Head Injury And Coma Flashcards
What is a head injury?
Any trauma to the scalp, skull, or brain.
What is an Acquired Brain Injury?
Damage to the brain, which occurs after birth and is not related to a congenital or a degenerative disease.
What does a head injury not always equal?
A Brain injury
What is a traumatic brain injury?
A non-degenerative, non-congenital insult to the brain from an external mechanical force
What could a traumatic brain injury possibly lead to?
temporary or permanent impairment of cognitive, physical and psychosocial functions with an associated diminished or altered state of consciousness.
What percentage of HI are males?
70%
What percentage of people with TBI die?
50%
What percentage of HI happens to children under 15 y/o?
33-50%
What percentage of 75 y/os have a HI?
40%
What do over half HI involve?
Alcohol
What political decisions were made to prevent HI?
- Seatbelt laws 1983
• Drink driving testing 1983
* Helmets on motorbikes
• Helmets on bicycles
What is the most common type of Head Injury?
Closed Head Injury
How does a closed Head Injury occur?
Result of rapid acceleration or deceleration, head is rocked back and forth or rotated, and brain must follow movement of skull
How does an open or penetrating head wound happen?
Skull is opened and brain exposed and damaged e.g., bullet wound or collision with a sharp object
How does a Crush Injury occur?
Head caught between two hard objects e.g., wheel of car and road
Often damages base of skull and nerves of brain stem rather than brain itself
What is a primary injury?
• Damage occurring at the time of impact
e.g. skull fracture, bleeding, blood clots, shearing
What is Secondary Damage?
Damage that evolves over time after the trauma
• e.g. cerebral oedema, seizures, haematoma or increased intracranial pressure (ICP)
What is the process of assessment?
ATLS
GCS
Extent
What are the three steps of Pre- Hospital Management?
Resuscitation
Primary Survey
Secondary Survey
What does ATLS stand for?
Advanced Trauma Life Support
What are the stages for ATLS (primary survey)
Airway maintenance and Cervical Spine Protection
Breathing and Ventilation
Circulation and haemorrhage control
Disability – neurological status: GCS, pupils
Exposure – undress the patient
What are the stages of secondary survey
Other injuries
• History
• Age
• A–Allergies
• M – Medications currently used (e.g. warfarin)
• P – Past illness/medical history/pregnancy
• L–Lastmeal
• E – Event/emergency related to the injury
What is GCS?
Glasgow Coma Scale
What is the score rating for an eye opening response?
Spontaneously 4
To speech 3
To pain 2
No response 1
What is the scoring for best verbal response?
Oriented to time, place and person 5 Confused 4 Inappropriate words 3 Incomprehensible sounded 2 No response 1
What os the scoring for best motor response?
Obeys command 6 Moves to localised pain 5 Flexion withdrawals from pain 4 Abnormal flexion 3 Abnormal extension 2 No response
What are the breakdowns in scoring in the GCS?
Minimal 5 Mild 14 or 15 Moderate 9-13 Severe 5-8 Critical 3-4
What is the first assessment that will happen at the hospital?
A ct scan
Why is a CT scan gold standard in suspected brain injury?
• Easy to perform
• Quick
• Can detect the presence of blood and fractures, which are the most crucial lesions to identify.
What should a CT scan involve in patients who are GCS<15?
The cervical spine
What might a CT scan find?
Brain injury Focal injury - diffuse injury Traumatic haemoatoma - contusion - diffuse axonal injury External haematoma Subdural ^ Interacerebral ^
What is a focal injury?
An area of localized injury that may cause pressure within the brain.
What are focal injuries also known as?
Mass lesions
What are the most common types of mass lesions?
Heamatomas and contusions
What is a haematoma?
a blood clot within the brain or on its surface. • Can may occur anywhere within the brain.
What is a cerebral contusion?
Bruising of brain tissue
What is Extradural Haematoma?
Collection of blood in ‘potential’ space between skull and outer protective lining that covers the brain (dura mater)
What is Subdural Haematoma?
Collection of blood in space between dura mater and arachnoid mater
What causes Sub-arachnoid haemorrhage?
