Sudden death of an immunocompetent young adult caused by novel (swine origin) influenza A/H1N1-associated myocarditis

Abstract

The main cause of death from novel (swine origin) influenza A/H1N1 infection is acute respiratory distress syndrome. Most fatal cases are immunocompromised patients or patients with a severe underlying disease. Here, we report a fatal case of acute interstitial myocarditis associated with novel influenza A/H1N1 infection in an immunocompetent young woman. A previously healthy 18-year-old woman experienced malaise, diarrhea, and fever for several days prior to a sudden collapse at home. Autopsy revealed a predominantly lymphocytic myocarditis in the absence of a significant respiratory tract infection. Infection with novel (swine origin) influenza A/H1N1 was confirmed by PCR analysis of blood as well as myocardial tissue. Influenza-caused diarrhea with consecutive hypokalemia potentially contributed to the fatal outcome of the myocarditis, characterized by ventricular fibrillation. In conclusion, sudden death by myocarditis may be a rare complication of novel influenza A/H1N1 infection in otherwise healthy individuals, even in the absence of significant respiratory tract infection.

The cardiovascular manifestations of influenza: A systematic review

“…The most commonly reported arrhythmias are atrioventricular conduction block [44,45] and ventricular fibrillation [42,[46][47][48]. Cardiac arrhythmias in influenza infection are mostly secondary to underlying fulminant myocarditis.…”

Clinical Presentation

“…Also, a documented influenza myocarditis was reported due to 2009 pandemic H1N1 virus occurred in a previously healthy adult (Haessler et al, 2010). Another reported fatal case of acute myocarditis in an immunocompetent young woman, the autopsy revealed a predominantly lymphocytic myocarditis (Gdynia et al, 2011). On the other hand, cases diagnosed with fulminant myocarditis were described in pediatric population with fatal outcomes within a 30-day of presentation (Bratincsák et al, 2010).…”

Risk Factors Associated with Severe Clinical Outcomes of Pandemic H1N1 Infection

“…While the main cause of death was usually acute respiratory distress syndrome (ARDS) in patients with an underlying co-morbidity, there have been several reported cases of critical illness or death in patients, resulting from myocarditis, with no underlying condition [25][26][27][28][29][30][31][32][33].…”

“…With the exception of 0-1 year old group in general the severity of clinical outcome appeared to be directly proportional to age [5,7,9,10,12,13]. Other key risk factors leading to severe clinical outcomes were asthma, COPD and obesity [10][11][12][13][14][15]although there were a number of severe clinical cases with no known underlying condition [7,[25][26][27][28][29][30][31][32][33]. …”