Myocarditis

11/98 medslides.com 1

Myocarditis


Myocarditis

• Definition: any inflammation or degeneration of the heart

• Autopsy• Endomyocardial biopsy

– may provide greater insight into the pathogenesis, etiology, and treatment


Important Causes of Myocarditis

• Infection– Viral– Bacterial, rickettsial, spirochetal– Protozoal, Metazoal– Fungal

• Toxic– anthracyclines, catecholamines, Interleukin-2, alpha 2

interferon

• Hypersensitivity


Viral Infection

• Coxsackie (A, B)• Echo• Influenza (A, B)• Polio• Herpes simplex• Varicella-zoster• Epstein-Barr• Cytomegalovirus • Mumps

• Rubella• Rubeola• Vaccinia• Coronavirus• Rabis• Hepatitis B• Arbovirus• Junin virus• Human immunodeficiency


Bacterial, rickettsial, spirochetal

• Corynebacterium diphtheriae

• salmonella typhi• Beta-hemolytic streptococci• Neisseria meningitidis• Legionella pneumophila• Listeria monocytogenes• Camphylobacter jejuni• Coxiella burnetii (Q fever)

• Chlamydia trachomatis• Mycoplasma pneumoniae• Chlamydia psittaci

(psittacosis)• Rickettsia rickettsii (Rocky

Mountain spotted fever)• Borrelia burgdorferi (Lyme

disease)• Mycobacterium

tuberculosis


Protozoal, Metazoal, Fungal

Protozoal• Trypnosoma cruzi (Chagas’

disease)• Toxoplasma gondi

Metazoal• Trichinosis• Ehinococcosis

Fungal• Aspergillosis• Blastomycosis• Candidiasis• Coccidioidomycosis• Cryptococcosis• Histoplasmosis• Mucormycosis


Drugs Causing Hypersensitivity Myocarditis

Antibioticsamphoericin Bampicillinchloramphenicolpenicillintetracyclinestreptomycin

Sulfonamidessufadiazinesufisoxazole

Anticonvulsantsphenindionephenytoincarbamazepine

Antitubercuousisoniazidparaaminosalicylate

Anti-inflammatoryindomethacinoxyphenbutazonephenylbutazone

Diureticsacetazolamidechlorthalidonehydrochlorothiazidespironolactone

Otheramitriptylinemethyldopasulfonylureastetanus toxoid


Clinical Manifestations

• Most cases of acute myocarditis are clinically silent• 60% of pts had antecedent flulike symptoms• Large number identified by heart failure symptoms• 35% of pts with myocarditis and HF have chest pain• May mimic an acute MI with ventricular dysfunction,

ischemic chest pain, ECG evidence of injury or Q waves


Clinical Manifestations

• May present with syncope, palpitation with AV block or ventricular arrhythmia

• May cause sudden death– myocarditis found at autopsy in 20% of Air Force recruits

with sudden death*

• May present with systemic or plumonary thromboembolic disease

JAMA 1986; 256:2696-2699


Blood studies

• Sed rate elevation 60%• White count elevation 25%• CK-MB elevation 12%

• a 4 fold rise in IgG titer over a 4-6 wk period is required to document an acute viral infection

• Heart specific antibodies are nonspecific for myocarditis; also found in dilated cardiomyopathy


Electrocadiogram

• sinus tachycardia is most common• diffuse ST-T wave changes• myocardial infarction pattern• conduction delay and LBBB in 20%• complete heart block causing Stokes-Adams

attacks (particularly in Japan), but rarely require a permanent pacer

• supraventricular and ventricular arrhythmias


Myocarditis

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11/98 medslides.com 13H9925 8-30-98


Echocardiography

• Useful tool in managing patients with acute myocarditis– LV systolic dysfuntion is common with

segmental wall motion abnormalities

– LV size is typically normal or mildly dilated

– wall thickness may be increased

– ventricular thrombi detected in 15%


Endomyocardial Biopsy

• RV bioptome permit repetitive sampling• biopsy should be applied early after onset

of symptoms to maximize yield - resolution may be seen in four days on serial biopsies

• Dallas criteria for active myocarditis“an inflammatory infiltrate of the myocardium with necrosis and/or degeneration of adjacent myocytes not typical of the ischemic changes associated with coronary artery disease”


Imaging Studies

• Gallium 67 (avid for inflammation) showed promise for screening active myocarditis

• Indium 111-antimyosin monoclonal antibody (avid for injured myocardium)

sensitivity 83% specificity 53% + predictive value 92%

• endomyocardial biopsy remains the diagnostic standard


Myocardial Treatment Trial111 patients with active myocarditis

Age 42 14 years

Sex 62% male

Ejection fraction 0.24 0.10

Chest pain 35%

Increase MB-CK 12%

Flulike symptoms 59%

Increased ESR 61%

Elevated WBC 24%

Fever 18%

Circulation 1991;84(suppl II):II-2


Treatment

• majority of patients have a self-limited disease• management of LV dysfunction similar to other

forms of congestive heart failure• ? exercise may intensify inflammatory response• consider anticoagulation to prevent thromboemboli• consider temporary pacer for complete AV block• ? prednisone and azathioprine - no apparent

benefit seen in the Myocarditis Treatment Trial

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Myocarditis