Myocarditis is a condition characterized by inflammation of the myocardium. Viral infection is the major causative factor.
Presentation
Mild cases of myocarditis seldom produce any symptoms. In severe cases, the following symptoms are experienced:
- Pain in the chest
- Onset of arrhythmia
- Feeling of shortness of breath, during activity or even at rest
- Development of fatigue
- Swelling in the legs, arm or ankle due to fluid retention
- Common symptoms of viral infections such as headache, fever, body ache, pain in the joints, diarrhea and or soreness in throat
If children are affected by myocarditis, then the following signs and symptoms are evident:
- Onset of fever and rapid breathing
- Difficulty in breathing
- Development of bluish to grayish color of skin
Workup
The following tests are employed for diagnosing the condition of myocarditis:
- Electrocardiogram: This is a non-invasive test, which measures the electrical activity of the heart. It also helps in detecting abnormal heart rhythms.
- Holter monitor: Some abnormalities noticed in the electrocardiogram, would call for further investigation. A holter monitor is a device that records the heart rhythm round the clock and helps in arriving at appropriate diagnosis.
- Imaging studies such as X-ray of the chest and MRI of the heart are carried out. Such tests would reveal inflammation of the muscles of the heart and help in appropriate diagnosis [8].
- Echocardiogram is indicated which would help reveal heart enlargement, poor pumping of the heart and valve problems if any.
- Blood tests: Blood tests to measure the levels of white and red blood cells would be done. An elevated level would suggest infection as the causative factor.
- Biopsy and cardiac catheterization: These are done to check for presence of inflammation of the myocardium [9].
Treatment
In several cases, myocarditis can resolve without treatment promoting complete recovery. However, many cases may demand an appropriate treatment plan which would primarily focus on correcting the underlying condition. The various treatment methods that are employed include [10]:
- Medications such as antibiotics to treat bacterial infections and anti-inflammatory agents to lessen the swelling in the legs and ankles are prescribed. In addition, digoxin and diuretics to remove excess water from the body in order to reduce the swelling caused due to fluid retention are also administered .
- Ventricular assist device or intra-aortic ballon pump is indicated in severe cases.
- Heart transplantation is usually the last resort and employed when there is severe damage to the heart.
Prognosis
Individuals who can successfully survive fulminant myocarditis usually have a favorable prognosis. It was observed that majority of the patients do well even without a transplant. The onset of left ventricular dysfunction is less severe in individuals with fulminant myocarditis. Individuals with mild symptoms, completely recover with no cardiac dysfunction [6]. However, in patients suffering from giant cell myocarditis, 89% of them did not survive or had to undergo transplantation with median survival period of just 5.5 months after transplant [7].
Etiology
Viral infections are the most common cause of myocarditis. The various pathogens that are known include parvovirus B19, coxsackievirus B, Epstein-Barr virus, adenovirus and echoviruses. Individuals with HIV/AIDS are also susceptible to develop the condition. In certain cases, bacterial and fungal agents can also cause myocarditis [2].
Underlying disease conditions such as inflammatory conditions, systemic lupus erythematosus and connective tissue diseases can also favor the development of myocarditis. In addition, certain medications such as antibiotics like penicillin, anti-seizure medications and illegal drugs can cause certain toxic reactions which can lead to inflammatory reactions in the myocardium of the heart.
Epidemiology
The exact incidence of myocarditis is not known. From the available data, it has been estimated that the condition causes about 1 to 10 cases per 100,000 individuals. The median age of onset of the disease is about 42 years. It has also been estimated that, 5 to 20% of sudden death among young adults occurred due to onset of myocarditis. About 50% of individuals with HIV develop myocarditis as a secondary complication [3] [4].
Pathophysiology
The condition of myocarditis occurs due to response to an infection which causes the middle layers of the heart muscles to undergo inflammation. Such a type of disease can also strike healthy individuals and it may rapidly progress to arrhythmia and heart failure. Myocarditis can further be classified into the following 4 categories which include:
- Fulminant myocarditis primarily occurs due to viral infection causing ventricular dysfunction. The condition can either resolve spontaneously or it can even turn fatal.
