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Show ORIGINAL CONTRIBUTION Third Cranial Nerve Palsy From Midbrain Neurocysticercosis: Repeated Exacerbation on Tapering Corticosteroids Ji Soo Kim, MD, Seon- Mi Jeong, BSc, So Young Moon, MD, and Seong- Ho Park, MD Abstract: Third cranial nerve palsy is rare in neurocysticercosis and is usually caused by supratentorial or subarachnoid lesions with accompanying hydrocephalus or meningitis. We report a patient who presented with third cranial nerve palsy caused by neurocysticercosis involving the midbrain. The patient showed repeated exacerbation of symptoms on tapering corticosteroids. The experience with this patient indicates that tapering of corticosteroids should be performed very slowly in such cases. ( JNeuro- Ophthalmol 2004; 24: 217- 220) The clinical manifestations of neurocysticercosis ( NCC) are varied and depend on the topography, number, and size of the lesions, as well as the status of the host's immune response to the parasite ( 1). Common neuro- ophthalmo-logical signs include papilledema, pupillary abnormalities, and nystagmus ( 2). Third cranial nerve palsy in NCC is rare ( 3,4), and is usually associated with supratentorial or subarachnoid lesions with accompanying hydrocephalus or meningitis ( 2,3). Only a small number of reports have described third cranial nerve palsy in patients with NCC involving the midbrain ( 5- 7). We report such a case in which the third cranial nerve palsy recurred or became aggravated repeatedly upon tapering corticosteroids. CASE REPORT A 59- year- old man had diplopia and drooping of the lid OS. One day prior he had experienced blurred vision and an aching headache. He had no history of diabetes or hypertension. Four days after symptom onset, examination showed ptosis OS. He had anisocoria, with the pupil OS 1.5 mm Department of Neurology, Seoul National University College of Medicine, Seoul National University Bundang Hospital. This study was supported by a grant ( R05- 2001- 000- 00616- 0) from the Korea Science & Engineering Foundation. Address correspondence to Ji Soo Kim, MD, Seoul National University College of Medicine, Department of Neurology, Seoul National University Bundang Hospital, 300 Gumi- Dong, Bundang- Su, Seongnam- Si, Gyeonggi- Do, 463- 707, Korea; E- mail: jisookim@ snu. ac. kr larger than the pupil OD. Pupillary response to light was impaired OS. Extraocular movements were normal OD. Abduction was normal OS, but adduction, supraduction, and infraduction were reduced to approximately one- third of the normal range ( Fig. 1). Fourth cranial nerve function was considered normal OS because intorsion of the left eye was preserved on attempted downward gaze. The remainder of the examination was unrevealing. Magnetic resonance imaging ( MRI) of the brain revealed nodular lesions in the midbrain tegmentum and occipital pole, which were surrounded by ring enhancement and edema ( Fig. 2). The results of testing undertaken to screen for malignancies, including tumor markers, ultrasonography of the abdomen, and computed tomography of the chest, were normal. Enzyme- linked immunosorbent assay for anticysticercal antibody in serum was negative. However, an examination of the cerebrospinal fluid showed a highly positive enzyme- linked immunosorbent assay for cysticercus of 0.41 ( normal range < 0.18), 8/ mm3 of white blood cells, and 96 mg/ dL of protein. The patient was treated with praziquantel 50 mg/ kg per day for 15 days and intravenous methylprednisolone, 1 g per day for six days. He experienced resolution of the headache and ptosis within five days. The adduction OS also improved to approximately two- thirds the normal range and infraduction to half the normal range. However, the impaired supraduction OS remained unchanged. The intravenous methylprednisolone was changed into oral prednisolone 60 mg per day, which was tapered to 20 mg per day over the following 30 days. Three days after tapering, the prednisolone to 20 mg per day, he returned to the clinic with recurrence of ptosis OS. He also had exotro-pia and a dilated pupil OS. Supraduction was absent OU and infraduction was absent OS. Adduction OS was reduced to approximately one third of the normal range. Supraduction did not improve with the doll's eye maneuver. One week after increasing the prednisolone to 40 mg per day, the ptosis resolved. However, during the ensuing two months, the reduced ductions of other extraocular movements remained unchanged despite maintenance of J Neuro- Ophthalmol, Vol. 24, No. 3, 2004 217 JNeuro- Ophthalmol, Vol. 24, No. 3, 2004 Kim et al FIG. 1. Pretreatment presentation shows ptosis, a slightly dilated pupil, and reduced supraduction, infraduc-tion, and adduction OS, which are findings consistent with a left third cranial nerve palsy. the prednisolone at 40 mg per day. Follow- up MRI, four months after the initial MRI, showed that the size of the lesion had decreased, but that a substantial amount of surrounding edema persisted ( Fig. 3). The patient received an another course of intravenous methyprednisolone ( 1 g/ day) for five days, and the supraduction OU improved to one- quarter the normal range, while adduction and infraduction OS improved to approximately two- thirds and one- half the normal range, respectively. He was placed on oral prednisolone 40 mg/ d, which was tapered to 15 mg per day over the following two FIG. 2. Pretreatment brain magnetic resonance imaging ( MRI). A: T2- weighted axial scans show high intralesional and perilesional signal centered in the left tegmental midbrain (/ eft) and extending into the diencephalon { right). There is also a high- signal lesion in the left occipital pole. B: Enhanced T1- weighted axial scans show ring enhancement of the midbrain (/ eft) and occipital lesions { right). 