Skip to Main Content

++

Key Features

++
Essentials of Diagnosis
++

  • Most common causes of viral myocarditis

    • Adenoviruses

    • Coxsackie A and B viruses

    • Echoviruses

    • Parvovirus

    • Cytomegalovirus

    • Influenza A virus

  • HIV can also cause myocarditis

  • Polymerase chain reaction (PCR) technology enhances ability to identify the pathogen

++
General Considerations
++

  • There are two major clinical patterns: sudden and gradual onset

  • Sudden-onset heart failure(HF)

    • Occurs in an infant or child who was relatively healthy in the hours to days previously

    • This malignant form is usually secondary to overwhelming viremia with tissue invasion in multiple organ systems, including the heart

  • Gradual onset of cardiac symptoms

    • May be a history of upper respiratory tract infection or gastroenteritis in the previous month

    • This more insidious form may have a late postinfectious or autoimmune component

  • Acute and chronic presentations occur at any age and with all types of myocarditis

++

Clinical Findings

++

  • Signs of HF are variable, but in a decompensated patient with fulminant myocarditis include

    • Pale gray skin

    • Rapid, weak, and thready pulses

    • Breathlessness

  • More subacute presentation signs include

    • Increased work of breathing, such as orthopnea

    • Difficulty with feeding in infants

    • Exercise intolerance

    • Edema of the face and extremities

  • Tachycardia

  • Heart sounds may be muffled and distant; an S3 or S4 gallop (or both) are common

  • Murmurs are usually absent, although a murmur of tricuspid or mitral insufficiency may be heard

  • Moist rales are usually present at both lung bases

  • Liver is enlarged and frequently tender

++

Diagnosis

++
Imaging
++

  • Radiography

    • Generalized cardiomegaly is seen along with moderate to marked pulmonary venous congestion

  • Echocardiography

    • Demonstrates four-chamber dilation with poor ventricular function and AV valve regurgitation

    • A pericardial effusion may be present

    • Patients with a more acute presentation may have less ventricular dilation than those with a longer history of HF-related symptoms

  • Cardiac MRI

    • Abnormalities in T2-weighted imaging (consistent with myocardial edema, inflammation) and global relative enhancement (evidence of capillary leak) are evident in acute myocarditis

    • Requires general anesthesia in infants and young children, which is associated with significant risk in those with HF

++
Diagnostic Procedures
++

  • Electrocardiography

    • Classically, there is low-voltage QRS in all frontal and precordial leads with ST-segment depression and inversion of T waves in leads I, III, and aVF (and in the left precordial leads during the acute stage)

    • Dysrhythmias are common

    • Atrioventricular and intraventricular conduction disturbances may be present

  • Myocardial biopsy

    • An inflammatory infiltrate with myocyte damage can be seen by hematoxylin and eosin staining

    • Viral PCR testing of the biopsy specimen may yield a positive result in 30–40% of patients

    • Results can be falsely negative if area of active myocarditis was missed

++

Treatment

++

  • See Heart Failure

  • Digitalis

    • Can be dangerous when child with myocarditis is rapidly deteriorating

    • Should be used with great caution because may cause ventricular dysrhythmias

  • Administration of ...

Pop-up div Successfully Displayed

This div only appears when the trigger link is hovered over. Otherwise it is hidden from view.