Head Injury Flashcards
What is a primary insult?
Focal and/or diffuse brain trauma
What is a secondary insult?
Hypotension - low arterial BP
Hypoxia - low blood oxygen
Infection
Haematoma - bleeding in/ around brain
What is used for initial assessment of head injury?
Conscious level assessed using GCS
Scored out of 15
Correlates with severity of head injury
13-15 is mild, 9-12 moderate, 3-8 is severe
What can be the clinical consequences of head injury?
Permanent physical disability, post traumatic epilepsy, intracranial infection, psychiatric illness, chronic subdural haemorrhage, punch drunk dementia and fatal outcome
What does the brainstem and cerebellum form?
Hindbrain
Positioned in posterior cranial fossa
What does the brainstem contain?
Vital centres providing neurological control of respiration and heart function
Describe some scalp injuries
Similar to skin - abrasions, bruises, lacerations and incisions
Common is laceration
Blunt force injury may not be visible on the scalp and hair can obscure the sizable injuries
May only have bleeding/bruising in deeper layers of scalp
Is adult or infant skull more able to cope with distortion?
Infant as their skulls are not fully fused yet
What is a linear skull fracture?
Commonly temporo-parietal from blow or fall onto side or top of head and my continue to skull base - hinge fracture
What is the depressed skull fracture?
Focal impact which may push fragments inwards to damage the meninges, blood vessels and the brain - risk of meningitis and post traumatic fracture
What is a comminuted skull fracture?
Mosaic
Fragmented skull - fracture radiates from point of impact
What is a ring skull fracture?
Fracture line encircling the foramen magnum caused by fall from height, usually landing on feet or head
Leading to skull base and cervical spine being forced together
What is a contre-coup fracture?
Fracturing of orbital planes in anterior fossa caused by a fall onto back of head
Oppisite side to injury
Describe intracranial haemorrhage
Can be extradural, subdural and subarachnoid haemorrhage
Accumulation of blood within rigid skull so increase ICP and compression of brain - LOC
What can happen if ICP increases?
Without innervation then ultimately death will occur by compression of brainstem as herniation of cerebellar tonsils into foramen magnum
Describe an extradural haemorrhage
Bleeding occurring between dura and skull - strips dura off inner surface of skull
Under high pressure as arterial bleeding
What is a common cause of extradural haemorrhage?
Bleeding from middle meningeal artery where it crosses the inner aspect of squamous temporal bone, due to fracture with secondary damage to artery
Describe the lucid interval in EDH
Victim of injury seems okay, without neurological symptoms but can deteriorate quickly after
Describe a subdural haemorrhage
Bleeding underneath the dura and above the arachnoid
Usually caused by bleeding from bridging veins which pass from surface of brain to drain large channels within dura
How does subdural haemorrhage happen?
Rotational or shearing forces cause bridging veins to stretch and tare
Frequently occurs without skull fracture
Small brain at more risk as greater compacity for movement
What can chronic subdural haemorrhage lead to?
Chronic confusion - may be mistaken for dementia
Particularly in the elderly
Describe subarachnoid haemorrhage
Bleeding beneath arachnoid membrane
Common cause is natural disease - rupture of cerebral artery (berry) aneurysm
Also seen in association with cerebral contusions
Describe traumatic basal SAH
Typically result of a forceful impact to upper part of side of neck causing abrupt rotational movement of head leading to rupture of vestibulo-basilar circulation - collapse and rapid death
What are intrinsic brain injury?
Cerebral oedema - brain swelling with raised ICP
Cerebral contusion and laceration - direct mechanical damage to brain substance
What is coup contusion?
When head is struck with heavy blow - found directly under site of impact
Describe diffuse traumatic axonal injury
Not just caused by trauma
Diagnosis can only be made microscopy of brain tissue but may get concomitant damage to small blood vessels within brain
What areas are particularly susceptible to displaying tDAI?
Corpus collosum, para sagittal white matter, posterior internal capsule and dorsolateral aspects of rostral brainstem and cerebral peduncles