218 © 2004 Lippincott Williams & Wilkins Third Cranial Nerve Palsy from Midbrain Neurocysticercosis JNeuro- Ophthalmol, Vol. 24, No. 3, 2004 FIG. 3. Follow- up MRI four months after corticosteroid and praziquantel treatment. T2- weighted ( A) and gadolinium- enhanced ( B) MRIs reveal resolving cysticercal granuloma, still with ring enhancement and substantial surrounding edema in the midbrain. In contrast, the granuloma in the occipital pole shows a near- complete resolution. months. Three days after tapering the prednisone to 15 mg per day, he revisited the clinic with worsening of ocular ductions OS. Examination showed no supraduction, infra-duction, or adduction OS. He was treated with intravenous dexamethasone 16 mg per day for seven days and albendazole 1200 mg per day for 14 days. The intravenous dexamethasone was changed to prednisolone 40 mg per day and tapered by 5 mg every two weeks. The extraocular movements continued to improve. However, when the prednisolone reached 20 mg per day, the ptosis OS redeveloped, and on treating with intravenous dexamethasone 16 mg per day for four days, the ptosis disappeared. The dexamethasone was then replaced with prednisolone 35 mg per day. The prednisolone was tapered by 5 mg each month. Fifteen months after symptom onset, with prednisone 10 mg every other day, he displayed supraduction of one- half the normal range OU, infraduction OS up to two- thirds the normal range, and normal adduction OS. The pupil measured 3 mm OD and 4 mm OS with normal reaction to light OU. The prednisolone was discontinued two months later without recurrence during the next two years. DISCUSSION Our patient met the diagnostic criteria of definite NCC, as proposed by Del Brutto et al ( 1). NCC, the most common helminthic infection of the central nervous system, is caused by the encysted larval stage of the tapeworm Taenia solium ( 1). The protean clinical manifestations of NCC are being increasingly recognized in industrialized countries. Neuro- ophthalmological signs are usually caused by associated meningitis or hydrocephalus, and the recognition of these findings may provide a clue to the presence of serious neurologic disease ( 2). Hydrocephalus, found in 25% of NCC, is often accompanied by sixth cranial nerve palsy or optic neuropathy secondary to long- standing papilledema ( 2). Third cranial nerve palsy, relatively rare in NCC, usually occurs because of brainstem compression by a supra-tentorial lesion or to memngitis with secondary hydrocephalus. Isolated third cranial nerve palsy from a midbrain parenchymal lesion has rarely been reported and is known to have a very high mortality ( 5- 7). In our patient, the third 219 JNeuro- Ophthalmol, Vol. 24, No. 3, 2004 Kim et al cranial nerve palsy worsened repeatedly on tapering corticosteroids. The initial impairment was confined to the OS and suggested the involvement of the left third cranial nerve fascicle. However, supraduction deficits of both eyes observed during the next examination indicated that the lesion extended into the opposite third cranial nerve nucleus or fascicle. The lesion might also have involved the supranuclear structures subserving upward gaze ( 8), but the lack of an improvement in supraduction with the doll's eye maneuver in both eyes makes this possibility less likely. The treatment of NCC remains a subject of debate. Most NCC patients have been treated with surgery, antihelminthic drugs ( albendazole or praziquantel), or corticosteroids. Corticosteroids have been used to reduce peri- lesional edema after surgical treatment or during antihelminthic medical treatment ( 9,10). In our patient, whenever prednisolone was tapered to 15 to 20 mg per day, symptoms recurred or were aggravated, and resolved or improved promptly on increasing the prednisolone dose. We were able to avoid recurrence by tapering corticosteroids very slowly. Lui et al ( 11) and Corral et al ( 12) have also described a significant relationship between the rate of tapering of corticosteroids and symptom recurrence. Although physicians are reluctant to use corticosteroids for extended periods because of their unacceptable side effects, these agents may be effective in patients with massive inflammation and surrounding edema. Our experience in this case also indicates that tapering of corticosteroids should be performed very slowly and carefully in NCC patients, especially when the lesions involve critical structures such as the brainstem. REFERENCES 1. 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