부산대학교 도서관

Abstract.: Background:: Infection by the influenza virus may pass undetected inmany adult patients attended to in the emergency departmentbecause its diagnosis usually relies on clinical manifestations,which can be distorted by symptoms of a preexisting disease,superposed complications or nontypical manifestations ofinfluenza virus infection (confusing symptoms).Patients andMethods:: We performed this observational, prospective study with anantigen detection test by indirect immunofluorescence assay(IFA) to estimate the presence of influenza virus infection insuch patients. No confirmatory test was performed to validate apositive or negative IFA result. Then we compared those who wereantigen positive to those who were negative and also analyzedthose who were positive classified by age, comorbidity andclinical presentation. We also evaluated the use of medical andhospital resources and vaccination status. Posterior pharynxswab specimens from 136 consecutive adult patients, 74 women and62 men with a mean age of 68.7 ± 17.9 (range: 18–97) yearsattended to in the emergency department of a university hospitalin Barcelona during the 1999–2000 influenza epidemic wereexamined. Tested patients presented either a classical influenzasyndrome, a deterioration of a previous condition or any abruptonset of symptoms without an obvious cause.Results:: Influenza A virus antigen was detected in 99 (72.8%) ofthe 136 patients included in the study. Confusing symptoms werepresent in 86 patients with laboratoryconfirmed influenza and 40of them lacked influenza syndrome. Prostration, aching and feverout of proportion to catarrhal symptoms (disproportionateprostration) and cough were independent predictors for thisdiagnosis (OR = 5.14; 95% CI: 1.98–13.35, p = 0.001 and OR =4.40, 95% CI, 1.65–11.75, p = 0.03, respectively). Among the 99patients who tested positive, 72 were ≥ 65 years of age. Thisolder positive group compared to the 27 also positive < 65(non-old) had a tendency to show symptoms mediated by cytokinesless frequently: malaise was present in 76.4% of the olderpositive patients vs 92.6% in the non-old positive ones, p =0.07. The equivalent percentages for muscle ache were: 56.9% vs77.8%, p = 0.06; for dysthermia: 54.2% vs 70.4%, p = 0.08; forheadache: 35.2% vs 66.7%, p = 0.005, and for disproportionateprostration: 47.2% vs 66.7%, p = 0.08. Cough was more frequentin the older positive group: 94.4% vs 77.8%, p = 0.02. Olderpositive patients were also hospitalized and receivedantibiotics more frequently than the non-old positive ones:65.3% vs 40.7%, p = 0.03 and 81.9% vs 63.0%, p = 0.046,respectively. Hospitalization was independently correlated withthe presence of complications (OR = 4.5, 95% IC 1.27–15.95, p =0.02). Patients with the highest comorbidity, evaluated with theCharlson scale, were more inadequately vaccinated than thosewith moderate or low comorbidity.Conclusion:: Influenza virus infection has a great and underestimatedimpact in the emergency department during influenza epidemics.High frequency of confusing symptoms, which overcome classicalinfluenza syndrome in adult people with comorbidity, may explainthis effect. Disproportionate prostration and cough are symptomsthat independently predict its diagnosis in the global adultpopulation, whereas in the elderly, fever and cough shouldarouse this suspicion whether or not they present classicsymptoms. In our setting, individuals with high comorbidity areinadequately vaccinated.