A 68-year old patient with Alzheimer disease was brought to the

emergency room by the staff of a local nursing home. He presented as lethargic

with a sallow complexion. He had an admission temperature of 102.4F and a

respiratory rate of 33/minute. During respiration, the right side of his chest

moved better than the left. He showed dense consolidation of the lower lobe of

the left lung on physical exam. A sputum sample revealed blood and a greenish

color.

A chest x-ray showed tight consolidation of the left lung with

evidence of formation of cavities in the lung tissue from cytotoxic damage. The

patient complained of chills in the exam room, combined with his fever. A smear

of his sputum demonstrated no acid-fast bacteria.

What

is your presumptive diagnosis for this case?