Clinical characteristics of nonresolving or slow-resolving pneumonia

Kim, Se Kyu

Abstract

Unapparent resolution of pulmonary infiltrates is a common consultative problem for the pulmonologist. Nonresolving and slowly resolving pneumonias pose a diagnostic challenge. Nonresolving pneumonia or slow-resolving pneumonia is used to define the clinical situation in which an adequate resolution of radiographic infiltrates or clinical symptoms is not achieved despite appropriate antibiotic treatment for pneumonia. Nonresolving pneumonia represents treatment failure as a result of an infectious cause such as inappropriate initial antibiotic therapy and resistant or unusual microbial infection, and a noninfectious cause. It is critical to be able to identify patients with nonresponding pneumonia and to identify patients at risk for progressive pneumonia to institute appropriate therapy. A variety of abnormalities in host defense may result in delayed resolution of pneumonia. The most common host-related factors associated with a delayed resolution are older age, DM, smoker, COPD, and immunocompromised state. When these factors are present, the infection may be expected to take longer than usual to clear. Noninfectious etiologies of nonresolving pneumonia include neoplasms, pulmonary hemorrhage, pulmonary embolism, sarcoidosis, eosinophilic pneumonia, pulmonary edema, acute respiratory distress syndrome, bronchiolitis obliterans organizing pneumonia, drug-induced pneumonitis, and pulmonary vasculitis. The sheer number of alternative diagnoses, both infectious and noninfectious, can overwhelm the clinician and lead to unnecessary testing. Knowledge of typical resolution patterns and risk factors for delayed resolution can aid the clinician and prevent an exhaustive search for alternative etiologies. A systematic approach to the diagnostic evaluation should be considered.