Episode 23 - Influenza Diagnosis and Management in the Emergency Department

  Jeff: Welcome back to Emplify, the podcast corollary to EB Medicine’s Emergency Medicine Practice. I’m Jeff Nusbaum, and I’m back with my co-host, Nachi Gupta. This month, we’re talking about a topic that is ripe for review this time of year. We’re talking Influenza… Diagnosis and Management. Nachi: Very appropriate as the cold is settling in here in NYC and we’re already starting to see more cases of influenza. Remember that as you listen through the episode, the means we’re about to cover one of the CME questions for those of you listening at home with the print issue handy. Jeff: This month’s issue was authored by Dr. Al Giwa of the Icahn School of Medicine at Mount Sinai, Dr. Chinwe Ogedegbe of the Seton Hall School of Medicine, and Dr. Charles Murphy of Metrowest Medical Center. Nachi: And this issue was peer reviewed by Dr. Michael Abraham of the University of Maryland School of Medicine and by Dr. Dan Egan, Vice Chair of Education of the Department of Emergency Medicine at Columbia University. Jeff: The information contained in this article comes from articles found on pubmed, the cochrane database, center for disease control, and the world health organization. I’d say that’s a pretty reputable group of sources. Additionally, guidelines were reviewed from the american college of emergency physicians, infectious disease society of america, and the american academy of pediatrics. Nachi: Some brief history here to get us started -- did you know that in 1918/1919, during the influenza pandemic, about one third of the world’s population was infected with influenza? Jeff: That’s wild. How do they even know that? Nachi: Not sure, but also worth noting -- an estimated 50 million people died during that pandemic. Jeff: Clearly a deadly disease. Sadly, that wasn’t the last major outbreak… fifty years later the 1968 hong kong influenza pandemic, H3N2, took between 1 and 4 million lives. Nachi: And just last year we saw the 2017-2018 influenza epidemic with record-breaking ED visits. This was the deadliest season since 1976 with at least 80,000 deaths. Jeff: The reason for this is multifactorial. The combination of particularly mutagenic strains causing low vaccine effectiveness, along with decreased production of IV fluids and antiviral medication because of the hurricane, all played a role in last winter’s disastrous epidemic. Nachi: Overall we’re looking at a rise in influenza related deaths with over 30,000 deaths annually in the US attributed to influenza in recent years. The ED plays a key role in outbreaks, since containment relies on early and rapid identification and treatment. Jeff: In addition to the mortality you just cited, influenza also causes a tremendous strain on society. The CDC estimates that epidemics cost 10 billion dollars per year. They also estimate that an epidemic is responsible for 3 million hospitalized days and 31 million outpatient visits each year. Nachi: It is thought that up to 20% of the US population has been infected with influenza in the winter months, disproportionately hitting the young and elderly. Deaths from influenza have been increasing over the last 20 years, likely in part due to a growing elderly population. Jeff: And naturally, the deaths that we see from influenza also disproportionately affect the elderly, with up to 90% occurring in those 65 or older. Nachi: Though most of our listeners probably know the difference between an influenza epidemic and pandemic, let’s review it anyway. When the number of cases of influenza is higher than what would be expected in a region, an epidemic is declared. When the occurrence of disease is on a worldwide spectrum, the term pandemic is used. Jeff: I think that’s enough epidemiology for now. Let’s get started with the basics of the influenza virus. Influenza is spread primarily through direct person-to-person contact via expelled respiratory secretions.