A65 year-old man presents to the hospital with a one week history of malaise, headache, fever, and chills. he is admitted and over the next week his disease progressed with a worsening cough and shortness of breath. his physical exam was benign except for pulmonary compromise. the patient is current on all of their vaccinations and has no recent travel history. a chest radiograph showed multilobar infiltrates. other significant laboratory findings include an elevated white blood cell count with increased polymorphonuclear neutrophils. because the patient had a prior history of drug abuse and alcoholism, a toxicology screen and hiv serology were performed. both were negative. a bronchoscopy was performed, with a bronchoalveolar lavage (bal) showing many white blood cells, but no organisms. calcofluor white stains for fungi and direct fluorescent-antibody stain (dfa) for pneumocystis were also negative. routine bacterial culture of the bal was negative.