Acute Myocarditis


Article Author:
Mohammad Al-Akchar


Article Editor:
John Kiel


Editors In Chief:
Kranthi Sitammagari
Mayank Singhal


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beata Beatty
Beenish Sohail
Nazia Sadiq
Hajira Basit
Phillip Hynes


Updated:
12/2/2018 12:29:36 AM

Introduction

Myocarditis is inflammation of the myocardium, the cardiac muscle. Acute myocarditis is most commonly caused by viral illness, however, it may less commonly be caused by non-infectious etiologies. Myocarditis can be further divided into acute, sub-acute, or chronic, and may either affect a focal part of the myocardium or have diffuse involvement. Its clinical presentation may vary from a subtle chest pain or fever, to life-threatening congestive heart failure or dysrhythmia, or even death. Clinical diagnosis is often challenging, and management is usually supportive. [1][2][3]

Etiology

Causes of acute myocarditis can be separated into infectious and non-infectious. In 50% of cases, no cause can be identified; hence, myocarditis is commonly idiopathic. In patients with an identified cause, the most commonly implicated etiology is viral (similar to pericarditis), of which enteroviruses, notably Coxsackie B, are the most common. Other viral pathogens include Human Immunodeficiency Virus (HIV), adenovirus, and hepatitis C. Other infectious causes include parasitic (e.g., Trypanosoma cruzi), bacterial (e.g., diphtheria or tuberculosis), helminths, or fungal. Non-infectious causes of myocarditis include granulomatous inflammatory diseases (e.g., sarcoidosis or giant cell myocarditis), systemic lupus erythematosus, Eosinophilic myocarditis, polymyositis and dermatomyositis, and collagen vascular disease.[4] Cases due to cocaine abuse have also been reported in the literature [5]

Epidemiology

Given the variable clinical presentation, clinical diagnosis is difficult. The diagnosis is frequently missed and it is difficult to estimate the true incidence of acute myocarditis. However, incidence is estimated to be 10 to 22 per 100,000 cases with an estimated 1.5 million cases worldwide in 2013 [6]. It also is estimated that the myocardium is involved in up to 5% of patients who develop an acute viral illness. Acute myocarditis is more common in younger adults and appears to affect both sexes and various races equally [7][8].

Pathophysiology

It is believed that myocarditis (and its complications) is largely immune mediated. For example, in infectious etiologies, the microbial agent gains entry through the respiratory or gastroenterology tract and then binds to its specific receptor in the heart. This leads to intracellular replication, resulting in cell damage and lysis. This process may result in immune dysfunction, in which molecular mimicry plays an important role and further enhances cardiac damage. If the damage is severe and prolonged, this can result in dilated cardiomyopathy.[9]

Histopathology

The histopathology of acute myocarditis is varied and depends on the organism and extent of myocardial damage. One may see a variety of white cells and the damage may be focal or diffuse. Necrosis with involvement of the coronary vessels may also be seen. In long-standing cases, one may also see fibrosis. Note that endomyocardial biopsy is not routinely performed in nonfatal cases and histopathology are generally only available in cases which are fatal.

History and Physical

The clinical presentation of acute myocarditis is highly variable, ranging from asymptomatic, to subtle to cardiogenic shock and even sudden cardiac death. There are no pathognomonic clinical features. The classic presentation is similar to that of heart failure with symptoms of dyspnea, orthopnea, and leg swelling. Palpitations and syncope may also occur. In one study of clinically suspected cases, about a quarter of patients had reduced LVEF, sustained ventricular arrhythmias or symptoms of low cardiac output [10]. When the pericardium is involved, as in myopericarditis, chest pain with features similar to pericarditis will arise. As the most common cause of myocarditis is viral, a viral prodrome (fever, arthralgia, fatigue), usually 1 to 2 weeks prior to the onset of heart failure symptoms, may be described by the patient. The 2013 European Society of Cardiology position statement on myocarditis breaks the presentation down to three distinct but overlapping clinical profiles: acute coronary syndrome-like (chest pain not explained by evidence supporting CAD), new onset or worsening heart failure (in the absence of known HF or CAD), and life-threatening conditions (arythmia, cardiogenic shock, severely impaired LV function) [11]. Other manifestations of an infectious agent, such as dysphagia in patients with Chagas disease (caused by Trypanosoma cruzi) or neurological symptoms in patients infected with diphtheria, also may occur. In addition, patients with a non-infectious etiology often will have manifestations of their underlying systemic disease, such as skin or kidney involvement in patients with connective tissue disease. 

