Head Injury Lecture Flashcards
What is Primary brain injury?
From the time of injury
What is Secondary brain injury
Due to consequences of injury, partly preventable
What is the pathophysiology of brain injury?
Release of excitatory amino acids (glutamate, aspartate)
Binding to receptors (eg NMDA)
Release of intracellular calcium, activation of phospholipases, breakdown of cell membrane, cell swelling, activation of apoptosis.
How does Primary brain injury lead to Secondary brain injury?
Loss of blood-brain-barrier, leucocyte infiltration - inflammation
Loss of cerebral autoregulation of blood pressure - ischaemia
Loss of cerebral autoregulation of blood flow – metabolic de-coupling – even more ischaemia causing further brain oedema
What is and what makes up CPP?
Cerebral perfusion pressure = mean arterial pressure – intracranial pressure
CPP = MAP - ICP
After a head injury what CPP should you aim for?
> 60mmHg
ie MAP > 80mmHg and keeping ICP
What is normal adult ICP?
9-11mmHg
What is an open head injury?
Open - penetrating (missile)
What is a closed head injury?
Acceleration/deceleration/rotation (non-missile)
What does “raccoon” or “panda eyes” mean?
Skull base fracture - anterior cranial fossa
What does the Battle sign over mastoid area
Middle cranial fossa - skull base fracture
Focal signs (2)
Lateralising motor signs
Pupillary responses to light (3rd nerve palsy)
What kills patients with head injury (3)
Hypoxia
Hypotension
Raised ICP
How long before there is irreversible neuronal damage with circulatory arrest
5mins
When should you request a CT head scan in trauma? (4)
Any patient with..
a skull fracture
not orientated (GCS
Types of traumatic intracranial bleeding from outside to inside(6)
From outside to inside Extradural haematoma Subdural haematoma Traumatic subarachnoid haemorrhage Intracerebral contusion Intracerebral haematoma Intraventricular haemorrhage
What are the considerations in Invasive Care Management (5)
Sedation Ventilation BP Glucose Temp.
How does sedation help with intensive care of head injury? (3)
Reduces cerebral metabolic rate
Reduces cerebral blood flow
Reduces ICP
How does ventilation help with intensive care of head injury? (2)
Maintains adequate oxygenation pO2 13-15kPa
Maintain normocapnia pCO2 4-4.5kPa
What should you do to BP in an intensive care management of head injury
Maintain CPP of >60mmHg
Cerebral Protection following injury (6)
CSF Drainage - reduces ICP
Mannitol - improves micro-perfusion
Hypertonic saline - may be better than mannitol
Hyperventilation - temporary effect 2-4hrs
Hypothermia
Decompressive craniectomy
Late effects of head injury (3)
Epilepsy
CSF leak
Cognitive Problems
Where can CSF leak?
Into the nose
Into the middle ear
Cognitive problems after head injury
Post concussion syndrome
- Poor conc., headache, poor memory, lethargy
