Subarachnoid haemorrhage Flashcards
Define the term Subarachnoid haemorrhage
Defined as a bleed in the subarachnoid space, space between the arachnoid and pia mater, two meningeal layers
Subarachnoid haemorrhage is a bleed in which part of the brain
In the subarachnoid space
The subarachnoid space is a space between which two layers of the meninges
arachnoid and pia mater
CSF is found between which two meninges
Arachnoid and pia mater - within the subarachnoid space
Name the two classifications of a subarachnoid hemorrhage
Traumatic subarachnoid haemorrhage
Spontaneous subarachnoid haemorrhage
Define the term Traumatic subarachnoid haemorrhage
Refers to a subarachnoid haemorrhage in the presence of trauma e.g., fall, assault, road traffic collision
Define the term Spontaneous subarachnoid haemorrhage
Refers to a subarachnoid haemorrhage in the absence of trauma e.g., ruptured of a cerebral aneurysm, arteriovenous malformation
What are the two key risk factors for subarachnoid hemorrhage
Smoking
Hypertension
Name the 4 modifiable risk factors for subarachnoid hemorrhage
- Hypertension
- Smoking
- Alcohol abuse
- Substance misuse e.g. cocaine
Name the non-modifiable risk factors for subarachnoid hemorrhage
- Sex: higher incidence in female
- Race: higher incidence in Japanese/Finnish populations
- Family history of aneurysms
- Genetic predisposition: seen in conditions such as sickle cell anaemia, Marfan syndrome, Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease
- Age: 45-70
subarachnoid hemorrhage has a higher incidence in:
a) males
b) females
b) females
What genetic conditions are a risk factor for subarachnoid hemorrhage
Sickle cell anaemia
Marfan syndrome
Ehlers-Danlos syndrome
Autosomal dominant polycystic kidney disease
What is the key (red flag) symptom of a subarachnoid hemorrhage
- Sudden-onset or ‘thunderclap’ headache
- Severe headache that reaches maximum intensity within seconds
- Often described as the “worst headache of my life”
- Described as a :blow to the back of the head”
What are the 3 symptoms that make up the Meningism picture
- Headache
- Photophobia (difficult tolerating light)
- Neck stiffness
What brings about a Meningism picture
Occurs when there is meningeal irritation
Name the signs of subarachnoid hemorrhage
- Neck stiffness
- Cranial nerve palsy (e.g. third nerve palsy)
- Reduced consciousness (coma)
- Diplopia (double vision)
- Ptosis (dropping of upper eyelid)
Name the two classic signs of meningism
Kernig’s sign
Brudzinski’s sign
What two conditions cause a meningism picture
Bacterial meningitis
Subarachnoid haemorrhage
What is the Kernig’s sign
It is one of the classic signs of meningism
It refers to the inability to fully extend at the knee when the hip is flexed at 90º due to pain due to the stretching of the meninges
What is the Brudzinski’s sign
It is one of the classic signs of meningism
It occurs when on spontaneous flexion of the knees and hips on active flexion of the neck
What is the gold standard investigation for subarachnoid haemorrhage
CT head
If the CT head is negative, what other investigation must you conduct for subarachnoid haemorrhage
Lumbar puncture
Describe what you would see on a CT head if a patient had a subarachnoid haemorrhage
- Hyperdense material (bright on CT) is seen filling the subarachnoid space.
- Most commonly the hyperdense material is apparent around the Circle of Willis, on account of the majority of berry aneurysms occurring in this region (~65%), or in the Sylvian fissure (lateral sulcus (~30%))
The sensitivity of CT to the presence of subarachnoid blood is strongly influenced by both the amount of blood and the time since the haemorrhage.
