Head Trauma

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Head Trauma
Yi Sia
Surgical HMO
The Royal Melbourne Hospital
Overview of Anatomy
Meninges
Blood Supply to
Dura
Brain
Circle of Willis
Venous Drainage
Ventricular System
Physiology
Intracranial pressure
 Pressure within the cranial cavity
 Cranial cavity is encased by a skull which is a rigid cavity
 80% brain, 10% CSF, 10% blood
 Normal ICP < 15mmHg or < 20cmH2O
Monro-Kellie Doctrine
Cerebral Blood Flow
 = 50-55ml/100g of brain tissue per minute
 Severely elevated ICP can cause decreased CBF and
brain ischaemia
 CBF depends on cerebral perfusion pressure (CPP)
 CPP = MAP – ICP
 Autoregulation can compensate for modest reductions
in CPP, leading to relatively stable CBF
Classifications of Head Trauma
Classifications of Head Trauma
Mechanism
•
Blunt
High velocity (MVA) vs low velocity (fall, assault)
•
Penetrating
Gunshot wounds, other penetrating injuries
Morphology
•
•
Intracranial lesions
o
Primary brain injuries
Immediate result of trauma
o
Secondary brain injuries
Develop later as a result of complications
Skull fractures
o
Vault
Linear vs stellate, depressed/non-depressed, open/closed
o
Basilar
With/without CSF leak
Severity
•
Minor
GCS 13-15
•
Moderate
GCS 9-12
•
Severe
GCS 3-8
Traumatic Brain Injury
 An acquired brain injury caused by a blow to the head or by
the head being forced to move rapidly forward or backward,
usually with some loss of consciousness
 ~150 people admitted to hospital with TBI per 100,000
population per year
 The leading causes are

Falls (42%)

MVA (29%)

Assault (14%)

Other unintentional injuries
 Males > females
 Peak incidence is in the age group 15-24 years
Primary Brain Injuries
 Concussion
 Diffuse axonal injury (intracerebral shearing)
 Focal brain injury
•
Cerebral contusion
•
Haemorrhage/haematoma
Secondary Brain Injury
 Cerebral ischaemia/hypoxia
 Cerebral swelling/oedema
 Hydrocephalus (obstructive, communicating)
 Infection
 Intracranial bleeding
•
Extradural haemorrhage
•
Subdural haematoma
•
Subarachnoid haemorrhage
•
Intracerebral haemorrhage
Extradural Haemorrhage
 Between skull and dura
 Injury to middle meningeal
artery or one of its branches
 Characteristic biconvex
shape
 May present as decreased
consciousness or following a
lucid internal
Subdural haematoma
 Between dura and
arachnoid
 Ruptured communicating
veins
 Common in elderly
 Can be acute, subacute,
or chronic
SAH and Contusions
SAH
Increased attenuation in
CSF spaces – filling of the
sulci over cerebral
hemispheres
Intracerebral
bleed/haemorrhagic
contusion
Inferior frontal and anterior
temporal lobes are common
sites
Skull Fractures
 Indicates severe impact
 Simple #s – linear or stellate
 Depressed #s
 Compound #s
 Base of skull #s
 Anterior cranial fossa – periorbital haematomas (“panda
eyes”), subconjunctival haemorrhage, CSF rhinorrhoea
 Middle cranial fossa, involving petrous temporal bone – CSF
otorrhoea, bruising over mastoid area (“Battle’s sign”)
Clinical Assessment
Primary survey and resuscitation
A – Airway, C-spine protection
B – Maintain adequate oxygenation (hypoxia causes vasodilatation
and raised ICP)
C – Ensure adequate BP (ischaemia results in secondary brain injury)
D – GCS, pupils
Eye Opening
Verbal Response
Motor Response
Spontaneous
4
Oriented
5
Obeys commands
6
To speech
3
Confused
4
Localises pain
5
To pain
2
Inappropriate words
3
Withdraws
4
None
1
Incomprehensible sounds
2
Decorticate
3
None
1
Decerebrate
2
None
1
Secondary Survey
 Take an AMPLE history
 Fully assess head and neck for injury including
• Examination of skull vault
• Signs of BOS #s (panda eyes, Battle’s sign, CSF
rhinorrhoea/otorrhoea)
 Repeat vital signs
 Repeat GCS
 Neurological examination
 General examination for other injuries
Signs and Symptoms
Common signs and symptoms of raised ICP
Headache
Altered mental state, especially irritability and depressed
level of alertness and attention
Nausea and vomiting
Papilloedema
Visual loss
Diplopia
Cushing’s triad: HTN, bradycardia, irregular respirations
Imaging in Head Trauma
Indications for CT scanning (Canadian CT Head Rule)
 CTB is required for patients with minor head injuries (i.e.
witnessed LOC, definite amnesia, or witnessed disorientation in
a pt with GCS 13-15 and any one of the following:
High risk for neurosurgical intervention
Moderate risk for brain injury on CT
• GCS <15 at 2/24 post injury
• Amnesia before impact (>30 min)
• Suspected open or depressed skull #
• Dangerous mechanism (e.g. ped vs car,
occupant ejected from vehicle, fall from
height >3 feet or 5 stairs
• Any sign of BOS #
• Vomiting (>2 episodes)
• Age >65yo
Medical Management
 Intravenous fluids

Aim is to maintain normovolaemia
 Hyperventilation
 Normocarbia is preferred
 Mannitol
 Acute neurological deterioration in a normotensive pt is a
strong indication for administering mannitol
 Anticonvulsants
 Prophylactic phenytoin reduces the incidence of seizures in
the first week of injury
Surgical Management
 Scalp wounds
 Depressed scalp #s
 Intracranial mass lesions (EDH, SDH, intracerebral
haematoma)

Decompressive craniotomy/craniectomy

ICP monitor
Summary
 Head trauma causes significant morbidity and mortality
 The primary focus of treatment is to prevent secondary
brain injury
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