Resolution of bilateral multifocal subretinal cysticercosis without significant inflammatory sequelae

Khalid Sabti,* MD, FRCSC; David Chow,* MD, FRCSC; Vivek Wani,t MS, FRCS(Edin); Mubarak Al-Ajmi, t FRCS(Glasg)

Cysticercosis is caused by Cysticercus cellulosae, the most common platyhelminth infesting the

human eye. 1 C. cellulosae is the larval stage of the tapeworm Taenia solium. The adult worm lives in the intestine, whereas the larva can exist in various tis­sues, including the eye. Humans are usually infected following the ingestion of undercooked meat contain­ing viable larvae. Although humans are usually the final hosts, ocular involvement is more typical when humans act as the intermediate hosts. The eye is the most common site of organ involvement following infection by Cysticercosis (13% to 46% of cases).1·2

Within the eye the subretinal space is most often in­volved;3 the organism has also been noted in the ante­rior chamber,4 vitreous,4•5 subconjunctival space,4

eyelids,6 orbit? and, rarely, optic nerve canal.8

Clinically most patients present with a unilateral unifocal subretinal lobulated cystic lesion. In most cases surgical intervention is performed to remove the organism from the subretinal space to prevent the severe inflammatory sequelae often associated with the death of the organism. We present a case of bilat­eral multifocal subretinal cysticercosis that resolved without significant inflammatory sequelae after a short course of systemic prednisone therapy.

CASE REPORT

A 35-year-old man from Bangladesh presented with a 4-day history of blurry vision in his right eye associ-

From *the Department of Ophthalmology, Royal Victoria Hospital, McGill University, Montreal, Que., and t Al-Bahar Eye Center, Kuwait City, Kuwait

Originally received Apr. 18, 2000 Accepted for publication Feb. 20, 2001

Reprint requests to: Dr. Kha1id Sabti, PO Box 25427, Safat, Kuwait, 13115; albahar@kuwaiteyecare.org

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214 Resolution of cysticercosis-Sabti et al

ated with an inferior visual field defect. He had a 6-month history of non-insulin-dependent diabetes mel­litus. On examination, his visual acuity was 20/20 in both eyes. The anterior segment was normal bilateral­ly. Fundus examination of the right eye showed a superior serous retinal detachment extending close to but not involving the macula. Within the subretinal space of the serous retinal detachment was a single whitish multilobulated lesion about 3 to 4 disc areas in size (Fig. 1). Fundus examination of the left eye was normal.

A thorough systemic investigation was ordered. Therapy was started with prednisone (60 mg/d admin­istered orally), and the patient was asked to come back in 10 days. On the second visit the detachment had resolved significantly but not entirely. With the reso­lution of subretinal fluid the detail of the subretinal cystic lesion was seen clearly and appeared clinically consistent with subretinal cysticercosis. The cystic lesion had migrated to a lower location, just temporal to the macula. Systemic investigation showed mild eosinophilia and normal erythrocyte sedimentation

Fig. 1-Fundus photograph of right eye at presentation, show­ing subretinal cysticercosis with overlying serous retinal detachment above superior arcade.

Resolution of cysticercosis-Sabti et al

Fig. 2-Right eye 51/2 weeks after presentation. Left: Fundus photograph, showing migration of subretinal cysticercosis, with char­acteristic lobulated structure. Right: Fluorescein angiogram, showing hyperfluorescence of scolex.

rate. Serologic testing for HIV, toxoplasmosis, toxo­cariasis and syphilis gave negative results . The enzyme-linked immunosorbent assay (ELISA) for cysticercosis gave a positive result. Computed tomog­raphy (CT) of the brain and roentgenography of the limbs did not reveal calcifications. Analysis of stool samples for ova and parasites gave negative results on three occasions.

The oral prednisone therapy was continued, and the patient was asked to come back in 2 weeks. After 2 weeks the detachment had resolved completely, and the subretinal cysticercosis cyst was in the same posi­tion. The left eye remained clear, with no lesions. The patient was advised to taper the steroid gradually and to come back in 2 weeks. When he returned, his vision was 20/30 in both eyes, with no retinal detachment in

Fig. 3-Fundus photograph of left eye 51/2 weeks after presen­tation, showing onset of multifocal subretinal cysticercosis.

the right eye. The subretinal cysticercosis remained the same in the right eye (Fig. 2). The fundus of the left eye, however, showed two subretinal cystic lesions along the superior and inferior arcades (Fig. 3) associated with a small serous detachment inferiorly. The anterior segment was normal in both eyes. The steroid dosage was increased to 60 mg/d, and surgical intervention was considered. The patient was then lost to follow-up.