There are no specific physical exam findings associated with myocarditis. Physical examination may range from normal to features similar to that of heart failure, including S3 gallop, jugular venous distention, peripheral edema, and tachycardia. In addition, patients with ventricular dilatation may have a mitral regurgitation murmur, which is classically described as an apical pansystolic murmur. A pericardial friction rub may be appreciated, especially if there is concurrent pericarditis. Additional findings may suggest underlying disease in non-infectious etiologies. In addition, patients with eosinophilic myocarditis will have a pruritic maculopapular rash. When the pericardium is involved, a friction rub also may be heard on cardiac auscultation.

Evaluation

Diagnosis of acute myocarditis is challenging because other clinical entities may mimic the diagnosis. This is further complicated by the variable clinical presentation of acute myocarditis. Acute myocarditis should be suspected in patients with clinical signs and symptoms concerning for the illness regardless of workup, especially in young patients (age 25-50) with no history of cardiac disease. Clues related to underlying etiology may support the diagnosis, such as viral prodrome or signs of connective tissue disease. [12][13][14]

Initial evaluation for acute myocarditis should include an EKG, echocardiogram, serum troponin and BNP. Troponin elevation, which is usually dramatic, is present in more than half of the patients. BNP is useful to assess for evidence heat failure and ventricular stretch, which may suggest myocarditis in the right clinical picture. EKG often shows nonspecific ST changes; however, it also may show sinus tachycardia or ventricular arrhythmias (40% of patients). In addition, changes consistent with pericarditis, including diffuse ST elevation, may be present in those with pericardial involvement. An echocardiogram is useful in assessing the degree of cardiac dysfunction and in helping rule out other causes including valvular disease.

Chest radiograph is neither sensitive nor specific for myocarditis but may show an enlarged heart size, pulmonary vascular congestion or pleural effusion. CT Angiography to evaluate for other causes of chest pain may be indicated. Percutaneus coronary angiography is indicated in patients at high risk for coronary arter disease to help rule out ischemic cause of cardiac dysfunction in the right setting. Imaging with cardiac magnetic resonance seems to be promising and may help differentiate ischemic from non-ischemic etiologies of dilated cardiomyopathy. In addition, a complete blood count with differential showing eosinophilia may hint to eosinophilic myocarditis. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are usually elevated but non-specific. Viral antibody testing can be done in the right setting; however, specificity is low and often can result in a delay in diagnosis without any change in management.

Endomyocardial biopsy, though rarely done due to its invasive nature, is the gold standard for diagnosis of myocarditis. According to the Heart Failure Society of America, biopsy should be reserved for patients with acute deterioration of the cardiac function of unknown etiology that is failing usual medical therapy. The classic histological findings include lymphocytic infiltrates with myocyte necrosis as described by the Dallas criteria.

Treatment / Management

Management is primarily supportive but also includes treating any identifiable cause. Patients with heart failure should receive standard treatment including beta-blockers, angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers, and diuretics if needed. Immunosuppressive therapy has not shown clinical benefit and therefore should not be used routinely except in patients who have underlying systemic autoimmune or granulomatous inflammatory diseases. Although viral etiology is the most commonly identified cause, the efficacy of antiviral therapy is unknown and routine antiviral therapy is not recommended. Non-steroid anti-inflammatory agents should be avoided in the acute setting as they may impair healing of the myocardium. In severe cases, mechanical support devices such as an intra-aortic pump or left ventricular assist devices also can be used, with consideration of heart transplant as well. In these instances, it is important to consider a transfer to tertiary care centers for surgical support if needed. Patients may develop dysrhythmias or left atrial or ventricular thrombus requiring anticoagulation. Finally, patients should be counseled on limiting exercise and avoiding alcohol, especially in the acute phase, as it may increase viral replication. Long-term follow-up with serial echocardiography is recommended.[15][16]

Differential Diagnosis

  • Acute Coronary Syndrome
  • Coronary artery disease
  • Coronary vasospasm
  • Myocardial ischemia/infarction
  • Pulmonary edema
  • Unstable angina
  • Congestive Heart Failure
  • Pericarditis
  • Pericardial effusion

