Severe Acute Lung Injury Caused by Mycoplasma pneumoniae: Potential Role for Steroid Pulses in Treatment

Published evidence of pathogenetic mechanisms of acute respiratory distress syndrome (ARDS) in mycoplasmal lung infections suggests that the pulmonary injury is related to a cell-mediated immune response. Therefore, steroids may play a role in the treatment of severe cases. We describe a patient who had Mycoplasma pneumoniae pneumonia that progressed to severe ARDS requiring mechanical ventilation and who had improvement with prednisolone pulses. Severe pulmonary injury due to Mycoplasma pneumoniae is extremely unusual, and there are only scarce descriptions of patients who needed invasive ventilatory support [1]. In this report, we describe a previously healthy young man who, while receiving effective antibiotic treatment, developed adult respiratory distress syndrome (ARDS) related to M. pneumoniae infection. He was treated with high doses of corticosteroids. After he received treatment, his condition improved radiologically and clinically, and gasometric parameters improved in a temporal pattern consistent with a causal relation between this improvement and the administration of pulses of methylprednisolone. A review of the literature on the subject supports the idea that lung injury in mycoplasmal infections is the result of an excessively vigorous cell-mediated immune response. The down-regulation of this response would be the pathophysiological substrate for corticosteroid usefulness.