Viral Myocarditis


Article Author:
Michael Kang


Article Editor:
Jason An


Editors In Chief:
Kranthi Sitammagari
Mayank Singhal


Managing Editors:
Avais Raja
Orawan Chaigasame
Carrie Smith
Abdul Waheed
Khalid Alsayouri
Trevor Nezwek
Radia Jamil
Erin Hughes
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:
3/8/2019 4:43:40 PM

Introduction

Myocarditis is an inflammatory process of the myocardium. It can present as an acute, subacute, or chronic disease phase and may present with either focal or diffuse involvement of the myocardium. In symptomatic patients, the presentation can be highly variable from generalized fatigue, malaise, chest pain, congestive heart failure (CHF), cardiogenic shock, arrhythmias and even cardiac arrest.

In the United States and other developed countries, viral infections are most frequently the cause of myocarditis. In developing countries, rheumatic carditis, Chagas disease, and complications related to advanced HIV/AIDS also provide important causes of myocarditis. Other causes include toxic myocarditis, which is related to drugs that may cause an insidious form of the disease.

Myocarditis is diagnosed based on clinical presentation. Diagnosis is classically confirmed by endomyocardial biopsy (EMB) via established histologic, immunologic, and immunohistochemical criteria.[1][2][3][4][5]

Etiology

The etiology is thought to be caused by a variety of infectious and non-infectious causes. Among the infectious causes, viruses are presumed to be the most common pathogen. In North America and Europe the most frequently implicated viruses include enteroviruses, including coxsackievirus. Parvovirus B-19 and human herpesvirus 6 are frequent culprits as well. Other pathogens that have been implicated include various bacteria, fungi, protozoa, and helminths. Other common but non-infectious causes of myocarditis include autoimmune disorders such as systemic lupus erythematosus (SLE), Wegener’s granulomatosis, and giant cell arteritis.

Epidemiology

The incidence of myocarditis is approximately 1.5 million cases worldwide per year. Incidence is usually estimated between 10 to 20 cases per 100,000 persons. The overall incidence is unknown and probably underdiagnosed.  In the United States, the frequency of myocarditis is difficult to ascertain as many cases are subclinical. In community-based populations, the prevalence and outcomes of myocarditis are unknown as epidemiologic studies suggest that the majority of Coxsackie B virus infections, an important cause of myocarditis are subclinical, thus following a benign course.

According to some estimates, 1% to 5% of all patients with acute viral infections may involve the myocardium.

Pathophysiology

Myocarditis begins with the direct invasion of an infectious agent and its subsequent replication within or around the myocardium causing myonecrosis.[6][7]

This leads to the destruction of the cardiac tissue from the infiltration and replication of the infectious agent. Later, the host cellular immune responds and the cytotoxic effects of host immunity are activated by the offending agent.

There may also be a toxic effect of exogenous or endogenous chemicals produced by the systemic pathogen directly on the myocyte.

Three stages of the disease process:

  • Acute: defined by direct viral cytotoxicity and focal or diffuse necrosis of the myocardium
  • Subacute: defined by an increase in autoimmune-mediated injury with activated T cells and B cells and subsequent antibody production creating cardiac autoantibodies along with inflammatory proteins. There are higher concentrations of anti-b-myosin antibodies in patients with myocarditis with dilated cardiomyopathy than in control groups.
  • Chronic: defined by diffuse myocardial fibrosis and cardiac dysfunction that may lead to dilated cardiomyopathy and its sequelae such as CHF, ventricular dysrhythmias, and abnormal ECG findings.

Histopathology

Endomyocardial biopsy (EMB) typically is recommended after other causes of heart failure such ischemic heart disease, valvular lesions, and other causes of cardiomyopathy have been excluded. Endomyocardial biopsy is recommended should the likelihood of the results change management or impact prognosis. Classic histologic examination of the endomyocardial biopsy will reveal cellular infiltrates, which are usually histiocytic and mononuclear with or without associated myocyte damage. Specific findings include eosinophilic, granulomatous, and giant cell myocarditis. The infiltrates are highly variable, often associated with varying degrees myonecrosis. With subacute and chronic myocarditis, interstitial fibrosis may result from the previous insult of the myocardial cytoskeleton.

Toxicokinetics

Toxic drug-induced myocarditis is a term used to describe myocarditis caused by illicit drugs or drugs used as part of chronic medical management. Many drugs such as cocaine, phenothiazines, alcohol, TCA antidepressants, and lithium to name a few, are known to cause myocarditis over time. Frequently, toxic myocarditis will run an insidious course resulting in CHF and dilated cardiomyopathy, often irreversible.

