Initial clinical management of symptomatic adult patients during influenza A (H1N1) epidemics.
BACKGROUND
Pandemic influenza A (H1N1) has emerged rapidly in Argentina since May 2009. Preliminary comparisons with seasonal influenza suggest that H1N1 disproportionately affects younger patients, generally causing mild disease, but in a minority of cases can be lethal.


OBJECTIVE
The aim of this study was to develop a clinical tool for the initial management of patients with influenza-like syndrome, within the context of the novel H1N1 virus epidemic, to detect patients who need further investigation (e.g., chest X-ray study) for the diagnosis of pneumonia.


METHODS
We prospectively studied 1090 consecutive patients with influenza-like syndrome for a period of 15 days. Based on the presence of inspiratory crackles and the level of transcutaneous pulse oximetry, we selected 217 patients requiring chest X-ray study, and pneumonia was confirmed in all of these patients.


RESULTS
Among the patients with pneumonia, 132 viral diagnostic tests were available, from which specimens tested by real-time reverse-transcriptase polymerase-chain reaction (RTPCR) were positive for H1N1 in 61 patients (46%). Comparison between RTPCR-positive and RTPCR-negative patients did not show any significant difference. Eighty-seven randomly selected patients with influenza-like syndrome, but without crackles and with O(2) saturation>96%, received chest X-ray studies; none demonstrated pulmonary infiltrates.


CONCLUSIONS
Within the context of an influenza epidemic with the new H1N1 virus, the use of two simple and accessible clinical signs permits a rapid differentiation between those patients requiring close monitoring vs. those with mild and self-resolving disease.
Sala
Hernando
H
Hospital Nacional A. Posadas, El Palomar, Argentina.
Roca
Jaime Segovia
JS
Zerbo
Cecilia
C
Garcia
Rodrigo
R
Cabral
Graciela
G
Fernandez
Alejandra
A
Tummino
Carlos
C
Baldini
Matias
M
Rizzo
Oscar
O
D000328:Adult; D001118:Argentina / Q000453:epidemiology; D001785:Blood Gas Monitoring, Transcutaneous; D058872:Epidemics; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012135:Respiratory Sounds / Q000175:diagnosis