Enhancing Healthcare Team Outcomes

Acute myocarditis has many causes, and its presentation can range from asymptomatic to mild to severe. Most patients need admission due to risk of rapid progression to life-threatening conditions including decompensated cardiomyopathy and heart failure, ventricular dysrhythmias and death. In addition to the attending physician, the nurse and other staff are critical for serial monitoring of these patients. All patients need to be educated on the need for rest and abstaining from alcohol and tobacco. The pharmacist should educate the patient on the need to remain compliant with their medications (beta blocker or ACE inhibitor). Most of these patients also have mild to moderate dyspnea and hence may benefit from chest physical therapy. Because of fatigue, a physical therapy consult is recommended to help build exercise endurance. Enrollment in a cardiac rehab program is beneficial for most patients. Finally, the patient should be educated on a healthy lifestyle, maintaining a healthy body weight and a low fat diet.[17][18] (Level V)

Outcomes

The general outcome after viral myocarditis is good. However, recovery can be long and may take 3-7 years. However, some patients may develop left ventricular dilatation and may need ongoing treatment for heart failure and/or arrhythmias. a few patients may require a heart transplant. Those who exhibit the soluble Fas ligand at presentation generally tend to have a good prognosis, whereas those who have antimyosin autoantibodies have a worse outcome. Cardiogenic shock can occur but is rare. The mortality for acute myocarditis is about 20% at 12 months, and at 4 years, there is a 56% survival. Patients who require a ventricular assist device while awaiting a heart transplant generally do not fare well if the wait is more than 1-2 weeks.[15][19] (Level V)


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Acute Myocarditis - Questions

Take a quiz of the questions on this article.

Take Quiz
A 36-year-old male complains of a 2-day history of chest pain. The pain has been continuous and does not change with activity. He has no past medical history and no cardiac risk factors. Vital signs show normal blood pressure, mild tachycardia and tachypnea, and an oxygen saturation of 90 percent on room air. The cardiopulmonary exam is normal. An ECG shows a rate of 106, right axis deviation, left ventricular hypertrophy, PR depression, and T wave inversions in V2 to V5. Troponin and CPK-MB are minimally elevated. Select the most likely diagnosis.



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Select the medication that is contraindicated in acute myocarditis.



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 33-year-old male with no past medical history is admitted for shortness of breath, fatigue, and leg edema. He is managed conservatively after clinical suspicion of myocarditis. Which of the following must confirm the diagnosis?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 30-year-old woman is admitted to the hospital for a 5-day history of progressive fatigue and shortness of breath. She reports no chest pain. She reports that she had experienced "flu-like" symptoms for 2 weeks. She is physically active at baseline; however, she recently has been experiencing shortness of breath after walking one block.On physical examination, the temperature is normal, blood pressure is 130/80 mmHg, pulse rate is 93/min, and respiration rate is 20/min. Oxygen saturation is 95% with the patient breathing room air. There is elevated jugular venous pressure, and the patient has crackles at the bases of the lungs bilaterally. There is 2+ pitting edema in the lower extremities. There is no chest wall tenderness. Her drug screen is normal, and her troponin is mildly elevated. Which of the following medications should be avoided in this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 30-year-old woman is admitted to the hospital for a 5-day history of progressive fatigue and shortness of breath. She reports no chest pain. She reports that "flu-like" symptoms two weeks. She is physically active at baseline; however, she recently has been experiencing shortness of breath after walking one block. On physical examination, the temperature is normal, blood pressure is 130/80 mmHg, pulse rate is 93/min, and respiration rate is 20/min. Oxygen saturation is 95% with the patient breathing room air. There is elevated jugular venous pressure, and the patient has crackles at the bases of the lungs bilaterally. There is 2+ pitting edema in the lower extremities. There is no chest wall tenderness. His drug screen is normal, and his troponin is mildly elevated. Which of the following medications should be avoided in this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Acute Myocarditis - References

