26. Brain edema

Question 1

Types of cerebral edema

Answer 1

1. Vasogenic
2. Cytotoxic
3. Interstitial

Question 1

Define brain edema

Answer 1

Swelling that occurs in the brain caused by an accumulation of excess fluid in the brain tissue

Question 2

Vasogenic brain edema

Answer 2

Damage to BBB, leading to extracellular edema high in protein (extravasations of serum proteins). Edema spreads in white matter along nerve fibers.

Commonly in early phase of traumatic injury or in late phase of ischemia

Diagnosis: T2-weighted MRI
- Space-occupying lesions (abscess, hemorrhage)
- Perifocal in tumors
- Generalized in meningoencephalitis

Treatment
- Corticosteroids

Question 3

Cytotoxic edema

Answer 3

1. Decreased ion-gradient bw. intra- and extracellular space.
2. Na+, Cl-, H20 moves into the neurons
3. VG Ca+ channels damaged
4. Ca2+ influx
5. Fluid accumulation in cells

Typical in early phase of cerebral ishcemia or in late phase of traumatic injury

Dx diffuse-weighted MRI

Question 4

Interstitial edema

Answer 4

Develops in occlusive hydrocephlus. Increased CSF pressure leads to the CSF being pushed across ependymal layer of the ventricles into brain paranchyma

Dx
- CT: hypodense halo around ventricles
- MRI: high intensity on T2-weighted

Question 5

General management of brain edema

Answer 5

Main: reduce the increased ICP
- Causative treatment
- Osmodiuretics (mannitol, glycerol)
- Loop diuretics (decr. CSF production)
- Controlled hyperventilation
- Barbiturate narcosis
- Decompression craniectomy
- If hydrocephalus: CSF drainage