Subdural haemorrhage Flashcards
Define subdural haemorrhage.
A subdural haematoma is a collection of blood between the dural and arachnoid coverings of the brain
Bleeding is from bridging veins between cortex and venous sinuses (vulnerable to deceleration injury)
As the volume of the haematoma increases, brain parenchyma is compressed and displaced, and the intracranial pressure may rise and cause herniation
What does subdural haematoma look like on CT? What can a chronic subdural haematoma look like?
Sickle-shaped, banana shaped (may develop a tailed appearance)
Chronic subdural haematoma may have a loculated appearance, as adhesions develop as part of the membrane producing process pathologically.
How common is subdural haematoma? Who do they commonly affect?
- Affects 11% to 20% of patients admitted to hospital with mild to severe traumatic brain injury
- Account for 50-60% of intracranial haematomas
- More likely after falls that RTAs
- Occur commonly in patients with coagulopathy (iatrogenic or pathological)
What is the aetiology of subdural haematoma?
Trauma (whether acute or chronic)
Less commonly:
- Ruptured cerebral aneurysms/vascular malformations (i.e. AVM or dural fistula)
- Cerebral hypotension
- Malignancy
What happens to chronic subdural haematomas over time?
- they become loculated
- they enlarge over time - thought to be due to either osmotic gradients that encourage the flow of cerebrospinal fluid across neomembranes into a hyperosmotic haematoma or repeated haemorrhage from the vascularised neomembranes
What are the risk factors for subdural haematoma?
- Old age (>65yrs) - elderly are most susceptible, as brain atrophy makes bridging veins vulnerable
- Recent trauma - but the trauma is often forgotten as it was so minor or so long ago (up to 9 months)
- Coagulopathy and anticoagulant use - worst with Vit K antagonists
- Without trauma - eg ↓icp; dural metastases
- Epileptics and alcoholics
What is the sequence of events in a subdural haematoma?
- Trauma may have been months ago
- Conscious level fluctuates (in 35%) ( “evolving stroke”)
- Accummulating blood raises ICP and may cause midline shift away from side of clot
- If untreated causes tentorial herniation and coning
What are the symptoms of subdural haematoma?
Conscious level fluctuates (in 35%) ( “evolving stroke”)
- +/- insidious physical or intellectual slowing,
- sleepiness,
- headache (from raised ICP or meningeal irritation)
- personality change/confusion
- unsteadiness
- nausea/vomiting
What are the signs of subdural haematoma?
- Raised ICP
- Seizures
- Localising neurological symptoms - e.g. unequal pupils, hemiparesis - may occur late, usually >1month after injury
- Diminished GCS- EVM
- eye - variable, anisocoria may indicate brainstem herniation
- verbal - difficult to assess if ventilated
- motor - if the patient is able to follow commands, more subtle indicators of impaired motor function (e.g., the presence of a pronator drift) may be noted
Other:
- loss of bowel and bladder continence
- sensory changes - parenchymal dysfunction
- speech or vision problems - cortical dysfunction
What investigations should you do for a suspected subdural haemorrhage?
non-contrast CT - subdural fluid collection
Other:
- MRI - subdural fluid collection
- plain skull X-ray - ?skull fracture or presence of intracranial shrapnel
What does this CT show?
- Clot +/- mildine shift (beware of bilateral isodense clots)
- Crescent-shaped collection of blood over 1 hemisphere
- Sickle shape differentiates subdural from extradural haemorrhage
- On the left the cerebral sulci are prominent and would have been larger prior to this event
- Brain has shrunk within the skull from atherosclerosis and poor perfusion, leaving large subarachnoid spaces - a quick rotation of the head is enough to tear a bridging vein, causing this haematoma
How do you manage subdural haematoma?
- Reverse clotting abnormalities urgently
- Surgical management depends on size of clot/chronicity/ clinical picture
- Those with >10mm or with midline shift >5mm need craniotomy/burr hole washout
- Antiepileptics e.g. phenytoin
- Mannitol
- Address cause of trauma e.g. falls, abuse
What are the complications of subdural haematoma?
Coma
Epilepsy - if the patient has seizures within the first week and has a severe brain injury, the likelihood is higher that they will have seizures beyond the first week
Stroke - large swelling/compression of vessels can cause ischaemia
Neurological deficits - recovery is variable
List some factors which would suggest poorer functional outcomes after subdural haematoma.
- old age
- severity
- low GCS
- midline shift
- early need for surgery
- raised ICP
