Discussion
Diagnosis With Brief Discussion
- Diagnosis
- Pulmonary Paragonimiasis
- Radiologic Findings
- Contrast-enhanced axial CT (Figs. 1, 2) and HRCT images (Fig. 3, 4) show continuous ovoid and elongated poorly enhancing consolidation from the subpleural aspect of the posterior segment of the RUL to the peripheral aspect of the anterior segment of the RUL. Necrotic fluid as well as two gas-filled cysts can also be seen in anterior segment of the RUL with surrounding subtle GGA (ground glass attenuation).
- Brief Review
- Human paragonimiasis is caused by the trematode Paragonimus westermani or other Paragonimus species through the ingestion of raw or partially cooked freshwater crabs or crayfish infected with metacercaria. Main endemic areas of this disease are East Asia, Southeast Asia, Latin America (primarily Peru), and Africa (primarily Nigeria). The lung is the target organ, although cutaneous and cerebral paragonimiasis have also been described. Patients with disease present with fever, chest pain, and respiratory symptoms such as chronic cough and hemoptysis. Diagnosis is confirmed through the detection of parasite eggs in the sputum, pleural fluid, or feces. In addition, the larvae can often be found via bronchial brushing. Intradermal and serologic tests are also available.
Radiologic findings correlate well with the stage of the disease, i.e., the penetration of juvenile worms through the diaphragm into the pleural cavity can cause pleural effusion or pneumothorax. Once the parasites reach the lung, patchy airspace consolidations can be observed, a phenomenon that reflects the presence of exudative or hemorrhagic pneumonia which can cavitate. Contrast–enhanced CT performed during this stage may show hypoattenuating fluid-filled cysts surrounded by hyperattenuating consolidation in the adjacent lung. Linear areas of increased opacity or hyperattenuation indicate peripheral atelectasis or worm migration. Worm cysts, whose diameters range from 0.5 to 1.5 cm, are better visualized after the consolidation resolves and manifest as either solitary or multiple nodules or gas-filled cysts depending on their content and their communication with the airway. Chest radiographic and CT findings include a ring shadow usually less than 3 mm thick and a crescent-shaped area of increased opacity or hyperattenuation within the cyst indicating that the worms have attached to the wall. Complications of cysts include pleural effusion, empyema, and pneumothorax.
- References
- 1. Im JG, Whang HY, Kim WS, et al. Pleuropulmonary paragonimiasis: radiologic findings in 71 patients. AJR 1992;15-:39-43.
2. Im JG, Kong Y, Shin YM, et al. Pulmonary paragonimiasis: clinical and experimental studies. RadioGraphics 1993; 13:575-586.
3. Kim TS, Han J, Shim SS, et al. Pleuropulmonary paragonimiasis: CT findings in 31 patients. AJR 2005; 185:616-621.
4. Martnez S, Restrepo CS, Carrillo JA, et al. Thoracic Manifestations of Tropical Parasitic Infections: A Pictorial Review. RadioGraphics 2005; 25:135-155.
- Please refer to
- Case 259 Case 295 Case 349 Case 409 Case 502 Case 527 Case 537 Case 585 Case 612 Case 676 Case 684 Case 715 Case 741 Case 828 Case 885
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- Keywords
- Lung, Infection, Parasitic infection,