Clinical diagnosis of influenza in the ED

Abstract

Background Timely and accurate diagnosis of influenza remains a challenge, but is critical for patients who may benefit from antiviral therapy. This study determined the test characteristics of provider diagnosis of influenza, final ED electronic medical record (EMR) diagnosis of influenza, and influenza like illness (ILI) in patients recommended to receive antiviral treatment according to Centers for Disease Control and Prevention (CDC) guidelines. Additionally, we evaluated the compliance with CDC antiviral guidelines. Methods A prospective cohort of adults presenting to a tertiary care ED with an acute respiratory illness who met CDC criteria for recommended antiviral treatment were enrolled and tested for influenza. A clinical diagnosis of influenza was assessed by asking the clinician: “Do you think this patient has influenza?” ILI was defined according to current CDC criteria. Results In this cohort of 270 subjects, 42 (16%; 95% CI 11-20%) had influenza. Clinician diagnosis had a sensitivity of 36% (95% CI 22-52%) and specificity of 78% (95%CI 72-83%); EMR final ED diagnosis had a sensitivity of 26% (95% CI 14-42%) and specificity of 97% (95% CI 94-99%); ILI had a sensitivity of 31% (95% CI 18-47%) and specificity of 88% (95% CI 83-92%). Only 15 (36%) influenza positive patients received antiviral treatment. Conclusion Clinician diagnosis, final ED EMR diagnosis and ILI have low sensitivity for diagnosing influenza, and there is overall poor compliance with CDC antiviral treatment recommendations. Improved methods of influenza diagnosis are needed to help guide management in the clinical setting.

Clinical decision making in the emergency department setting using rapid PCR: Results of the CLADE study group

“…As developments in small molecule and monoclonal therapies for influenza infection grow [21][22][23][24], the importance of access to rapid, sensitive diagnostics capable of guiding antiviral prescribing and treatment decisions will become important, a finding supported by our experience. Requirements for diagnostic support of suspected influenza cases is particularly relevant given recent experience demonstrating that clinical recognition of influenza in presenting ED patients lacks sensitivity [25,15]. Our experience confirms that of previous investigators who found that clinical sensitivity for influenza among ED patients was 36% [25].…”

The frequency of influenza and bacterial coinfection: a systematic review and meta‐analysis

“…The CDC recommends simultaneous antiviral and antibiotic use in the event of influenza‐related pneumonia or suspected bacterial coinfection in patients with influenza 58. However, as previous observational studies have shown, patients admitted to the hospital with influenza are more likely to receive antibiotics than antiviral medications 59, 60. Our findings suggest that while patients hospitalized with moderate to severe influenza may be coinfected with both viral and bacterial pathogens, many patients will likely not be coinfected.…”

“…Our findings suggest that while patients hospitalized with moderate to severe influenza may be coinfected with both viral and bacterial pathogens, many patients will likely not be coinfected. Thus, although recognition and treatment of potential bacterial coinfections is important, particularly community‐acquired pneumonia in which pathogens are difficult to detect,61 clinicians should consider treatment of potential underlying viral processes as well, particularly for high‐risk patients 60. Furthermore, to avoid overuse of antibiotics, our study suggests that routine cultures are advisable in patients hospitalized with influenza, particularly those started on antibiotic therapy empirically.…”

Influenza and Viral Pneumonia

“…A clinician diagnosis of influenza had a positive likelihood ratio of 1.63 and negative likelihood ratio of 0.82. 77 Likelihood ratios are an interesting way of providing the accuracy of symptoms or clinical diagnosis because they allow for the estimate of the probability of a disease after taking into account the pre-test probability 78 (Fig. 3).…”

“…In fact, clinicians failed to clinically diagnose influenza in approximately two-thirds of influenza-confirmed patients in a prospective series. 77 Ultimately, clinicians need to pay close attention to surveillance data, and if there is evidence of influenza activity in the area where they practice, any acute febrile respiratory illness should place influenza as a high possibility in the differential diagnosis. In the United States, the Centers for Disease Control and Prevention provide weekly data on influenza activity according to regions in the country.…”