Paragonimiasis is a parasitic infection caused by the Paragonimus species (most commonly Paragonimus Westermani) of lung flukes and is particularly common in East Asia however the more than 30 species of the flukes are becoming more prevalent worldwide. Commonly causing a pulmonary syndrome consisting of lung parenchymal hemorrhage and hemoptysis, the species is becoming more and more notorious for causing intracerebral hemorrhage, as those with both acute and chronic cerebral paragonimiasis appear at risk of having cerebral hemorrhages. The group from West China Hospital at Sichuan University set out to characterize cerebral paragonimiasis and its impact on cerebrovascular disease.
The authors retrospectively analyzed the clinical and imaging characteristics, diagnosis and treatment outcomes of 10 patients with hemorrhagic cerebral paragonimiasis. The group had an average age of 15.7 years and ranged from 4 to 46 showing the younger cohort that the disease affects. The diagnosis of paragonimiasis was done by ELISA serologic testing for Paragonimus-specific IgG antibody and blood eosinophil quantification was conducted on blood samples. The manifestations of the paragonimiasis were vascular malformation, tumor apoplexy, subarachnoid hemorrhage, intraventricular hemorrhage, cavernous hemangioma, subdural hemorrhage and spontaneous intracerebral hemorrhage. Four out of the ten cases were confirmed by pathology. The hemorrhages seen were atypical of occult vascular malformations and the hemorrhages themselves had atypical appearances such as dot, strip, sheet or cord-shaped hematomas. Other imaging testing was done to rule out other cerebrovascular disease on an as needed basis. The misdiagnosis rate was approximately 100%.
The importance of early detection of paragonimiasis is exemplified by the fact that paragonimiasis can be cured by therapy upon early diagnosis but delayed treatment can cause death in as high as 5% of patients. The mechanism of hemorrhage is thought to be due to vessel wall changes caused by parasitic inflammation resulting in concentric thickening, lumen stenosis and occlusion, as well as erosion of the vessel wall causing subsequent rupture. The alarmingly high misdiagnosis rate and the known increase in prevalence of paragonimiasis makes this disease one that should not be overlooked, especially in areas where the parasite is endemic or in cases of atypical hemorrhagic stroke symptom presentation and appearance on imaging.