Think global –act local: High pediatric occult pneumonia rates in Israel may suggest different guidelines for obtaining a chest x-ray than in the United States

Background: The prevalence of occult pneumonia within a pediatric population shapes clinical guidelines regarding the use of chest radiography in children with fever but no other clinical signs of pneumonia. In Israel, where routine anti-pneumococcal immunization was slower to be introduced than in the United States, a 2006 study revealed a 20.6% prevalence, suggesting that chest x-rays may still be indicated in children presenting with fever alone. In this study, using 2010 data, we sought to determine the frequency of pediatric occult pneumonia in Israel since the introduction of the vaccine. Methods: Charts were reviewed for 957 random patients between age 2 months and 10 years who presented to an urgent care center in Jerusalem in 2010 with a chief complaint of fever or respiratory symptoms and had a chest x-ray performed. Data collected included radiologist interpretation of the chest x-ray, significant respiratory findings (tachypnea, decreased air entry, rales, hypoxia), and demographic information. Results: The overall percentage of occult pneumonia was 12.3% (95% CI:10.4-14.6). Under age two, the rate was 10.7% (CI: 8.5-13.6). The rate for those between the ages of 2-5 years was 14.0% (CI: 10.3-18.7). For those ages 5-10 years, the rate was 16.0% (CI: 10.7-23.3). Conclusions: The prevalence of occult pneumonia in Israel suggests that chest x-ray is still an important tool in the search for fever without clinically obvious source, contrary to United States guidelines, where prevalence is lower. The age related changes may reflect the beginning of the effect of anti-pneumococcal vaccination.