Subarachnoid haemorrhage Flashcards
(35 cards)
Define a Subarachnoid Haemorrhage
presence of blood within the subarachnoid space, i.e. deep to the subarachnoid layer of the meninges
What two layers of the brain does blood sit between in a Subarachnoid Haemorrhage?
pia mater and arachnoid membrane
What are two ways we can classify a Subarachnoid Haemorrhage?
Spontaneous (70%)
Traumatic (30%)
What are some RF for a Subarachnoid Haemorrhage?
Smoking
HTN
excessive alcohol
Cocaine use
FHx
Which patients is a Subarachnoid Haemorrhage more common in?
Female pts
Black pts
Age 45-70yrs
Subarachnoid Haemorrhage is particularly associated with what conditions …?
Sickle cell anaemia
CT disorders - Marfans / Ehlos Danlos / APKD / coarctation of aorta (aneurysms)
Neurofibromatosis
List some causes of a spontaneous Subarachnoid Haemorrhage
Intracranial aneurysms
Arteriovenous malformation
Pituitary apoplexy
Arterial dissection
mycotic (infective aneurysms)
Perimesencephalic (idiopathic venous bleed)
What are the presenting features of a Subarachnoid Haemorrhage?
Headache: sudden onset, THUNDERCLAP
Nausea & vomiting
Meningism (neck stiffness / photophobia
back pain
Syncope / Coma
Seizures
Sudden death
ECG: ST elevation
Name and describe 2 physical tests which can demonstrate meningismus in Subarachnoid Haemorrhage?
Kernig sign:
Flex knee to 90 degrees >
Hip flexed to 90 degrees > Extend knee - elicit pain
Brudzinski sign:
Patient lies supine > flex neck > elicit knee flexion
What focal neurological signs might you see in a pt with Subarachnoid Haemorrhage?
Hemiparesis
Occulomotor nerve palsy
What clinical signs in the eye might you see in a pt with Subarachnoid Haemorrhage?
Retinal haemorrhage
Papilloedema - blurring of borders of optic disc
Isolated complete III-nerve palsy. *
- secondary to compression by a posterior communicating artery (PCOM) aneurysm or / damage to the nerve due to blood in the subarachnoid space
What Investigations would you do for a pt with Subarachnoid Haemorrhage?
CT
1. W/in 6 hours: non contrast CT brain - show hyperdense blood ( if normal- no LP )
2. Outside 6 hours: Non contrast CT brain - if normal DO LP
LP / CSF
Performed 12 hours after onset of symptoms - xanthchromia
After SAH confirmed: looking for a cause
CT Angiography- for cause e.g. aneurysm / AVM
What are the benefits of doing a CT brain for a pt with Subarachnoid Haemorrhage?
Quick - 30 mins
Blood distribution can indicate site of aneurysm
Detect early hydrocephalus
What time frame is optimal to CT scan a pt with suspected Subarachnoid Haemorrhage?
w/in 6 hours = 100 % sensitivity
> 1 week = 50%
What will CT of brain show in a patient with Subarachnoid Haemorrhage?
Will see hyperattenuation due to fresh clots.
Acute blood is hyper-dense / bright on CT
Often see blood in basal cisterns, sulci, ventricular system.
Where should pts with Subarachnoid Haemorrhage be managed?
Specialist neurosurgical unit
When would you order a LP for a patient with a suspected Subarachnoid Haemorrhage? ?
Confirm SAH if CT is negative (no blood seen in 7% pts)
at least 12 hours after onset of symptoms to allow for xanthochromia (up to 1 week)
What findings are you looking for in a LP to confirm a Subarachnoid Haemorrhage? ?
- Xanthochromia- RBC breakdown. (distinguishes SAH from ‘traumatic tap’)
- normal or raised opening pressure
- blood stained
- lymphocytic reaction
- elevated protein
What are some predictive factors in Subarachnoid Haemorrhage?
consciousness
CT Scan
How should you ensure a pt with an aneurysm is kept before treatment to prevent re-bleed of Subarachnoid Haemorrhage?
strict bed rest
controlled BP
No straining e.g. toilet
What kind of MRI is useful for imaging Subarachnoid Haemorrhage?
Echo gradients show haemosiderin (black blob)
T2 FLAIR - increased T2 signal = blood (T2 shows water as white)
(Burton, Dr said “2 ladies drinking tea with a dash of milk” to remember this)
When would Angiography be performed and why in the context of a Subarachnoid Haemorrhage?
To understand causative pathology :
e.g. CT intracranial angiogram for vascular lesion such as aneurysm or AVM
What surgical intervention can be used for Subarachnoid Haemorrhage?
Coil
- interventional radiologist
- endovascular approach> catheter into arterial system> platinum coil into aneurysm, sealing it off from artery.
Clipping
- neurosurgeon
- craniotomy and clipping off the anueurysm
Where should pts with Subarachnoid Haemorrhage be managed?
Specialist neurosurgical unit
Immediate referral once SAHis confirmed
