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MYOCARDITIS WITH INFLUENZA B INFECTION

1997; Lippincott Williams & Wilkins; Volume: 16; Issue: 6 Linguagem: Inglês

10.1097/00006454-199706000-00018

1532-0987

Randall Craver, Kelly Sorrells, Robert S. Gohd,

Viral Infections and Vectors

Occasionally influenza B infection has been associated with a mild myocarditis, documented by serologic studies only. It is rarely fatal, but in cases that are fatal the illness has followed a more prolonged course. We present a 6-year-old with a fatal myocarditis and a rapid clinical course. Influenza B virus was isolated from the nasopharynx. Clinical history. The 6-year-old previously healthy black female developed chest pain, diarrhea, vomiting, weakness and lethargy, not associated with fever or cough, 1 day before admission. At the hospital blood pressure was 70/palpable with a heart rate of 145/min. By chest roentgenogram her heart was minimally enlarged and there were ST segment elevations on the electrocardiogram. She was given dopamine and dobutamine and transferred to our hospital. Three hours after admission she became bradycardic with a wide complex rhythm. Resuscitation attempts were unsuccessful. Premortem nasopharyngeal specimens contained influenza B virus demonstrated by fluorescent antibody and by culture. No enteroviruses, including coxsackieviruses, were isolated using monkey kidney, human embryonic kidney and fibroblast RC 5 cell lines (BioWhittaker, Walkersville, MD). Autopsy results. The heart was minimally enlarged at 110 g (expected for age, 94 g) with slight biventricular dilatation. The pale myocardium was slightly flabby. Histologically there were random foci of myocyte necrosis associated with edema and a lymphocytic infiltrate. Immunoperoxidase demonstrated that most of the lymphocytes were T cells. The coronary vasculature was normal without thrombosis, aneurysm or inflammation. Postmortem viral cultures of liver, lung and heart were negative for the above three cell culture lines. The influenza B obtained from the nasopharynx during life was subtyped as B/Beijing/184/93-LIKE by the Centers for Disease Control and Prevention. Discussion. Lymphocytic myocarditis associated with viral infection may occur as isolated endemic events with little year to year variation, or during epidemic outbreaks. The clinical course varies. The initial presentation can be cardiac arrest unresponsive to resuscitation. If the acute phase is survived, chronic dilated cardiomyopathy or complete recovery can occur. Three possible mechanisms may account for the myocardial damage: (1) direct viral invasion of the myocardium; (2) autoimmune process; or (3) damage to the coronary vasculature.1 Our case, with no demonstrable virus in the heart, no coronary vascular abnormality and predominantly T cell lymphocytic infiltrates within the heart, supports the autoimmune mechanism. Influenza viruses were associated with myocarditis during the epidemic of 1918.2 The relationship of influenza B to myo/pericarditis was noted in 1958.3 Four individuals with myo/pericarditis had elevated antibody titer to influenza B. Two had pericarditis, 1 had subacute myocarditis that resolved and 1 had fatal chronic myocarditis. Myocarditis was described in a second report involving 6 adult patients who had 4-fold increases in antibody titers to influenza B virus.4 All 6 survived. From 126 Scandinavian recruits with electrocardiographic changes suggestive of myocarditis, 2 had a 4-fold increase in antibody titers to influenza B.5 Elevated titers to influenza A and B (not further specified) were reported in 55 of 201 Russian males with myocarditis6 and 1 of 24 cases in Scandinavia.7 Influenza B was recovered from the nasopharynx of a 34-year-old woman at delivery with acute onset of dilated cardiomyopathy. After several cardiac arrests and other clinical complications, she died 6 weeks after onset of symptoms.8 The case resembles ours in that influenza was isolated from the nasopharynx and cardiac complications occurred. Although rare, influenza B infections have been associated with myocarditis. Deaths have followed a chronic or subacute clinical course in adults. This 6-year-old is the youngest patient described with acute myocarditis associated with influenza B and is the only death described during the acute illness. Randall D. Craver, M.D. Kelly Sorrells, M.D. Robert Gohd, Ph.D. Louisiana State University Medical Center and New Orleans Children's Hospital; New Orleans, LA