title: Pediatric parapneumonic pleural effusion: epidemiology, clinical characteristics, and microbiological diagnosis.
abstract: BACKGROUND
  In recent years an increase in the incidence and severity of parapneumonic pleural effusion (PPE) in pediatric populations has been observed. Streptococcus pneumoniae remains the main causal agent. New molecular and antigen techniques have increased the microbiological diagnosis of this pathology.
  
  
  OBJECTIVE
  To describe the epidemiology and clinical characteristics of PPE in our population.
  
  
  METHODS
  Prospective study of patients under the age of 18 years admitted for PPE in a tertiary-care pediatric hospital in Barcelona (Spain) between September 2003 and December 2006.
  
  
  RESULTS
  One hundred ninety cases of PPE were diagnosed. The annual incidence of PPE in the population under 18 years of age increased from 19.9 cases per 100,000 in 2004 to 35.2 per 100,000 in 2006. S. pneumoniae was the main causal agent identified: 82.9% of the 21.6% patients with positive culture. Non-vaccine serotypes (NVS) predominated (81.5%), and serotype 1 was responsible for 38.5% of cases. The use of polymerase chain reaction (PCR) test to detect S. pneumoniae increased etiological diagnosis from 21.6% to 42.1%. Antigen assays used to detect pneumococcus in pleural fluid demonstrated 87.9% sensitivity and 100% specificity when PCR was used as the gold standard.
  
  
  CONCLUSIONS
  There has been an increase in the incidence of PPE that parallels the increase in CAP. S. pneumoniae remains the principal causal agent, and NVS clearly predominate. The use of PCR to detect S. pneumoniae substantially increases etiologic diagnosis. The use of antigen assays to detect pneumococcus in pleural fluid is a quick and sensitive diagnostic method, and thus a valid alternative to PCR.
authors.affiliation: Department of Pediatrics, Infectious Diseases Unit, Hospital Sant Joan de Déu, Universitat de Barcelona, Barcelona, Spain.
authors.forename: Susanna
authors.initials: S
authors.lastname: Hernández-Bou
authors.forename: Juan José
authors.initials: JJ
authors.lastname: García-García
authors.forename: Cristina
authors.initials: C
authors.lastname: Esteva
authors.forename: Amadeu
authors.initials: A
authors.lastname: Gené
authors.forename: Carles
authors.initials: C
authors.lastname: Luaces
authors.forename: Carmen
authors.initials: C
authors.lastname: Muñoz Almagro
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D010996:Pleural Effusion / Q000453:epidemiology / Q000382:microbiology*; D011014:Pneumonia / Q000150:complications*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*