University Journal of Surgery and Surgical Specialities

ISSN 2455-2860 2020, Vol. 6(2)

2 CASE REPORTS OF OPTIC CHIASMAL SYNDROME BAVYA M Department of Ophthalmology, MADRAS MEDICAL COLLEGE AND GOVERNMENT GENERAL HOSPITAL

Abstract : The optic is one of the most important Anterior segment examination of the right eye was normal. Right structures in neuro ophthalmologic diagnosis. The eye showed sluggish pupillary reaction to light. Fundus of right arrangement of visual fibres in the chiasm accounts for eye showed disc edema with peripapillary hemaorrhages[FIG 1]. characteristic defects in the visual fields caused by such Left eye vision was 3/60 which improved to 6/36 with correction. diverse processes as compression , inflammation , Left eye showed sluggish pupillary reaction to light. Otherwise demyelination, ischemia and infiltration. Two cases are anterior segment was normal. Fundus showed disc edema with a presented here. The first case presented with right temporal haemorrhage in the superotemporal quadrant[FIG 2]. Both eyes field defect with central of the left eye and bilateral showed lens changes. papilledema. MRI SCAN showed it as suprasellar astrocytoma. The second case presented with temporal field defect and left eye optic atrophy. MRI SCAN showed it as pituitary macro adenoma or dorsal sella . Thus showing the importance of ocular examination in identifying intracranial tumours. Keyword :, temporal field defect, papilledema, optic atrophy INTRODUCTION The optic chiasm is one of the most important structure in FIG 1: Right Eye papilledema neuro-ophthalmologic diagnosis. Damage to the optic chiasm can occur from direct or indirect effects of a variety of lesions. Some of them are pituitary adenomas, suprasellar , , and aneurysms originating from the internal carotid artery. During pregnancy pituitary adenomas become symptomatic. It enlarges resulting in compression of the chiasma and resulting visual defects. Secondary empty sella can be associated with chiasmal syndrome. It can follow surgeries involving removal of suprasellar meningiomas and craniopharyngiomas. optic FIG 2:Left Eye Papilledema chiasmal syndromes present with the characteristic field Automated perimetry of both eyes were performed. Right eye defects with papilledema, optic atrophy or sea saw showed absolute defects in the temporal field[FIG 3,5]. Left eye nystagmus. showed absolute defects in the fixation area[FIG 4,6]. MRI Scan CASE 1: revealed a well enhancing suprasellar mass lesion compressing A 56 year female came with complaints of defective vision in left and optic chiasma – displacing it superiorly and the left eye and field defect in the left temporal region and causing erosion of the underlying dorsum sellae and obstructive right temporal region for the past 20 days. History of dilation of the lateral and fourth ventricles and compression of headache for the past 15 years which increased in intensity the . Features were suggestive of suprasellar for the past 20 days, was associated with vomiting. She was astrocytoma[FIG 7] Neurosurgery opinion was obtained and the not a known case of diabetes mellitus, hypertension. She patient is planned for craniotomy It is a case of optic chiasmal attaine menopause at 50 years of age. On examination right syndrome with bilateral papilloedema eye vision was 6/36 which improved to 6/24 with correction.

An Initiative of The Tamil Nadu Dr. M.G.R. Medical University University Journal of Surgery and Surgical Specialities

temporal pallor [FIG 8] while left eye showed primary optic atrophy [FIG 9].

FIG 3: Field Chart Of Right Eye enlarged view FIG 8: Fundus showing temporal pallor in Right eye

FIG 9: Fundus showing optic atrophy of Left eye FIG 4: Field Chart of Left Eye enlarged view Automated perimetry showed absolute field defects in temporal region in the right eye [FIG 10]. Left eye automated perimetry could not be done due to poor vision

FIG 5: Field Chart Of Right Eye FIG 10: Field chart of Right eye

FIG 11: MRI BRAIN FIG 6: Field Chart of Left Eye MRI Brain with contrast showed a well-defined T1 isointense T2 Flair hyperintense mass lesion measuring 3x2.72cm noted arising from sella extending to suprasellar region .The lesion causing compression of bilateral optic nerves .Features were suggestive of pituitary macroadenoma / dorsal sella meningioma [FIG 11] Patient was referred for physician opinion and neurosurgery department It was diagnosed as a case of optic chiasmal syndrome with left eye primary optic atrophy. FIG 7: MRI BRAIN DISCUSSION: MRI Scan revealed a well enhancing suprasellar mass lesion Chiasmal syndrome is the set of signs and symptoms that compressing left optic nerve and optic chiasma – displacing it are associated with lesions of the optic chiasm manifesting superiorly and causing erosion of the underlying dorsum sellae and as various impairments of the according to the obstructive dilation of the lateral and fourth ventricles and location of the lesion along the optic nerve It can be compression of the third ventricle. divided into anterior, middle and posterior locations The CASE 2: classic anterior chiasmal lesion affects the optic nerve A 46 year old female patient came with complaints of defective fibers and the contralateral inferonasal fibers located in vision left eye since 3 months. She had no history of headache or Willebrand’s knee. This will produce an ipsilateral optic vomiting .Not a known case of diabetes mellitus, hypertension. She neuropathy, often manifested as a central scotoma , and a attained menopause at 45 years of age. On ocular examination right defect involving the contralateral superotemporal field. eye had a vision of 6/18. Anterior segment was normal. Left eye This is also known as a junctional scotoma. Middle lesions had a vision of 1/60. Left eye pupil showed relative afferent pupillary affecting the uncrossed temporal fibers are rare. These defect. Both eyes showed lens changes. Right eye fundus showed can result in a nasal or binasal hemianopia. Lesions in the body of the chiasm most commonly disrupt the crossing

