CHESTS RADIOGRAPHS AND CT FINDINGS IN THO RACIC ACTINOMYCOSIS

The aim of this study was to evaluate chest radiographs and computed t omography (CT) in patients with thoracic actinomycosis. Material and m ethod: Chest radiographs and CT scans of 9 patients with proved thorac ic actinomycosis were reviewed. CT scans were performed after intraven ous contrast administration. Results: Airspace consolidation was prese nt in the upper lobes in 6 patients and in the lower lobes in 3. Cavit ations not apparent on the radiographs were seen on CT s in 2 cases. M ediastinal lymphadenopathies were seen on CT s in 2 cases, in one the infection extended through the mediastinal pleura into the mediastinum . Pleural thickening adjacent to the airspace consolidation was identi fied in 6 cases. Chest wall invasion occurred in 4 cases with a wavy p eriostal reaction involving ribs adjacent to the site of parenchymal i nvolvement in 3 cases. Extension into the abdomen through the diaphrag m was seen in one case.Discussion: In humans, actinomycosis involves t he thorax in 15% of the cases. Thoracic and pulmonary parenchymal invo lvement is usuary secondary to aspiration of colonized material from t he orophraynx in patients with poor oral hygiene. There is a basilar p redominance of the disease, but some studies have reported apical pred ominance. The pulmonary infection leads to an airspace consolidation m ainly in the lung periphery. The infection may extend across fissures and through the pleura. Chest wall and bone invasion are not uncommon. A wavy periosteal reaction involving ribs is said to be highly sugges tive of pulmonary actinomycosis. Conclusion: Thoracic actinomycosis is characterized by airspace consolidation with adjacent pleural thicken ing. Chest wall invasion with a wavy periosteal reaction is higly sugg estive.