Respiratory tract infections in adults.

Most upper respiratory tract infections are caused by viruses, but recognition of the cause of a particular illness is impossible based on clinical findings alone. Epiglottitis caused by type B Hemophilus influenzae can occur in adults with the same threat to upper airway obstruction as in children. An approach to the diagnosis of pneumonia is outlined and pneumonias caused specifically by viruses, mycoplasma, and bacteria are described.