Mechanical Injuries

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Mechanical Injuries

• Of
• Brain and Meniges

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• 1? Traumatic Lesions
• 2? Alterations

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1? Traumatic Lesions

• Extracerebral lesions
• Intracerebral lesions

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1? Traumatic Lesions

• Close injury
• Open injury

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Extracerebral Lesions

• Epidural bleeding
• Subdural bleeding
• Subaracnoid bleeding
• Intraventricular bleeding

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Intracerebral Lesions

• Contusions
• Lacerations (or Wounds)

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2? Alterations

• Circulatory disorder
• Necroses and hemorrhages
• Post-traumatic hydrocephalus
• Secondary infections
• Fat and air embolism

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Epidural

• Bleeding

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Epidural Bleeding

• Epidural / Extradural
• Hemorrhage / Hematoma

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Causes

• Skull fracture
• Separation of dura and skull bone
• Tear of a dural artery ,its branches
• and/or occasionally of a vein

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• Most common site lateral convexity of a cerebral
  hemisphere
• Location it almost always at the site of a
  skull fracture

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• Uncommon occur in the elderly
• Children skull deformation with separation of
  the dura from the bone without skull fracture

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• Acute hematoma artery bleeding
• Delayed hematoma venous bleeding, transient
  arterial spasm

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Progression of the bleeding

• Space occupying hematoma
• Increase intracranial pressure
• Confusion
• Alteration of consciousness
• Pupillary dilatation on the hematoma side
• Central respiratory failure

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• If venous bleeding ,or transient arterial spasm
  Lucid interval
• Consciousness (may be) ,no signs of confusion
  occipital poles and/or cerebellum

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Chronic Epidural Hematoma

• The hematoma spontaneously shrinks and becomes
  encapsulated by fibrous connective tissue.

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Subdural

• Bleeding

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Subdural bleeding

• Trauma
• Rupture of aneurysm
• Arteriovenous malformation

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• Vein
• - Tearing of one or
• - Several bridging vein
• - Insignificant trauma (sometime)
• abnormally located blood vessels

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• Artery
• - particularly in branches of the middle
• cerebral artery
• - severe cortical contusions and bleeding
• into subarachnoid space
• (usually) tears of arachnoid membrane

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• Artery
• - More frequently on the side opposite
• the impact
• - (May) without brain contusions
• or significant subarachnoid hemorrhage

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Time of onset

• Acute within 12 to 24 hr.
• Subacute from 24 hr. to 7 d.
• Chronic more than 7 d.

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• Most Location over the convexities and the
  lateral aspects of the cerebral hemisphere
• Often extend over the base of frontal and
• temporal lobes
• Occasionally between the hemisphere

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• In skull intact occur as often as with skull
  fracture
• Rare in the posterior cranial fossa , around the
  brain stem and cerebellum

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Chronic Subdural Hematoma

• Enlargement if untreat
• Isotonicity
• Local presence of fibrinolytic enzymes bleeding
  tendency

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Subaracnoid

• Bleeding

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Subaracnoid bleeding

• Trauma / Nontrauma
• Extension of intraventricular hemorrhage

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• Moderately severe blow to the face or forehead
• Sudden ,usually severe hyperextension of the head
  , as from a fall onto the forehead

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• Subarachnoid over the brain stem and basal
  cisterns hydrocephalus
• Forgetfulness , confusion , psychotic state
• Spasticity of the lower extremities

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Intraventricular

• bleeding

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Intraventricular bleeding

• Most often arterial in origin
• Trauma
• Non-trauma such as rupture AVM or Aneurysms

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Intracerebral

• Lesions

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• Contusions
• Lacerations (Wounds)

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Contusions

• Contusion hemorrhage
• Contusion necrosis
• Contusion tear

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Intracerebral Hematoma

• In the deeper portions of contusions
• More frequent in the frontal and /or temporal
  lobes
• Location white matter gt grey matter

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Intracerebral Hematoma

• Secondary rupture into the ventricular system
  and/or the subarachnoid space usually does not
  occur.

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Lacerations

• Stab wounds
• Gunshot wounds

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Gunshot wounds

• Shearing forces within brain tissue
• Expansile cavitation
• Distant contusions (hemorrhages)

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Classification of

• Contusions
• According to causative mechanism

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• Depending on site and direction of impact
• Coup , Intermediary coup , Contrecoup
• Independent of site and direction of impact
• Fracture contusion , Gliding contusion ,
• Herniation contusion

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Axonal injury

• Shearing forces due to blunt head injuries
• Focal , diffuse
• Early ,the areas little or no change on gross
  examination of the white matter
• Older lesions slightly gray pallor

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2? Alterations
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2? Alterations

• Circulatory disorder
• Necroses and hemorrhages
• Post-traumatic hydrocephalus
• Secondary infections
• Fat and air embolism

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Circulatory disorder

• Swelling of the brain edema and cell necrosis
• Usually reversible
• Perifocal surrounding a 1? brain lesion
• Generalize a primary lesion , shock

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Other rare causes

• Obstruction of the superior sagittal sinus
• Traumatic thrombus or obstruction in internal
  carotid artery

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Necroses/Hemorrhages

• Vascular compression
• Shearing lesions

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Necroses/Hemorrhages

• Many lesion are large such as midbrain and pons
• If rapidly progressing space occupying lesion
  secondary lesion may appear within 30 mins. After
  injury
• Hemorrhage sometimes small or absent

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Hydrocephalus

• Traumatic or Non-traumatic cause
• White matter loss following a shearing lesion and
  degeneration of myelinated axons
• Distension of ventricles by elevated pressure of
  the CSF

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Secondary infections

• Meningitis
• Intracerebral abscesses

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Meningitis

• An infected open injury caused by a foreign body
• A fracture in the wall of one of the cranial
  sinuses associated with a tear in the dura and
  arachnoid

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Intracerebral abscesses

• In the vicinity of the primary lesion
• Complication rupture into the underlying
  ventricle (Pyocephalus)

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Fat and air embolism

• Primary or Secondary lesions
• Fat embolism fractures , stab wound at neck
• Air embolism stab wound at neck , a skull
  fracture lacerating a paranasal dural sinus