| Abstract|| |
Cysticercus cellulosae, the larval form of the tapeworm Taenia solium, is the causative organism of cysticercosis, in which humans are the intermediate hosts in the life cycle. Cysticercus cellulosae may become encysted in various bodily tissues, usually the central nervous system (CNS), eyes, and subcutaneous tissues. An immunologic reaction with fairly intense inflammatory signs and symptoms may be produced, and the surrounding structures may be compressed. We report a radiological study based on ultrasonography and MRI showing intraocular cysticercosis associated with vitreous detachment, which is a very rare entity. Intraocular cyst is usually associated retinal detachment but in the following case, vitreous detachment is seen, which is hence proven with the help of color Doppler study.
Keywords: Cysticercosis, intraocular, MRI, ultrasonography, vitreous detachment
|How to cite this article:|
Parashari UC, Khanduri S, Qayyum FA, Bhadury S. A radiological case report on intraocular cysticercosis with associated vitreous detachment and neurocysticercosis. Ann Trop Med Public Health 2012;5:367-9
|How to cite this URL:|
Parashari UC, Khanduri S, Qayyum FA, Bhadury S. A radiological case report on intraocular cysticercosis with associated vitreous detachment and neurocysticercosis. Ann Trop Med Public Health [serial online] 2012 [cited 2020 Jun 3];5:367-9. Available from: http://www.atmph.org/text.asp?2012/5/4/367/102062
| Introduction|| |
Intraocular cysticercosis is a common parasitic infestation of the eye where humans are the intermediate hosts in the life cycle of the tapeworm Taenia solium by ingesting fecally contaminated food and water. The eggs ingested by humans hatch and the larvae of these eggs, cysticercus cellulosa, penetrate the intestinal wall and disseminate throughout the body and invade various organs such as the central nervous system, eye, skeletal muscles, and subcutaneous tissue. Radiological diagnosis is made on the basis of ultrasonography, CT, and MRI. They are very specific and sensitive modalities for the diagnosis of cysticercosis. Cysticercosis is easily diagnosed by orbital imaging as its appearance is highly specific. CT and MR imaging not only confirm the diagnosis but also help to rule out neurocysticercosis. Intraocular cysticercosis is rare and can be highly destructive because the cyst gradually grows in size and leads to painless progressive loss of vision. Associated brain parenchymal extension is rare and has been reported in the following case report. Medical treatment of intraocular cysticercosis should be avoided because death of the organism can release toxic substances, which can lead to intense inflammation with eventual phthisis. Early surgical removal of the parasite is the treatment of choice.
| Case Report|| |
A 10-year-old girl came to the hospital with the history of painless progressive loss of vision, irritation, and redness of the left eye. There was no history of trauma or diabetes. She also presented with a recent history of loss of consciousness and convulsions, for which, she is not taking any medication. On ophthalmic examination, her visual acuity was 6/6 in the right eye and 6/9 in the left eye. Anterior segment in both eyes was clear. Slit lamp examination showed a small opacification in the posterior surface of the lens. On fundus examination, a colloid cyst 4 × 5 disc diameter was seen in the infero-posterior quadrant of the vitreous cavity. There was also associated vitreous detachment. Hematological studies showed eosinophilia and elevated ESR. Stools were negative for any form of helminthiasis. On B-scan, a free floating, sonolucent ring with well-defined margins was seen in between the vitreous and retina [Figure 1]a. The presence of an intracystic central hyperechoiec, curvilinear, highly reflective eccentric dot suggestive of scolex was seen. There was evidence of posterior detachment of vitreous membrane floating freely in the posterior segment [Figure 1]b and c. Color Doppler study showed retinal vasculature intact to the retinal membrane, which is a differentiating feature between retinal detachment and vitreous detachment [Figure 2]. Routine MRI of the brain on scanner (Magnetom Symphony: Aperto) was conducted. In axial T1WI (3 mm slice thickness with 4 mm table feed), a tiny lesion in the posterior quadrant of the left eyeball was seen [Figure 3]a. A tiny eccentric hypo intense speck was seen in it suggestive of scolex. T2W and T1 W sequences in coronal and sagittal planes were uninformative [Figure 3]b and c. MR study of brain was also performed, which revealed a solitary eccentric focus with a hypodense dot in the center in the right parietal region with associated mild perifocal edema [Figure 3]d. Medical treatment was contraindicated in the following case. The cyst was surgically removed with pars plana vitrectomy.
