Head Trauma Flashcards
What is a closed head injury
Associated with blunt trauma = skull fractures, focal brain injuries, diffuse brain injuries and ICP
What is an open head injury
Dura mater and cranial contents are penetrated, brain tissue is open to environment
Main problem with scalp lacerations
Range from minor to very serious
Hypovolaemia
What are the potential complications for a skull fracture
Intracranial haemorrhage, cerebral damage and cranial nerve damage
What is a linear non displaced skull fracture
- bone has broken but not moved out of alinement
- accounts for 80% of all fractures
- 50% occur in temporal-parietal region of skull
- if it is open there is a risk of infection
- potential injury to middle meningeal artery (extramural bleeding)
What is a depressed skull fracture and what causes it
- Where part of the skull has sunken in
- High energy direct trauma to small surface area of head with a blunt object
What regions are must susceptible to depressed skull fracture and what are its complications
- frontal and parietal area of skull as the bones are thin
- Bony fragments may be driven into brain
What is a basilar skull fracture and how is it caused
- A basilar skull fracture is a break of a bone in the base of the skull. Generally extension of linear fracture to base of skull
- high energy trauma with impact to head.
How would you spot a basilar skull fracture
- CSF fluid from ears
- Periorbital bruising around eyes
- Bruising behind ears over the mastoid process (known as a battle sign)
- Facial paralysis
- Hearing loss
What is an open skull fracture
- Fracture to the skull where there is a break in the skin and an open wound
- Brian tissue may be exposed to environment
Complications of an open skull fracture
- High mortality rate
- Associated trauma to multiple body systems
4 causes of traumatic brain injury
- primary (direct)
- secondary (indirect)
- coup-contrecoup injury
- swelling
What is a coup/contrecoup injury
Coup is direct injury of brain colliding with side of skull
Contrecoup is the other side of the brain colliding with the opposite side of skull as it bounces back
What leads to an increase of intracranial pressure and what further problems does it lead to
- Accumulations of blood within the skull or swelling of the brain
- Squeezes the brain against the bony prominences within the cranium
What does a normal MAP and ICP range from
MAP - 85-95mmhg
ICP - Below 15mmhg.
What is CPP and how is it calculated
Cerebral Perfusion Pressure
CPP = MAP - ICP
The difference between mean arterial pressure and intracranial pressure
How is CPP important, what does it measure
Pressure gradient driving cerebral flood flow (CBF) which is important for oxygen and metabolite delivery.
Homeostatic measures are in place in normal brain to auto regulate its blood flow so blood flow is always provided regardless of blood pressure by altering resistance of cerebral blood vessels
Homeostatic measures often lost in head trauma, cerebral vascular resistance usually increased and brain becomes vulnerable to changes in blood pressure. Areas of brain can become ischaemic and rely on cerebral perfusion pressure to get adequate blood flow.
What is an epidural hematomas and it’s symptoms
Above the dura mater
Collection of blood between skull and dura mater, the outermost protective membrane covering your brain
Usually an artery gets torn by a skull fracture
Symptoms - LOC, severe headache
What is a subdural hematoma
Below the dura mater, split into 3 categories
Acute - similar to epidural but occurs more slowly as it is below dura. Can be either venous or arterial
Subacute - always venous and not arterial
Chronic - associated with elderly or alcoholic
What is an uncal herniation
Rising intracranial pressure causes portions of the brain to move from one intracranial compartment to another. Compresses the 3rd cranial nerve ( oculomotor). Causes one sided pupil dilation. Life threatening emergency.
What are3 types of hematomas
Epidural hematoma
Subdural hematoma (3 categories)
Uncal herniation
What is normal intracranial pressure
15mmHg
What is cerebral herniation
When brain tissues move from one part of the brain to another adjacent part of the brain. Usually causes when another condition causes swelling or pressure inside the brain.
Signs of cerebral herniation
Unresponsive patient with both
- unequal pupils or bilaterally fixed and dilated pupils
- decerebrate posturing or no motor response to painful stimuli
What are chemoreceptors
Sensors located in the central and peripheral nervous system
Detect changes in oxygen, carbon dioxide and ph levels.
Change is detected, sends message to brain to engage bodies repossess to restore homeostasis
Eg if increased levels of co2 were detected, bodies response would be to increased RR to try remove co2.
What are barrow receptors
Are mechanoreceptors located in the carotid sinus and in the aortic arch.
Function - sense pressure changes by responding to change in the tension of the arterial wall. The baroreflex mechanism is a fast response to changes in blood pressure.
What is the. 90,90,9 rule
Drop of Sa02 less than 90 doubles the chance of death
A drop of systolic BP to less than 90 doubles the chance of death
Drop of patients GCS to less than 9 or a drop of two or more points doubles the chance of death
What are two types of head injury
Open - dura mater and cranial contents are penetrated, and brain tissue is open to environment
Closed - usually associated with blunt trauma, skull fractures, focal brain injuries or diffuse brain injuries, and ICP
Potential complications of a skull fracture
Intracranial haemorrhage, cerebral damage, cranial nerve damage
What regions if the skull is most susceptible to depressed skull fractures
And complicated of depressed skull fracture
Frontal and partial as bones are relatively thin
Bony fragments may be driven into the brain
Accumulations of blood within the skull or swelling of the brain can lead to an increase of pressure within the cranial vault. What further problems does this lead to?
