同: bitemporal hemianopsia

WordNet

blindness in one half of the visual field of one or both eyes (同)hemianopsia

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/11/17 14:09:02」(JST)

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Bitemporal hemianopsia (aka bitemporal heteronymous hemianopsia or bitemporal hemianopia) is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field. It is usually associated with lesions of the optic chiasm, the area where the optic nerves from the right and left eyes cross near the pituitary gland.

Causes

In bitemporal hemianopsia vision is missing in the outer (temporal or lateral) half of both the right and left visual fields. Information from the temporal visual field falls on the nasal (medial) retina. The nasal retina is responsible for carrying the information along the optic nerve, and crosses to the other side at the optic chiasm. When there is compression at optic chiasm the visual impulse from both nasal retina are affected, leading to inability to view the temporal, or peripheral, vision. This phenomenon is known as bitemporal hemianopsia. Knowing the neurocircuitry of visual signal flow through the optic tract is very important in understanding bitemporal hemianopsia.

Bitemporal hemianopsia most commonly occurs as a result of tumors located at the mid-optic chiasm. Since the adjacent structure is the pituitary gland, some common tumors causing compression are pituitary adenomas and craniopharyngiomas. Also another relatively common neoplastic etiology is meningiomas. An etiology of vascular origin is an aneurysm of the anterior communicating artery which arise superior to the chiasm, enlarge, and compress it from above.

Etymology

The absence of vision in half of a visual field is described as hemianopsia.

The visual field of each eye can be divided in two vertically, with the outer half being described as temporal, and the inner half being described as nasal.

"Bitemporal hemianopsia" can be broken down as follows:

bi-: involves both left and right visual fields
temporal: involves the temporal visual field
hemi-: involves half of each visual field
anopsia: blindness (formed by a(n) ^no + opsis ^vision + ia)

External links

Case report of Bilateral Hemianopsia Due to Pituitary Adenoma. Clinical Cases and Images. at blogspot.com
1872363522 at GPnotebook

UpToDate Contents

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1. 鞍部腫瘤の原因、症状、および評価 causes presentation and evaluation of sellar masses
2. 急性持続性視力喪失が認められた成人に対するアプローチ approach to the adult with acute persistent visual loss
3. ゴナドトロピン産生下垂体腺腫，およびその他の臨床的に非機能性の下垂体腺腫の
臨床症状および診断 clinical manifestations and diagnosis of gonadotroph and other clinically nonfunctioning pituitary adenomas
4. 脳腫瘍の臨床所見および診断 clinical presentation and diagnosis of brain tumors
5. 成人における詳細な神経学的検査 the detailed neurologic examination in adults

English Journal

Stroke intervention for middle cerebral artery thrombus in a young patient with an ipsilateral Spetzler-Martin grade V arteriovenous malformation.

Abla AA, Dumont TM, Kan P, Hopkins LN, Siddiqui AH, Levy EI.SourceDepartment of Neurosurgery and Toshiba Stroke Research Center, USA.
Journal of neurointerventional surgery.J Neurointerv Surg.2012 Feb 19. [Epub ahead of print]
A patient (in their late 20s) was admitted with a right frontal stroke, left hemiparesis and hemianopsia, and a National Institutes of Health Stroke Scale (NIHSS) score of 11. CT perfusion imaging revealed an ischemic penumbra. A CT angiogram showed a Spetzler-Martin grade V arteriovenous malformati
PMID 22345144

Acute, monocular vision loss from Rathke's cleft cyst.

Bohnstedt BN, Patel NB, Hagen MC, Fulkerson DH.SourceDepartment of Neurosurgery, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Journal of clinical neuroscience : official journal of the Neurosurgical Society of Australasia.J Clin Neurosci.2012 Feb 13. [Epub ahead of print]
Rathke's cleft cysts are benign, non-neoplastic sellar lesions that are often asymptomatic. The rare patient with symptoms may present with pituitary dysfunction, headache, or visual problems. Visual deficits are generally consistent with a chiasmal syndrome as associated with other sellar lesions.
PMID 22336223