My hospitalized patient with pneumonia has now suffered an acute myocardial infarction (MI). Can acute infection and MI be related?

Yes! Ample epidemiological studies implicate infection as an important risk factor for MI.1 The increased risk of MI has been observed during the days, weeks, months or even years following an infection.

A 2018 paper reported a several-fold risk of MI during the week after laboratory-confirmed infection caused by a variety of respiratory pathogens such as influenza virus (6-fold), respiratory syncytial virus (4-fold), and other respiratory viruses (3-fold). 2 Among patients hospitalized for pneumococcal pneumonia, 7-8% may suffer an MI.3,4 One study found a 48-fold increase in the risk of MI during the first 15 days after hospitalization for acute bacterial pneumonia.5 Similarly, an increase in the short-term risk of MI has been observed in patients with urinary tract infection and bacteremia.6

The risk of MI appears to be the highest at the onset of infection and correlates with the severity of illness, with the risk being the highest in patients with pneumonia complicated by sepsis, followed by pneumonia and upper respiratory tract infection. Among patients with pneumonia, the risk exceeds the baseline risk for up to 10 years after the event, particularly with more severe infections.1

Potential mechanisms of MI following infections include release of inflammatory cytokines (eg, interleukins 1, 6, tumor necrosis factor alpha) causing activation of inflammatory cells in atherosclerotic plaques, in turn resulting in destabilization of the plaques. In addition, the thrombogenic state of acute infections, platelet and endothelial dysfunction may increase the risk of coronary thrombosis at sites of plaque disruption beyond clinical resolution of the acute infection. 1


  1. Musher DM, Abers MS, Corrales-Medina VF. Acute infection and myocardial infarction. N Engl J Med 2019;380:171-6.
  2. Kwong JC, Schwartz KL, Campitelli MA, et al. Acute myocardial infarction after laboratory-confirmed influenza infection. N Engl J Med 2018;378:345-53.
  3. Musher DM, Alexandraki I, Graviss EA, et al. Bacteremic and nonbacteremic pneumococcal pneumonia: a prospective study. Medicine (Baltimore) 2000;79:210-21.
  4. Musher DM, Rueda Am, Kaka As, Mapara SM. The association between pneumococcal pneumonia and acute cardiac events. Clin Infect Dis 2007;45:158-65.
  5. Corrales-Medina VF, Serpa J, Rueda AM, et al. Acute bacterial pneumonia is associated with the occurrence of acute coronary syndromes. Medicine (Baltimore) 2009;88:154-9.
  6. Dalager-Pedersen M, Sogaard M, Schonheyder HC, et al. Risk for myocardial infarction and stroke after community-acquired bacteremia: a 20-year population-based cohort study. Circulation 2014;129:1387-96.

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My hospitalized patient with pneumonia has now suffered an acute myocardial infarction (MI). Can acute infection and MI be related?

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