An Initiative of The Tamil Nadu Dr. M.G.R. Medical University University Journal of Surgery and Surgical Specialities

nasal retinal fibers. This leads to a bitemporal hemianopia. The field have affected the body of the chiasm. A posterior chiasm of vision may still be full when both eyes are open but stereovision lesion should produce defects on the temporal sides of the will not be possible. Because macular fibers cross more posteriorly central visual field. The patients are managed according to in the chiasm, they are damaged in posterior chiasmal syndrome. the etiology. This leads to a smaller, paracentral bitemporal field loss. Because CONCLUSION the temporal macular fibers have not been damaged, it is possible to Chiasmal syndrome can present with papilledema or optic preserve color vision and visual acuity. Posterior lesions may also atrophy depending on the etiology. Pituitary adenomas involve the and cause a contralateral homonymous rarely cause papilledema. These two cases emphasize the hemianopia. Optic disc pallor may be apparent with an importance of ocular examination in detecting tumors ophthalmoscope if the result is longstanding. If the lesion does not involving the chiasma affect the lateral uncrossed fibers , the pallor may take on a bow-tie References: configuration. This is due to loss of retinal ganglion cells nasal to the 1.Foroozan R. Chiasmal syndromes. Current opinion in macula in the papillomacular bundle. Compressive lesions often ophthalmology. 2003 Dec 1;14(6):325-31. cause headache and may compress the third ventricle leading to 2. Cushing H. The chiasmal syndrome: of primary optic papilledema. More commonly associated with suprachiasmal lesions atrophy and bitemporal field defects in adults with a invade or compress the third ventricle. The etiologies of chiasmal normal . Archives of Ophthalmology. 1930 syndromes can be intrinsic and extrinsic causes. Intrinsic implies May 1;3(5):505-51. thickening of the chiasm itself and extrinsic implies compression by 3. Mejico LJ, Miller NR, Dong LM. Clinical features another structure. Other less common causes of chiasmal syndrome associated with lesions other than in are metabolic, toxic, traumatic or infectious in nature. Intrinsic patients with an optic chiasmal syndrome. American etiologies include gliomas and . Gliomas of the journal of ophthalmology. 2004 May 31;137(5):908-13. optic chiasm are usually derived from . These tumors are 4. WAGENER HP, CUSICK PL. Chiasmal syndromes slow growing and more often found children. However, they have a produced by lesions in the posterior fossa. Archives of worse prognosis, especially if they have extended into the Ophthalmology. 1937 Dec 1;18(6):887-91. . They are frequently associated with 5. Levin LA. Topical diagnosis of chiasmal and type 1 (NF-1). Their treatment involves the retrochiasmal disorders. Walsh and Hoyt clinical resection of the optic nerve. The supposed artifactual nature of neuro-ophthalmology, 6th ed. Baltimore: Williams & Willebrand's knee has implications for the degree of resection that Wilkins. 2005:503-73. can be obtained, namely by cutting the optic nerve immediately at 6. Savino PJ, Glaser JS, Schatz NJ. Traumatic chiasmal the junction with the chiasm without fear of potentially resulting syndrome. Neurology. 1980 Sep 1;30(9):963-. visual field deficits. The vast majority of chiasmal syndromes are compressive. There are several compressive etiologies, the usual suspects are pituitary adenomas ,craniopharyngiomas and meningiomas. Pituitary tumors are the most common cause of chiasmal syndromes. Visual field defects may be one of the first signs of non-functional pituitary tumor. These are much less frequent than functional adenomas. Systemic hormonal aberrations such as cushing's syndrome, galactorrhea and usually predate the compressive signs. Pituitary tumors often encroach upon the middle chiasm from below. is one of the few acute chiasmal syndromes. It can lead to sudden visual loss as the hemorrhagic adenoma rapidly enlarges. The embryonic remnants of Rathke’s pouch may undergo neoplastic change called a . These tumors may develop at any time but two age groups are most at risk. One peak occurs during the first twenty years of life and the other occurs between fifty and seventy years of age. Craniopharyngiomas generally approach the optic chiasm from behind and above. Extension of craniopharyngiomas into the third ventricle may cause hydrcephalus. Meningiomas can develop from the arachnoid layer. Tuberculum sellae and sphenoid planum meningiomas usually compress the optic chiasm from below. If the meningioma arises from the the posterior chiasm is damaged. Medial sphenoid ridge types can push on the chiasm from the side. Olfactory groove subfrontal types can reach the chiasm from above. Meningiomas are also associated with neurofibromatosis type 1. Women are more prone to develop meningiomas. MANAGEMENT Visual fields associated with chiasmal syndrome usually leads to an MRI. Contrast can delineate arterial aneutysms and will enhance most intrinsic chiasmal lesions. If a mass is confirmed on MRI, an endocrine panel can help determine if pituitary adenoma is involved. In patients with functional adenomas diagnosed by other means, visual field tests are a good screen to test for chiasmal involvement. Junctional classically show ipsilateral optic disc neuropathy with contralateral superotemporal defects. Bitemporal hemianopia with or without central scotoma is present if the lesions

An Initiative of The Tamil Nadu Dr. M.G.R. Medical University University Journal of Surgery and Surgical Specialities

An Initiative of The Tamil Nadu Dr. M.G.R. Medical University University Journal of Surgery and Surgical Specialities