Bitemporal hemianopia: Difference between revisions

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==Pathophysiology==
==Pathophysiology==
Hemianopia results from a lesion of the [[optic chiasm]]. This is the area where optic nerves from the right side of the brain cross over to the left and vice versa. Visual information from the temporal [[visual field]] is transmitted by the nasal retina and information from the nasal field is transmitted by the temporal [[retina]].  At the [[optic chiasm]], nasal fibers of the [[retina]] cross over to other side of the brain and carry information to the higher visual brain centers.  Thus, a lesion in the [[optic chiasm]] affects the nasal fibers of both [[retina]]s.  It is when this disruption in the circuitry occurs that there is a loss of information from both of the outer visual fields.
Hemianopia results from a lesion of the [[optic chiasm]]. This is the area where optic nerves from the right side of the brain cross over to the left and vice versa. Visual information from the temporal [[visual field]] is transmitted by the nasal retina and information from the nasal field is transmitted by the temporal [[retina]].  At the [[optic chiasm]], nasal fibers of the [[retina]] cross over to other side of the brain and carry information to the higher visual brain centers.  Thus, a lesion in the [[optic chiasm]] affects the nasal fibers of both [[retina]]s.  It is when this disruption in the circuitry occurs that there is a loss of information from both of the outer visual fields.
==Causes==
Most of the causes of bitemporal hemianopia are due to disorders of the pituitary gland and its surrounding structures.
===Common Causes===
*[[Pituitary tumor|Pituitary macroadenoma]]
*[[Craniopharyngioma]]
*[[Meningioma]]
*[[Aneurysm]] of the [[anterior communicating artery]]
===Causes by Organ System===
{|style="width:80%; height:100px" border="1"
|style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" | '''Cardiovascular'''
|style="height:100px"; style="width:75%" border="1" bgcolor="Beige" | No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Chemical / poisoning'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Dermatologic'''
|bgcolor="Beige"| [[Dermatochalasis]]
|-
|-bgcolor="LightSteelBlue"
| '''Drug Side Effect'''
|bgcolor="Beige"| [[Chloroquine retinopathy]]
|-
|-bgcolor="LightSteelBlue"
| '''Ear Nose Throat'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Endocrine'''
|bgcolor="Beige"| [[Pituitary adenoma|Pituatary macroadenoma]], [[Prolactinoma]]
|-
|-bgcolor="LightSteelBlue"
| '''Environmental'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Gastroenterologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Genetic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Hematologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Iatrogenic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Infectious Disease'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Musculoskeletal / Ortho'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Neurologic'''
|bgcolor="Beige"| [[Chloroquine retinopathy]], [[Pituitary adenoma|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]]
|-
|-bgcolor="LightSteelBlue"
| '''Nutritional / Metabolic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Obstetric/Gynecologic'''
|bgcolor="Beige"| [[Hypophyseal hypertrophy in pregnancy]]
|-
|-bgcolor="LightSteelBlue"
| '''Oncologic'''
|bgcolor="Beige"| [[Adamantinoma of sella turcica]], [[Craniopharyngioma]], [[Glioma of third ventricle]], [[Pituitary adenoma|Pituitary macroadenoma]], [[Prolactinoma]], [[Meningioma]], [[Suprasellar tumors]]
|-
|-bgcolor="LightSteelBlue"
| '''Opthalmologic'''
|bgcolor="Beige"| [[Dermatochalasis]], [[Optic neuropathy]], [[Optic chiasmal syndrome]], [[Bilateral blepharoptosis]], [[Traumatic chiasmal syndrome]]
|-
|-bgcolor="LightSteelBlue"
| '''Overdose / Toxicity'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Psychiatric'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Pulmonary'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Renal / Electrolyte'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Rheum / Immune / Allergy'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Sexual'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Trauma'''
|bgcolor="Beige"| [[Traumatic chiasmal syndrome]]
|-
|-bgcolor="LightSteelBlue"
| '''Urologic'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Dental'''
|bgcolor="Beige"| No underlying causes
|-
|-bgcolor="LightSteelBlue"
| '''Miscellaneous'''
|bgcolor="Beige"| No underlying causes
|-
|}
===Causes in Alphabetical Order===
*[[Adamantinoma of sella turcica]]<ref>http://www.ncbi.nlm.nih.gov/pmc/articles/PMC510604/?pa</ref>
*[[Aneurysm of anterior communicating artery]]
*[[Bilateral blepharoptosis]]<ref>http://www.ncbi.nlm.nih.gov/pubmed/21158577</ref>
*[[Chloroquine retinopathy]]<ref>http://www.neurology.org/content/24/12/1135.abstract</ref>
*[[Chronic chiasmal arachnoiditis]]<ref>http://www.ncbi.nlm.nih.gov/pmc/articles/PMC512211/</ref>
*[[Craniopharyngioma]]
*[[Dermatochalasis]]<ref>http://www.ncbi.nlm.nih.gov/pubmed/12644764</ref>
*[[Dolichoectasia of internal carotid arteries]]<ref>http://www.ncbi.nlm.nih.gov/pubmed/2139057</ref>
*[[Enlarged third ventricle]]<ref>http://bjo.bmj.com/content/62/8/536.full.pdf</ref>
*[[Glioma of third ventricle]]
*[[Hypophyseal hypertrophy in pregnancy]]<ref>http://www.ncbi.nlm.nih.gov/pubmed/14082282</ref>
*[[Intracranial vascular loop]]
*[[Meningioma]]
*[[Obstructive hydrocephalus]]
*[[Optic chiasmal syndrome]]
*[[Optic neuropathy]]
*[[Pituitary adenoma|Pituitary macroadenoma]]
*[[Prolactinoma]]
*[[Suprasellar tumors]]
*[[Traumatic chiasmal syndrome]]


