resolution of bilateral multifocal subretinal cysticercosis without significant inflammatory...
TRANSCRIPT
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; [email protected]
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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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Key words: cysticercosis; Cysticercus cellulosae; Taenia soliurn; ocular infections, parasitic; subretinal cysticercosis
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