological reaction, an infectious-allergic myocarditis is indicated.

The disease does not always have a pronounced clinic, so sometimes an acute process becomes chronic. In severe cases, myocarditis can cause valve damage and heart failure.In order to avoid such complications, timely diagnostics should be carried out based on instrumental and laboratory tests.

Video: Myocarditis due to allergies

Description of myocarditis

Myocarditis is a disease characterized by inflammation and damage to the heart muscle (according to the Myocarditis Foundation). Pathology can affect the children's body (the so-called children's myocarditis) and adults, including people who have never had any heart disease.

The muscular layer of the heart - the myocardium - is compressed to pump blood through the entire body. Because myocarditis affects the heart cells (cardiomyocytes) and the conduction system, it can cause irregular heartbeats (or a change in heart rate, called arrhythmia). As a result, blood circulation decreases.

Myocarditis can lead to a reduction in blood flow in certain parts of the body, also contributes to the formation of blood clots in the heart and can trigger a stroke or heart attack (myocardial infarction). This does not always occur, but the likelihood of complications increases several times with severe myocarditis. Sometimes scar tissue (fibrosis) can develop in the myocardium, which increases the risk of long-term complications.

Is myocarditis a heart attack? No, but sometimes one pathology can lead to the development of another. Symptoms of myocarditis, when they appear, are often similar to signs of a heart attack, as there is also pain in the chest and shortness of breath. The most significant long-term complication associated with myocarditis is chronic heart failure.

Myocarditis - and the serious symptoms associated with it - accounts for 45% of heart transplants in the United States each year.

The most common causes of myocarditis — infections and autoimmune diseases — cannot always be prevented. But there are some things you can do to reduce the risk of infection.


  • Strengthen the immune system.
  • Adhere to the anti-inflammatory diet.
  • Prevent infection of the body.
  • Practice good hygiene habits.
  • Limit autoimmune reactions in combination with the control of stressful situations.

Signs of myocarditis

In 5-20% of cases, myocarditis does not manifest itself and the person feels generally healthy. Most patients with myocarditis have no noticeable symptoms or they are mild.

Common symptoms of myocarditis:

  • Shortness of breath, especially during exercise or emotional tension. You may experience shortness of breath or rapid breathing (tachycardia). Dyspnea is also possible at night.
  • Fatigue and weakness.
  • Palpitations or abnormal heart rhythms (tachycardia and arrhythmia).
  • Chest pain or pressure.
  • Swelling of the legs and arms due to fluid retention (called peripheral edema). Most often, swelling appears in the ankles and lower legs.
  • Dizziness.

Other symptoms associated with the infectious-allergic process occurring in the body:

  • Headache.
  • Pain in various parts of the body, especially in the calf muscles.
  • Joint pain.
  • Fever.
  • A sore throat.
  • Diarrhea.
  • Sudden loss of consciousness.
  • Increased risk of heart failure, thrombosis, stroke, or heart attack.

Myocarditis symptoms usually develop in about one or two weeks after a viral disease or other infectious process begins to develop. Manifestations of the heart are a sign that inflammation and damage has spread to the heart and interferes with normal blood circulation. In this case, the body fights infection, forcing the immune system to produce specific antibodies, which in some cases begin to attack the heart cells. As a result, scar tissue can form in the myocardium, which prevents the heart from properly contracting.

What type of damage in the long run can cause myocarditis?

Recovery time after myocarditis often depends on the severity of the course of the disease and the general state of human health. It may take several months to feel completely healthy, and sometimes even longer if there is any irreparable violation.

Myocarditis is the cause of permanent damage to the heart, and in some cases against its background may occur:

  • Sudden death.
  • Heart failure.
  • Heart attack.
  • Stroke.
  • Cardiac arrhythmia.

Myocarditis can cause heart failure, causing blood to stop flowing to the brain and other organs. Also, disruption of the heart can cause blood to clot inside the heart chambers and turn into clots. These thrombotic formations can clog the coronary arteries, causing myocardial infarction. If a blood clot breaks blood circulation in the brain, then a stroke develops. Arrhythmias on the background of myocarditis can also contribute to the development of sudden cardiac arrest.

