Reasons patients present to the emergency department might change during epidemics and be a valuable component of a disease surveillance system.

We hypothesize that the frequency of reasons patients present to the emergency department will change during epidemics and might be a valuable component of a disease surveillance system. We found support for this hypothesis over a two-year period with high frequency days of fever clustering during two periods of increased hospital influenza activity, but not during any other period during the two-years. This methodology appears to be superior to the previous use of triage nurses defining patients with symptom complexes. Such a system could result in online monitoring, be independent of the medical personnel (use of admission secretary), and might be able to identify various epidemics including increased hospital disease activity due to bio-terror attacks, influenza, and food poisoning. This would have important implications for limiting the spread of disease and for the acute planning of distribution of medical resources. Studies are warranted in various settings to determine whether or not changes in the daily frequencies of reasons patients present to the ED will allow identification of epidemics.

Increased complaints of fever in the emergency room can identify influenza epidemics.

BACKGROUND: In developing countries, it may be easier to use the reasons why patients come to the emergency room (ER) instead of sentinel practices to identify influenza epidemics. METHODS: We studied the reasons why adult patients present to the ER in order to attempt to predict increased hospital activity as a result of influenza. The daily frequency of presenting symptoms during the 30 days of maximal influenza activity was compared to the other days of the study period (335 days). RESULTS: During the influenza period, more patients presented with fever, syncope or near syncope, cough, asthma attack, and paralysis than on the days outside of this period. On 50% of the days, eight or more patients presented with fever, an 8.36 (95% CI=4.6-15.19) higher frequency than during the rest of the year. During the subsequent year, days with excess presentations by patients with a principal complaint of fever predicted increased hospital activity due to influenza with no false-positive periods. CONCLUSIONS: We conclude that an increase in the number of patients presenting to the ER complaining of fever can identify increased hospital influenza activity.