Purpose: To determine the frequency and the clinical characteristics of Mycoplasma pneumoniae pneumonia in the elderly.
Methods: Analysis of cases of M pneumoniae pneumonia accumulated as part of a prospective study of community-acquired pneumonia.
Results: Sixty-four (4.9%) of 1300 patients had pneumonia due to M pneumoniae. Six (9.3%) of the 64 were 65 years of age or older. None of the elderly patients had a discharge diagnosis of M pneumoniae compared with 21 of those 64 years of age or younger (36%). Sixty-four percent of the patients with M pneumoniae received erythromycin therapy compared with 45% of 1118 of the patients with community-acquired pneumonia. The clinical features of the six elderly patients with M pneumoniae did not allow distinction from other causes of pneumonia. One patient presented with normal pressure pulmonary edema due to infection with both M pneumoniae and respiratory syncytial virus; a second patient had his Salmonella carrier state converted to bacteremia during his episode of M pneumoniae. Three presented as nonspecific pneumonia in the elderly, while one patient had a slowly resolving infection due to a narrowed bronchus. The 58 patients who were 64 years of age or younger demonstrated four previously unrecognized or underemphasized features of M pneumoniae infection--prolonged thrombocytopenia, one patient; recurrent pulmonary hemorrhage, one patient; thrombocytosis, 45% of the patients; and prolonged hospital stay, eight (13.7%) of the 58 patients. Only one patient died (1.5%) and this was a result of Shy-Drager syndrome.
Conclusions: Mycoplasma pneumoniae accounts for 4.9% of community-acquired pneumonia requiring hospitalization, and 9% of these patients were 65 years of age or older. There are no clinical features that distinguish this form of pneumonia from that due to other agents. The mortality rate from this infection is low even in the elderly.