Head injury - Intracerebral, Subdural and Extradural Haemorrhage, and diffuse axonal injury Flashcards Preview

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Flashcards in Head injury - Intracerebral, Subdural and Extradural Haemorrhage, and diffuse axonal injury Deck (57):



What is an extradural haemorrhage?


A collection of blood that forms between the inner surface of the skull and outer layer of the dura, which is called the endosteal layer. EDH typically follows a linear skull vault fracture tearing a branch of the middle meningeal artery. Extradural blood accumulates rapidly over minutes or hours.




Which artery is most commonly implicated in an extradural haemorrhage?



Middle meningeal artery




When might you suspect an extradural haemorrhage?


After any skull fracture - especially temporal/parietal bone. Typically after trauma to the eye




Where does blood accumulate in an extradural haemorrhage?



Between bone and Dura




What are symptoms of an extradural haemorrhage?


  • Lucid interval following trauma, then progressively decreasing GCS
  • Increasingly severe headache
  • Vomiting
  • Confusion
  • Seizures




What are signs of an extradural haemorrhage?

Raised ICP signs (in sequence)

  1. Lucid progressing to Decreased GCS
  2. Ipsilateral myadriasis (hutchison's pupil), with Contralateral Hemiparesis + Brisk reflexes + Upgoing plantars
  3. Tetraplegia + Bilateral fixed dilated pupils
  4. Late signs - Bradycardia, Increased BP, Respiratory depression (cushings triad)




What is the general progression of extradural haemorrhage from initial insult?



Lucid period -> decreased GCS, signs of rasied ICP -> hemiparesis, brisk reflexes, hutchison's pupil, coma, bilateral limb weakness, resp depression




What would differentials be for someone who you suspected might have an extradural haemorrhage?


  • Epilepsy
  • Carotid dissection
  • Carbon monoxide poisoning




Why do individuals with an extradural haemorrhage get a hutchison's pupil?



Caused by herniation of the uncus impinging on the occulomotor nerve




Why do individuals with extradural haemorrhage develop bradycardia as a late sign?

As part of Cushing's Triad/Reflex:

  • Increase in systolic and pulse pressure
  • Bradycardia
  • Irregular respiration

Baroreceptors in the aortic arch detect the initial increase in blood pressure and trigger a parasympathetic response - induces bradycardia, which signifies the second stage of the reflex




Why do those with extradural haemorrhage develop Hypertension as a late sign?

As part of Cushing's Reflex

  • Disturbed repiratory pattern
  • Bradycardia
  • Hypertension

In response to raised ICP, the body attempt to restore adequate perfusion to the ischaemic brain, as raised ICP reduces flow of blood into the brain




Why can those with an extradural haemorrhage develop irregular/depressed breathing?

As part of Cushing's Reflex

  • Disturbed repiratory pattern
  • Bradycardia
  • Hypertension

Distortion and/or increased pressure on the brainstem causes an irregular respiratory pattern and/or apnea




How would you investigate a suspected extradural haemorrhage?


  • Imaging - CT Scan
  • Skull X-ray - shows fracture line
  • DON'T DO AN LP!!!


What is the following diagnosis?



Extradural haemorrhage




Why do extradural haemorrhage show up as a biconcave hyperattenuated area on CT?



Due to the insertion points of the dura to the suture lines of the skull




How would you manage someone with an extradural haemorrhage?


  • Stabilise and transfer to neurosurgery
  • Surgery - clot evacuation and ligation
  • May require intubation/ventilation




What is a subdural haematoma?


A type of hematoma, usually associated with traumatic brain injury. Blood gathers between the inner layer of the dura mater and the arachnoid mater.




What layers of the meninges does a subdural haemorrhage occur between?



Dura and arachnoid mater




What is the cause of a subdural haemorrhage?

Rupture of bridging veins, caused by:

  • Trauma (most commonly)
  • Decreased ICP
  • Dural metastases





What are risk factors for subdural haemorrhage?


  • Falls - elderly, alcoholics
  • Anticogulation




What are symptoms of a subdural haemorrhage?


  • Fluctuating level of conscioussness
  • Physical/intellectual slowing
  • Sleepiness
  • Headache
  • Personality change
  • Unsteadiness




What are signs of a subdural haemorrhage?


  • Signs of raised ICP
  • Focal deficits - hemiparesis, sensory loss
  • Seizures
  • Stupor
  • Decreased GCS
  • Late features - Hypertension, Bradycardia, Depressed resp rate






What investigations would you do in someone with suspected subdural haemorrhage?



Imaging - CT/MRI




What might you see on CT/MRI in someone with a subdural haemorrhage?


  • Clot +/- midline shift
  • Crescent-shaped collection of blood oer 1 hemisphere




How would you manage a subdural haemorrhage?


Refer to neurosurgery

  • Reverse clotting abnormalities
  • Surgery - if >10mm haemorrhage or >5mm midline shift
  • Address cause of trauma - falls, abuse




What head injuries can cause focal neurological signs or seizures?


  • Diffuse axonal injury
  • Contusion
  • Intracerebral haematoma
  • Extra-cerebral haematoma - Extra-dural haematoma, Sub-dural haematoma




What GCS score would you consider intrubating someone?



GCS < 8 - unable to maintain own airway




Why are those who are elderly, drink alcohol or who have dementia more at risk of subdural haemorrhage?



