대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pulmonary Actinomycosis

Radiologic Findings

PA chest radiograph demonstrates a small nodular opacity in the right middle lung field. Contrast-enhanced chest CT scan demonstrates multiple small, irregular-shaped or ill-defined nodules in peripheral lower lung fields. Brain MRI shows right sphenoid sinusitis with adjacent osteomyelitis.
After treatment, previously noted bilateral multiple peripheral pulmonary nodules and right sphenoid sinusitis with osteomyelitis have improved.

Follow-up brain MRI after Tx

Follow-up chest CT after Tx

Brief Review

Actinomyces are Gram-positive, anaerobic bacteria, and they are commensals of the human oropharnynx, gastrointestinal tract and female genitalia, often routinely cultured from these mucosa-lined orifices. Pulmonary actinomycosis probably results from aspiration of oropharyngeal or gastrointestinal secretions into the respiratory tract. Support for this theory comes from reports of a higher prevalence of alcoholism in patients with pulmonary actinomycosis and radiologically from the basal predominance of the disease. Pulmonary actinomycosis probably starts when saliva, or other material laden with Actinomyces species, is aspirated into a minor bronchus, causing atelectasis and a pneumonitis.
Parenchymal patterns of pulmonary actinomycosis include cavitary or multifocal, peripheral pulmonary nodule, mass, or consolidation. On CT, consolidation with central low attenuation is found in 62-75 %, and 50-73 % is combined with adjacent pleural thickening. The disease initially manifests as a small, poorly defined, peripheral pulmonary nodule with or without interlobular septal thickening, and it gradually increases to segmental air-space consolidation, which suggests bronchogenic spread of the disease. If therapy is not adequate, the lesion slowly progresses, forming central areas of low attenuation with a cavity. In later stages, lung parenchyma may be destroyed and the infection may extend across fissures to a neighbouring lobe (trans-fissural extension), the pleura, or chest wall, with abscess formation in these areas.

References

1. Edited by M. A. Woodhead and A. Ortqvist. Pulmonary actinomycosis, Eur Respir J 2003; 21: 545–551
2. JY Han, KN Lee, JK Lee et al. An overview of thoracic actinomycosis: CT features. Insights Imaging. 2013 Apr; 4(2): 245–252.

Keywords

Lung, Infection,