traumatic Injuries Flashcards
What are the three most common causes of truamatic head injury
Heamorrhage, penetrating injury, Diffuse
What is concussion?
Is a clinical term as pathological term isn’t understood, but is typically associated with loss of reflexes, unconscienceness and temporary respiratory arrest
What is the downside of hard skull prtecting brain
Is very hard so rapid change in momentum can cause contussions
What is the site of impact called
Coup and on oppisite side is called countercoup
What are the secondary effects of traumatic injury
- Acute ○ Ischemia ○ Hypoxia ○ Raised ICP (not quite acute, slightly delayed) - Delayed/Chronic ○ Infection ○ Epilepsy
Different types of skull fractures
Linear, depressed, comminuted
What are the most common sites of contussion
inferior frontal lobe and inferiorlateral temporal lobe due to the base of the skull having a stepwise nature
What is the pathogenesis of a contussion
Will leave a yellow scar, atrophy and brain shrinking, often at tips of gyri and also accumualte heamidesorin
Different types of heamorrhage
Epidural, sub-dural, sub arachnoid and intracerebral
What region is at risk of tearing in lacerations by foreign objects
The ponto-medullary region can tear and heamorrhage leading to instantaneous death
What is diffuse Axonal injury
Damage and atrophy/death of axons due to raised ICP, ischemia, haemorrhage, hypoxia and laceration and small vessel heamorrhage
What can be seen macroscopically from DAI
Corpus collasum atrophy, enlarged ventricles
What is the pathogenesis of DAI
Swelling of neurons, axon rupture/blockage leading to protein accumulation in the soma and hence cells swell, known as neuronal spheriods
Consequences of brain injury
Infection, hydrocephalus, epilepsy and chronic truamatic encephalopathy
What is seen with chronic truamatic encephalopathy
Recurrent knocks(trauma and concussion) to the head leading to neuronal loss, tau and a-beta plaque formation, scar tissue which can lead to brain atrophy and predisposition to epilepsy
Consequences of raised ICP
Initial compensation from reduced Blood flow and CSF (total of 150ml), once this compensation fails then herniation and pressure must be released to prevent death
Causes of raised ICP
- Trauma
- Tumour
- Infarction
- Haemorrhage
- Infection
- Cerebral Oedema
- CSF occlusions
Describe central oedema
Is either vasogenic of cytotoxic
Vasogenic odema
Is compromised BBB leading to swelling, can be treated with steriods, hypocapneo and isotonic solutions
Cytotoxic odema
Caused by cell swelling as a consequence of direct cell damage leading to compromised membrane and ion channel failure, doesn’t respond to steroids and can be caused by stroke/haemorrhage
What is Cushing’s Triad
Response to raised ICP, increased Respiration, increased blood pressure and bradycardia
Common signs in sub-falcrine herniation
Headache, nausea and vomiting. Usually a sign of predisposition to other hernations
Common signs in transtentorial herniation
Contralateral Third nerve palsy (ptosis, mydriasis and occulamotor dysfunction (down and out). Typically PNS will go first in ischemia. There will also be compression of ippsilateral PCA hence honomynous heminopia with macular sparing. Compression of Reticular Activating system and therefore LOC. Also Kurnahan’s Notch and loss of motor function