Papilledema pathophysiology: Difference between revisions
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{{Papilledema}} | |||
{{ | {{CMG}}; {{AE}} {{KD}} | ||
==Overview== | ==Overview== | ||
[[Papilledema]] is in general the result of transmission of [[increased intracranial pressure]]<ref>{{cite journal |author=Tso MO, Hayreh SS |title=Optic disc edema in raised intracranial pressure. IV. Axoplasmic transport in experimental papilledema |journal=Arch. Ophthalmol. |volume=95 |issue=8 |pages=1458–62 |year=1977 |month=August |pmid=70201 |doi= |url=}}</ref> to the anterior end of [[optic nerve]] through optic nerve sheath. | |||
==Pathophysiology== | ==Pathophysiology== | ||
* The [[optic nerve]] sheath is contiguous with the [[subarachnoid space]] of the [[brain]] and is regarded as an extension of the [[central nervous system]]. | |||
* [[ | * The cranium and the [[vertebral body]], along with the relatively inelastic [[dura]], form a rigid container, such that an increase in any of the contents of the [[dura]] (brain, blood and [[cerebrospinal fluid]]) can cause [[increased intracranial pressure]]. | ||
* The | * The [[increased intracranial pressure]] is transmitted through to the [[optic nerve]] via the [[optic nerve]] sheath. | ||
* [[ | * The anterior end of the [[optic nerve]] stops abruptly at the eye. Hence the pressure is asymmetrical and this causes a pinching and protrusion of the [[optic nerve]] at its head. | ||
* The | * The fibers of the [[Ganglion cell|retinal ganglion cell]]s of the [[optic disc]] become engorged and bulge anteriorly. | ||
* | * Persistent and extensive [[optic nerve]] head swelling, or [[optic disc]] [[edema]], can lead to loss of these fibers and permanent visual impairment. | ||
* | * Papilledema may be absent in cases of prior [[optic atrophy]]. In these cases, the absence of papilledema is most likely secondary to a decrease in the number of physiologically active nerve fibers. | ||
==References== | ==References== | ||
{{ | {{reflist|2}} | ||
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Latest revision as of 17:04, 11 June 2015
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Kalsang Dolma, M.B.B.S.[2]
Overview
Papilledema is in general the result of transmission of increased intracranial pressure[1] to the anterior end of optic nerve through optic nerve sheath.
Pathophysiology
- The optic nerve sheath is contiguous with the subarachnoid space of the brain and is regarded as an extension of the central nervous system.
- The cranium and the vertebral body, along with the relatively inelastic dura, form a rigid container, such that an increase in any of the contents of the dura (brain, blood and cerebrospinal fluid) can cause increased intracranial pressure.
- The increased intracranial pressure is transmitted through to the optic nerve via the optic nerve sheath.
- The anterior end of the optic nerve stops abruptly at the eye. Hence the pressure is asymmetrical and this causes a pinching and protrusion of the optic nerve at its head.
- The fibers of the retinal ganglion cells of the optic disc become engorged and bulge anteriorly.
- Persistent and extensive optic nerve head swelling, or optic disc edema, can lead to loss of these fibers and permanent visual impairment.
- Papilledema may be absent in cases of prior optic atrophy. In these cases, the absence of papilledema is most likely secondary to a decrease in the number of physiologically active nerve fibers.