Traumatic Brain Injury

Question 1

Hemorrhage types [2]

Answer 1

Extracranial

Intracranial

Question 2

Hemorrhage subtypes
Extracranial [3]
Define [1]

Answer 2

Epidural or extradural
Subdural
Subarachnoid

Bleeding occurs within skull and outside brain tissue

Question 3

Hemorrhage subtypes

Intracranial types [4]

Answer 3

Dependent on location
Lobar
Thalamic
Pontine 
Cerebellar

Question 4

Epidural haematoma = extradural haematoma
Define [1]
Usual cause [1]
Presentation initially [4] and as bleeding progresses

Answer 4

Occupies space between dura and skull
Ax: trauma to temple, just lateral eye causes # temporal/parietal bone causing laceration of middle meningeal artery and pain
Presentation:
- Lucid interval pattern: head injury with no LOC, few hrs to days
- Subsequent: reduced GCS (2* rising ICP)
- severe headache, vomiting, confusion, fits
- Hemiparesis with brisk reflexes, upgoing plantars
- If bleeding continues: dilation ipsilateral pupil, bilateral limb weakness, shock

Question 5

Subdural hemorrhage
Define [1]
Usual cause
Presentation [7]

Answer 5

Hemorrhage occurs between dura and arachnoid
Usual cause: head trauma
Sy:
- fluctuating GCS, +/- insidious physical or intellectual slowing, sleeping
- headache
- personality change
- unsteadiness
Si: increased ICP
- seizures
- localising neurological features (unequal pupils, hemiparesis) occur LATE and LONG AFTER injury

Question 6

Subarachnoid hemorrhage
Define [1]
Usual cause [1]
Presentation [4]

Answer 6

Bleeding occurs within arachnoid space
Source: trauma but may be spontaneous SAH
Presentation:
- Thunderclap headache, occipital
- LOC, seizures
- Nausea, vomiting
- Meningism

Question 7

SAH
How do you confirm? [2]
What do you do once SAH is confirmed? [2]
What other investigations to do? [2]

Answer 7

CT head (shows hyper dense/bright areas)
LP if CT negative - used to exclude - at least 12h after, positive will develop xanthochromia with normal/raised opening pressure.

Referral to neurosurgery to be made as soon as SAH is confirmed.
Aim of investigation after this is to determine underlying cause: CT intracranial angiogram

Question 8

SAH due to intracranial aneurysm management [5]

Answer 8

1. Prevent re-bleeding of aneurysm
   - Strict bed-rest, well controlled BP, avoid straining
2. 21d course nimodipine to prevent vasospasm
3. External ventricular drain - temporary tx for hydrocephalus
4. Frequent neuro obs
5. Endovascular Coiling by interventional neuroradiologist within 72h in a stable patient

Question 9

SAH due to intracranial aneurysm

Complications [5]

Answer 9

1. Re-bleeding (in around 30%)
2. Vasospasm (also termed delayed cerebral ischaemia), typically 7-14 days after onset
3. Hyponatraemia (most typically due to syndrome inappropriate anti-diuretic hormone (SIADH))
4. Seizures
5. Hydrocephalus
6. Death

Question 10

Explain why dilation of ipsilateral pupil occurs in extradural hematoma

Answer 10

As the haematoma expands the uncus of the temporal lobe herniates around the tentorium cerebelli and the patient develops a fixed and dilated pupil due to the compression of the parasympathetic fibers of the third cranial nerve.

Question 11

Investigation Extradural hematoma [3]

Answer 11

• CT head: biconvex/lense shaped haematoma (tough dural attachments keep haematoma more localised) that are limited by suture lines
• Skull XR: # lines across course of middle meningeal vessels
• LP CONTRAINDICATED

Question 12

Mx extradural hematoma [4]

Answer 12

• ABCDE (intubation and ventilation, reduce ICP)
• Stabilise and transfer to neurosurgical unit for
- craniotomy with clot evacuation
+/- bleeding vessel ligation

Chronic
- If incidental finding or if it is small in size with no associated neurological deficit then it can be managed conservatively with the hope that it will dissolve with time

Question 13

Chronic Subdural Hematoma

RF [3]

Answer 13

RF:

• elderly (cerebral atrophy makes bridging veins vulnerable; chronic)
• falls (epilepsy, alcohol, AF, cataracts)
• anticoagulation

Question 14

CT head findings Subdural Hematoma [2]

Mx [2]

Answer 14

• CT head: crescent/sickle cell shaped haematoma over 1 hemisphere +/- midline shift
• Crosses suture lines

Mx: conservative unless neurological deficit, irrigation and evacuation with Burr-hole craniostomy; craniotomy if clot has organised

Question 15

SAH signs [2]

Answer 15

• Kernig’s sign: severe stiffness of hamstrings causes inability to straighten leg when hip flexed to 90o
• Terson’s syndrome: retinal, macular and vitreous bleeds (5x increase in mortality)

Question 16

Lab investigations for SAH [5]

Answer 16

•	Bloods: 
- FBC (leucocytosis)
- clotting (raised prolonged INR and PT)
- U&E (hyponatraemia)
- troponin (elevated)
•	ECG: tall peaked T waves, ST depression and prolonged QTc

Question 17

Causes of spontaneous SAH [7]

Answer 17

Intracranial aneurysm* (saccular ‘berry’ aneurysms): this accounts for around 85% of cases. Conditions associated with berry aneurysms include adult polycystic kidney disease, Ehlers-Danlos syndrome and coarctation of the aorta
Arteriovenous malformation
Pituitary apoplexy
Arterial dissection
Mycotic (infective) aneurysms
Perimesencephalic (an idiopathic venous bleed)

Question 18

Pathophysiology of extradural hematoma: explain the pattern of lucid interval [4]

Answer 18

The brief regain in consciousness is termed the ‘lucid interval’ and is lost eventually due to the expanding haematoma and brain herniation.

As the haematoma expands the uncus of the temporal lobe herniates around the tentorium cerebelli

• the patient develops a fixed and dilated pupil
• due to the compression of the parasympathetic fibers of the third cranial nerve.

Question 19

Presentations
Acute subdural hematoma [2]
Chronic subdural hematoma [2]

Answer 19

Presenting few days after injury
Usually due to high impact trauma like acceleration-deceleration injuries (think similar to mechanism of shaken baby syndrome)
- Produces hyperdense/bright lesion on CT

A chronic subdural haematoma is a collection of blood within the subdural space that has been present for weeks to months.

• Infants who have shaken baby syndrome
• Produces hypodense lesions on CT

Question 20

Intraventricular haemorrhage

• describe 2 different presentations
• CT findings

Answer 20

In children it can occur due to the prematurity of the periventricular vascular structures.
In adults it may be caused by an extension of subarachnoid haemorrhage, vascular lesions (e,g. aneurysms or arteriovenous malformations) or tumours.

On CT imaging it appears as hyperdensity within the dark CSF spaces within the ventricles.

Question 21

Intraventricular haemorrhage:

Complications

Answer 21

Patients with intraventricular haemorrhage at risk of obstructive hydrocephalus and this would required surgical CSF diversion.