Neurological injuries: Head

Question 1

When should depressed consciousness be ascribed to intoxication?

Answer 1

Only after brain injury has been excluded

Question 2

Aims for high flow O2?

Answer 2

PaO2 >13kPa (98 mmHg)

PaCO2 in the normal range (4.5-5kPa; 34-48 mmHg)

Question 3

Risks of PaCO2 imbalance in the brain?

Answer 3

If too low then brain vasculature will constrict risking ischaemia
If too high then vasculature will dilate too much and raise intracranial pressure

Question 4

When should you avoid using a nasopharyngeal airway?

Answer 4

If there are basal skull fractures

Question 5

Head injury does not cause what?

Answer 5

Hypotension

Question 6

How do you calculate cerebral perfusion pressure?

Answer 6

Mean arterial pressure - intra-cranial pressure

need to maintain MAP >80 mmHg with IV fluids

Question 7

Which part of the GCS is most predictive of the outcome of head injury?

Answer 7

Motor

Question 8

GCS <8?

Answer 8

Intubate as tounge might block airway

Question 9

What warrants a CT within one hour?

Answer 9

GCS <13 (<15 at 2 hours)
Open/depressed skull fracture
Any sign of basal skull fracture
Post-traumatic seizure
Focal neurological deficit
>1 episode of vomiting

Question 10

What warrants a CT within 8 hours?

Answer 10

Amesia/loss of consciousness with any 1 of:
Over 65, bleeding/clotting disorders, dangerous mechanism of injury, >30 mins retrograde amnesia of events
Warfarin treatment alone

Question 11

Signs of basal skull fracture:

Answer 11

Battle’s sign (behind ear)
Panda eyes (periorbital bleeding)
Haemotympanum
CSF otorrhoea/rhinorrhoea (CSF has high sugar so test with urine dipstick)

Question 12

Appearance of new vs old blood on CT?

Answer 12

New looks white

Old looks grey like brain tissue

Question 13

Signs of extradural haemorrhage:

Answer 13

Dilated pupil
Oculomotor nerve palsy
Lucid interval in 1/3 of patients (minutes to hours)
Initially may lose consciousness but will regain
Biconvex
Commonly temporo-parietal - MMA
Good prognosis if early treatment

Question 14

Features of subdural haemorrhage:

Answer 14

Crescent shape
Venous blood from the rupture of the bridging dural veins
Can be acute or chronic (elderly, alcoholics, anticoagulant)
Mass effect

Question 15

Non-accidental cause of subdural haemorrhage?

Answer 15

Shaken baby syndrome

Question 16

Features of subarachnoid haemorrhage:

Answer 16

Traumatic/spontaneous e.g. ruptured aneurysm
Bleed into the ventricles, sulci and gyri
Tearing of small leptomeningeal arteries causing vasospasm and ischaemia

Question 17

How do you treat leptomeningeal tear and vasospasm?

Answer 17

Nimodipine (CCB) 60mg oral/NG tube helps reduce ischaemia

Question 18

Causes of spontaneous SAH:

Answer 18

85% is saccular 'berry' aneurysms associated with polycystic kidney disease, Ehlers-Danlos syndrome and coarctation of the aorta
AV malformation
Pituitary apoplexy
Arterial dissection
Mycotic (infective) aneurysms
Perimesencephalic

Question 19

Subarachnoid haemorrhage presentation:

Answer 19

Headache, N+V
Meningism: photophobia and neck stiffness
Coma, seizures and sudden death
ST elevation may be seen on ECG

Question 20

How to confirm subarachnoid haemorrhage?

Answer 20

CT
If CT negative then a lumbar puncture 12 hours after onset to test for xanthochromia - if +ve then urgent neurosurgical referral

Question 21

Management of SAH:

Answer 21

Vasospasm = nimodipine
Aneurysm = coil/craniotomy + clipping (rarer)
Hydrocephalus treated with an external ventricular drain/long-term ventriclo-peritoneal shunt

Question 22

Complications of SAH:

Answer 22

Hyponatraemia from SIADH
Re-bleeding (30%)
Vasospasm (aka cerebral ischaemia)
Seizures
Hydrocephalus
Death

Question 23

Differential between acute and chronic subdural haemorrhages?

Answer 23

Acute will be from the MMA and will be hyper dense on CT (white)
Chronic will be from fragile dural bridging veins (elderly, alcoholic, baby) and will be hypodense/dark grey on CT

Question 24

Features of cerebral contusion:

Answer 24

Small bleeds shown as small white spots on CT
Can be subtle
Often frontal/temporal due to impact with the sphenoid ridge/orbital plates

Question 25

Features of diffuse axonal injury:

Answer 25

Bad prognosis
Acceleration/deceleration causes shearing of neuro axons
Widespread WMI
Hard to see on CT - swollen brain, sometimes pinpoint haemorrhages due to capillary rupture
Need MRI - can be in vegetative state forever

Question 26

What is concussion?

Answer 26

Stretching of white matter fibres

Question 27

Symptoms of concussion?

Answer 27

Nausea
Amnesia
Confusion
Loss of consciousness/concentration
Dizziness
Usually temporary