Haemorrhagic Stroke: Subdural

Question 1

Definition

Answer 1

Subdural haemorrhage occurs when blood accumulates between the dura and arachnoid mater (subdural space), forming a collection known as a subdural haematoma (SDH).

Question 2

Epidemiology/ Risk factors

Answer 2

Age: older patients = chronic SDH
MC = Px have a small brain
- alcoholics
- dementia
- babies that have suffered trauma
* making bridging veins more vulnerable *
Coagulopathy or anti coagulation medication

Question 3

Aetiology

Answer 3

Rupture of bridging cortical vein due to shearing. Deceleration injuries and in abused children (shaken baby syndrome)
Acute = < 3 days old
- Due to trauma
Chronic = > 21 days old
- Associated with cortical atrophy e.g elderly or alcoholics
- Bridging veins are more prone to rupture with cortical atrophy
- Requires lower impact trauma compared to acute
- Because, there is cortical atrophy, subdural space is larger, these haematomas can enlarge significantly over time whilst patients remain asymptomatic

Question 4

Pathophysiology

Answer 4

Trauma either due to deceleration, violent injury or due to dural metastases resulting in bleeding from bridging veins between the cortex + venous sinuses
Bridging veins bleeding + form a haematoma between dura + arachnoid = this reduces pressure + bleeding stops.
Days/weeks later the haematoma starts to autolyse due to the massive increase in chronic + osmotic pressure thus water is sucked into the haematoma resulting in haematoma enlarging = gradual rise in intra-cranial pressure (ICP) over many weeks
Shifting midline structures away from the side of the clot + if untreated leads to eventful tectorial herniation + coning (brain herniates through foramen magnum - causes significant damage).

Question 5

Acute Subdural haemorrhage Signs

Answer 5

• Symptom onset within 3 days of inciting event
• May have a lucid interval
• Reduced consciousness (fluctuating GCS)
• Headaches + vomiting
• Slurred speech
• Focal neurological deficit e.g. weakness or fixed dilated pupil, CN3 palsy
• CUSHING’S TRIAD: bradycardia, widened pulse pressure + irregular breathing
• Seizures

Question 6

Chronic Subdural Haemorrhage Signs

Answer 6

• Insidious onset usually in the elderly or alcoholics
• Progressive confusion and cognitive deficit
• Headaches and vomiting
• Focal neurological deficit e.g. weakness or fixed dilated pupils

Question 7

Investigations

Answer 7

FIRST LINE = Non-contrast CT head: CRESCENT collection around the surface of the brain which is not limited by the suture lines of the skull unlike an extradural haemorrhage + Midline shift or herniation
- Acute = hyper-dense (bright)
- Subarachnoid = hypo-dense (dark)

Question 8

Treatment

Answer 8

BURR HOLES + craniotomy
Non surgical = IV Mannitol to reduce ICP

Question 9

Complications

Answer 9

Brain stem herniation