Head Trauma

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Head Trauma

• Yi Sia
• Surgical HMO
• The Royal Melbourne Hospital

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Overview of Anatomy
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Blood Supply to Dura
Meninges
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Circle of Willis
Brain
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Ventricular System
Venous Drainage
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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 lt 15mmHg or lt 20cmH2O

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Monro-Kellie Doctrine
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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

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Classifications of Head Trauma
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
Primary brain injuries Immediate result of trauma
Secondary brain injuries Develop later as a result of complications
Skull fractures
Vault Linear vs stellate, depressed/non-depressed, open/closed
Basilar With/without CSF leak
Severity
Minor GCS 13-15
Moderate GCS 9-12
Severe GCS 3-8
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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 gt females
• Peak incidence is in the age group 15-24 years

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Primary Brain Injuries

• Concussion
• Diffuse axonal injury (intracerebral shearing)
• Focal brain injury
• Cerebral contusion
• Haemorrhage/haematoma

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Secondary Brain Injury

• Cerebral ischaemia/hypoxia
• Cerebral swelling/oedema
• Hydrocephalus (obstructive, communicating)
• Infection
• Intracranial bleeding
• Extradural haemorrhage
• Subdural haematoma
• Subarachnoid haemorrhage
• Intracerebral haemorrhage

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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

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Subdural haematoma

• Between dura and arachnoid
• Ruptured communicating veins
• Common in elderly
• Can be acute, subacute, or chronic

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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

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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
  (Battles sign)

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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 Eye Opening Verbal Response Verbal Response Motor 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
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Secondary Survey

• Take an AMPLE history
• Fully assess head and neck for injury including
• Examination of skull vault
• Signs of BOS s (panda eyes, Battles sign, CSF
  rhinorrhoea/otorrhoea)
• Repeat vital signs
• Repeat GCS
• Neurological examination
• General examination for other injuries

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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
• Cushings triad HTN, bradycardia, irregular
  respirations

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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 lt15 at 2/24 post injury Suspected open or depressed skull Any sign of BOS Vomiting (gt2 episodes) Age gt65yo Amnesia before impact (gt30 min) Dangerous mechanism (e.g. ped vs car, occupant ejected from vehicle, fall from height gt3 feet or 5 stairs
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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

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Surgical Management

• Scalp wounds
• Depressed scalp s
• Intracranial mass lesions (EDH, SDH,
  intracerebral haematoma)
• Decompressive craniotomy/craniectomy
• ICP monitor

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Summary

• Head trauma causes significant morbidity and
  mortality
• The primary focus of treatment is to prevent
  secondary brain injury