INTRODUCTION Orbital cysticercosis is well documented disease entity but isolated involvement of extra ocular muscle by Cysticercus cellulosae is uncommon. Cysticercosis is serious health problem in developing countries, commonly seen in Latin American, Eastern Europe, India, Pakistan, Indonesia and China. It is caused by Cysticercosis cellulose, which is a larval form of pork tapeworm Taenia solium. Rarely it is caused by the larvae of beef tapeworm T. saginata. Humans are infected by eating contaminated raw pork or beef or by drinking contaminated water.
We hereby present two cases of cysticercosis affecting the EOM discussing their presenting features, investigations done, treatment prescribed and their follow-up.
CASE REPORT 1 - A 35 years old non-diabetic and non-hypertensive man presented with history of pain in left eye since 2 months with drooping of upper eye
Figure 1: Showing proptosis of left eye
lid since one month duration along with protrusion of globe and lacrimation. There was no fever, nausea, vomiting, visual disability and double vision. No redness was noted in the affected eye. The left eye’s movements were restricted in horizontal gaze. Corneal sensations were normal. Examination of right eye did not reveal any abnormality.
Investigations
All routine investigation including Hb, ESR, CBC, TDLC, blood urea, serum creatinine, random blood sugar, SGOT, SGPT, ELISA for HIV, T3, T4, TSH level and X-ray chest were in normal limits. On ophthalmic examination his vision was 20/20 OU. S/L examination and fundus (on direct ophthalmoscopy) were normal. IOP was 17.0 mmHg (by applanation tonometer) in both eyes. CNS examination was normal.
On imaging:- B. Scan- left eye disclosed a cystic lesion measuring 6x5mm with hyperechoic speck (Scolex) within it, causing compression over posterior aspect of eyeball with bulky lateral rectus muscle.
Figure: 2 B Scan of left eye showing cystic lesion with scolex.
CT scan orbit was done which suggested mild proptosis of left eyeball with enhancing lesion measuring 6x6 mm seen in lateral rectus with thickening of lateral rectus muscle in its anterior 2/3rd.
Figure 3: CT Scan
Eccentric module sign of scolex was seen within the lesion. Remaining findings were normal in CT appearance. So a diagnosis of proptosis left eye with ptosis left eye as a manifestation of cysticercosis of lateral rectus was made.
CASE REPORT 2
A young girl of age 7 yrs. came to our O.P.D. with complaints of a mass in the inner portion of her right eye of duration since one month, noticed by her parents that increased gradually in size. She also complained of watering. The patient was vegetarian and from low profile family. On examination of right eye a fleshy, red, protuberant mass of size 1.0cm x 0.5cm was seen at the medial part of palpebral aperture. Eyes were orthophoric but the growth was restricting the movements of right eye towards the medial side. Rest of the extraocular movements were normal. Vision of the patient was normal in both eyes and the IOP with applanation tonometer was within normal limits. Both eyes fundi were also normal.
Figure 4-Showing a mass in the nasal side of palpebral aperture.
Investigations
1.Complete urine profile – No abnormality detected
2.Stool examination: No abnormality detected
3.Hematology:
Hb:12.7gm%
TLC: Within normal range
DLC: Within normal range
ESR – 25mm in first hour
5. USG right eye- Showed a well defined cystic anechoic lesion of size 9.8 x 4.5mm in medial rectus muscle with a small 1.2 x 1.7mm echogenic speck noted in mid portion of anechoic area.
Figure 5-showing enlargement of medial rectus muscle
6. NCCT & CECT of head and orbit- stated a well defined cystic lesion with enhancing walls and tiny intralesional hyperdense speck involving anterior portion of medial rectus muscle. Medial rectus muscle was bulky and edematous.
Figure 6
Both USG & CT findings suggested the diagnosis of cysticercosis of medial rectus muscle.
Discussion
Cysticercosis is a serious health problem in developing countries like Latin America. Asia and Africa specially in areas of poverty and poor hygiene(1,2). As per the Indian literature, ocular involvement occurs in 1.8-4.5% cases only(3). Despite the high incidence of brain and ocular involvement in cypticercosis, extraocular muscle cycticercosis is rare(5). It has been reported primarily in pediatric and young adult population(4). In a series of 9 patients of cysticercosis, extra ocular muscle involvement was as following- MR in 5, IR in 5, SR in 2 & LR in 2 cases. 4 patients had moderate to severe inflammation around the cyst. In one of our case, the cyst was located in LR muscle of left orbit which is a less common site but the other case showed the involvement of MR. However the cyst may lodge in any of extra ocular muscle. The prominent symptoms are protusion of eyeball, pain, diplopia, ptosis and diminution of vision.
Imaging modalities like orbital USG, CT scan, or MRI brain with orbital cuts are essential for diagnosis. Brain parenchymal involvement was not seen in our patients as seen in most of the studies on ocular cysticercosis(6). Literature on the treatment for orbital cysticercosis is quite conflicting. Resolution of the lesion can occur spontaneously or after therapy. The parasite if left untreated eventually dies after 2 to 4 years. Cysticidal therapies can provoke the inflammatory response around residual dying cysticerci due to release of toxin. So the therapy must be individualized according to location of parasite and activity of the disease. Combination of oral albendazole (15 mg/kg b.w.) and steroid ( 1 mg/kg b.w.) may be efficacious in selected cases provided there is no threat to vision as a consequence of therapy(7). In our case the patient was given minimum dose steroid which was followed by combined steroid and albendazole therapy.
In conclusion involvement of extra ocular muscles by cysticercus cellulose is very rare. Rarer still is the involvement of LR muscle presenting clinically as unilateral ptosis, mild proptosis and pain. B scan is best investigation module and conservative treatment with albendazole and steroid after ruling out CNS involvement show early regression.
REFERENCES
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