[Etiological diagnosis of pneumonia--a critical view].

OBJECTIVES To search literature related to the etiological diagnosis of acute pneumonia in children. SOURCES Systematic review of Medline and Lilacs databases. SUMMARY OF THE FINDINGS The use of new diagnostic methods such as immunological techniques and polymerase chain reaction has proven invaluable for specific diagnosis and epidemiological investigation, showing adequate sensitivity, specificity and promptness of results, with the aim of guiding therapy properly. Review of epidemiological studies of community acquired pneumonia showed that Streptococcus pneumoniae is still one of the most significant etiologic agents in all age groups, in developing and industrialized countries. Resistance of this agent to penicillin and cephalosporins is increasing in all continents and is worrisome. Atypical agents such as Mycoplasma pneumoniae and Chlamydia pneumoniae are common in community acquired pneumonia, mainly in children older than 4 years, representing one third of the cases in industrial countries. However, their prevalence in developing countries remain to be determined. Respiratory syncytial virus is also a very common etiology of community acquired pneumonia and may cause severe infections, mainly in infants and younger children. The introduction of new conjugated vaccines for Streptococcus pneumoniae and Haemophilus influenzae type b resulted in significant reduction of morbidity and mortality of pneumonia in children. CONCLUSIONS A significant impact on morbidity and mortality of acute pneumonia in children is likely to occur if microbiological and antimicrobial control is continuously and dynamically performed, thus allowing for the development of new vaccines, particularly against the respiratory syncytial virus.