Causes of Infectious and Allergic Myocarditis

There are many reasons why myocarditis can occur. Experts believe that when the myocardium is inflamed or damaged, it is usually a sign of an infectious lesion. In this case, the disease is not hereditary, that is, it is not transmitted from parents to their children.

Two of the most common causes of myocarditis are:

  1. Viral or bacterial infections.
  2. Autoimmune reactions that affect the heart.

Allergic (autoimmune) myocarditis may be of the following types:

  • Transplantation.
  • Whey
  • Drug.
  • Post-vaccination.

A wide variety of infectious diseases can lead to myocarditis, including viruses, bacteria, chlamydia, rickettsia, fungi and protozoa. Viruses most often cause infectious diseases that cause acute myocarditis.

Viruses associated with the development of myocarditis

The root cause of myocarditis was first identified in experimental and epidemiological studies in the 1950s and 1960s when studying the response of antibodies in patients to myocarditis. These studies showed that enteroviruses, including Coxsackie viruses, were present in patients with myocarditis. When using molecular methods for the determination of viral infections in the 1980s, other viruses associated with myocarditis were also detected. Most often, the following viruses were found in the hearts of sick people:

  • Parvovirus B19
  • Human Herpes Virus 6
  • Enterovirus (Coxsackie virus).

Studies identifying the causes of myocarditis are rarely performed in many parts of the world, including South America, the Middle East, Asia and Africa, so the prevalence in these regions is not determined.

Parvovirus B19 is a virus that causes the so-called “fifth disease”, also known as slapped check syndrome, most often seen in children 6–10 years old. The virus spreads mainly by airborne droplets (for example, by coughing) from infected people to healthy ones.

Symptoms of the disease appear about a week after infection, and they usually last for a week.

  • Small children usually develop a rash on their cheeks; teenagers and young people can develop this rash in other parts of the body, including the arms and legs.
  • In adults, parvovirus B19 is associated with arthritis, aplastic anemia (lack of red blood cell synthesis), serious birth defects and miscarriages during pregnancy.

Most of the population has antibodies against B19, which indicates that they experienced infection. Also, many people are exposed to parvovirus B19 without long-term complications. Parvovirus B19 vaccines are not available.

The human herpes virus is a relatively new virus that has been under study for the past decade. They are usually infected at an early age (in some cases up to 1 month after birth). About 20% of infant visits to the emergency room due to fever can be caused by HHV-6. As with other herpes viruses, most people get it chronically. After the initial infection, it is in a dormant state in the salivary glands and the bone marrow throughout a person’s life. When a virus is secreted with saliva, symptoms appear that include a rash and fever. Children may have roseola infantum disease, also known as “the sixth disease,” which is associated with HHV-6 infection. An association of the virus with hepatitis and encephalitis is also noted. Multiple sclerosis, chronic fatigue syndrome, fibromyalgia and myocarditis are associated with HHV-6 infection.

Enteroviruses , in particular the Coxsackie virus, were associated with myocarditis.

  • Cocksackie virus causes a disease of the hand, foot and mouth.
  • Coxsackie B viruses cause relatively mild symptoms, similar to chills.
  • Myocarditis, pericarditis (inflammation of the pericardium), meningitis (inflammation of the outer membranes of the spinal cord) and pancreatitis (inflammation of the pancreas) were associated with enterovirus infections. Symptoms usually include a mild rash and a nose / throat infection.

Myocarditis Bacteria

Both Corynebacterium diptheriae and Staphylococcus aureus were capable of causing myocarditis. Both of these bacteria are widely distributed and are found in nature and are generally harmless.

Corynebacterium diptheriae are bacteria that cause diphtheria, an acute infectious infection that contributes to the death of tonsil cells and throat. This in turn contributes to the formation of pseudomembranes in the back of the throat.The disease occurs primarily in unimmunized children of school age, as well as in old people and people with weakened immunity. There are diphtheria vaccines that are widely available.

