Description
Acute myocarditis and cardiomyopathy are serious heart conditions affecting children. Myocarditis involves inflammation of the heart muscle, often triggered by viral infections. Cardiomyopathy encompasses various heart muscle diseases, including hypertrophic cardiomyopathy, the most common type in children. Symptoms may include chest pain, rapid heartbeat, fatigue, and swelling. Diagnosis involves tests like echocardiograms, and treatment varies based on the cause and severity, including medications, supportive care, and in some cases, heart transplantation. Early medical attention is crucial for better outcomes. Pediatric cardiologists play a vital role in managing these conditions in children.
Résumé
- Myocarditis and cardiomyopathy in children are significant cardiac disorders, with viral myocarditis being a major cause of mortality and morbidity. Myocarditis involves inflammation and necrosis of the myocardium, leading to congestive heart failure, arrhythmias, and potentially sudden death. Diagnosis involves evaluating acute phase reactants, cardiac biomarkers, ECG, echocardiography, and in select cases, cardiac MRI and endomyocardial biopsy. Treatment is primarily supportive, focusing on managing heart failure with medications like diuretics, ACE inhibitors, and inotropes, along with mechanical support when needed.
- The WHO and ISFC define myocarditis as an inflammatory disease of the heart muscle diagnosed by histological and immunopathological evidence. Dallas criteria further defines it by the presence of inflammatory infiltrates and myocyte damage of non-ischemic origin. Inflammatory cardiomyopathy is myocarditis associated with left ventricular dysfunction and dilated cardiomyopathy involves dilation and impaired contraction of the ventricles, not due to abnormal loading conditions or coronary artery disease.
- Viral infection is the most common etiology of myocarditis. Viruses like Coxsackievirus B, adenovirus, and parvovirus B19 are frequently implicated. HIV, Dengue, and H1N1 can also cause myocarditis, with varying severity. Non-viral causes include leptospirosis, Lyme disease, Chagas disease, and drug toxicities.
- The pathogenesis of viral myocarditis includes an initial acute viral invasion stage with cell necrosis, followed by an immune response stage where T cells cause damage through immune mimicry. The final chronic phase may involve fibrosis, remodeling, and dilated cardiomyopathy. Clinical presentations of viral myocarditis range from asymptomatic to fulminant, with symptoms varying by age.
- Investigations for myocarditis include first-line tests like ESR, CRP, AST, and cardiac biomarkers. Second-line investigations include radionucleotide scans, cardiac MRI, and endomyocardial biopsy. Cardiac MRI is a promising modality for early diagnosis and characterization. Endomyocardial biopsy, guided by cardiac imaging, remains the gold standard for diagnosis but is not routinely done due to sampling error and procedural risks.
- Management strategies involve categorizing myocarditis into stable and unstable cases. Stable patients receive supportive care with diuretics, ACE inhibitors, and aldosterone antagonists. Unstable patients may require IV inotropes, vasodilators, mechanical ventilation, and ECMO support. Anti-arrhythmic and anti-coagulant medications may also be necessary. While antiviral agents and immunosuppression have limited roles, IVIG can be useful in certain cases.
- The prognosis of myocarditis is variable, with outcomes ranging from complete recovery to dilated cardiomyopathy and death. Factors indicating poor prognosis include low ejection fraction, high pulmonary systolic pressure, and need for ventilation or ECMO. Future directions include increased use of cardiac MRI, targeted therapies, and interventions to prevent biotransformation to dilated cardiomyopathy.
Exemple de certificat
À propos des intervenants
Dr Bharat Parmar
PROFESSEUR ET CHEF DU SERVICE DE PÉDIATRIE au Collège de MÉDECINE ZYDUS, Hôpital Civil.
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