Head injuries Flashcards
Describe primary and secondary classification of head injuries
Primary - immediately after injury
Secondary - at least hours after injury
Types of primary HIs and subtypes
Focal: haematoma or contusion
Diffuse: concussion or diffuse axonal injury
Types of haematoma
Extradural
Subdural
Intracerebral
Types of contusion
Coup at side of impact
Contrecoup at opposite side of impact
Describe diffuse axonal injury and what it can lead to
Shearing of interface between grey and white matter following acceleration-deceleration to the brain damaging the intracerebral axons and dendritic connections
Cerebral oedema which increases ICP
Describe contusion
Trauma to head causes blood to mix with cortical tissue due to micro haemorrhages
Damage leads to oedema or IC haemorrhage which can cause coma or death
Definition of concussion
Head injury with loss of brain function caused by stretching of axons (impaired neurotransmission, loss of ion regulation, decreased cerebral blood flow)
Describe traumatic and non traumatic classification of head injuries
Traumatic: open or closed
Non-traumatic e.g CVA, tumour, infection, anoxia
Signs of basilar skull fractures
CSF rhinorrhoea due to meningeal tears
Raccoon eyes
Battle sign
Haemotympanum
Criteria for urgent CT head with HIs
GCS <13 or GCS <14 >2 hrs after injury
Suspected open, depressed or base of skull fracture
Focal deficit
Seizure
Loss of consciousness WITH age >65 or coagulopathy
Where does blood collect in an extradural haemorrhage
Between the inner skull and periosteal dura mater
Which artery is most commonly severed in an EDH and why
Middle meningeal artery (anterior branch?)
Runs behind pterion which is weakest part of skull
In what age groups are EDH more common and why
<20 because with increasing age the dura sticks more firmly to the skull
Describe the events that occur after an EDH
LOC from injury
Lucid interval
Rapid decline in consciousness as haematoma enlarges
Herniation
CT head features in EDH
Biconvex haematoma
Midline shift
Ventricle compression
What limits shape of haematoma in EDH
Suture lines
Different management for small and large EDH
Small: observe for few hours, neuro follow up
Large: craniotomy, clot evacuation
Complications of EDH
Brain damage Coma Seizure Weakness AV fistula
Where does blood collect in a subdural haemorrhage
Between the arachnoid and meningeal dura mater
Types of SDH
Chronic: >3 weeks
Subacute: 3-21 days
Acute: <3 days
Why does risk of SDH increase with age
Cerebral atrophy with age increases risk of rupture of the cortical bridging veins
CT head features in SDH
Sickle shaped as doesn’t cross falx cerebri
Acute: white
Chronic: dark
Management for SDH
Acute: relieve ICP, neurosurgery
Symptomatic chronic: burrholes
Small chronic: serial imaging
What worsens prognosis of SDH
Need surgery
On anticoagulants
Where does blood collect in a subarachnoid damage
Between pia and arachnoid mater
Symptoms of SAH
Thunderclap headache Meningism Nausea and vomiting Focal neurological deficits Loss of consciousness
Cause of SAH
Berry aneurysm rupture (at points of bifurcation in the anterior circulation)
CT head features of SAH
Spider like shape of hyperdensity due to blood (appears bright) in arachnoid
Diagnosis of SAH
LP to rule out meningitis and look for RBCs and xanthochromia (if no signs of raised ICP)
Management of SAH
Stabilise patient Prevent rebleeding Give Ca channel blockers to treat cerebral vasospasms Correct hyponatraemia Neurosurgical intervention if large
Mortality rate of SAH
30-90%
What worsens prognosis of SAH
Worse GCS
Worse neurological deficit
Complications of SAH
Hydrocephalus - blood in SA space which prevents CSF absorption Focal neurological deficit Coma Seizures Headaches Decline in cognitive function Hypopituitarism
How to read CT head
Intracranial or intracerebral Shape Density - dark means ischaemia or oedema, bright means blood Cerebral oedema Ventricles Midline shift
Risk factors for berry aneurysm
Smoking Alcohol Hypertension Family history Autosomal dominant polycystic kidney disease