Myocarditis is also a common autopsy finding in patients with cocaine abuse. While the mechanism is largely unknown, many largely believe it is due to its increased sympathomimetic effect, severe oxidative stress, and even metabolite interactions with ion channels. Myocarditis may account for the myocardial anatomic changes that predispose the patient to ventricular dysrhythmias associated with sudden death.

History and Physical

Patients typically will present with a flu-like illness, including fever, malaise, myalgias, vomiting, and diarrhea.

  • Adults will typically present with dyspnea, chest pain, and arrhythmias. Vital signs will be abnormal, including fever, tachycardia, tachypnea and sometimes hypotension. No single sign or symptom will be specific to make the diagnosis, but a presentation with chest pain or CHF often indicates a poor prognosis.
  • Children will often present with grunting respirations and intercostal retractions. Infants will often present with the fulminant syndrome, fever, hypoxia with cyanosis, respiratory distress/failure, and even cardiac arrest. Much like adults, long-term prognosis correlates with severity of their initial presentation.

Evaluation

Most patients will present with abnormal ECG that are widely variable. This included sinus tachycardia, widened QRS patterns, low voltage, prolonged QT, variable atrioventricular (AV) blocks, and even acute myocardial infarction (AMI) pattern.[8][9][10][11]

Cardiac markers, such as troponin, may be elevated, but during which course of the disease process is mostly unknown. Higher levels of troponin likely correlate with more myocardial damage as it is indicative of myonecrosis, but negative values do not rule out the diagnosis. Other tests that should be ordered include complete blood count (CBC), erythrocyte sedimentation rate (ESR), and c-reactive protein (CRP). The white count, ESR, and CRP may be elevated but are not diagnostic in any way.

Viral antibody titers should also be ordered and should include coxsackievirus group B, HIV, CMV, Ebstein-Barr virus, hepatitis and influenza viruses. Titers will typically increase by four-fold during the acute phase with gradual fall with the progression of the disease process. Serial titers may be helpful.

Cardiac ECHO should be ordered and may show nonspecific findings such as reduced left the ventricular function, global hypokinesis, and even regional wall motion abnormalities.

Contrast MRI or nuclear studies can show the extent of inflammation and cellular edema, although this may still be non-specific.

Endomyocardial biopsy (EMB), while considered the “gold standard” for diagnosis, is rarely utilized as it has limited sensitivity and specificity, as inflammation across the myocardium may be diffuse or focal in myocarditis. More importantly, histologic diagnosis rarely has an impact on therapeutic approaches.

Treatment / Management

Treatment, for the most part, is supportive and aimed at preserving left ventricular function and can range from a simple limitation of activity to rhythm and CHF management, ventricular assist devices and even cardiac transplantation down the road. Multicenter trials evaluating immunosuppressive therapies have shown no benefit at this time. In the chronic stage, CHF symptoms tend to predominate, and standard pharmacologic treatments for CHF are indicated.

Pearls and Other Issues

All patients diagnosed or suspected to have acute myocarditis should be admitted to the hospital and be monitored for hemodynamic instability. Immediate complications of myocarditis include ventricular dysrhythmias, left ventricular aneurysm, CHF, and dilated cardiomyopathy. The mortality rate is up to 20% at 1 year and 50% at 5 years.  Despite optimal medical management, overall mortality has not changed in the last 30 years.

Enhancing Healthcare Team Outcomes

The diagnosis and management of viral myocarditis is complex and is best done with a multidisciplinary team that includes a cardiologist, intensivist, nurse practitioner, cardiac surgeon, an internist, and an infectious disease expert. Once the diagnosis is made, the treatment is largely supportive. All symptomatic patients need ICU monitoring.  Immediate complications of myocarditis include ventricular dysrhythmias, left ventricular aneurysm, CHF, and dilated cardiomyopathy. The mortality rate is up to 20% at 1 year and 50% at 5 years.  Despite optimal medical management, overall mortality has not changed in the last 30 years.[12] (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.

Viral Myocarditis - Questions

Take a quiz of the questions on this article.

Take Quiz
What is the most common cause of myocarditis in adolescents?



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
Myocarditis is most frequently associated with which of the following organisms?



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
Which of the following family of viruses are the most common cause of viral cardiomyopathy?



