Clinical relevance and characteristics of pleural effusion in patients with Mycoplasma pneumoniae pneumonia

Data regarding parapneumonic pleural effusion in Mycoplasma pneumoniae pneumonia (MP) patients are limited. In this study MP patients with pleural effusion tended to be younger and had longer hospital stays and more common use of systemic steroids compared to those without pleural effusion. In 5 of the 6 patients for whom pleural fluid data were available, the pleural effusion was lymphocyte-predominant rather than polymorphonuclear leukocyte-predominant; these patients also had elevated adenosine deaminase levels. Taken together, these results indicate that MP patients with pleural effusion may have a more severe form compared to those without pleural effusion. M. pneumoniae should be considered an aetiological agent of lymphocyte-predominant pleural effusion.