Myocarditis caused by Staphylococcus aureus is usually observed against the background of reproduction of a huge amount of bacteria in the blood. This disease is called sepsis. Previously, myocarditis was a fairly common complication of sepsis, especially when antibiotics were not widely available. Myocarditis caused by S. aureus can lead to abscesses that form directly on the heart.

Parasites associated with myocarditis

A number of tick-borne diseases are associated with myocarditis, including:

  • Borrelia burgdorferi.
  • Some types of Ehrlichia.
  • Some types of babesia.

Pathogens contribute to the development of diseases such as Lyme disease, ehrlichiosis, babesiosis.

Borrelia burgdorferi is a tick-borne bacterium that causes Lyme disease. The reservoir of the parasite or its place of preservation is live mice. Ticks are carried by mice and can infect humans, especially during the warm summer months.Bacteria enter human blood, where they continue to grow and sometimes provoke a rash. Symptoms are non-specific and include fatigue, fever, headache, muscle and joint pain. If B. burgdorferi spreads throughout the body without treatment (simple antibiotics), it can cause facial paralysis (lowering of a part of the face), meningitis (infectious inflammation of the brain / spinal cord), joint pain, heart palpitations and myocarditis.

Ehrlichia are bacteria that cause ehrlichiosis. Bacteria live in a certain type of white blood cell called monocyte. In the wild, mice (the same mice that transmit Lyme disease) and white-tailed deer can tolerate these bacteria that live in the blood. Ticks feed on their hosts, multiply, and then infect humans. Often the disease causes a sudden severe fever, fatigue, muscle aches and headache within a week after the tick bite. Many of these cases are self-resolving; others require antibiotic treatment. In addition to the low white cell count, low platelet counts, anemia and abnormal liver function, and renal failure can be observed. Ehrlichiosis is diagnosed mainly by a medical history, including a history of tick bites, fever, and symptoms, in addition to laboratory tests that identify bacteria in leukocytes. Ehrlichiosis can be the cause of myocarditis.

Babesia - the simplest that cause babesiosis. This parasite lives in the red blood cells of domestic animals, especially in mice and deer. The simplest are spread by ticks, which consume blood from infected red blood cells. Then the parasite continues to feed on people and infect them, where the parasite gradually passes through the life cycle of the parasite in human erythrocytes. Approximately 25% of adults and 50% of infected children have no symptoms.

Babesiosis can manifest symptoms of influenza, including irregular fever, chills, headaches, lethargy, pain, and general bad feeling. In severe cases, anemia, dyspnea, and jaundice may occur. If the infection is recognized, it can be treated with antibiotics. In severe cases, a blood transfusion is performed to reduce the parasitic load. Babesiosis can cause myocarditis.

Trypanosoma cruzi - this infection causes Chagas disease. Like the previous pathogen (Babesia), this small parasite lives in the red blood cells of wild or domestic mammals. When the animal defecates, it leaves T. cruzi in the feces. Also, the parasite spreads through “kissing bugs”. When the pathogen enters the human body through a bite wound or mucous membranes, most often the mouth, it enters the bloodstream, where it invades red cells, replicates and breaks them. Further absorbed by other bugs, which continue to infect other people. Therefore, this disease is more often defined among representatives of the low-income population.

The acute phase of Chagas disease often goes unnoticed (a localized tumor at the site of infection). After 10–20 years of chronic infection, internal organs, especially the heart, can suffer greatly and then heart failure occurs. Acute cases are treated with antiparasitic drugs; effective therapy for chronic cases is not available. Chagas disease usually causes deterioration of the electrical activity of the heart.

Diagnosis and treatment of myocarditis

There are several ways to diagnose myocarditis.

  • Laboratory tests (blood test) can reveal the level of troponin or creatine kinase (cardiac isoenzymes are elevated).

Histopathology of viral myocarditis

  • An ECG can also detect abnormal heart rhythms, T-wave inversions and ET saddle inversions.
  • Some physicians may do imaging studies to look for an enlarged heart or perform a myocardial biopsy to get signs of inflammation, such as swelling, lymphocyte enlargement and macrophage enlargement.

Treatment of myocarditis depends on the underlying cause of the disease and the severity of the patient's symptoms.

