Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary 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 ... Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.