Intracranial Haemorrhage Flashcards
(39 cards)
What fluid does a subarachnoid haemorrhage bleed into?
CSF
What are the most common reasons for a subarachnoid haemorrhage to occur?
- Berry aneurysm
- Sometimes AVM
Where in the circle of willis are berry aneurysms usually found?
junctions between branching arteries
What is the main presenting feature of a subarachnoid haemorrhage and why?
Sudden onset SEVERE headache
(often described as being hit with brick/baseball bat)
Due to full systolic blood pressure entering the CSF space after aneurysm ruptures (normally this pressure =0)
Why can subarachnoid haemorrhages cause symptoms similar to that of meningitis?
- Rupture of aneurysm causes release of inflammatory chemicals into CSF space
- Irritation of meninges causes neck pain and stiffness and photophobia
Other than symptoms of meningitis, what can present in a subarachnoid haemorrhage?
- decreased conscious level
- neurological deficit
- retinal/vitreous haemorrhage on fundoscopy
- CN III palsy - due to compression from bleed
What are the potential differentials for a sudden onset headache?
Subarachnoid Haemorrhage
Migraine
Benign coital cephalgia (due to patient over-exerting themself, often during sex)
Why does CSF appear black on CT whilst acute blood appears hyperintense?
CSF - not a lot of electrons to pick up X-Rays
Blood - rich in ions => lots of electrons to pick up X-Rays
Explain the appearance of a subarachnoid haemorrhage on CT
Hyperintense distribution in shape of circle of willis in centre of image
If a CT scan for a suspected subarachnoid haemorrhage is negative, what further investigation should be done, and what can be found?
Lumbar Puncture (don't delay unless contraindicated) Either blood stained CSF or xanthochromic appearance (yellow due to blood break down products)
What is meant by a “traumatic tap”?
Blood is found in lumbar puncture due to rupturing a small vessel when taking the sample
NOT because blood is in the CSF
What artery is catheterised during a CT angiogram of the head?
Femoral artery feeds catherter up to each artery supplying brain
- allows injection of contrast
Why would contrast appear to be escaping on a CT angiogram?
Aneurysm has ruptured and contrast is leaking and forming a haematoma
What are the main complications of subarachnoid haemorrhage?
- Re-bleeding
- Delayed ischaemic deficit
- Hydrocephalus
- Hyponatraemia
- Seizures
Why do aneurysms usually stop bleeding relatively quickly?
Arteries go into vasospasm
=> causing clotting
How are aneurysms walled off from the main circulation to prevent re-bleeding?
- Clipping of aneurysm
- Endovascular techniques - platinum coils used to “plug” aneurysm
What causes delayed ischaemia after a subarachnoid haemorrhage?
- inflammatory chemicals cause irritation of other vessels
- vessels spasm and constrict => cause a stroke
How soon after a subarachnoid haemorrhage does delayed ischaemia usually occur?
Days 3-12
What symptoms usually present if a patient has developed delayed ischaemia?
- altered conscious level
- focal neurological deficit
What drug can be given to reduce chances of vasospasm after subsarachnoid haemorrhage?
Nimodipine - Ca2+ channel blocker
A good fluid intake should be maintained after a subarachnoid haemorrhage. What is meant by “Triple H” fluid therapy?
Hypervolaemia - central line fluids
Hypertension - give inotropes
Haemodilution (dilute the blood)
Ischaemic areas of the brain appear dark on CT, but what are any hyperintense lesions inside this section?
secondary bleeding into the dead brain
What consequence of a subarachnoid haemorrhage can cause hydrocephalus?
inflammatory products from the bleed can bock either:
- CSF pathways
- Arachnoid granulations
How is hydrocephalus treated?
External ventricular drain (EVD)
VP Shunt
