Transcript Head Trauma
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