Diagnosis and interventions in lower respiratory tract infections

In the elderly and in immunocompromised patients, respiratory tract infections are still a major cause of morbidity and mortality. The choice of a specific antibiotic treatment in pneumonia depends on the identification of the causative pathogen or on a judgment concerning the probable causative micro-organism. This judgment should be based on all the information obtained from clinical signs and symptoms, laboratory investigations of sputum and blood, and the pattern of infiltrations on chest X-ray. Different causative pathogens can be expected in bacterial and "atypical" community-acquired pneumonia than in hospital-acquired pneumonia. For the same reason, immunocompetent and immunocompromised patients have to be distinguished from each other. In chronic obstructive pulmonary disease, bronchial defenses will be impaired. Exacerbations can result from different causes, including infections of the bronchial mucosa. Most of these infections are of viral origin. Exacerbated pulmonary disease will result from bacterial bronchitis only in some patients. It is often difficult to assess the diagnosis "bacterial bronchitis." Evaluation of the effect of antibacterial treatment in exacerbated pulmonary disease is also difficult. Therapeutic interventions for these clinical conditions have to be directed primarily toward restoring or improving pulmonary host-defense factors. Fluoroquinolones, including lomefloxacin, have been shown to be effective in the treatment of lower respiratory tract infections caused by susceptible bacteria. Lomefloxacin presents a number of advantages: the drug has good bioavailability after oral and parenteral administration and penetrates well into bronchial secretions and lung tissue. In addition, lomefloxacin has no influence on the metabolic clearance of the methylxanthines theophylline and caffeine, which has been demonstrated for enoxacin, ciprofloxacin, and pefloxacin.