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For further information, see CMDT Part 10-42: Infectious Myocarditis
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Essentials of Diagnosis
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Often follows an upper respiratory infection
May present with chest pain (pleuritic or nonspecific) or signs of heart failure
Echocardiogram documents cardiomegaly and contractile dysfunction; initial heart size is generally normal with thickened walls
Myocardial biopsy, though not sensitive, may reveal a characteristic inflammatory pattern; MRI has a role in diagnosis
COVID-19 myocarditis has been reported between 3% and 58% of people based on underlying myocardial risk and imaging
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General Considerations
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Cardiac dysfunction due to primary myocarditis is presumably caused by either an acute viral infection or a post viral immune response
Causes include
RNA viruses
Picornaviruses (coxsackie A and B, echovirus, poliovirus, hepatitis virus)
Orthomyxovirus (influenza)
Paramyxoviruses (respiratory syncytial virus, mumps)
Togaviruses (rubella)
Flaviviruses (dengue fever, yellow fever)
DNA viruses
Adenovirus (A1, 2, 3, and 5)
Erythrovirus (Bi9V and 2)
Herpesviruses (human herpes virus 6 A and B, cytomegalovirus, Epstein-Barr virus, varicella-zoster)
Retrovirus (HIV)
Bacteria
Chlamydia (Chlamydophila pneumoniae, C psittaci)
Haemophilus influenzae
Legionella
Pneumophilia
Brucella
Clostridium
Francisella tularensis
Neisseria meningitis
Mycobacterium (tuberculosis)
Salmonella
Staphylococcus
Streptococcus A, Streptococcus pneumoniae
Tularemia
Tetanus
Syphilis
Vibrio cholera
Spirocheta
Borrelia recurrentis
Leptospira
Treponema pallidum
Rickettsia
Fungi
Actinomyces
Aspergillus
Candida
Cryptococcus
Histoplasma
Nocardia
Protozoa
Helminthic
Ascaris
Echinococcus granulosus
Schistosoma
Trichenella spiralis
Wuchereria bancrofti
Myo-pericarditis due to SARS-CoV-2
Has been a concern during the COVID-19 pandemic; much remains unknown
Speculation is that the Spike protein binds to the angiotensin-converting enzyme 2 (ACE-2) membrane receptor on cardiomyocytes creating direct cellular injury and T-lymphocyte-mediated cytotoxicity augmented by a cytokine storm
In a German study of 100 patients who had recovered from COVID-19, cardiac MRI revealed some degree of abnormality in 78 patients, with inflammation noted in 60, independent of severity of the illness
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Patients may present several days to a few weeks after the onset of an acute febrile illness or a respiratory infection or they may present with heart failure without antecedent symptoms
Onset of heart failure may be gradual or may be abrupt and fulminant
In acute fulminant myocarditis, low output and shock may be present with severely depressed LV systolic function
A pericardial friction rub may be present
In the European Study of Epidemiology and Treatment of Inflammatory Heart Disease,
Pulmonary and systemic emboli may occur
Pleural-pericardial chest pain is common
Examination reveals tachycardia, a gallop rhythm, and other evidence of heart failure or conduction defects
At times, the presentation may mimic an acute myocardial infarction with ST changes, positive cardiac markers, and regional wall motion abnormalities despite normal coronaries
Microaneurysms may also occur and may be associated with serious ventricular arrhythmias
Approximately 10% of all ...