Influence of age in the clinical differentiation of atypical pneumonia in adults
Naoyuki Miyashita1, Yasuhiro Kawai2, Mika Kubo2, Kazunobu Ouchi2 and Niro Okimoto1
1Department of Internal Medicine I, Kawasaki Medical School, Okayama, Japan, 2Department of Pediatrics, Kawasaki Medical School, Okayama, Japan
Background and objective: The Japanese Respiratory Society (JRS) scoring system is a useful tool in the early and simple presumptive diagnosis of atypical pneumonia, Mycoplasma pneumoniae and Chlamydia pneumoniae pneumonia. However, it has been suggested that it seems to be difficult to diagnose atypical pneumonia in the elderly using this system. In the present study, we evaluated the accuracy and usefulness of the JRS scoring system in the different age groups.
Methods: We analyzed 262 cases of M. pneumoniae, 98 cases of C. pneumoniae and 364 cases of common bacterial pneumonia.
Results: The frequency of co-morbid illnesses and higher risk classes in the elderly (age ≥60 years) group was significantly higher than those of non-elderly patients (age <60 years) in both atypical pneumonias. One or more additional etiological factors were found more frequently in the elderly group than in non-elderly patients. The diagnostic sensitivity and specificity for atypical pneumonia were 39% and 88% for the elderly group and 86% and 88% for age non-elderly group, respectively. When the diagnostic sensitivity was analyzed for different ages stratified into 10-year groups, the sensitivity was highest in the 18–29-year-old group and decreased in order from the youngest to the oldest age group.
Conclusions: Our results indicate that it is difficult to distinguish between atypical pneumonia and bacterial pneumonia in the elderly using the JRS scoring system. When treating patients aged ≥60 years, physicians should choose fluoroquinolones or β-lactams + macrolides as empirical first-choice drugs, so as to always include potential antibiotic cover for atypical pathogens.