Influenza pneumonia.
BACKGROUND
Influenza and pneumonia are common childhood illnesses, but few studies have been conducted on influenza-related pneumonia in children. The aim of this study was to describe the frequency and characteristics of laboratory-documented and radiologically detected influenza pneumonia in children.


METHODS
This study involved children treated at the Department of Pediatrics, Turku University Hospital, from 1980 through 2003. Influenza A or B infection was documented with the use of antigen detection from nasopharyngeal aspirates. Children with chest radiographs obtained during influenza episodes were identified. Chest radiographs were reevaluated by a pediatric radiologist for verification of pneumonic infiltrates. Clinical and laboratory data were collected from medical records.


RESULTS
Pneumonia was detected in 134 (14%) of 936 children with influenza infection. The most frequent signs of influenza pneumonia were fever and cough. Of these children, 47% had no specific clinical signs or symptoms suggesting pneumonia. White blood cell count was <15 x 10/L in 89% and serum C-reactive protein concentration <80 mg/L in 85% of the children. One-half of the children had solely interstitial infiltrates, one-fourth solely alveolar and one- fourth both alveolar and interstitial infiltrates on the chest radiograph. The hospitalization rate was 68%, and the median duration of hospitalization was 2 days. Complicated pneumonias were rare, and mortality was low (0.7%).


CONCLUSIONS
Pneumonia is detected in a minority of children treated for influenza at a tertiary center. Unlike in adults, influenza pneumonia in children is usually a benign illness, and the mortality is low.
Lahti
Elina
E
Department of Pediatrics, Turku University Hospital, Vähä-Hämeenkatu 1A3, 20500 Turku, Finland. elkrla@utu.fi
Peltola
Ville
V
Virkki
Raimo
R
Ruuskanen
Olli
O
D002097:C-Reactive Protein / Q000032:analysis; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D009980:Influenza A virus / Q000302:isolation & purification; D009981:Influenza B virus / Q000302:isolation & purification; D007251:Influenza, Human / Q000150:complications* / Q000453:epidemiology; D007958:Leukocyte Count; D008297:Male; D011014:Pneumonia / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D011024:Pneumonia, Viral / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D011859:Radiography
D002097:C-Reactive Protein