subdural

Question 1

definition of subdural

Answer 1

a collection of blood that developsbetween the surface of the brain and the dura mater.

Acute: Within 72 h.Subacute: 3–20 days.Chronic: After 3 weeks.

Question 2

aetiology of subdural

Answer 2

trauma - rapid accelaration and decellaration of the brain = shearing forces between tear veins (bridging veins) that travel from dura to the cortex

without trauma (eg reduced ICP; dural metast ases)

bleeding occurs between dura and aracgnoid membranes

• gradually raises ICP, shifting midline structures away from the side of the clot
• if untreated, eventual tentorial herniation and coning.

in children consider non-accidental injury

Question 3

RF for subdural

Answer 3

elderly - brain atrophy makes bridiging veins vulnerable

falls - epileptics, alcoholics

anticoagulation

Question 4

epidemiology of subdural

Answer 4

Acute: Tend to occur in younger patients/associated with major trauma(5–25% of cases of severe head injury).

More common than extradural haemorrhage.

Chronic: More common in elderly, studies report incidence of 1–5 per 100 000.

Question 5

sx of subdural

Answer 5

acute

• trauma w/ head injury,
• reduced consciousness

subacute

• worsening headache 7-14days after injury
• altered mental status

chronic

• headache
• confusion
• cognitive impairment
• psychiatric symptoms
• gait deterioration
• focal weakness
• seizures

sleepiness

personality change

flucutuating consciousness in 35%

might not be hisyory of head trauma - be suspicious in elderly and alcoholics

Question 6

signs of subdural

Answer 6

acute

• reduced GCS
• ipsilateral fixed dilated pupil - if large haematoma = midline shift, compression of ipsilateral CN3
• reduced consciousness and bradycardia - from pressure on brainstem

chronic

• neuron exam may be normal
• raised intracranial pressure
• seizures
• focal neurological signs >1month later
  
  • 3/6 CN palsy
  • papilloedema
  • hemiparasis
  • reflex asymmetry
  • unequal pupils

Question 7

Ix of subdural

Answer 7

CT head crescent/sickle shaped mass, concave over brain surface

• and blood will tend to extend along he falciform ligament and over the tentorium cerebelli
• acute - hyperdense, become isodense over 1-3wks ( presence may be inferred from signs such as effacement of sulci, midline shift, ventricular compression and obliteration of basal cisterns)
• chronic - hypodense - approaching density of CSF

MRI brain - higher sensitivity - especially for isodense/small

both show clot +- midline shift

Question 8

acute mx for subdural

Answer 8

ALS protocol, pritoities of cervical spine control and ABC

sig risk of cervical spine injury

disability - GCS, pupillary reactivity

If signs of raised ICP, head elevation and consider osmotic diuresis with mannitol and/or hyperventilation.

Once stabilised, obtain CT-head.

Question 9

conservative mx of subdural

Answer 9

Especially if small and minimal midline shift (SDH<10 mm thickness, andmidline shift<5 mm).

Question 10

surgical mx of subdural

Answer 10

prompt Burr hole or craniotomy and evacuation if symptomatic >10mm, with >5mm midline shift (better outcome within 4hr)

intracranial pressure monitoring devices placed

Question 11

chronic mx of subdural

Answer 11

:If symptomatic or there is mass effect on imaging, surgical treatment with Burr hole or craniotomy and drainage (a drain may be left in for 24–72 h).

symptomatic SDH without significant mass effect is best managed conservatively with serial imaging to monitor for spontaneous resorption.

Haematomas that have not fully liquefied may require craniotomy with membranectomy.

Question 12

children mx of subdural

Answer 12

younger children may be treated by percutaneous aspiration via an open fontanelle or if this fails, placement of a subdural to peritoneal shunt.

Question 13

comp of subdural

Answer 13

raised ICP

cerebral oedema pre-disposing to secondary ischaemic brain damage

mass effect (transtentorial or uncal herniation).

post-op

• seizures
• recurrence - up to 33%
• intracerebral haemorrhage
• subdural empyema
• brain abscess/meningitis
• tension pneumocephalus

Question 14

Px of subdural

Answer 14

acute

• underlying brain injury most important factor
• The mortality is high from a traumatic SDH at around 60%.
  
  • The mortality increases if there is associated brain parenchymal injuries and is higher in those with other injuries.
  • The mortality is significantly improved if there is rapid immediate neurosurgical intervention, no evidence of raised intracranial pressure and good oxygen perfusion.

chronic

• better than acute
• lower incidence of underlying brain injury
• good outcomes in 3/4 in those treated by surgery