Subdural Haemorrhage

Question 1

What is a subdural haemorrhage?

Answer 1

• Collection of blood between the dural and arachnoid coverings of the brain, caused by rupture of the bridging veins
• As the volume of the haemorrhage increases, brain parenchyma is compressed and displaced, and the intracranial pressure may rise and cause herniation

Question 2

How are subdural haemorrhages classified?

Answer 2

Classification →
1. Acute (<3 days old, hyperdense, typically due to trauma),
2. Subacute (4-20 days old, hyperdense),
3. Chronic (>21 days old, hypodense, typically due to rupture of the bridging veins)

Question 3

What are the risk factors for subdural haemorrhage?

Answer 3

Falls (epileptics, alcoholics)
Low ICP
Dural metastases
Alcohol & Age (>65)– these both cause brain atrophy, which stretches the veins.
Anticoagulation

Question 4

What are the presenting symptoms of subdural haemorrhage?

Answer 4

1. Acute
   - History of TRAUMA with head injury
   - Reduced conscious level
2. Subacute
   - Worsening headache 7-14 days after injury
   - Altered mental state
3. Chronic
   - Headache
   - Confusion
   - Cognitive impairment
   - Gait deterioration
   - Focal weakness
   - Seizures
   - Sleepiness

Question 5

Describe the aetiology of a subdural haemorrhage

Answer 5

TRAUMA (usually due to rapid acceleration and deceleration of the brain) – the trauma may have been up to 9 months ago

Question 6

What signs of subdural haemorrhage can be found on physical examination?

Answer 6

(clinical effects can be delayed)
1. Acute
- Reduced GCS
- Ipsilateral fixed dilated pupil (if a large haematoma cause a midline shift)
- Pressure on brainstem –> reduced consciousness + bradycardia (and hypertension)
- confusion, seizures, lucid interval
2. Chronic
- Neurological examination may be NORMAL
- Focal neurological signs (e.g. 3rd nerve palsy)

Question 7

What investigations are used to diagnose/ monitor subdural haemorrhages?

Answer 7

1. Non- contrast CT Head first line. Can see subdural fluid collection. Hyperdense areas (appear brighter) indicated recent haemorrhage whereas hypodense (appear darker) indicate older bleeding. Crescenteric (concave)in shape & not limited by suture lines.
2. MRI Brain - higher sensitivity than CT ( if neurological features unexplained by CT findings)
   - Will show clot +/- midline shift
   - Look for crescent shaped collection of blood over 1 hemisphere – the sickle shape differentiates subdural blood from extradural haemorrhage (lens shaped)

Question 8

How is a subdural haemorrhage managed?

Answer 8

1. ACUTE
   - ALS protocol
   - Watch out for cervical spine injury
   - If raised ICP consider osmotic diuresis
   a. Conservative - if small
   b. Surgical – for irrigation/evacuation
   - Burr twist drill and burr hole craniotomy – 1st line
   - decompressive Craniotomy – 2nd line
2. Chronic
   - If symptomatic - Burr hole or craniotomy and drainage
   - antiepileptics + stop anticoagulants/antiplatelets
   - ICP monitoring (try reduction methods)
   a. Assess any causes of the trauma
   b. Children
   - Younger children may be treated with percutaneous aspiration via an open fontanelle

Question 9

Identify the possible complications of subdural haemorrhage

Answer 9

Raised ICP
Cerebral oedema
Herniation
Post-Op - seizures, recurrence, intracerebral haemorrhage, brain abscess, meningitis, tension pneumocephalus

Question 10

Summarise the prognosis of subdural haemorrhage

Answer 10

1. Acute
   - Underlying brain injury will affect function
2. Chronic
   - Better outcome than acute subdural haemorrhages
   - Lower incidence of underlying brain injury