Echinococcosis Hydatid Disease

Echinococcosis is caused by infestation of tissue with the encysted larval stage of Echinococcus granulosa, the dog tapeworm. Human infection occurs through ingestion of food contaminated by viable ova or by oral contamination from hands after handling infected dogs. The ingested larvae penetrate the intestinal tract, gain access to the bloodstream and are disseminated; they most commonly affect the lungs, liver, bone and brain. Following parasitic embolization, the larvae form a progressively enlarging uniloculated cyst and the cyst wall differentiates into an internal germinal layer from which daughter cysts form. This causes further growth of the cyst, which becomes filled with fluid and germinating parasitic particles known as "hydatid sand" [23].

CNS involvement occurs in 2-3% of patients with systemic echinococcosis. Children are most often affected and, in countries where echinococcosis is common, up to 50% of all childhood CNS "tumors" prove to be echinococ-cal cysts. Echinococcal cysts are customarily solitary and confined to the white matter of the cerebral hemispheres, although cerebellar, intraventricular and intrasellar cysts have been reported. Unlike NCC, there is negligible glial inflammatory reaction and, therefore, minimal peri-lesional edema. Clinically, children with echinococcal cysts most often present with signs of increased ICP and few focal findings. The clinical picture in adults mimics that of any other space-occupying lesion.

The diagnosis of echinococcosis is made in the presence of peripheral blood eosinophilia, a positive Casoni's intradermal skin test and Weinberg's complement fixation test. CT and/or MRI best demonstrate the parenchymal lesions. The appearance is that of a large, spherical cyst with sharply defined borders that rarely show fine enhancement - a paucity of surrounding edema. The cyst contents have imaging characteristics similar to those of CSF. Calcification of the cyst wall itself should raise the suspicion of a hydatid cyst [23].

Cure Your Yeast Infection For Good

Cure Your Yeast Infection For Good

The term vaginitis is one that is applied to any inflammation or infection of the vagina, and there are many different conditions that are categorized together under this ‘broad’ heading, including bacterial vaginosis, trichomoniasis and non-infectious vaginitis.

Get My Free Ebook

Post a comment