Cerebral edema: Difference between revisions

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'''Cerebral edema''' or '''cerebral œdema''' is an excess accumulation of water in the intracellular and/or extracellular spaces of the [[brain]].
'''Cerebral edema''' or '''cerebral œdema''' is an excess accumulation of water in the intracellular and/or extracellular spaces of the [[brain]].


==Types of Cerebral Edema==
==Types==


Four types of [[Cerebrum|cerebral]] [[edema]] have been distinguished<ref>{{cite journal | author=Qureshi AI, Suarez JI | title=Use of hypertonic saline solutions in treatment of cerebral edema and intracranial hypertension | journal=Critical Care Medicine | volume=28 | issue=9 | year=2000 | pages=3301–3313 | pmid=11008996 | doi=10.1097/00003246-200009000-00032 | unused_data=DUPLICATE DATA: pmid=11008996 }}</ref>:
Four types of [[Cerebrum|cerebral]] [[edema]] have been distinguished<ref>{{cite journal | author=Qureshi AI, Suarez JI | title=Use of hypertonic saline solutions in treatment of cerebral edema and intracranial hypertension | journal=Critical Care Medicine | volume=28 | issue=9 | year=2000 | pages=3301–3313 | pmid=11008996 | doi=10.1097/00003246-200009000-00032 | unused_data=DUPLICATE DATA: pmid=11008996 }}</ref>:


===Vasogenic Cerebral Edema===
===Vasogenic===
Due to a breakdown of tight endothelial junctions which make up the [[blood-brain barrier]] (BBB). This allows normally excluded intravascular proteins and fluid to penetrate into cerebral parenchymal extracellular space.
Due to a breakdown of tight endothelial junctions which make up the [[blood-brain barrier]] (BBB). This allows normally excluded intravascular proteins and fluid to penetrate into cerebral parenchymal extracellular space.
Once plasma constituents cross the BBB, the edema spreads; this may be quite fast and widespread. As water enters white matter it moves extracellularly along fiber tracts and can also affect the gray matter.
Once plasma constituents cross the BBB, the edema spreads; this may be quite fast and widespread. As water enters white matter it moves extracellularly along fiber tracts and can also affect the gray matter.
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:Climbers may also suffer [[high altitude pulmonary edema]] ([[HAPE]]), which affects the lungs. While not as life threatening as HACE in the initial stages, failure to descend to lower altitudes or receive medical treatment can also lead to death.
:Climbers may also suffer [[high altitude pulmonary edema]] ([[HAPE]]), which affects the lungs. While not as life threatening as HACE in the initial stages, failure to descend to lower altitudes or receive medical treatment can also lead to death.


===Cytotoxic Cerebral Edema===
===Cytotoxic===
In this type of edema the BBB remains intact.
In this type of edema the BBB remains intact.
This edema is due to the derangement in cellular [[metabolism]] resulting in inadequate functioning of the sodium and potassium pump in the [[glial cell]] membrane. As a result there is cellular retention of sodium and water. There are swollen astrocytes in gray and white matter. Cytotoxic edema is seen with various intoxications ([[dinitrophenol]], triethyltin, [[hexachlorophene]], [[isoniazid]]), in [[Reye's syndrome]], severe [[hypothermia]], early [[ischemia]], [[encephalopathy]], early [[stroke]] or [[Hypoxia (medical)|hypoxia]], cardiac arrest, pseudotumor cerebri, and cerebral toxins.
This edema is due to the derangement in cellular [[metabolism]] resulting in inadequate functioning of the sodium and potassium pump in the [[glial cell]] membrane. As a result there is cellular retention of sodium and water. There are swollen astrocytes in gray and white matter. Cytotoxic edema is seen with various intoxications ([[dinitrophenol]], triethyltin, [[hexachlorophene]], [[isoniazid]]), in [[Reye's syndrome]], severe [[hypothermia]], early [[ischemia]], [[encephalopathy]], early [[stroke]] or [[Hypoxia (medical)|hypoxia]], cardiac arrest, pseudotumor cerebri, and cerebral toxins.


===Osmotic Cerebral Edema===
===Osmotic===
Normally cerebral-spinal fluid (CSF) and extracellular fluid (ECF) [[osmolality]] of the brain is slightly lower than that of plasma. When plasma is diluted by excessive water intake (or [[hyponatremia]]), [[syndrome of inappropriate antidiuretic hormone]] secretion (SIADH), [[hemodialysis]], or rapid reduction of blood [[glucose]] in hyper[[osmolar]] [[hyperglycemic]] state (HHS), formerly hyperosmolar non-ketotic acidosis (HONK), the brain osmolality will then exceed the serum osmolality creating an abnormal pressure gradient down which water will flow into the brain causing edema.
Normally cerebral-spinal fluid (CSF) and extracellular fluid (ECF) [[osmolality]] of the brain is slightly lower than that of plasma. When plasma is diluted by excessive water intake (or [[hyponatremia]]), [[syndrome of inappropriate antidiuretic hormone]] secretion (SIADH), [[hemodialysis]], or rapid reduction of blood [[glucose]] in hyper[[osmolar]] [[hyperglycemic]] state (HHS), formerly hyperosmolar non-ketotic acidosis (HONK), the brain osmolality will then exceed the serum osmolality creating an abnormal pressure gradient down which water will flow into the brain causing edema.


