Clinicoradiologic features of pleuropulmonary Paragonimus westermani on Kyusyu Island, Japan

Recently, the number of new cases of Paragonimus westermani in humans has gradually increased, and paragonimiasis is a re-emerging public health issue in Kyusyu, Japan. We review our recent experience with pleuropulmonary Paragonimus westermani.

Pulmonary paragonimiasis was diagnosed in 13 patients at the Third Department of Internal Medicine, Miyazaki Medical College between 1993 and 1999.

Both sputum and bronchoscopic examinations revealed ova in four of nine patients; bronchoscopy yielded ova in two additional patients. Twelve patients (92%) had respiratory symptoms, including cough (92%), sputum and/or hemoptysis (92%), and chest pain (46%). Chest radiography and CT showed pleural lesions (62%) and parenchymal lesions (92%). Of note was the high frequency of solitary nodular lesions (62%), mimicking lung cancer, tuberculosis, or fungal diseases. Immunodiagnosis and bronchoscopic examination were also useful for diagnosis. Praziquantel treatment was very effective and had minimal side effects. One patient required surgical decortication for empyema in spite of treatment with praziquantel. Eosinophilia was noted in peripheral blood and body fluids, which was probably due to increased levels of interleukin-5.

Our findings indicate that our patients with Paragonimus westermani presented with a wide variety of radiographic findings, which were different from the classic presentations reported earlier. Bronchoscopic examination and serologic tests are very useful for accurate diagnosis. As dietary habits change and international transportation increases, it appears likely that paragonimiasis will also increase in frequency in various parts of the world.