References

Mehta JJ,Vindhyal MR,Boppana VS,Farhat A, Focal Myopericarditis Presenting as Acute ST-Elevation Myocardial Infarction. Kansas journal of medicine. 2018 Aug     [PubMed]
Jois A,Zannino D,Curtis N,Cheung M,Burgner DP,Chen KYH, Arterial Structure and Function Following Viral Myocarditis. Pediatric cardiology. 2018 Sep 3     [PubMed]
Mert GÖ,Radi F,Mert KU, The diagnostic challenge: Takotsubo cardiomyopathy vs. acute myocarditis. Heart     [PubMed]
Takeuchi S,Kawada JI,Okuno Y,Horiba K,Suzuki T,Torii Y,Yasuda K,Numaguchi A,Kato T,Takahashi Y,Ito Y, Identification of potential pathogenic viruses in patients with acute myocarditis using next-generation sequencing. Journal of medical virology. 2018 Jul 16     [PubMed]
Dionne A,Dahdah N, Myocarditis and Kawasaki disease. International journal of rheumatic diseases. 2018 Jan     [PubMed]
Chang JJ,Lin MS,Chen TH,Chen DY,Chen SW,Hsu JT,Wang PC,Lin YS, Heart Failure and Mortality of Adult Survivors from Acute Myocarditis Requiring Intensive Care Treatment - A Nationwide Cohort Study. International journal of medical sciences. 2017     [PubMed]
Baessler B,Luecke C,Lurz J,Klingel K,von Roeder M,de Waha S,Besler C,Maintz D,Gutberlet M,Thiele H,Lurz P, Cardiac MRI Texture Analysis of T1 and T2 Maps in Patients with Infarctlike Acute Myocarditis. Radiology. 2018 Aug 7     [PubMed]
Leong K,Kane JM,Joy BF, Acquired Cardiac Disease in the Pediatric Intensive Care Unit. Pediatric annals. 2018 Jul 1     [PubMed]
Datta T,Solomon AJ, Clozapine-induced myocarditis. Oxford medical case reports. 2018 Jan     [PubMed]
Saricam E,Saglam Y,Hazirolan T, Clinical evaluation of myocardial involvement in acute myopericarditis in young adults. BMC cardiovascular disorders. 2017 May 22     [PubMed]
Abutaleb ARA,McNally EM,Khan SS,Anderson AS,Carr JC,Wilcox JE, Myocarditis in Duchenne Muscular Dystrophy After Changing Steroids. JAMA cardiology. 2018 Aug 29     [PubMed]
Maisch B,Alter P, Treatment options in myocarditis and inflammatory cardiomyopathy : Focus on i. v. immunoglobulins. Herz. 2018 Aug     [PubMed]
Godishala A,Yang S,Asnani A, Cardioprotection in the Modern Era of Cancer Chemotherapy. Cardiology in review. 2018 May/Jun     [PubMed]
Zheng YM,Yang J,Liao QH, [Health related quality of life on severe hand, foot and mouth disease patients]. Zhonghua liu xing bing xue za zhi = Zhonghua liuxingbingxue zazhi. 2017 Apr 10     [PubMed]
Veronese G,Ammirati E,Cipriani M,Frigerio M, Fulminant myocarditis: Characteristics, treatment, and outcomes. Anatolian journal of cardiology. 2018 Mar 13     [PubMed]
Global, regional, and national incidence, prevalence, and years lived with disability for 301 acute and chronic diseases and injuries in 188 countries, 1990-2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet (London, England). 2015 Aug 22     [PubMed]
Virmani R,Robinowitz M,Smialek JE,Smyth DF, Cardiovascular effects of cocaine: an autopsy study of 40 patients. American heart journal. 1988 May     [PubMed]
Mason JW,O'Connell JB,Herskowitz A,Rose NR,McManus BM,Billingham ME,Moon TE, A clinical trial of immunosuppressive therapy for myocarditis. The Myocarditis Treatment Trial Investigators. The New England journal of medicine. 1995 Aug 3     [PubMed]
Caforio AL,Pankuweit S,Arbustini E,Basso C,Gimeno-Blanes J,Felix SB,Fu M,Heliö T,Heymans S,Jahns R,Klingel K,Linhart A,Maisch B,McKenna W,Mogensen J,Pinto YM,Ristic A,Schultheiss HP,Seggewiss H,Tavazzi L,Thiene G,Yilmaz A,Charron P,Elliott PM, Current state of knowledge on aetiology, diagnosis, management, and therapy of myocarditis: a position statement of the European Society of Cardiology Working Group on Myocardial and Pericardial Diseases. European heart journal. 2013 Sep     [PubMed]
Sudden unexpected death in a case of necrotizing eosinophilic myocarditis., Fersini F,Fais P,Cerquetti I,Mazzotti MC,Palazzo C,Leone O,Pelotti S,, Legal medicine (Tokyo, Japan), 2019 Mar 7     [PubMed]
The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature., Bejiqi R,Retkoceri R,Maloku A,Mustafa A,Bejiqi H,Bejiqi R,, Open access Macedonian journal of medical sciences, 2019 Jan 15     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of PA-Hospital Medicine. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for PA-Hospital Medicine, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in PA-Hospital Medicine, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of PA-Hospital Medicine. When it is time for the PA-Hospital Medicine board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study PA-Hospital Medicine.