Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Pleuropulmonary paragonimiasis
- Radiologic Findings
- Chest CXR : Bilateral hydropneumothorax
Chest CT : Bilateral hydropneumothorax, subpleural nodular lesions in the left upper lobe
Recurrent bilateral pleural effusion after 4 months.
The patient had a history of having freshwater crab preserved in soy sauce.
Paragonimiasis metacercariae was found in the pleural fluid.
- Brief Review
- P. westermani gains entrance to its human host as an encysted metacercariae within freshwater crabs and crayfish. Once ingested the larvae escape from the cyst in the small intestine, penetrate the intestinal wall, and enter the peritoneal cavity. In 3-8 weeks, they penetrate the diaphragm and pleura and enter the lung. The larvae mature into adult flukes within the lung, and cystic cavities form around the flukes.
On radiographs, during the process of pleural penetration by juvenile worms, pneumothorax or pleural effusion is seen, and during the process of larval migration within the lung, patch migrating air-space cosolidation appears. The appearance of pulmonary lesions on radiographs varies with the stage of the infection and the surrounding tissue reaction. The initial finding is patchy air-space consolidation due to hemorrhagic pneumonia caused by the migrating worm. At this stage pleural effusion and pneumothorax is frequently seen. As juvenile worms mature into adults, they tend to settle down , and cysts form around them (worm cysts).
On radiographs, peripheral linear shadows 2-4mm thick and 3-7cm long and invariably extending from the pleural surface suggest worm migration tracks or peripheral atelectasis caused by obstruction of small airways by the worm.
On CT scans round low-attenuation cystic lesions (5-15mm), filled either with fluid or air, were characteristically seen within the consolidation. Peripheral linear opacities were suggestive of worm migration tracks on CT scans. Other finding were variable-sized nodules and bronchiectasis.
- References
- 1. JG Im, HY Whang, WS Kim, MC Han, YS Shim, SY Cho. Pleuropulmonary paragonimiasis: radiologic finding on 71 patients Am. J. Roentgenol., Jul 1992; 159:39-43.
2. H. Mukae, H. Taniguchi, N. Matsumoto, H. Tiboshi, J.-i. Ashitani, S. Matsukura, and Y.Nawa Clinicoradiologic Features of Pleuropulmonary Paragonimiasis westermani on Kyusyu Island, Japan Chest, August 1, 2001; 120(2): 514 - 520
- Keywords
- Lung, Pleura, Infection, Parasitic infection,