The inner most layer around the brain tissue
Between the dura mater and arachnoid mater
The outermost layer, between the skull and dura mater
Usually due to rupture of a blood vessel (e.g. berry aneurysm or AVM). Pain typically felt at the back of the head
Usually due to trauma causing damage to one of the bridging veins. Trauma may be minor and could be many months ago. Can be acute or chronic.
Due to direct moderate / severe head trauma. Typically around the eye, causing fracture of the temporal or parietal bone, resulting in laceration of the middle meningeal artery and/or vein
Sudden onset, painful
Possible dull headache
Likely, and often severe, but not sudden onset
May become impaired quickly – if so, a very bad prognostic indicator
Fluctuates, often over weeks or even months
Classically, an initial lucid period, followed by impaired consciousness
May be present; are a poor prognostic indicator
Often insidious. May involve memory impairment, epilepsy, drowsiness, dizziness. Often occur weeks / months after injury
CT – should show irregular shaped bleed. If absent, and still suspicious, do LP to confirm (blood in CSF, CSF turn yellow when left to stand – xanthochromia)
CT / MRI – classically shows a crescent of blood around the brain tissue, and midline shift
CT / MRI – described as a lens shaped lesion – meaning it is biconvex.
LP is contraindicated!
X-ray may show skull fracture
If few symptoms, surgical clipping of platinum coiling of aneursm, or if AVM then balloon therapy and stening are beneficial. Give Nimodipine to reduce risk of vasospasm (and ↑ survival) as long as BP can be maintained.
Burr hole or craniotomy
Surgery to evacuate blood and ligate bleeding vessels
- Acutely appears more dense than surrounding brain
- Gradually, blood component are absorbed, and its density drops
- Can be hard to see in the subacute phase, as it may be isodense with brain tissue
- Chronically, it will appear hypodense (darker) than brain tissue