Campaña Sida

C LINICA L PRAC TIC E

Clinical Practice

This Journal feature begins with a case vignette highlighting a common clinical problem. Evidence supporting various strategies is then presented, followed by a review of formal guidelines, when they exist. The article ends with the authors’ clinical recommendations.

STRATEGIES AND EVIDENCE
Diagnosis and Treatment of Pneumonia

M ANAGEMENT OF COMMUNITY A CQUIRED P NEUMONIA
ETHAN A. HALM, M.D., M.P.H., AND ALVIN S. TEIRSTEIN, M.D.

A 65-year-old man with hypertension and degenerative joint disease presents to the emergency department with a three-day history of a productive cough and fever. He has a temperature of 38.3°C (101°F), a blood pressure of 144/92 mm Hg, a respiratory rate of 22 breaths per minute, a heart rate of 90 beatsper minute, and oxygen saturation of 92 percent while breathing room air. Physical examination reveals only crackles and egophony in the right lower lung field. The white-cell count is 14,000 per cubic millimeter, and the results of routine chemical tests are normal. A chest radiograph shows an infiltrate in the right lower lobe. How should this patient be treated?
THE CLINICAL PROBLEM

There areapproximately 4 million cases of community-acquired pneumonia in the United States each year, resulting in about 1 million hospitalizations.1-3 Inpatient management of pneumonia is more than 20 times as expensive as outpatient care and costs an estimated $9 billion a year.2,3 The length of hospitalization is the key determinant of inpatient costs.2,4 Previous studies have found wide variations inthe rates and lengths of hospitalization among patients with pneumonia that are not explained by differences in the characteristics of the patients or the severity of disease.5-10 This article focuses on the initial management of community-acquired pneumonia in immunocompetent adults.
From the Department of Health Policy (E.A.H.) and the Divisions of General Internal Medicine (E.A.H.) andPulmonary and Critical Care Medicine (A.S.T.), Department of Medicine, Mount Sinai School of Medicine, New York. Address reprint requests to Dr. Halm at the Department of Health Policy, Box 1077, Mount Sinai School of Medicine, 1 Gustave L. Levy Pl., New York, NY 10029, or at ethan.halm@mountsinai.org.

Patients with pneumonia usually present with cough (more than 90 percent), dyspnea (66 percent),sputum production (66 percent), and pleuritic chest pain (50 percent), although nonrespiratory symptoms can also predominate.11,12 Elderly patients may report fewer symptoms.13,14 Unfortunately, information obtained from the history or physical examination cannot rule in or rule out the diagnosis of pneumonia with adequate accuracy.15 All rigorous definitions of pneumonia require the finding of apulmonary infiltrate on a chest radiograph.16 The initial antibiotic regimen should be chosen empirically to cover common typical and atypical pathogens (Table 1). Pneumonia due to atypical organisms (Mycoplasma pneumoniae, legionella species, and Chlamydia pneumoniae) accounts for 20 to 40 percent of cases and cannot be differentiated from cases due to typical bacteria on the basis of the patient’shistory, the results of the physical examination, or findings on chest radiographs.17,18 Two large observational cohort studies found that antibiotic regimens that cover both typical and atypical organisms are associated with a lower risk of death than regimens that cover just typical bacteria.19,20 Although rigorous data regarding the duration of therapy are limited, most experts recommend atotal of 10 to 14 days. Intravenous therapy with antibiotics that have a high level of oral bioavailability (e.g., fluoroquinolones) may be no better than oral therapy with such antibiotics in patients with uncomplicated infections who have a functioning gastrointestinal tract.21,22
Risk Stratification and the Decision to Hospitalize

Between 30 percent and 50 percent of patients who are...