== [[Bitemporal hemianopia overview|Overview]] ==
== [[Bitemporal hemianopia overview|Overview]] ==

Revision as of 18:17, 30 November 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

Bitemporal hemianopia is a specific type of visual disturbance in which sight in the outer half of the visual field of each eye is lost. As a result, the patient retains central vision but loses sight at the edges of his or her vision. This is not always obvious to a patient because one tends to focus conscious attention more on objects in the center of the visual field.

Hemianopia signifies a loss of half of the visual field, and bitemporal denotes the two lateral, or temporal, sides of the head. By contrast, homonymous hemianopia signifies that the same half of each visual field is lost, ie all vision on the left, or on the right, of the midline. Such a pattern of visual loss is caused by damage to the more distal part of the optic radiation, most commonly by a stroke.

Etymology

"Bitemporal hemianopia" 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)

Pathophysiology

Hemianopia results from a lesion of the optic chiasm. This is the area where optic nerves from the right side of the brain cross over to the left and vice versa. Visual information from the temporal visual field is transmitted by the nasal retina and information from the nasal field is transmitted by the temporal retina. At the optic chiasm, nasal fibers of the retina cross over to other side of the brain and carry information to the higher visual brain centers. Thus, a lesion in the optic chiasm affects the nasal fibers of both retinas. It is when this disruption in the circuitry occurs that there is a loss of information from both of the outer visual fields.

Causes

Most of the causes of bitemporal hemianopia are due to disorders of the pituitary gland and its surrounding structures.

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

Overview

Historical Perspective

Pathophysiology

Causes

Natural history and Complications

Diagnosis

History and Symptoms |Physical Examination |Laboratory tests |Electrocardiogram | Chest X Ray | CT | MRI | Echocardiography or Ultrasound | Other imaging studies | Alternative diagnostics

Treatment

Medical therapy | Surgical therapy

Related Chapters

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  1. ↑ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC510604/?pa
  2. ↑ http://www.ncbi.nlm.nih.gov/pubmed/21158577
  3. ↑ http://www.neurology.org/content/24/12/1135.abstract
  4. ↑ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC512211/
  5. ↑ http://www.ncbi.nlm.nih.gov/pubmed/12644764
  6. ↑ http://www.ncbi.nlm.nih.gov/pubmed/2139057
  7. ↑ http://bjo.bmj.com/content/62/8/536.full.pdf
  8. ↑ http://www.ncbi.nlm.nih.gov/pubmed/14082282
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