|Figure 1: B-scan ultrasound of left eye shows a small well-defined rounded sonolucent mobile ring with high reflective eccentric dot (scolex) in between retina and vitreous (a). Associated posterior vitreous detachment is also seen (b and c)|
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|Figure 2: Color Doppler study shows posterior vitreous detachment with retinal vasculature intact to the retinal membrane|
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|Figure 3: Axial T1W MR (a) image shows a tiny lesion in the posterior quadrant of the left eyeball (thin white arrow). A tiny eccentric hypo intense speck is seen in it, suggestive of scolex. Axial T2W (b is uninformative. Axial FLAIR image of brain (c) showing a small inflammatory granuloma in right inferior parietal region (neurocysticercosis)|
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| Discussion|| |
Human cysticercosis is a parasitic infection caused by cysticercus cellulosae, the larval form of the cestode, Taenia solium. Food habits, poor hygiene, autoinfection, or travelling patterns may be responsible for their distribution. Cysticercosis is caused by the dissemination of the larval form of the pork tapeworm, Taenia solium.  The adult worm lives in the intestine of humans. These humans shed the proglottids containing the eggs in their feces. The eggs are ingested by pig where a cysticercus is developed in the muscle. In Taenia solium, humans can also be the intermediate host. Clinical presentations of cysticercosis in human may involve the CNS, eye, or other viscera. Ocular involvements include cysts in eyelids, extraocular muscles, orbit, conjunctiva, anterior chamber, uvea, retina-vitreous, and optic nerve.  Although there are various reports of isolated ocular and intraocular cysticercosis in the literature, there are few reports of cysticercosis involving the eye and brain.  Medical treatment is known to cause severe ocular complications, which may lead to loss of the eye.  The subconjunctival space is a common site, followed by the eyelid, optic nerve, retro-orbital space, and lacrimal gland. All the extraocular muscles are involved in myocysticercosis.  The most common presenting features are restricted ocular motility with diplopia, and recurrent pain and redness.  Intraocular cysticerci are easily diagnosed by ophthalmoscopy because of their visibility. Cysticercosis is easily diagnosed by orbital imaging as its appearance is highly specific. CT and MRI imaging not only confirm the diagnosis but also help to rule out neurocysticercosis. The radiological findings of cysticercosis - a cystic lesion with a central nodule that represents the scolex - are very similar in all affected organs. On MRI, cysticercosis lesions appear hyperintense, with well-defined edges, which show a hypointense eccentric nodule within, representing the parasite's head and is called the scolex. The presence of a scolex in a cystic lesion usually suggests the diagnosis of cysticercosis. , Trans-scleral approaches are used for subretinal cyst positioned anterior to the equator. The pars plana vitrectomy or transvitreal approach is used for intravitreal cyst and subretinal cyst located posterior to the equator. Vitreous cysts are more common than retinal or subretinal cysts, and the inferotemporal subretinal cyst is the most commonly affected quadrant in the retina.  The passage of the endoparasite may incite inflammation and can even result in the formation of a chorioretinal scar. Histopathological examination of the parasite showed the scolex and suckers. The differential diagnosis of ocular cysticercosis is hydatid cyst, which rarely affects the eye. Hydatid cysts of the eye are larger and mostly require surgical excision. The other important differential diagnosis is orbital pseudotumor or idiopathic myositis. The genesis of convulsion in a patient with neurocysticercosis may be due to inflammation, cerebral tissue gliosis, and preference of the cyst to travel to the cerebral hemisphere. Cysts that are active or undergoing degeneration (colloidal cysts) are the most epileptogenic.  If there are both intraocular and CNS cysticercus cysts, then the complete intraocular cyst must be removed surgically first, followed by anti-parasitic medication such as albendazole and praziquantel or with corticosteroids. We do not want to kill the intraocular live parasite initially because it could induce severe intraocular reactions and thereby cause eventual blindness. Combined intravitreal surgery by removing the subretinal cysticercus cyst and subsequent medical treatment for CNS parasitosis was safe and effective.
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Umesh C Parashari
Department of Radio Diagnosis, Era's Lucknow Medical College, Lucknow
Source of Support: None, Conflict of Interest: None
[Figure 1], [Figure 2], [Figure 3]