Subarachnoid haemorrhage
Pathophysiology
Spontaneous rather than traumatic bleeding into the
subarachnoid space
Raised intracranial pressure
Compression of the brain
Vascular spasm with possible infarction
Neurological damage and possible herniation
Incidence
10% of cerebrovascular disease
15 per 100 000 per year
5 - 13% of CVAs
Causes
i. Saccular
(`berry`) aneurysm 70%
ii, Arterovenous malformation 10%
iii. No
lesion found 20%
Hypertension (therefore smoking) is a developmental
factor
Other factors - trauma, polycystic kidney disease,
vascular disease, haemorrhagic disorders
i.
Found on circle of Willis and adjacent branches
Incidental finding on 1% of post mortems
Symptoms
cause by:
Spontaneous rupture, (usually with no PMH)
Space occupying lesion
Pressure effects on surrounding
tissues, eg. painful third nerve palsy
ii. Arterovenous
malformation
Developmental in origin
Usually within the hemispheres
May cause focal epilepsy
After one bleed they re - bleed at 10% per year
Clinical
features of SAH
Sudden devastating headache
Followed by vomiting and loss of consciousness
Remains comatosed or drowsy
for several hours to several days
Neck stiffness
Positive Kernig`s sign (leg at 90` to abdomen, then
straighten leg)
Papilloedema sometimes present, possibly with
retinal haemorrhages
Confusion, restlessness, irritability, photophobia,
Convulsions
Investigations
CT shows subarachnoid or intraventricular
blood
LP not required if diagnosed by CT, blood at first then
yellow staining (xanthochromic) after a few hours
Carotid and vertebral angiography if patient fir enough
for surgery, (ie below 60 and not in a coma)
Differential
diagnosis
Severe migraine
Acute meningitis
Complications
60% die after their first haemorrhage
50% of cases dead or moribund on arrival
Patients who are comatosed or
have neurological deficit have a poor prognosis
Blood clot leading to CSF blockage and hydrocephalus -
this will cause deterioration of consciousness a few days or weeks after the
original event
Management
In demonstrated aneurysm clipping may have excellent
results
Bed rest and supportive measures
Control hypertension
Dexamethasone and antifibrinolytics
are of debatable benefit
Nimodipine, (Calcium channel blocker) reduces
mortality
Nursing
Management
Bed rest
Control pain
Control nausea and emesis
Care of unconscious patient
Nutrition and hydration
Repetition of communications
Explanation to relatives
Pre and post op care
Observations
TPR
BP
GCS