Not usually caused by HI - commonly caused by arteriovenous malformation (AVMs).
• Although: Sometimes damage to the brain can result in aneurysms which can lead to haemorrhage
What is Intracerebral Haematoma?
• Blood vessel within brain bursts, allowing blood to leak inside brain
• Sudden increase in pressure can cause damage to surrounding brain cells
What is contusion comparable to?
bruises in other parts of the body - areas of injured or swollen brain mixed with blood that has leaked out of arteries, veins, or capillaries.
What is contusion caused by?
small blood vessel leaks, usually most evident on scans after 24 hours
When is contusion most commonly seen?
base of the front parts of the brain, but may occur anywhere.
• Coup injury occurs under the site of impact
• Contre-coup injury occurs on the side opposite the area that was hit.
Where does coup injury occur?
Under site of impact
Where does Contre-coup injury occur?
The side opposite the area that was hit
What is diffuse Axonal injury?
Microscopic changes that cannot be seen on CT scans and that are scattered throughout the brain
What can initial scans show with diffuse Axonal Injury?
Normal/subtle lesions
When is Diffuse Axonal Injury normally diagnosed?
on delayed or repeat scans - may show new lesions/hyperdense foci
What is one of the most common types of brain injury and also the most devastating?
Diffuse Axonal
What does Diffuse Axonal injury result from?
Results from brain moving back and forth in skull as a result of acceleration or deceleration
What does Diffuse Axonal Injury refer to?
impaired function and gradual loss of some axons.
What happens if enough axons are injured in Diffuse Axonal Injury?
then the ability of nerve cells to communicate with each other and to integrate their function may be lost or greatly impaired, possibly leaving severe disabilities.
What does Diffuse Axonal Injury also cause?
brain cells to die, which causes swelling in the brain
What should we assume with head injury?
C-spine injury until proven otherwise
With cervical spine injuries what may the patient need?
• Person may require spinal nursing until safety can be established
• May need cervical spine stabilised by a collar
• May require surgical management
When is no treatment required for in regards to skull and facial fractures?
most linear skull fractures, simple breaks or “cracks” in the skull (conservative management).
When are fractures to the skull problematic and what may they cause?
Fractures of the base of the skull are problematic
• May cause injury to nerves, arteries, or other structures.
What can happen if a fracture extends into the sinuses?
there may be leakage of CSF from the nose or ears.
• Most leaks will stop spontaneously.
• Sometimes necessary to insert a lumbar drain
What are depressed skull fractures?
those in which part of the bone presses on or into the brain.
What may depressed skull fractures requires?
May require surgical treatment.
• ORIF - open reduction internal fixation – a surgical procedure to fix a severe bone fracture (#), or
break
What does skull and facial fractures depend on?
Damage caused depends upon the region of the brain in which they are located and also upon the possible coexistence of any associated diffuse brain injury.
Can skull and facial fractures be repaired?
need to wait for swelling to reduce, patient to stabilise, etc.
Why do people go directly from the emergency room to the operating room?
Often to remove a large hematoma or contusion that is significantly compressing the brain or raising the pressure within the skull.
After surgery, where is observation and monitoring held?
In the intensive care unit
What may enlarge over the first hours or days after head injury?
Contusions or haematomas
When may haematomas be discovered?
when a neurological exam worsens or when ICP increases.
What is one of the main goals of ICU monitoring/management?
To prevent secondary insults
What are some secondary insults?
• Hypoxia
• Hypotension
• Mass lesions
• Controlling ICP (pre- and post surgery) to prevent herniation
What is hydrocephalus?
build-up of fluid inside the skull that leads to brain swelling
What does hydrocephalus do?
puts pressure on the brain pushing the brain up against the
skull and damaging brain tissue.
How can hydrocephalus occur?
• The flow of CSF is blocked.
• The fluid isn’t properly absorbed into the blood.
• Overproduction of the fluid
How can you treat hydrocephalus?
- Surgically remove the blockage
* Drain the fluid
What can high interracial pressure be caused by?
