Clinical predictors of influenza in children.
BACKGROUND
It is difficult to diagnose influenza infection on clinical grounds alone. Available rapid diagnostic tests have limited sensitivities.


OBJECTIVE
To develop a prediction model that identifies children likely to have influenza infection.


METHODS
Prospective study.


METHODS
Emergency department of a children's hospital. Patients All patients with a febrile respiratory illness during the influenza season of winter 2002 were eligible. A prospective sample of 128 children who were suspected of having influenza infection based on predetermined criteria was enrolled. Each patient received a nasal wash for viral culture.


METHODS
Clinical features that are most predictive of influenza infection in children.


RESULTS
The mean +/- SD age of patients was 6.2 +/- 5.2 years; 50% were boys. Viral isolates included the following: influenza A, 45 patients (35%); influenza B, 13 (10%); other viruses, 10 (8%); negative results, 60 (47%). Demographic and clinical findings were not significantly different between the influenza A and influenza B groups. Cough (P =.003), headache (P =.04), and pharyngitis (P =.04) were independently associated with influenza infection. This triad used as a prediction model for influenza infection had a sensitivity of 80% (95% confidence interval [CI], 69%-91%); specificity, 78% (95% CI, 67%-89%); and likelihood ratio for a positive viral culture for influenza, 3.7 (95% CI, 2.3-6.3). The posttest probability of this clinical definition is 77% (95% CI, 63%-91%).


CONCLUSIONS
The triad of cough, headache, and pharyngitis is a predictor of influenza infection in children.
Friedman
Marla J
MJ
Department of Pediatrics, Alfred I. duPont Hospital for Children, Wilmington, Delaware, USA. marla.friedman@mch.com
Attia
Magdy W
MW
D002648:Child; D003371:Cough / Q000209:etiology; D005260:Female; D006261:Headache / Q000209:etiology; D006801:Humans; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000175:diagnosis*; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D008962:Models, Theoretical; D010612:Pharyngitis / Q000209:etiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity