Beware of Mimics in Diagnosing, Treating Influenza

SAN ANTONIO – Influenza can present with a wide range of symptoms which overlap with several life-threatening conditions. Emergency physicians especially must be able to rapidly identify patients at risk for complications and those who require immediate resuscitation, according to a new review.

A study published recently in the Journal of Emergency Medicine discusses how, given the wide range of symptoms, emergency physicians must maintain a broad differential diagnosis in the evaluation and treatment of patients presenting with influenza-like illnesses.1

This review, led by authors from the San Antonio Military Medical Center at Fort Sam Houston, TX, focused on objective and subjective symptoms commonly associated with influenza and discussed important mimics of influenza viruses. The goal was to offer a practical approach to their clinical evaluation and treatment.

Background information in the report noted that influenza-like symptoms are common in the ED, with the infection accounting for more than 200,000 hospitalizations annually. Past research has indicated that signs and symptoms of influenza can be confused with those of many other viral upper respiratory tract infections. Furthermore, human parainfluenza virus, adenoviruses, enteroviruses, and paramyxoviruses, might initially cause influenza-like illness. Even the early presentation of mild or moderate cases of flavivirus infections such as dengue might mimic influenza, and some cases of West Nile fever have been clinically misdiagnosed as influenza. 

Study authors suggested the most reliable means of identifying influenza in the ED is rapid antigen detection, although consideration of local prevalence also is required. High-risk populations, they wrote, include children younger than 4 years, adults older than 50 years, adults with immunosuppression or chronic comorbidities, pregnancy, obesity, residents of long-term care facilities, and several others.

While the Centers for Disease Control and Prevention recommends treatment with neuraminidase inhibitors in these populations, this report cautioned that as many as 70% of patients with flu-like symptoms might actually have a mimic – whether from infectious and noninfectious sources.

“The emergency physician must be aware of life-threatening mimics and assess for these conditions while beginning resuscitation and treatment,” study authors emphasized.

  1. Simon E, Long B, Koyfman A. Clinical Mimics: An Emergency Medicine-Focused Review of Influenza Mimics. J Emerg Med. 2017 Feb 15. pii: S0736-4679(16)31138-6. doi: 10.1016/j.jemermed.2016.12.013. [Epub ahead of print] PubMed PMID: 28215397.

Share Your Thoughts