Squeezes the brain against bony prominences within the cranium
Can lead to coning - the brain is forced through a small opening at the base of the skull where it meets the spinal cord, causing respiratory and cardiovascular difficulty
What is increased ICP
Accumulation of blood within the skull or swelling of the brain leading to increased of pressure within cranial vault
What is cerebral spinal fluid and what is its function
Found in subarachnoid space
Cushion brain within the skull and serve as shock absorber for central nervous system
Helps with circulating nutrients and chemicals filtered from blood and removes waste products from brain
What is the medulla oblongata and function
Lowest part of brain stem, where brain stem connects the brain to spinal cord
Transmit signals between spinal cord and higher parts of brain and controlling automatic activities such as heart beat and respiration.
What is intracranial haemorrhage and symptoms of it
Bleeding between brain tissue and skull or within brain tissue itself. Can be life threatening
Headache, nausea, vomiting, tingling, weakness, numbness, paralysis of face arm or leg
What is cerebral damage
Distruption to normal function of the brain that is caused by a blow, bump or jolt to the head, the head suddenly or violently hitting an object or when an object pierces skull and enters brain tissue
What is cranial nerve damage
Damage to the cranial nerves such as the motor nerve, causing cranial nerve palsy or a sensory nerve causing pain or diminished sensation.
Cranial nerve disorder may cause pain, vertigo, hearing loss, weakness or paralysis
What would you expect to see in mild elevation of ICP
- increased BP
- decreased pulse rate
- patient may initially attempt to localise and remove painful stimuli, followed by withdrawal and extension
- cheyne-stokes respiration
- effects are reversible with prompt treatment
What would you expect to see with moderate elevation of ICP
-Widened pulse pressure and bradycardia
- pupils sluggish and non reactive
- central neurogenic hyperventilation
- decerebrate posturing
- survival possible but not without neurological impairment
What would you expect to see with marked elevation
- fixed and dilated blown pupil
- ataxic respirations
- flaccid paralysis
- irregular pulse rate - changes in QRS complex, st segment or t wave
- fluctuating blood pressure or hypotension
- most patients do not survive high levels of ICP
What are Cheyne-stokes respiration’s
Condition causing abnormal breathing during sleep. Often includes periods of apnoeas or stopped breathing
What are kussmaul respiration’s
Characterised by deep rapid breathing pattern. Typically an indication that the body or organs have became too acidic
What are ataxic/bigot respiration’s
Abnormal pattern of breathing characterised by groups of regular deep inspirations followed by regular or irregular periods of apnoea
What happens when ICP is increased, what is the normal and critical threshold for CPP, and how does body respond to decrease of CPP
- ICP increased, decreases cerebral perfusion pressure and cerebral blood flow
- normal range of CPP 70-80mmHg, critical threshold of 60mmHg
- body responds to decrease of CPP by increasing MAP, causing ICP to increase
What is a diffuse brain injury (cerebral contusion) and S/S
Caused by rapid acceleration /deceleration force
Results in transient dysfunction of the cerebral cortex
Confusion and disorientation for several minutes, possible LOC
What is the cerebral cortex
Thin layer of tissue often In brain often referred to as grey mater. Is grey because there is a lack of insulation of these nerves that make other nerves appear white. Covers the cerebrum.
What is retrograde and anterograde amnesia
Retrograde - loss of memories that occurred before trauma injury
Anterograde amnesia - prevents new memories being formed after a traumatic injury or brain injury
What is diffuse brain injury (axonal injury)
Involves stretching, shearing, or tearing of nerve fibres with subsequent axonal damage
Often results from high speed rapid acceleration/deceleration forces, causing brain to move within the skull
Axons are part of the nerve cells that allow neutrons to send messages between them are disrupted
Injury to the axon can cause brain cells to die - leads to swelling of the brain
What is a focal brain injury (cerebral contusion)
- Brain tissue is bruised or damaged in local area
- Greater neurological deficits
- Acceleration/deceleration forces and direct blunt head trauma
- frontal lobe is most commonly affected
- the reaction of the injured tissue will be to swell, leading to increased ICP
Describe the 6 parts of GCS motor response
Obeys commands Moves to localised pain Flexion withdrawal from pain Abnormal flexion (decorticate) Abnormal extension (decerebrate) No response
What is Cushings triad
Signs that are indicative of increased intracranial pressure, increased pressure in the brain
- bradycardia
- irregular respiration’s
- widened pulse pressure (large difference between systolic and diastolic pressure)
Symptoms of increased ICP
Weakness, lethargy, headaches, vomiting, blurred vision, changes in behaviour
