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Subarachnoid haemorrhage (SAH) (Risk factors (Smoking, Alcohol, CT…
Subarachnoid haemorrhage
(SAH)
Definition
Neurological disorder of
intracranial bleed into the
subarachnoid space
Epidemiology
Age 25-65y
Uncommon
Pathophysiology
Usually aneurysms at site of PCA-IC,
ACA-AC, or bifurcation MCA
Spontaneous arterial bleed into subarachnoid space
Small warning leak before full rupture can cause
a sentinel headache beforehand
Often atraumatic, may have prior exertion
Risk factors
Smoking
Alcohol
CT disease
(Marfan's, Ehlers-Danlos)
HTN
Coagulation disorder
Family history
Aetiology
Vascular
Berry aneurysms
AVMs
Idiopathic
Congenital
Marfan's
Ehlers-Danlos
Neoplastic
CNS tumour
Clinical
presentation
Headache
Site
Usually occipital
Onset
Sudden
Character
Thunderclap, kicked in back of head
worst ever, first and worst
Radiation
Nil
Associated symptoms
Syncope/LOC, N+V
Timing
First and worst
May have had prodromal sentinel headache
Exacerbating/relieving factors
Severity
Worst headache ever
Syncope/LOC
Death
N+V
Seizures
Coma
Diagnosis
Examination
Neuro - GCS, focal signs, neck stiffness (Kernig's +ve),
CN exam and full upper and lower limb exams
(e.g. CN III palsy in PCA aneurysm)
Ophthal - may have subhyaloid/vitreous bleeds
Differentials
Stroke, TIA, migraine, CVT
Meningitis
History
SOCRATES headache
What doing beforehand
Investigations
Bedside
Obs, ECG (may show ischemia)
Bloods
FBC, CRP, U+E, LFTs,
clotting, lipids, glucose
CSF
AFTER CT
(check for raised ICP)
LP done >12h after headache onset
Bloody/xanthochromic (yellow)
Imaging
CXR (may have neurogenic pulmonary oedema)
CT head <12h (raised ICP, site of bleed)
CT angiography (site and number of aneurysms)
Grading
(mortality)
Grade 2 (10%)
Stiff neck, CN palsy
Mortality 10%
Grade 3
Drowsy
Mortality 40%
Grade 1
No signs
Mortality 0%
Grade 4
Drowsy, hemiplegia
Mortality 70%
Grade 5
Prolonged coma
Mortality 100%
Management
Definitive
Medical
Analgesia
Paracetamol, codeine, morphine
Anti-emetic
E.g. cyclizine, ondansetron
CCB
E.g. nimodipine
MOA: reduces vasospasm, thus reduces
morbidity from cerebral ischemia
Mannitol
Indication: raised ICP
MOA: reduces fluid overload
Surgical
Endovascular coiling (1L)
Clipping
Angioplasty +/- stenting
Conservative
Regular obs, pupils and GCS
Repeat CT if worsening
IV fluids (keep SBP<160)
Initial ABCDE
Intubate if GCS <8
Referral
Neurosurgery
May need ITU
Complications
Rebleeding
Commonest cause death
First few days
Cerebral ischemia
Due to vasospasm
Hydrocephalus
Due to arachnoid blockage
Need shunting/drainage
Hyponatremia
Cerebral salt wasting
Fluid restrict
Prevention
Prophylactic coiling
Only if large, uncontrolled HTN,
or history of bleeds