===Interstitial Cerebral Edema===
===Interstitial===
Occurs in obstructive hydrocephalus.
Occurs in obstructive hydrocephalus.
This form of edema is due to rupture of the CSF-brain barrier resulting in trans-ependymal flow of CSF which causes CSF to penetrate the brain and spread to the extracellular spaces and the white matter. This is differentiated from vasogenic edema in that interstitial cerebral edema CSF contains almost no protein.
This form of edema is due to rupture of the CSF-brain barrier resulting in trans-ependymal flow of CSF which causes CSF to penetrate the brain and spread to the extracellular spaces and the white matter. This is differentiated from vasogenic edema in that interstitial cerebral edema CSF contains almost no protein.

Revision as of 02:55, 28 September 2011

Cerebral edema

Cerebral edema or cerebral œdema is an excess accumulation of water in the intracellular and/or extracellular spaces of the brain.

Types

Four types of cerebral edema have been distinguished[1]:

Vasogenic

Due to a breakdown of tight endothelial junctions which make up the

blood-brain barrier
(BBB). This allows normally excluded intravascular proteins and fluid to penetrate into cerebral parenchymal extracellular space. Once plasma constituents cross the BBB, the edema spreads; this may be quite fast and widespread. As water enters white matter it moves extracellularly along fiber tracts and can also affect the gray matter. This type of edema is seen in response to trauma, tumors, focal inflammation, late stages of cerebral ischemia and hypertensive encephalopathy.

Some of the mechanisms contributing to BBB dysfunction are: physical disruption by arterial hypertension or trauma, tumor-facilitated release of vasoactive and endothelial destructive compounds (e.g. arachidonic acid, excitatory neurotransmitters, eicosanoids, bradykinin, histamine, and free radicals). Some of the special subcategories of vasogenic edema include:

Hydrostatic cerebral edema
This form of cerebral edema is seen in acute, malignant hypertension. It is thought to result from direct transmission of pressure to cerebral capillary with transudation of fluid into the ECF (extracellular fluid) from the capillaries.
Cerebral edema from brain cancer
Cancerous
blood-brain barrier. Dexamethasone can be of benefit in reducing VEGF secretion.[2]
High Altitude Cerebral Edema
endothelial cells of the blood-brain barrier.[3]
Symptoms can include headache, loss of coordination (ataxia), weakness, and decreasing levels of consciousness including disorientation, loss of memory, hallucinations, psychotic behavior, and coma. It generally occurs after a week or more at
gamow bag
can sometimes be used to stabilize the sufferer before transport or descending.
Climbers may also suffer
HAPE
), which affects the lungs. While not as life threatening as HACE in the initial stages, failure to descend to lower altitudes or receive medical treatment can also lead to death.

Cytotoxic

In this type of edema the BBB remains intact. This edema is due to the derangement in cellular

hypoxia
, cardiac arrest, pseudotumor cerebri, and cerebral toxins.

Osmotic

Normally cerebral-spinal fluid (CSF) and extracellular fluid (ECF)

hyperglycemic
state (HHS), formerly hyperosmolar non-ketotic acidosis (HONK), the brain osmolality will then exceed the serum osmolality creating an abnormal pressure gradient down which water will flow into the brain causing edema.

Interstitial

Occurs in obstructive hydrocephalus. This form of edema is due to rupture of the CSF-brain barrier resulting in trans-ependymal flow of CSF which causes CSF to penetrate the brain and spread to the extracellular spaces and the white matter. This is differentiated from vasogenic edema in that interstitial cerebral edema CSF contains almost no protein.

Treatment

Treatment approaches can include

diuretics and surgical decompression.[4]

References

  1. PMID 11008996. {{cite journal}}: Unknown parameter |unused_data= ignored (help
    )
  2. PMID 8823305. {{cite journal}}: Unknown parameter |unused_data= ignored (help)CS1 maint: multiple names: authors list (link
    )
  3. PMID 15692117. {{cite journal}}: Unknown parameter |unused_data= ignored (help)CS1 maint: multiple names: authors list (link
    )
  4. PMID 17613230
    .

dexamethasone

External links
Retrieved from "https://en.wikipedia.org/w/index.php?title=Cerebral_edema&oldid=452809424"