Clinical findings:
(1)
The patient suddenly experiences a unilateral loss of visual acuity.
(2) A retinal tear with choroidal hemorrhage can be seen near the optic disc on MRI.
(3) A motile larva may be found in the anterior chamber, attached to the iris with or without holes in the iris and corneal edema.
(4) Uveitis may be present.
(5) The patient may have subretinal hemorrhage with subretinal tracts.
(6) Variable increase in intraocular pressure.
(7) Variable eyelid edema.
(8) Variable conjunctival chemosis.
Laboratory testing:
(1)
Serologic tests for antibodies to gnathostoma antigens may be negative.
(2) Eosinophilia may be absent.
The diagnosis is supported by visualization of a larva, which is often only a few millimeters in length.
The worm can be removed by pars plana vitrectomy. The larva can then be speciated by appearance or other analysis. PCR can be performed on vitreous fluid if a larva is not seen.
