The Meninges + Subarachnoid Haemorrhage Flashcards
What are the meninges?
Periosteal dura mater
Meningeal dura mater
Arachnoid mater
Pia mater
What are the 4 important dural septa?
What do they separate?
- Falx cerebri: between cerebral hemispheres
- Falx cerebelli: between cerebellar hemispheres
- Tentorium cerebelli: between occipital lobe + cerebellum
- Diaphrgama sella: by sella turcica
What is CSF flow propelled by?
- production of new fluid
- ciliary action of ventricular ependymal
- vascular pulsations
Epidemiology of subarachnoid haemorrhage
- female > male
- 50-55 year olds
- more likely in black, Finnish + Japanese population
Presentation of subarachnoid haemorrhage
- thunder clap headache
- dizziness
- orbital pain
- double vision/visual loss (PComA can compress CN III)
- signs of meningism: photophobia, neck stiffness
Risk factors for subarachnoid haemorrhage
- hypertension
- smoking
- excessive alcohol consumption
- family history of aneurysms
- cocaine use
- trauma
- chronic kidney disease, Marfan’s syndrome, neurofibromatosis
Pathophysiology of subarachnoid haemorrhage
- often due to rupture of aneurysm in circle of Willis
- commonly berry aneurysms
- often in anterior or posterior communicating artery, or bifurcation of middle cerebral artery
What type of aneurysm most commonly causes subarachnoid haemorrhage and common locations?
- berry aneurysm
- anterior or posterior communicating artery or bifurcation of middle cerebral artery
What can a subarachnoid haemorrhage cause?
- microthrombi + vasoconstriction > cerebral ischaemia
- cerebral oedema
- apoptosis of brain cells
- cardiac failure - due to sympathetic response
- acute hydrocephalus due to blockage of CSF drainage by blood
Investigations of subarachnoid haemorrhage
- CT head
- CT angiogram to find location
- lumbar puncture after 12 hours
Lumbar puncture findings in subarachnoid haemorrhage
- increased opening pressure
- frank blood or xanthochromia
- high protein
- high red cell count
- normal white cells + glucose
What is xanthochromia?
Yellow colouring of CSF due to bilirubin in subarachnoid space
Treatment of subarachnoid haemorrhage
- airway support
- fluids
- monitor cardiovascular parameters
- calcium channel blockers e.g. nimodipine
- coiling
- clipping
- craniectomy - decompressive surgery
What is clipping treatment of subarachnoid haemorrhage?
Placement of spring clip around neck of aneurysm causing it to lose blood supply + shrivel up
What is coiling treatment of subarachnoid haemorrhage?
Insertion of platinum wire into aneurysm sac > thrombosis of blood within aneurysm
Why are calcium channel blockers given in treatment of subarachnoid haemorrhage?
Example
Prevent cerebral vasospasm due to sympathetic activation
nimodipine
What does the presence of xanthochromia in CSF suggest?
Subarachnoid haemorrhage occurred >12 hours ago
