Viral Infections in which cardiovascular manifestations dominate Flashcards
What is the definition and etiology of myocarditis?
• Definition: inflammation of the heart muscle. • Etiology: – Predominantly viral in North America and Europe. – Other infectious causes include bacterial and parasitic infection. – Noninfectious causes include inflammatory disorders and toxin-mediated events.
What are common viruses that have been shown to cause myocarditis?
– Enteroviruses (particularly Coxsackie B) – Adenovirus Cytomegalovirus – Epstein-Barr Virus – Parvovirus B19
what are less common viruses that can cause myocarditis?
– Arboviruses including Dengue virus – Herpes simplex virus – Measles virus – Respiratory syncytial virus – Rubella virus – Varicella-zoster virus – Influenza – Mumps – Polio – HIV – Hepatitis A virus – Hepatitis C virus
When does myocarditis spike? who is most at risk?
– In US- peak enterovirus activity in summer and fall. – Young children are most susceptible.
What is the pathophysiology of myocarditis?
• Direct myocyte invasion by infecting agent. • Development of CD4 and CD8 T-lymphocyte response. • Circulating antiheart antibody involvement described against contractile, structural, and mitochondrial proteins. • Exercise, pregnancy, malnutrition, cold exposure, and immunosuppression can lead to more severe enteroviral disease. • Presence of Coxsackie-Adenovirus receptor on cardiac myocytes.
explain the pathology seen in myocarditis? what can also help for diagnosing myocarditis?
• Dallas Criteria: – Active Myocarditis- Inflammatory cellular infiltrate with myocyte necrosis – Borderline Myocarditis- Inflammatory infiltrate without myocyte necrosis – No Myocarditis – Inflammatory infiltrates classified as either lymphocytic, eosinophilic, or granulomatous with differing levels of inflammation. – These criteria lack sensitivity. • Immunohistochemical stains can help with diagnosis by further classifying inflammatory infiltrate. – Myocarditis defined as “ immunohistochemical evidence of mononuclear infiltrates with more than 14 cells/mm squared on endomyocardial biopsy in addition to enhanced expression of HLA class II molecules” (Long, et al. Principles and Practice of Pediatric Infectious Disease, 5th edition.)
What are the clinical manifestations of myocarditis?
• Viral prodrome: myalgias, fevers, chest pain, dyspnea, tachypnea, gastroenteritis. • Abrupt onset of hemodynamic collapse. • Range of Cardiac Signs/Symptoms: Asymptomatic with EKG changes to cardiogenic shock.
What are the symptoms of viral myocarditis?
• Symptoms – Fatigue/irritability – Dyspnea – Palpitation – Chest pain – Syncope – +/- Fever
What are the signs of viral myocarditis?
– Pericardial rub – Sinus tachycardia – Atrial or ventricular arrhythmias – Conduction disturbances – Cardiomegaly – Right or left S3 or S4 gallop sounds – Congestive heart failure – Decreased peripheral pulses – Tachypnea – Hepatomegaly
What are other cardiac problems that can manifest and look like myocarditis?
• Other cardiac diseases can present in similar manner or concurrently. • Endocarditis- primary valvular disease, positive blood cultures, echo with vegetations. • Pericarditis-precordial chest pain, pericardial fluid, no arrhythmia. • Myocardial infarction can also be confused with myocarditis.
Explain the diagnosis of myocarditis?
• If clinically suspect: – CXRay – EKG – Echocardiogram – Labs • Nonspecific: elevations in ESR, CRP, serum transaminases, brain natriuretic protein, CK-MB, cardiospeciifc troponin elevation (in pediatrics). – MRI • Fuctional, morphologic, and tissue abnormalities can be visualized. – Endomyocardial biopsy
EKG findings of myocarditis?
• ST-segment elevations in two contiguous leads • T-wave inversions • ST-segment depressions • Q waves • Low-voltage complexes in standard and precordial leads • Other: tachycardia, arrhythmias, conduction disturbances. • Most changes resolve within 1-2 months.
Echocardiography findings with myocarditis?
• Heart wall motion abnormalities secondary to inflammation and edema of myocardium. • Valvular regurgitation • Left ventricular dilatation • Biventricular dysfunction seen in severe disease. • Useful to follow over time.
What is the Gold standard to diagnose myocarditis?
Endomyocardial Biopsy • Gold standard. – Has remained gold standard but has limited sensitivity and specificity. Must way risks vs benefits. Limited indications for using this as diagnostic tool. Useful if done earlier in course of illness.
How do you find the causative agent in myocarditis?
• Isolation directly from myocardial tissue • Isolation from other body sites/fluids • Serology • PCR • Epidemiologic clues
how do you manage myocarditis?
• Supportive therapy – Medications used: vasodilator therapy, diuretics, ACE inhibitors, Beta-Blockers – Treatment of arrythmias, bedrest. – Extreme cases: ventricular assist devices, ECMO.
what are some drugs we can give for the following viral etiologies? Influenza, CMV, VZV/HSV, Adenovirus, Parainfluenza, Enterovirus
– Influenza-Neuraminidase Inhibitors – CMV-Ganciclovir – VZV/HSV-Acyclovir – Adenovirus-Cidofovir – Parainfluenza/RSV -IV Ribavarin – Enterovirus-Pleconaril was used but now not available.
what are some complications of myocarditis? prevention?
• Complications: CHF, Arrythmias, Cardiac Rupture, Death, Dilated Cardiomyopathy. • Prevention: Hand hygiene, respiratory hygiene, sanitary food/water
What is the diagnosis of epstein barr?
• Heterophil Ab – Primarily IgM response – Appears during first 2 wks of illness and gone by 6 months. – Not reliable in kids<4yrs • Atypical Lymphocytosis -seen in 2nd week of illness and nonspecific. • Serology-See below. • Isolation of Virus- not routine. • PCR.
