subdural Flashcards
definition of subdural
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.
aetiology of subdural
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
RF for subdural
elderly - brain atrophy makes bridiging veins vulnerable
falls - epileptics, alcoholics
anticoagulation
epidemiology of subdural
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.
sx of subdural
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
signs of subdural
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
Ix of subdural
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
acute mx for subdural
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.
conservative mx of subdural
Especially if small and minimal midline shift (SDH<10 mm thickness, andmidline shift<5 mm).
surgical mx of subdural
prompt Burr hole or craniotomy and evacuation if symptomatic >10mm, with >5mm midline shift (better outcome within 4hr)
intracranial pressure monitoring devices placed
chronic mx of subdural
: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.
children mx of subdural
younger children may be treated by percutaneous aspiration via an open fontanelle or if this fails, placement of a subdural to peritoneal shunt.
comp of subdural
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
Px of subdural
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
