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
