Subdural haemorrhage

Question 1

What is shown?

Answer 1

Subdural heamorrhage - right sided, mixed-density

Question 2

Define subdural haemorrhage.

Answer 2

Collection of blood deep to the dural layer of the meninges (between dura mater and arachnoid mater).

The blood is not within the substance of the brain and is therefore called an ‘extra-axial’ or ‘extrinsic’ lesion. They can be unilateral or bilateral.

Question 3

How are subdural haematomas classified?

Answer 3

According to age:
1. Acute
1. Subacute
1. Chronic

Acute and chronic have important differences in clinical features and tx

Question 4

What is the most common cause of subdural haemorrhage?

Answer 4

High impact trauma e.g. acceleration-deceleration (coup-contrecoup injury)

Question 5

What does CT show in acute subdurals?

Answer 5

Crescentic collection
Hyperdense (bright)
+/- mass effect if large e.g. midline shift

Question 6

What is the general management of acute subdural haematomas?

Answer 6

If small: conservative, observation
If large: surgical management e.g. monitoring ICP and decompressive craniectomy

Question 7

What is the definition of a chronic subdural haematoma?

Answer 7

One that has been present for weeks to months

Question 8

What are the most common causes of chronic subdural haematomas?

Answer 8

Rupture of small bridging veins in the subdural space, causing slow bleeding

Question 9

Who is most at risk of chronic subdural haemorrhages?

Answer 9

• Elderly - brain atrophy increases stretching of bridging veins
• Alcoholics - thinner walls of bridging veins

NB: also seen in shaken baby syndrome

Question 10

How do chronic subdurals present?

Answer 10

Weeks to months of progressive confusion, reduced consciousness or neurological deficit.

Question 11

What does CT show in chronic subdural haematomas?

Answer 11

Crescentic shape, not restricted by suture lines
+/- mass effect
Hypodense (dark) compared to acute subdurals

Question 12

What is the management of chronic subdurals?

Answer 12

If incidentally found - conservative, may dissolve with time
If patient confused or has neurological deficit - surgical decompression with burr holes

Question 13

How can hypotension cause subdural bleeds?

Answer 13

Less CSF –> more traction of brain on surrounding structures –> tear of bridging veins

Question 14

What are the clinical features of subdural haemorrhage?

Answer 14

LOC after trauma or in ensuing days due to haematoma expansion (usually present in 48-72hrs)
If basilar skull fracture: racoon eyes (periorbital ecchymosis) and Battle’s sign (retroauricular ecchymosis), CSF rhinorrhoea/otorrhoea