Mild or moderate viral myocarditis may resolve itself, for which it is sufficient to control the patient's symptoms.

The most common treatment for moderate to severe myocarditis is steroids and medications that are used to treat heart disease / heart failure.

Drugs that can be prescribed for myocarditis:

  • Diuretics to help control swelling / fluid retention.
  • Digoxin, which helps prevent heart failure. It also improves heart muscle contractions and slows heartbeats, which can help control heart rate.
  • Milrinon and ACE inhibitors that help regulate heart rhythms.
  • Aldosterone agonists, which prevent scarring of the heart tissue, also remove excess fluid from the body.
  • Corticosteroids for treating inflammation of the heart and preventing further damage to the myocardium.
  • Antibiotics if the infection is the main cause.
  • Oxygen therapy to ensure sufficient oxygenation of the body.

If abnormal cardiac activity has been detected, a pacemaker may be required. In most cases, arrhythmias are eliminated after reducing the inflammatory process.

The doctor may also recommend rest, avoiding any strenuous activities and eating low-salt foods. After treatment of myocarditis, you will need to recover for a certain period of time and slowly return to physical activity.

Prevention and recovery after myocarditis

First of all, the immune system should be strengthened with the help of dietary nutrition.

  • Useful anti-inflammatory diet . It is necessary to include in the diet a large number of different fresh vegetables and fruits, so that a single serving consists of at least 30% of fresh products. For example, it can be leafy greens, berries, carrots, tomatoes, squash, cruciferous vegetables such as broccoli or cauliflower, asparagus, avocado, cranberries, blueberries, grapes. Other healthy foods for strengthening the heart include flaxseeds and chia, almonds and other nuts, olive oil, fish, dark chocolate (if caffeine is not contraindicated), legumes, fresh herbs, and green tea.
  • The amount of salt should be limited . Sodium (salt) aggravates the course of myocarditis and heart failure, because it promotes the flow of large amounts of fluid into the bloodstream. This requires intensive work from the heart to maintain blood circulation to normal. The best way to reduce salt intake is to avoid the use of processed foods, including fast food, frozen foods, canned goods, processed meats, cheeses, seasonings, ready-made soups, and packaged bakery products. Foods that damage the intestines and increase inflammation should be avoided, such as spicy additives, refined oils and trans fats.
  • It is necessary to control the intake of potassium in the body . If you need to take any medications to prevent heart failure, then you should talk to your doctor about their effect on the concentration of potassium in the body. In particular, it may be necessary to obtain less or more potassium from the diet, depending on the general condition and the medications that need to be taken. Low levels of potassium can slow the heart rate, so in such cases the trace element should be supplied in greater quantities than usual.
  • Consumption of caffeine and alcohol is better to reduce . Caffeine drinks, such as coffee or tea, can cause the heart to contract faster, which is dangerous for myocarditis. Alcohol also affects the heartbeat and potentially worsens cardiac arrhythmia or interferes with medication. When myocarditis is severe, alcohol or caffeine should not be consumed until the doctor allows it, because both can weaken the heart muscle.

Effective protection against viruses and infections must be provided.

  • Bacterial infections should be treated early to prevent complications . You should consult your doctor if you suspect that there is any serious infection, especially if it affects the respiratory system or the ability to breathe. After surgery, severe cuts, cutting or wounding of the skin, you need to carefully monitor your symptoms to detect signs of developing infection.
  • It is necessary to avoid close contact with those patients who have a viral or bacterial infection such as influenza . If the infection still happened, you need to think about the protection of other people, household members or fellow students / classmates.
  • You should practice safe sex and limit the number of your partners.
  • It is important to monitor personal hygiene, wash hands regularly, clean your house constantly, wash clothes daily and take a shower . The most favorite places for the spread of infection are hospitals or doctors' offices, nursing homes, kindergartens, schools, universities and gyms. After visiting them, appropriate hygienic procedures should be carried out.
  • It is undesirable to carry out tattoos, piercings, medical procedures or use drugs , especially if reusable needles are used.
  • We need to think about how to prevent tick bites . In particular, for protection, it is necessary to cover open skin when you have to be in high-risk areas. You should also check clothing and skin after walking in the woods, wash clothes and monitor the presence of pests around the house. If a tick or other infectious insect still bit, you should immediately consult a doctor.