CT head is very sensitive and specify if performed within how many hours from the time of symptom onset
Performed within 6 hours
If CT is performed > 6 hours from symptom onset, then what investigations must be conducted to exclude the diagnosis of subarachnoid hemorrhage
Lumbar puncture
When is a lumbar puncture used in investigating subarachnoid haemorrhage
Used to confirm SAH if CT is negative, particularly if CT head was performed > 6 hours since the time of symptom onset
What are the two features from a lumbar puncture that would be suggestive of a subarachnoid haemorrhage
Raised red cell count
Xanthochromia (the yellow colour of CSF caused by bilirubin)
When should a patient be referred to neurosurgery for a subarachnoid haemorrhage
Referral to neurosurgery to be made as soon as SAH is confirmed
What investigation is used once a subarachnoid haemorrhage is confirmed to locate the source of bleeding/ruptured aneurysm
CT intracranial angiogram
Why is a CT intracranial angiogram important to do once a diagnosis of subarachnoid haemorrhage is made
Used once a subarachnoid haemorrhage is confirmed to locate the source of bleeding/ruptured aneurysm
Name some of the complications of a subarachnoid haemorrhage
- Re-bleeding – most common in the first 12 hours
- Cerebral vasospasm (also termed delayed cerebral ischaemia) – typically 7-14 days after onset
- Hyponatraemia (most typically due to syndrome inappropriate anti-diuretic hormone (SIADH))
- Seizures
- Hydrocephalus
- Death
Cerebral vasospasm is a common complication of a subarachnoid haemorrhage.
How long after a subarachnoid haemorrhage would vasospasm typically develop?
Typically 7-14 days after onset
Rebleeding is the most common complication of a subarachnoid haemorrhage.
How long after a subarachnoid haemorrhage would rebleeding typically occur?
Most common in the first 12 hours
What is the initial management of subarachnoid hemorrhage
- ABCDE assessment
- GCS <8 – requires airway management
Surgical intervention are used to treat the aneurysms with the aim of repairing the vessel that has caused the subarachnoid hemorrhage to prevent rebleed.
Name the 2 surgical methods to repair the vessels
Coiling
Clipping
Coiling and clipping are two surgical techiques in which we use to repair the vessels that has caused the subarachnoid hemorrhage.
Which one of these techniques are done under interventional radiology
Coiling
Coiling and clipping are two surgical techiques in which we use to repair the vessels that has caused the subarachnoid hemorrhage.
Which one of these techniques are done under neurosurgery
Clipping
What is involved in the coiling surgical technique in manging subarachnoid haemorrhage
Done under interventional radiology
Involves inserting a catheter into the arterial system (endovascular approach and placing platinum coils into the aneurysm and sealing it off from the artery
What is involved in the clipping surgical technique in manging subarachnoid haemorrhage
Done by neurosurgery
Craniotomy and microscopic assisted clipping of the aneurysmal neck
A major part of managing subarachnoid haemorrhagic is treating the complications associated with them.
One such complication is cerebral vasospasm. What do we do in order to prevent vasospasm?
21 days course of Nimodipine 60mg – one every 4 hours
Nimodipine is used to prevent cerebral vasospasm - a complication associated with subarachnoid haemorrhage.
What drug class is it and what is its mechanism of action
Calcium channel blocker that targets the brain vasculature
A major part of managing subarachnoid haemorrhagic is treating the complications associated with them.
One such complication is hydrocephalus. How do we manage it if this does occur
Accumulation of CSF in the ventricular system
Insertion of a shunt to manage the hydrocephalus
A major part of managing subarachnoid haemorrhagic is treating the complications associated with them.
One such complication is seizures. How do we manage it if this does occur
Antiepileptic medications
Coiling and clipping are two surgical techiques in which we use to repair the vessels that has caused the subarachnoid hemorrhage.
Which technique is generally preferred and why?
Endovascular clipping is generally preferred over surgical clipping due to better long term survival rates
What is the gold standard investigation in assessing for an underlying cause of the subarachnoid haemorrhage?
Digital Subtraction Catheter Angiography (DSA)
Once a patient is diagnosed with subarachnoid haemorrhage, what is the essential next step (providing that you have already referred them to neurosurgery)
CT angiography
