Bitemporal hemianopia: Difference between revisions

Jump to navigation Jump to search
No edit summary
No edit summary
Line 22: Line 22:
==[[Bitemporal hemianopia overview|Overview]]==
==[[Bitemporal hemianopia overview|Overview]]==


==Historical Perspective and Etymology==
==[[Bitemporal hemianopia historical perspective|Historical Perspective and Etymology]]==
"Bitemporal hemianopia" can be broken down as follows:
==[[Bitemporal hemianopia pathophysiology| Pathophysiology]]==
*''bi-'': involves both left and right visual fields
*''temporal'': involves the temporal visual field
*''hemi-'': involves half of each visual field
*''anosia'': blindness (formed by ''a(n) <sup>no</sup> + opsis <sup>vision</sup> + ia'')
 
==Pathophysiology==
==Pathophysiology==
Hemianopia results from a lesion of the [[optic chiasm]]. This is the area where optic nerves from right cross over to the left and vice versa. Visual information from the temporal [[visual field]] falls on the nasal retina and information from nasal field falls on temporal [[retina]].  At the [[optic chiasm]] nasal fibers of [[retina]] cross over to other side and carries information to the higher centers.  Thus, when there is a lesion of [[optic chiasm]], the nasal fibers of both the [[retina]] are affected leading to loss of information from both the temporal (outer) visual fields.
Hemianopia results from a lesion of the [[optic chiasm]]. This is the area where optic nerves from right cross over to the left and vice versa. Visual information from the temporal [[visual field]] falls on the nasal retina and information from nasal field falls on temporal [[retina]].  At the [[optic chiasm]] nasal fibers of [[retina]] cross over to other side and carries information to the higher centers.  Thus, when there is a lesion of [[optic chiasm]], the nasal fibers of both the [[retina]] are affected leading to loss of information from both the temporal (outer) visual fields.

Revision as of 05:38, 19 July 2012

Template:DiseaseDisorder infobox

Template:Bitemporal hemianopia

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] ; Associate Editor(s)-In-Chief:Aditya Govindavarjhulla, M.B.B.S. [2]

Synonyms and keywords: Bitemporal hemianopsia

Overview

Historical Perspective and Etymology

Pathophysiology

Pathophysiology

Hemianopia results from a lesion of the optic chiasm. This is the area where optic nerves from right cross over to the left and vice versa. Visual information from the temporal visual field falls on the nasal retina and information from nasal field falls on temporal retina. At the optic chiasm nasal fibers of retina cross over to other side and carries information to the higher centers. Thus, when there is a lesion of optic chiasm, the nasal fibers of both the retina are affected leading to loss of information from both the temporal (outer) visual fields.

Causes

Common Causes

Causes by Organ System

Cardiovascular No underlying causes
Chemical / poisoning No underlying causes
Dermatologic Dermatochalasis
Drug Side Effect Chloroquine retinopathy
Ear Nose Throat No underlying causes
Endocrine Pituatary macroadenoma, Prolactinoma
Environmental No underlying causes
Gastroenterologic No underlying causes
Genetic No underlying causes
Hematologic No underlying causes
Iatrogenic No underlying causes
Infectious Disease No underlying causes
Musculoskeletal / Ortho No underlying causes
Neurologic Chloroquine retinopathy, Pituitary macroadenoma, Prolactinoma, Craniopharyngioma, Aneurysm of anterior communicating artery, Intracranial vascular loop, Meningioma, Enlarged third ventricle, Glioma of third ventricle, Chronic chiasmal arachnoiditis, Suprasellar tumors, Adamantinoma of sella turcica, Optic neuropathy, Optic chiasmal syndrome, Obstructive hydrocephalus, Traumatic chiasmal syndrome, Dolichoectasia of internal carotid arteries
Nutritional / Metabolic No underlying causes
Obstetric/Gynecologic Hypophyseal hypertrophy in pregnancy
Oncologic Adamantinoma of sella turcica, Craniopharyngioma, Glioma of third ventricle, Pituitary macroadenoma, Prolactinoma, Meningioma, Suprasellar tumors
Opthalmologic Dermatochalasis, Optic neuropathy, Optic chiasmal syndrome, Bilateral blepharoptosis, Traumatic chiasmal syndrome
Overdose / Toxicity No underlying causes
Psychiatric No underlying causes
Pulmonary No underlying causes
Renal / Electrolyte No underlying causes
Rheum / Immune / Allergy No underlying causes
Sexual No underlying causes
Trauma Traumatic chiasmal syndrome
Urologic No underlying causes
Dental No underlying causes
Miscellaneous No underlying causes

Causes in Alphabetical Order

See also

References


Template:WH Template:WS