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
What is the most common cause of 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
Which is the most common cause of viral-induced 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 2-week old male is brought to the emergency department in distress. His heart rate is 190, respiratory rate is 75, and he is pale. The heart sounds are distant and there is a gallop. Cardiomegaly is seen on chest radiograph. Echocardiogram shows dilated ventricles, dilated left atrium, and poor ventricular function. The electrocardiogram has low voltage. 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
What is the treatment for viral 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 17-year-old male, previously healthy, presents with an acute flu-like illness, malaise, fever and chest pain. During his work up he is found to have sinus tachycardia on ECG and an elevated troponin. He is admitted to the hospital for suspected acute myocarditis. Which clinical finding is most concerning for having a poor prognosis 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 17-year-old, previously healthy, female presents with an acute flu-like illness, fever, myalgias, shortness of breath, and chest pain. Her ECG shows sinus tachycardia. Her labs show elevated white blood cells and an abnormally elevated troponin. Her chest x-ray shows mild pulmonary edema with findings consistent with congestive heart failure. What is her 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
A 28-year old female with no past medical history presents with complaints of fatigue and shortness of breath ongoing the past week. Aside from a mild cold a few weeks ago, she denies any other complaints, including chest pain or fevers. She denies a history of smoking or drinking due to her religion. Her father died of a heart attack at the age of 42 following a long history of smoking and high cholesterol. Her mother has hypertension and ovarian cancer. Patient denies ever checking her blood pressure at home. On physical examination, her provider notes her heart is regular rate and rhythm. She has + 1 pitting edema bilaterally, and slight jugular venous distension (JVD). She is referred to a cardiologist for further workup who notes her vitals to be stable, and an EKG was normal. On echocardiogram, the patient is noted to have left ventricular ejection fraction (LVEF) about 37%. What is the most likely etiology of this patient's reduced heart function?



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

Viral Myocarditis - References

References

Bejiqi R,Retkoceri R,Maloku A,Mustafa A,Bejiqi H,Bejiqi R, The Diagnostic and Clinical Approach to Pediatric Myocarditis: A Review of the Current Literature. Open access Macedonian journal of medical sciences. 2019 Jan 15;     [PubMed]
Price JF, Congestive Heart Failure in Children. Pediatrics in review. 2019 Feb;     [PubMed]
Seo KW,Park JS, Sinus of Valsalva Aneurysm and Multiple Aortic Aneurysms Provoked by Viral Myocarditis. Korean circulation journal. 2019 Feb;     [PubMed]
Mavrogeni SI,Tsarouhas K,Spandidos DA,Kanaka-Gantenbein C,Bacopoulou F, Sudden cardiac death in football players: Towards a new pre-participation algorithm. Experimental and therapeutic medicine. 2019 Feb;     [PubMed]
Filipowicz A,Coca MN,Blair BM,Chang PY, ACUTE MYOCARDITIS WITH CARDIOGENIC SHOCK AND MULTIPLE ORGAN FAILURE, FOLLOWED BY BILATERAL PANUVEITIS MASQUERADING AS ENDOGENOUS ENDOPHTHALMITIS, DUE TO TOXOPLASMA GONDII IN AN IMMUNOCOMPETENT PATIENT. Retinal cases     [PubMed]
Gannon MP,Schaub E,Grines CL,Saba SG, State of the art: Evaluation and prognostication of myocarditis using cardiac MRI. Journal of magnetic resonance imaging : JMRI. 2019 Jan 13;     [PubMed]
Kurdi M,Zgheib C,Booz GW, Recent Developments on the Crosstalk Between STAT3 and Inflammation in Heart Function and Disease. Frontiers in immunology. 2018;     [PubMed]
Bailey JR,Loftus A,Allan RJC, Myopericarditis: recognition and impact in the military population. Journal of the Royal Army Medical Corps. 2018 Nov 14;     [PubMed]
Tselios K,Urowitz MB, Cardiovascular and Pulmonary Manifestations of Systemic Lupus Erythematosus. Current rheumatology reviews. 2017;     [PubMed]
Lazaros G,Oikonomou E,Tousoulis D, Established and novel treatment options in acute myocarditis, with or without heart failure. Expert review of cardiovascular therapy. 2017 Jan;     [PubMed]
Zhang T,Miao W,Wang S,Wei M,Su G,Li Z, Acute myocarditis mimicking ST-elevation myocardial infarction: A case report and review of the literature. Experimental and therapeutic medicine. 2015 Aug;     [PubMed]
Casadonte JR,Mazwi ML,Gambetta KE,Palac HL,McBride ME,Eltayeb OM,Monge MC,Backer CL,Costello JM, Risk Factors for Cardiac Arrest or Mechanical Circulatory Support in Children with Fulminant Myocarditis. Pediatric cardiology. 2017 Jan;     [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.