Myocarditis: Difference between revisions
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==Background==
==Background==
[[File:KVIR A 2180951 F0001 OC.jpg|thumb|Triggers of myocarditis. Myocarditis can be induced by both infectious and non-infectious pathogens, with viral infection being the most common cause (red background).]]
[[File:KVIR A 2180951 F0001 OC.jpg|thumb|Triggers of myocarditis. Myocarditis can be induced by both infectious and non-infectious pathogens, with viral infection being the most common cause (red background).]]
*Inflammatory (dilated) cardiomyopathy caused by necrosis of myocytes  
*Inflammatory cardiomyopathy caused by damage and necrosis of myocytes
**Viral-induced is the most common etiology<ref>Cooper LT Jr. Myocarditis. N Engl J Med. 2009 Apr 9;360(15):1526-38. doi: 10.1056/NEJMra0800028. PMID: 19357408; PMCID: PMC5814110.</ref>
*Clinical presentation ranges from smoldering heart failure to fulminant cardiogenic shock or sudden death
*Maintain a high index of suspicion in younger patients without traditional CAD risk factors


===Causes===
===Causes===
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**[[Chagas]] (most common cause worldwide)
**[[Chagas]] (most common cause worldwide)
**[[Trichinosis]]
**[[Trichinosis]]
**[[Sarcoidosis]]
**[[Systemic lupus erythematosus]]
**[[Diphtheria]]
**[[Diphtheria]]
**[[Lyme disease]]
**[[Lyme disease]]
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===Phases===
===Phases===
*Acute
*Acute
**Viral cytotoxicity and focal necrosis  
**Direct cytotoxicity and focal necrosis from viral, autoimmune, or toxins
*Subacute
*Subacute
**Host's humoral/immune response leading to further cell injury  
**Host's humoral/immune response (viral molecular mimicry and anti-myocyte antibody production) leading to further cell injury  
*Chronic
*Chronic
**Diffuse myocardial fibrosis and cardiac dysfunction
**Diffuse myocardial fibrosis and cardiac dysfunction
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*Typically young patients (20 - 50 years) with few risk factors for CAD  
*Typically young patients (20 - 50 years) with few risk factors for CAD  
*[[Chest pain]]  
*[[Chest pain]]  
*Pericardial friction rub
*New onset [[congestive heart failure]], which may include fatigue, orthopnea, or dyspnea on exertion
*Arrhythmias
*[[Flu-like symptoms]]
*[[Flu-like symptoms]]
**[[Fever]], [[fatigue]], [[myalgia]], [[nausea and vomiting]]
**[[Fever]], [[fatigue]], [[myalgia]], [[nausea and vomiting]]
**[[Tachycardia]] (out of proportion to fever)
**[[Tachycardia]] (out of proportion to fever)
**[[Tachypnea]]
**[[Tachypnea]]
*New onset [[congestive heart failure]]
*Pediatric patients: See [[myocarditis (peds)]]
*Pediatric patients:
*Consider this diagnosis in the septic-appearing patient who gets WORSE after receiving IV fluids
**Grunting
**Retractions
**Rhonchi
*Infants may have fulminant syndrome
**[[Fever]]
**Cyanosis
**[[Shortness of breath (peds)|Respiratory distress]]
**[[Tachycardia]]
**[[Heart failure]]
**[[Ventricular dysrhythmias]]


*Consider this diagnosis in the septic-appearing patient who gets WORSE after receiving IV fluids


==Differential Diagnosis==
==Differential Diagnosis==

Revision as of 20:08, 25 June 2025

This page is for adult patients. For pediatric patients, see: myocarditis (peds)

Background

Triggers of myocarditis. Myocarditis can be induced by both infectious and non-infectious pathogens, with viral infection being the most common cause (red background).
  • Inflammatory cardiomyopathy caused by damage and necrosis of myocytes
    • Viral-induced is the most common etiology[1]
  • Clinical presentation ranges from smoldering heart failure to fulminant cardiogenic shock or sudden death
  • Maintain a high index of suspicion in younger patients without traditional CAD risk factors

Causes

Phases

  • Acute
    • Direct cytotoxicity and focal necrosis from viral, autoimmune, or toxins
  • Subacute
    • Host's humoral/immune response (viral molecular mimicry and anti-myocyte antibody production) leading to further cell injury
  • Chronic
    • Diffuse myocardial fibrosis and cardiac dysfunction

Clinical Features


Differential Diagnosis

Consider other causes of CHF

Chest pain

Critical

Emergent

Nonemergent

Evaluation

Diffuse ST elevation in a patient with combined myocarditis and pericarditis.

Management

  • Acute phase
    • Antiviral agents (Pleconaril/Ribavirin) may be effective
    • COVID-related: limited/conflicting evidence regarding efficacy of high-dose steroids and/or IVIG [3]
  • Subacute phase
    • Studies have not shown efficacy of immunosupressants
    • Pediatric patients may receive high-dose IVIG
  • Chronic phase
    • Treatment for CHF symptoms
    • Ventricular Assist Devices (VAD)
    • Cardiac transplant

Disposition

  • If CHF is present, admit to monitored bed
  • If hemodynamically unstable, admit to ICU

Prognosis

  • Fulminant myocarditis has best prognosis
  • Mortality: 20% 1 yr/ 50% 5 yr
  • Children with 70% survival rate at 5 yrs

Complications

See Also

External Links

References

  1. ↑ Cooper LT Jr. Myocarditis. N Engl J Med. 2009 Apr 9;360(15):1526-38. doi: 10.1056/NEJMra0800028. PMID: 19357408; PMCID: PMC5814110.
  2. ↑ Mele D, Flamigni F, Rapezzi C, Ferrari R. Myocarditis in COVID-19 patients: current problems. Internal and Emergency Medicine. 2021. doi:10.1007/s11739-021-02635-w
  3. ↑ Mele D, Flamigni F, Rapezzi C, Ferrari R. Myocarditis in COVID-19 patients: current problems. Internal and Emergency Medicine. 2021. doi:10.1007/s11739-021-02635-w
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