Intraocular Gnathostoma spinigerum. Clinicopathologic study of two cases with review of literature

Abstract

Background: Live intraocular nematode is a rare occurrence that is mostly reported in Southeast Asian countries. Common nematodes that are seen live in the eye are microfilaria, Gnathostoma, and Angiostrongylus. Approximately 12 cases of intraocular gnathostomiasis have been reported in the literature.

Method: Two cases of intraocular gnathostoma, removed by vitrectomy in the first case and by paracentesis in the second case, are reported. Morphologic study of the parasites in wet preparation was performed under dissecting microscope and fixed in Karnovosky's fixative. Light microscopic and scanning electron microscopic studies were also performed.

Results: The first patient had anterior uveitis, multiple iris holes, and dense vitreous haze with fibrous proliferation over the optic disc. On resolution of the vitreous haze, a live worm was seen in the vitreous cavity. The second patient had anterior uveitis with secondary glaucoma, multiple iris holes, mild vitritis, and focal subretinal haemorrhage with subretinal tracts. Four days later a live worm was seen in the anterior chamber and removed. Microscopic study of the parasites from both patients revealed typical head bulb with four circumferential rows of hooklets, and fine cuticular spines were seen on the surface of the body.

Conclusions: Iris holes, uveitis, and subretinal haemorrhage with subretinal tract can be characteristic features of intraocular gnathostomiasis. Identification of this parasite can be made by typical features, which can be identified on light and scanning electron microscopic study.