[20] Subarachnoid Haemorrhage Flashcards
What is a subarachnoid haemorrhage?
Bleeding into the subarachnoid space
What is the subarachnoid space?
The area between the arachnoid membrane and the pia mater surrounding the brain
What are subarachnoid haemorrhages usually a result of?
Bleeding from a berry aneurysm in the Circle of Willis
What percent of the population are berry aneurysms present in?
4%
Do most berry aneurysms rupture?
No
What causes development of berry aneurysms?
Susceptibility of the elastic lamina to stressors such as hypertension and atherosclerosis
What is another less common cause of subarachnoid haemorrhage?
Trauma
What are the risk factors for subarachnoid haemorrhage?
- Hypertension
- Smoking
- Excessive alcohol consumption
- Cocaine use
- Genetic disorders
- Family history
- Age between 45-70
- Female gender
- Black ethnicity
What genetic disorders can predispose to subarachnoid haemorrhage?
- Adult polycystic disease
- Ehlers-Danlos Syndrome
- Neurofibromatosis
- Marfan’s Syndrome
Why might black ethnicity be a risk factor for subarachnoid haemorrhage?
They are at increased risk of hypertension
What is the most characteristic feature of a subarachnoid haemorrhage?
Sudden explosive headache
What is the sudden explosive headache of subarachnoid haemorrhage also known as?
Thunder clap headache
In what proportion of patients is a thunder clap headache the only symptom of subarachnoid haemorrhage?
1/3
Is the thunder clap headache more commonly distinguished by its severity or location?
Severity
What are some other possible presenting symptoms of subarachnoid haemorrhage?
- Stiff neck
- N&V
- Photophobia
- Diplopia
- Stroke-like symptoms
- Seizures
What may occur 3 weeks prior to subarachnoid haemorrhage?
Warning signs and symptoms
What are the warning signs and symptoms of subarachnoid haemorrhage related to?
Small leaks
What are the warning signs and symptoms of subarachnoid haemorrhage?
- Headaches
- Dizziness
- Orbital pain
- Diplopia
- Visual loss
- Sensory or motor disturbance
- Seizures
- Ptosis
- Bruits
- Dysphasia
What features may be found on examination in subarachnoid haemorrhage?
- Depressed level of consciousness
- Neck stiffness
- Intraocular haemorrhages
- Isolated pupillary dilation with loss of light reflex
- Focal neurological signs
What percentage of patients will have depressed level of consciousness in subarachnoid haemorrhage?
66%
What percentage of patients will have intraocular haemorrhages in subarachnoid haemorrhage?
15%
Why do patients with subarachnoid haemorrhage have neck stiffness?
Due to meningeal irritation because of blood in the CSF
What investigations may be useful in subarachnoid haemorrhage?
- CT scan without contrast
- Angiography
- Lumbar puncture
- ECG
What is a CT scan useful for in subarachnoid haemorrhage?
First line investigation - correctly identifies 95-98% of cases
What will a CT scan show in subarachnoid haemorrhage?
Hyperdense appearance of blood in basal cisterns
What is angiography useful for in subarachnoid haemorrhage?
Confirming the origin of the SAH
Which types of angiography are useful for identifying anuerysms as cause of subarachnoid haemorrhage?
- Cerebral angiography
- CT angiography
What is cerebral angiography?
Injecting radiocontrast through a catheter to the brain arteries
What can also be done using cerebral angiography?
Coiling of the aneurysm
What is CT angiography?
Visualising blood vessels with radiocontrast on CT scan
When is a LP useful in subarachnoid haemorrhage?
If CT scan is negative but history is suggestive and it is safe to do an LP
What can an ECG show in subarachnoid haemorrhage?
- QT prolongation
- Q waves
- Dysrhythmias
- ST elevation
What is it important not to mistake a subarachnoid haemorrhage for when looking at an ECG?
Acute MI
What are the differentials of subarachnoid haemorrhage?
- Other causes of headache
- Stroke
- Meningitis
- Trauma
- Cerebral venous sinus thrombosis
- Cervical or carotid dissection
- Hypertensive emergency
What is the aim of initial management in subarachnoid haemorrhage?
Prevent further bleeding and reduce the rate of complications
What is usually the initial step in managing subarachnoid haemorrhage?
Occlude the aneurysm to prevent bleeding
What is the preferred method for aneurysm occlusion in subarachnoid haemorrhage?
Endovascular obliteration by coiling
What do some patients require to occlude the aneurysm in subarachnoid haemorrhage?
Direct neurosurgical clipping
What is another immediate risk of subarachnoid haemorrhage?
Delayed cerebral ischaemia due to vasospasm
How is the risk of delayed cerebral ischaemia reduced in subarachnoid haemorrhage?
- Oral nimodipine (60mg/4 hours)
- Maintaining circulatory volume
What should every patient who has had a subarachnoid haemorrhage receive?
Specialist referral for investigation and definitive treatment
What supportive therapy may be needed for conscious patients with subarachnoid haemorrhage?
Analgesia and antiemetics
What supportive therapy may be needed for patients with reduced consciousness due to subarachnoid haemorrhage?
Intubation and ventilation
What should all surviving subarachnoid haemorrhage patients be advised of?
Secondary prevention
What are the most important secondary prevention measures in subarachnoid haemorrhage?
Treatment of hypertension and stopping smoking
What will a patient with residual impairment post-subarachnoid haemorrhage require?
Referral to rehabilitation services
What is the overall death rate of subarachnoid haemorrhage?
~50%
What proportion of subarachnoid haemorrhage survivors remain dependent?
1/3
What are the short term complications of subarachnoid haemorrhage?
- Rebleeding
- Delayed cerebral ischaemia
- Hydrocephalus
When is the risk of rebleeding highest?
In the first few days
What does rebleeding carry a high risk of?
Permanent disability and death
What happens in delayed cerebral ischaemia?
The blood vessel goes into spasm causing narrowing and dangerously low blood supply to the brain
What can occur as a result of delayed cerebral ischaemia?
Brain damage
What are the common symptoms of subarachnoid haemorrhage?
Increasing drowsiness with or without other stroke-like symptoms
What are the symptoms of hydrocephalus?
- Headache
- Vomiting
- Blurred vision
- Difficulty walking
What are the potential long term complications of subarachnoid haemorrhage?
- Epilepsy
- Cognitive dysfunction
- Changes in mood
What cognitive dysfunction can occur as a result of subarachnoid haemorrhage?
- Memory problems
- Planning problems
- Concentration problems
What mood changes can occur after a subarachnoid haemorrhage?
- Depression
- Anxiety
- PTSD