It is highly desirable to keep autoimmune reactions under control, for which you need to adhere to the following recommendations :

  • It is necessary to control stress factors, prevent nutritional deficiencies and sleep disorders.
  • High levels of stress can lead to many health problems, including those that affect the immune and cardiovascular systems. Uncontrolled stress is associated with an increased risk of heart disease, high blood pressure, and susceptibility to viral or bacterial pathogens.
  • To cope with some of the biggest worries and barriers in life, you can make a plan for adopting stress relief techniques. You can start with small exercises every day, acupuncture, meditation is also useful. Some are helped by practicing mindfulness, prayer, reading, writing, participating in the life of a social support group, practicing yoga and breathing exercises.

It is important to avoid risky drugs or dietary supplements, especially not agreed with your doctor.

  • Be careful with the use of new supplements and taking over-the-counter drugs, especially when there is myocarditis, because some of them can introduce into the stress and so weakened heart muscle. Sometimes the composition of drugs includes caffeine, which increases the heart rate. For example, medications for relieving headaches or for treating a cold / flu.
  • It is necessary to stop using tobacco and nicotine-containing products, since the chemicals contained in them can increase inflammation, worsen the course of arrhythmia, and cause damage to the arteries.
  • You should think about the proper intake of supplements that can help reduce inflammation. If you need to ask your doctor before taking any means. Some of them may be helpful. To protect the heart. In particular, it can be antioxidants, such as vitamin C and vitamin E, omega-3 fatty acids, coenzyme Q10, vitamin D and herbs (garlic, ginkgo, ginseng and hawthorn).

In the presence of edema should be properly approached to eliminate them. In particular, you can follow some practical tips.

Observe the amount of edema, for which you can weigh yourself every morning, to determine the sudden increase, indicating the accumulation of fluid in the body. An increase in weight of about one and a half kilograms, which appears suddenly or steadily gradually arrived over several days, may indicate an accumulation of fluid in the lungs, legs or stomach. In such cases, as a rule, heart failure worsens. If this is noted, especially along with other symptoms of dyspnea or chest pain, you should immediately consult a doctor.

It is important to limit the amount of fluid that is consumed daily, which will prevent swelling and deterioration of the general condition. If you feel thirst while doing this, you can try to rinse your mouth with water, take very small sips, suck on frozen grapes or ice chips, chew gum or brush your teeth. You can also ask your doctor about individually selected recommendations.

Exercise and similar loads should be performed with caution.

Exercise is a great way to prevent inflammation and increase immunity, but if you already have heart disease like arrhythmia, you must first approve the possible burden with your doctor. At the same time you need to behave cautiously, especially at the beginning of the recovery period. No need to do more than the doctor advises. If shortness of breath, pain or fatigue has begun to appear, then, most likely, too much load and you need to rest before you start repeating the exercises again.

Between the load it is desirable to take breaks to rest and relax. Very strenuous activities that make breathing difficult should be avoided. Instead, focus on calming activities such as walking, swimming, easy cycling and stretching.

Precautions against myocarditis

If you have to experience any signs or symptoms of myocarditis, you should contact the emergency room. This is especially true for severe shortness of breath, swelling, or chest pain. After surgery, you need to take special care to notice signs of myocarditis in time. Symptoms can quickly progress and be fatal, so you need to go to the emergency room at the first suspicion of heart problems.

Key points

  • Myocarditis is a disease characterized by inflammation and damage to the heart muscle.
  • Symptoms in myocarditis are not always pronounced, but heart attack-like symptoms may occur: chest pain, shortness of breath, and rapid heartbeat.
  • Myocarditis can increase the risk of developing scar tissue in the heart muscle, leading to heart attack, heart failure, or stroke.
  • The most common causes of myocarditis are viral infections, autoimmune diseases, and bacterial infections, which are often transmitted through drug use / medical manipulation or through tick / insect bites.

Video: Treatment of myocarditis. Clinic and diagnosis of myocarditis.

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