Due to cerebral atrophy - stretches venous bridges, making them more prone to rupture




How would you manage raised ICP?


  • Surgery to relieve pressure - Heamatoma, ventricular shunt
  • Osmotic agents - mannitol
  • Nurse with head at 30-45o (Venous return)
  • Reduce pain
  • Maintain good PO2, reduce PCO2
  • Reduce metabolism (reduce temperature, barbiturates)




What does the extent of retorgrade amnesia correlate with in a head injury?



Severity of injury - never occurs without anterograde amnesia




If someone had a head injury, when would you consider performing a CT within an hour of presentation?


  • GCS <13, or < 15 at 2hrs
  • Focal neurological deficit
  • Suspected open/depressed skull fracture
  • Signs of basal skull fracture
  • Post-traumatic seizure
  • Vomiting more than once




When would you consider doing a CT within 8 hrs of admission?

Any LOC/amnesia, and any of

  • Age >/= 65
  • Coagulopathy
  • High-impact injury
  • Retrograde amnesia >30 mins




When might you suspect a cervical spine injury in combination with a head injury?


  • GCS <13 on inial assessment
  • Clinical suspicion, plus any of:
    • 65 or older
    • High-impact injury
    • Focal neuro deficit
    • Paraesthesia of upper/lower limbs
  • Patient has to be intubated
  • Multi-region trauma




What are early complications of head injuries?


  • Subdural haemorrhage
  • Extradural haemorrhage
  • Seizures
  • Uncal herniation
  • CSF leak
  • Hydrocephalus
  • Cranial nerve palsies




What are late complications of head injury?


  • Subdural haemorrhage
  • Seizures
  • Diabetes insipidus
  • Parkinsonism
  • Dementia




When is alcohol an unlikely cause of coma?



If blood alcohol levels <44 mmol/L




When would you consider admitting someone with a head injury?


  • New, clinically significant abnormalities on CT
  • GCS <15 after CT
  • Other concerns - drugs/alcohol, other injuries, CSF leak, shock etc.




What are indicators of a bad prognosis in a head injury?


  • Old age
  • Decerebrate rigidity
  • Extensor spasm
  • Prlonged coma
  • Hypertension
  • Decreased PaO2
  • To > 39




If someone presented with a head injury, what would you do as part of your initial assessment?


  • Give oxygen if sats <92%
  • Intubate and hyperventilate if necessary
  • C-spine immobilisation
  • Fluid resus/circulation support
  • Treat seizures - lorazepam +/- phenytoin
  • Assess GCS - if <8 -> manual airway




What initial blood investigations would you consider in someone presenting with a head injury?


  • U+E's
  • Glucose
  • FBC
  • Blood alcohol
  • Toxicology screen
  • ABGs
  • Clotting




What are signs of a CSF leak caused by a head injury?


  • Rhinorrhoea
  • Otorrhoea
  • Blood behind ear drum
  • Basal skull fracture signs




What is diffuse axonal injury?

Severe form of head injury that occurs as a result of shearing and tensile strains produced by rotational movements of the brain within the skull. It often occurs in the absence of a skull fracture and cerebral contusions. Two main components exist:

  • Small haemorrhagic lesions in the white matter - corpus callosum and dorsolateral brainstem
  • Diffuse damage to axons - eventually degenerate, resulting in a loss of fibres in the white matter.




What are mechanisms of brain damage form a head injury?


  • Diffuse axonal injury
  • Neuronal and axonal damage from direct trauma
  • Brain oedema and raised ICP
  • Brain hypoxia
  • Brain ischaemia




What is an intracerebral haemorrhage?



Haemorrhage within the brain tissue itself




What are causes of intracerebral haemorrhage?


  • Hypertension
  • Trauma
  • Aneurysm rupture
  • Anticoagulation
  • Thombolysis




How might you distinguish an intracerebral haemorrhage from a stroke?



Very difficult - may have a headache with stroke symptoms


What is the following?



Intracerebral haemorrhage




Which imaging modality is best for visualising intracranial haemorrhage?



CT is best and quickest option




What are features of anterior base of skull fracture?


  • CSF rhinorrhoea
  • Subcutaneous haematoma around orbit - racoon eyes


  • Halo sign
  • Headache
  • Amnesia/confusion
  • Focal neuro signs
  • Seizures




What is halo sign?



Rapidly-expanding clear ring of fluid surrounding blood on discharge




What are features of posterior basal skull fracture?


  • CSF otorrhoea: leakage of CSF from the external auditory meatus
  • Subcutaneous hematoma behind the ear (Battle sign)


  • Headache
  • Amnesia; confusion, disorientation
  • Impaired consciousness
  • Dizziness, nausea, vomiting
  • Focal neurologic symptoms (see stroke)
  • Seizures
  • Sensory disturbances



What is the following?



Racoon eyes - sign of anterior base of skull fracture




What GCS score would indicate a mild head injury?







What GCS score would indicate a moderate head injury?







What GCS score would indicate a severe head injury?







How would you manage a mild TBI?


  • Monitoring  - 24 hrs
  • Simple analgesia
  • Athletes
    • Refrain from contact sports for a week - then reassess
    • Monitor in A+E - 6 hours




What would you lookfor on CT in someone with a suspected traumatic brain injury?


  • Midline shift
  • Hemorrhage and hematomas (see “Differential diagnoses of intracranial hemorrhages” below)
  • Diffuse axonal injury (DAI)