- Acute myocarditis also causes ventricular dysfunction, which progresses to dilated cardiomyopathy.
- Chronic active myocarditis is characterized by ventricular dysfunction accompanied by chronic inflammatory changes.
- Chronic persistent myocarditis, wherein there is no ventricular dysfunction but persistent histologic infiltrate [5].
Prevention
The following steps can to certain extent help in preventing the onset of myocarditis:
- Promptly treating all type of viral infections and preventing contact with those suffering from the same until they have completely recovered.
- Following good personal hygiene can help in preventing infections.
- Getting regular immunization shots would also go a long way in prevention against the types of viruses that may cause myocarditis.
Summary
Myocarditis is also referred to as inflammatory cardiomyopathy. It may present with mild symptoms that resolve on their own seldom requiring treatment. However, in many cases it can also cause severe symptoms and devastating complications. This may occur when the pumping action of the heart weakens to such an extent that it is no longer capable of pumping blood to the rest of the body. In addition, clots can also develop which would in turn pave way for development of heart attack or stroke [1].
Patient Information
- Definition: Myocarditis is inflammation of the myocardium of the heart. It is mostly caused due to viral infections that cause the muscles of the heart to undergo inflammation.
- Cause: Most commonly, viral infections are the major cause. In addition, allergic reactions to certain antibiotics, anti-seizure drugs or illegal drugs can also cause development of myocarditis.
- Symptoms: Symptoms of myocarditis include difficulty in breathing, shortness of breath at rest and during physical activity, chest pain, fatigue, fever, headache and body ache.
- Diagnosis: Myocarditis is diagnosed using electrocardiogram, holter monitor and imaging studies such as X-ray and MRI. In addition to these methods, blood tests, cardiac catheterization, biopsy and echocardiogram are also indicated.
- Treatment: Antibiotics form the preliminary basis of treatment regime if bacterial infections are the source of myocarditis. In addition, medications such as ACE inhibitors, beta blockers, diuretics are also administered for relieving the symptoms and correcting the underlying disease condition. Heart transplantation may also be required if there is severe damage to the heart muscles.
References
- Feldman AM, McNamara D. Myocarditis. N Engl J Med. Nov 9 2000;343(19):1388-98.
- Grist NR, Bell EJ.Coxsackie viruses and the heart.Am Heart J 1969; 77:295.
- Pulerwitz TC, Cappola TP, Felker GM, et al. Mortality in primary and secondary myocarditis. Am Heart J. Apr 2004;147(4):746-50.
- Eckart RE, Scoville SL, Campbell CL, et al. Sudden death in young adults: a 25-year review of autopsies in military recruits. Ann Intern Med 2004; 141:829.
- Miklozek CL, Crumpacker CS, Royal HD, et al. Myocarditis presenting as acute myocardial infarction. Am Heart J 1988; 115:768.
- McCarthy RE 3rd, Boehmer JP, Hruban RH, et al. Long-term outcome of fulminant myocarditis as compared with acute (nonfulminant) myocarditis. N Engl J Med. Mar 9 2000;342(10):690-5.
- Cooper LT Jr, Berry GJ, Shabetai R. Idiopathic giant-cell myocarditis--natural history and treatment. Multicenter Giant Cell Myocarditis Study Group Investigators. N Engl J Med. Jun 26 1997;336(26):1860-6.
- Hsiao JF, Koshino Y, Bonnichsen CR, Yu Y, Miller FA Jr, Pellikka PA, et al. Speckle tracking echocardiography in acute myocarditis. Int J Cardiovasc Imaging. Feb 2013;29(2):275-84.
- Karatolios K, Pankuweit S, Maisch B. Diagnosis and treatment of myocarditis: the role of endomyocardial biopsy. Curr Treat Options Cardiovasc Med. December 2007;9:473-81.
- Fuse K, Kodama M, Okura Y, Ito M, Hirono S, Kato K, et al. Predictors of disease course in patients with acute myocarditis. Circulation. Dec 5 2000;102(23):2829-35.