Neuro - head Injury

Question 1

Types of Intracranial bleed?

Answer 1

acute extradural (aka epidural)
acute subdural
subarachnoid
intracerebral

Question 2

coup?

Answer 2

traumatic brain injury: direct damage by impacted skull

Question 3

Contre coup?

Answer 3

brain squashed remotely from area of impact

Question 4

Classifications of traumatic brain injury (TBI)?

Answer 4

Classified as mild (GCS 13-15 at 30 mins post-injury)

moderate (GCS 9-12)

or severe (GCS ≤8)

with mild TBI (concussion) accounting for the vast majority of cases.

Question 5

Pathological consequences of head injury?

Answer 5

↑ICP
Focal neurological deficits.
Secondary brain injury: ↓perfusion from ↑ICP, vascular damage, or hypovolaemia.

Question 6

Cerebral perfusion and the Cushing reflex?

Answer 6

Cerebral perfusion pressure (CPP) = mean arterial pressure (MAP) – intracranial pressure (ICP)

A CPP of ≥70 mmHg is usually sufficient, and as ICP is usually ~10 mmHg, there is sufficient cerebral perfusion within normal MAP ranges.

As ICP rises, MAP may rise in response to maintain CPP.

The Cushing reflex is a combination of:
 ↑BP
irregular breathing
↓HR 
In response to ↑ICP.

Question 7

Concussion Sx?

Answer 7

Mild behavioural or cognitive changes, including confusion

Amnesia (retrograde)(anterograde)

LOC (up to 30 minutes)

(Focal neurological deficits can occur, though should raise suspicion for more severe injury)

Initial symptoms often resolve within minutes, but others – headache, nausea, dizziness, imbalance, fatigue, irritability – may persist for hours, days, or even weeks.

90% recover within 1-2 weeks, but persistence beyond this is possible and is known as postconcussion syndrome.

Question 8

Commonest type of bleed in TBI?

Answer 8

Subdural haematoma (SDH)

Question 9

SDH Sx?

Answer 9

Drowsy
Physical or cognitive slowing, personality changes
N + V
↑Signs of ICP
Urine incontinence (also suggests normal pressure hydrocephalus)

Can present WEEKS or MONTHS post trauma

Question 10

SDH risk factors?

3As

Answer 10

Age
Anticoags
Alcohol

Question 11

Epidural haematoma pathophysiology?

Answer 11

Bleed from vessels supplying skull or dura, causing dura to separate from skull

Commonly the middle meningeal artery beneath the temple

May have associated parietal or temporal fracture

RARE but carries HIGH mortality

Question 12

Loss of consciousness in extramural/epidural haematoma?

Answer 12

YES, from the initial impact

Then lucid period as haematoma expands

Eventually, expanding mass no longer accommodated

↑ICP leads to further LOC and uncal herniation through tentorium

Question 13

Patient comes to you after hitting their head hard on the right. Their right pupil was constricted when they arrived, and is now dilated. They have left sided hemiparesis, and 20 minutes later you notice their other pupil is affected, and they are starting to have seizures.

What’s going on?

Answer 13

Extradural haematoma!

Compression of CN3 as it passes through tentorium

Leads to constricted then dilated pupil on affected side, with contralateral hemiparesis

Eventually other pupil affected

Followed by coning as brain stem is pushed through foramen magnum

Question 14

Initial Ix in head injury?

Answer 14

• Glasgow coma scale (GCS)
• Amnesia? (indication of severity)
• (Consider cervical-spine injuries) X-ray ± CT if suspected.

(CT head)

Question 15

When to CT head <8 hr?

Answer 15

Use CT head guidelines or a clinical decision rule: NICE

Common criteria for scanning are any one of CSF NOT BAD:

if ***** then CT < 1 hr

• Comatose: GCS <13 on arrival or <15 2 hours post-accident.
**• Seizure
****• Suspected skull fracture Sx
•* Focal Neurological deficit
• Old i.e. age ≥65 plus amnesia, LOC, or dangerous mechanism
*****• Two or more vomiting episodes
• Blood thinners or bleeding disorder
• Amnesia (retrograde) of ≥30 mins pre-event
• Dangerous mechanism plus amnesia, LOC, or age ≥65:
cyclist/pedestrian vs. car without helmets,
MVC with ejection/rollover/other fatality,
fall >1 m or >5 stairs

Question 16

Sx of nasal skull fracture? (4)

Answer 16

1) panda eyes (periorbital ecchymosis)
2) Battle’s sign (mastoid ecchymosis)
3) heamotympanum
4) CSF leak from ear/nose

Question 17

succinct approach to head injury?

Answer 17

ABC
O2 if <92
immobilise neck
circulatory support
seizures? lorazepam +/- phenytoin
GCS (<8 ITU)
amnesia, →, ←
Ex survey
obs every 15min
Ix - bloods including alcohol and toxicology screen, ABG, clotting
neuro Ex
Hx
Ex wounds
Ex CSF leak/basal fracture Sx (yes? CT)
cervical XR/CT if tender/Sx
CT if appropriate +/- CAP

Question 18

CT finding - lentiform like a LEmon, skull fracture?

Answer 18

Extradural

Question 19

CT finding - banana shape all down one side, midline shift and ↓ ventricles?

Answer 19

subdural hematoma

Question 20

CT finding - hyperdense white areas in basal cisterns and sulci, highlighting their shape? (looks a bit like a star)

Answer 20

SAH

Question 21

CT finding - hypoattenuation (darkness) in a vascular distribution?

Answer 21

ischaemic stroke

Question 22

CT finding - ring enhancing lesion, as the walls are vascularised but the core isn’t? (white rim black centre)

Answer 22

abscess/ brain tumour

Question 23

initial Tx for head injury?

Answer 23

analgesia (pain ↑ICP)
if persistent Sx or focal neuro Sx or CT findings, urgent referral to neurosurgery
(if GCS<8 +/- open fracture refer before CT)

Question 24

when is it safe to discharge a head injury?

Answer 24

GCS 15
eating + drinking no V
neuro Sx largely resolved
someone to monitor them at home for 24 hours

Question 25

if pupils are unequal?

Answer 25

↑ICP
extradural haemorrhage
urgent neurosurgery

Question 26

how to exclude ↑ICP?

Answer 26

retinal vein fundoscopy

Question 27

why is amnesia important?

Answer 27

retrograde loss correlates with severity (never occurs w/t anterograde)

Question 28

Hx: temporal region skull fracture, causing a rupture of the middle meningeal artery…?

Answer 28

extradural haematoma