Subarachnoid Hemorrhage Flashcards
Causes of SAH
intracranial aneurysm (saccular ‘berry’ aneurysms - polycystic kidney disease)
conditions associated with berry aneurysm :hypertension,
Ehlers-Danlos syndrome and coarctation of the aorta
arteriovenous malformation
Von hippel indaag syndrome- cerebellar haemangiomas: these can cause subarachnoid haemorrhages
Clinical features of SAH
usually of sudden-onset (‘thunderclap’ or ‘hit with a baseball bat’)
severe (‘worst of my life’)
occipital
typically peaking in intensity within 1 to 5 minutes
there may be a history of a less-severe ‘sentinel’ headache in the weeks prior to presentation
nausea and vomiting
meningism (photophobia, neck stiffness)
coma
seizures
ECG changes including ST elevation may be seen
this may be secondary to either autonomic neural stimulation from the hypothalamus or elevated levels of circulating catecholamines
Diagnosis of SAH ?
First line - non contrast CT
- MUST be done WITHIN 6 hours of symptom onset
IF CT head done WITHIN 6 hours of symptom onset and is NORMAL then NO LP
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if CT head is done more than 6 hours after symptom onset and is normal
do
LP (usually done AFTER 12 hours of symptom onset - this is to allow the xanthochromia to develop
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If hemorrhage is confirmed must find the origin
identify a causative pathology that needs urgent treatment:
CT intracranial angiogram (to identify a vascular lesion e.g. aneurysm or AVM)
What is the management of SAH
Bed rest
Analgesia
VTE prophylaxis
Prevent vasospams - nimodipine
intracranial aneurysms are at risk of rebleeding and therefore require prompt intervention, preferably within 24 hours
most intracranial aneurysms are now treated with a coil by interventional neuroradiologists, but a minority require a craniotomy and clipping by a neurosurgeon
Complications of aneurysmal SAH ?
Re bleeding !!!
Common in the first 12 hours
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Hydrocephalus
-is temporarily treated with an external ventricular drain (CSF diverted into a bag at the bedside)
or if required, a long-term ventriculoperitoneal shunt
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hyponatraemia (most typically due to syndrome inappropriate anti-diuretic hormone (SIADH))
distinguish true SAH from a ‘traumatic tap’
xanthochromia
