Lower respiratory tract infections. Although lower respiratory tract infections are frequently diagnosed in a primary care setting, they are still associated with a significant morbidity and mortality, which warrants a careful approach to treatment. Knowledge of the most common cause based on the age of the patient, location where the infection was acquired, and clinical presentation helps to direct empiric treatment. A few basic laboratory studies, especially a sputum Gram stain, can allow for more specific treatment. Identification of patients at increased risk for virulent organisms should make the primary care physician consider inpatient treatment along with an aggressive diagnostic workup and broad-spectrum antimicrobial treatment. Prevention should always be considered. 