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