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A study on intraalveolar exudates in acute mycoplasma pneumoniae infection
Takeo Yoshinouchi1, Yuji Ohtsuki, Jiro Fujita
1Department of Internal Medicine II, Nagoya City University, Medical School, Nagoya, Japan.
Abstract:
Pathologic features of Mycoplasma pneumoniae infection (M. pneumonia) are generally non-specific, and the literature regarding the pathologic features of M. pneumonia with intraalveolar exudates is limited. Clinical and histopathological studies were performed in 3 patients with M. pneumonia which did not respond to erythromycin and minocycline, but all rapidly recovered after corticosteroid therapy. In pathologic findings, we observed intraalveolar exudates and focal organization in M. pneumonia, and its intraalveolar lesions were compared between M. pneumonia and bronchiolitis obliterans organizing pneumonia containing fibrin (BOOP). Immunohistochemical studies were performed using the streptavidin biotin peroxidase complex method with anti-alpha-smooth muscle actin antibody and anti-pancytokeratin AE1/AE3 antibody. In pathologic findings, more fibrin deposits in intaalveolar lesions were observed in M. pneumonia than in BOOP. In intaalveolar lesions of M. pneumonia, a larger amount of nuclear debris, more neutrophils, and more erythrocytes were noted. Myofibroblasts were observed in the organization of BOOP, while in the intaalveolar lesions of M. pneumonia, myofibroblasts were not observed. These results suggest that M. pneumonia with intraalveolar exudates responds well to corticosteroid and its intraalveolar lesions apparently differed from those in BOOP.
Insights
Mycoplasma pneumoniae pneumonia with intraalveolar exudates shows distinct pathologic features and responds well to corticosteroid therapy, differing from bronchiolitis obliterans organizing pneumonia.
Area of Science:
- Pulmonary Pathology
- Infectious Diseases
Background:
- Mycoplasma pneumoniae (M. pneumoniae) infections often present with non-specific pathologic features.
- Limited literature exists on M. pneumoniae with intraalveolar exudates.
Observation:
- Three patients with M. pneumoniae pneumonia resistant to antibiotics showed rapid recovery with corticosteroid therapy.
- Histopathological analysis revealed intraalveolar exudates and focal organization in M. pneumoniae.
Findings:
- Intraalveolar lesions in M. pneumoniae contained more fibrin, nuclear debris, neutrophils, and erythrocytes compared to bronchiolitis obliterans organizing pneumonia (BOOP).
- Myofibroblasts were present in BOOP organization but absent in M. pneumoniae intraalveolar lesions.
- Immunohistochemical studies differentiated M. pneumoniae from BOOP.
Implications:
- M. pneumoniae with intraalveolar exudates demonstrates a favorable response to corticosteroid treatment.
- Distinct pathologic differences exist between M. pneumoniae intraalveolar lesions and BOOP, aiding in diagnosis and treatment strategies.