RESUMO
Background: Community-acquired pneumonia in adults is a serious health problem in the ambulatory care setting. Aim: To define clinical variables associated with the presence of pneumonia in adult patients presenting with fever or respiratory symptoms to the emergency department. Material and methods: Prospective study carried out in the emergency department from the Catholic University Hospital in Santiago, Chile. Three hundred twenty-five patients (53±22 years) presenting fever or acute respiratory symptoms were included. After obtaining a clinical history and physical examination, the physician established a tentative diagnosis. Subsequently, a definitive diagnosis was made with the chest X rays. Results: Thirty-four percent of the patients had pneumonia. The clinical diagnosis of pneumonia before X-ray examination was variable among emergency physicians (positive likelihood ratio: 1.5-4.8) and showed only moderate sensitivity (79 percent) and specificity (66 percent). The clinical variables significantly associated with the presence of pneumonia were: advanced age (over 75 years), cardiovascular disease, fever, chills, sputum production, orthopnea, altered mental status, cyanosis, dullness on percussion, bronchial breath sounds, crackles, any abnormal vital sign (heart rate ³100 beats/min, respiratory rate ³20 breaths/min or temperature ³38°C) and oxygen saturation below 90 percent breathing air. Conclusions: Clinical judgment prior to observation of chest X rays had moderate sensitivity and specificity for the diagnosis of pneumonia. There were no individual clinical findings, or combination of findings, that could confirm or exclude the diagnosis of pneumonia for a patient suspected of having this illness.