When the patient returned to the clinic 2 months later, his vision was 20/50 in both eyes, and he had stopped taking the prednisone. No retinal detachment was seen in either eye on fundus examination. In the right eye there was residual hard exudate with sec­ondary retinal pigment epithelium changes temporal to

Fig. ~Fundus photograph of right eye 14 weeks after pre­sentation. Cysticercosis cyst has disappeared. There are resid­ual pigmentary changes and hard exudate in perimacular region.

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the macula. In the left eye there were mild retinal pig­ment epithelium changes in the region of the previous lesions. Surprisingly, the subretinal cysticercosis cysts had disappeared in both eyes. Careful fundus exami­nation with scleral depression and gonioscopy failed to detect the cysticercosis cysts in either eye. Two months later the patient's vision had improved to 20/30 in the right eye and 20/25 in the left, and fundus examination remained the same, with a resolving mac­ular star in the right eye (Fig. 4).

Six months after his initial presentation no new lesions had developed, and his visual acuity remained unchanged.

CoMMENTs

The diagnosis of cysticercosis is typically made by its characteristic clinical appearance.1 The organism without exception forms a cystic lobulated lesion. The cystic lobules correspond to the scolex of the larva, which is used for organism motility. Blood tests and serologic testing can be helpful in the diagnosis; how­ever, negative blood test results have been described in a pathologically proven sample taken during sur­gery.9 The seroprevalence of cysticercosis in endemic areas is 30%. 10 The sensitivity of the ELISA for cys­ticercosis ranges from 80% to 90%.11 Stool analysis for T. solium ova occasionally gives positive results. Examination of several samples and analysis by expe­rienced laboratory technicians can increase the yield of this test.

Although cysticercosis usually presents as a unilat­eral unifocal cyst, there have been a few reports of bilateral multifocal involvement.3·12·13 Our patient presented initially with unilateral unifocal involve­ment but progressed to bilateral multifocal involve­ment. We feel that it is important to follow patients with cysticercosis carefully, paying particular atten­tion to the possibility of multicentricity and bilateral involvement.

Following infection with the larvae, it is believed that the organism reaches the eye through the posteri­or ciliary arteries. Once in the eye, the organism prefers the subretinal space. 3 A few case reports have documented movement of the parasite within the sub­retinal space and from the subretinal space to the vit­reous.3·14 To our knowledge, there have been no doc­umented cases of the organism leaving the eye or of spontaneous resolution of intraocular cysticercosis. We have been unable to document where the organ­isms migrated to in our patient.

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The natural history of intraocular cysticercosis is often poor, with severe ocular damage and visual loss occurring in 80% of cases. 1·3 Following initial ocular infection many patients maintain excellent visual acuity for long periods, particularly if the lesions remain extra­macular. The eventual mechanism of visual loss is believed to be ocular damage occurring as a result of severe inflammation associated with death of the organ­ism, which may occur as late as 5 years after entry into the eye. As a result, most clinicians advocate controlled surgical removal of the organism on an elective basis.

There have been several reports of successful surgi­cal intervention.5•16·17 Ideally, the goal of surgery is to remove the cyst without rupturing the capsule. How­ever, if the cyst ruptures intraoperatively, a severe inflammatory response can often be avoided by per­forming a meticulous vitrectomy procedure and ad­ministering systemic steroid therapy postoperatively. Other management options include diathermy, photo­coagulation and cryotherapy. 18 These have met with limited success but may be reasonable options for smaller, extramacular cystsP

Our case is interesting in that with only intermittent systemic prednisone use, the bilateral multifocal lesions resolved without a significant inflammatory reaction and without visual loss. We do not know what role, if any, prednisone therapy played in the res­olution of the lesions.

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15. Kruger-Leite E, Jalkh AE, Quiroz H, Schepens CL. Intra­ocular cysticercosis. Am J Ophthalmoll985;99:252-7.

16. Luger MHA, Stilma JS, Ringens PJ, van Baarlen J. In-toto removal of a subretinal Cysticercus cellulosae by pars plana vitrectomy. Br J Ophthalmoll991;75:561-3.

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18. Santos R, Dalma A, Ortiz E, Sanchez-Bulnes L. Manage­ment of subretinal and vitreous cysticercosis: role of pho­tocoagulation and surgery. Ophthalmology 1979;86: 1501-7.

Key words: cysticercosis; Cysticercus cellulosae; Taenia soli­urn; ocular infections, parasitic; subretinal cysticercosis

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