[Evaluating severity of community-acquired pneumonia in adults].

Clinical evolution in patients affected by community acquired pneumonia varies from a mild and low risk infectious disease to an extremely severe, life threatening disease. Commonly, immunocompetent adults without co-morbidities or severe risk factors cared for at out patient clinic have low risk of complications and death (mortality below 1-2%); it increases to 5-15% in patients with co-morbidities and/or with specific risk factors that are admitted into the hospital and reaches 20-50% in those patients admitted into ICUs. Evaluation of severity in patients with pneumonia allows the prediction of disease evolution, establishing the proper setting of care, the type- of microbiological tests needed, and to choose the best empiric antibiotic treatment. It is suggested that patients be in three risk categories: low risk (mortality under 1-2%) susceptible to ambulatory treatment; high risk patients (mortality 20-30%) that need specialized wards; and intermediate risk patients, with co-morbidities and/or risk factors for complicated clinical evolution and death, but cannot be classified in a specific category. In the ambulatory setting, without availability of complete laboratory exams, it is recommended to evaluating the severity of pneumonia considering the following clinical variables: age over 65 years, presence of co-morbidities, sensorial compromise, vital signs alteration, degree of radiological involvement: multilobar, bilateral findings, cavitations), pleural effusion and arterial oximetry < 90%. However, clinical judgement and the physician's experience must predominate over predictive models, which are not infallible.