• A rise in pressure of the CSF, or
• A rise in pressure in the brain itself caused by a mass, haemorrhage or fluid around the brain, or cerebral oedema.
What is the Monro-Kellie Hypothesis in regards to ICP?
• Cranial compartment is incompressible
• Cranium (blood, brain tissue, CSF) is a fixed volume
• Any increase in volume of one of the constituents must be compensated by a decrease in volume of another
What can ICP cause?
Midline shift
What is the medical management of raised ICP?
▪Sedation (proprofol, benzodiazepines, barbituates) ▪Maximise Venous Drainage of Brain
▪CO2 control
▪Osmotic Diuretics (Mannitol, Frusemide)
▪CSF (cerebrospinal fluid) release
▪If need be: decompressive craniectomy
What is External Ventricular Drain?
A treatment that allows the temporary drainage of CSF from the ventricles of the brain, relieving raised intracranial pressure
When in an external ventricular drain inserted?
Inserted in theatre under a general anaesthetic.
What are indications for EVD?
- to relieve raised intracranial pressure (RICP)
• to divert infected CSF
• to divert bloodstained CSF following neurosurgery/haemorrhage - to divert the flow of CSF
What are burr holes?
Small holes drilled in the skull
and a tube is inserted to drain
the haematoma and relieve pressure
What is a Craniotomy?
An operation where a disc of bone is removed from the skull to
allow access to the underlying brain.
• After the surgery the bone is replaced
What is a craniectomy?
If the brain is very swollen the bone isn’t replaced until the swelling decreases, which may take several weeks.
What are the signs of neurological deterioration that would prompt re-appraisal?
• The development of agitation or abnormal behaviour
• A sustained decrease in conscious level of at least one point in the motor or verbal response or two points in the eye opening response of the GCS score
• The development of severe or increasing headache or persisting vomiting
• New or evolving neurological symptoms or signs, such as pupil inequality or asymmetry of limb or facial movement.
What are examples of hidden disabilities from TBI?
changes to personality, thinking and memory
• e.g. frontal lobe damage results in behavioural problems, such as loss of insight and self-restraint
What are the consequences of TBI?
Physical, sensory, cognitive, behavioural issues
• Seizures, depression, mood changes, personality
changes, aggression
• Impairs ability to live independently
• Affects relationships, jobs, previous lifestyle
Are communication problems after brain injury common?
Yes
What often has more significance than the physical changes of HI?
The cognitive and communicative impairments
What do people with aphasia do?
‘communicate better than they talk’
What do people with TBI do?
talk better than they communicate’.
What can cause comas?
- Head injury
• Alcohol / drugs / medication - Other neurological disease
- Metabolic disturbance
Where does coma derive from?
Greek ‘koma’ meaning deep sleep
What is the GCS scale score for a coma?
8 or less
What are the signs of coma?
Inability to eye open, verbalise or obey
• No sleep / wake cycle
• No voluntary movements
What two systems regulate and control consciousness?
Cerebral cortex
Reticular Activating System
What is the cerebral cortex composed of?
Grey and white matter
What is the function of the cerebral cortex?
• Perception
• Sensation (via thalamus) • Movement
• Vision
• Thought
What is the Reticular Activating System composed of?
Brainstem structure
What does the Reticular Activating System do?
Activates reticular formation (a diffuse network of nerve pathways in the brainstem connecting the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness.)
• Controls arousal, sleep and wakening
What are the functions of the brain stem?
• All autonomic functions
• Relays nerve signals between the brain and spinal cord
What are the three parts of the brainstem?
Pons
Midbrain
Medulla
What does the pons contain?
Contains nuclei that relay signals from the forebrain to the cerebellum, along with nuclei that deal primarily with sleep, respiration, swallowing, bladder control, hearing, equilibrium, taste, eye movement, facial expressions, facial sensation, and posture.
What is the midbrain associated with?
Associated with vision, hearing, motor control, sleep/wake, alertness, and
temperature regulation
What does the medulla contain?
The lower half of the brainstem that contains the cardiac, respiratory, vomiting, and vasomotor centres and regulate autonomic, involuntary functions such as breathing, heart rate, and blood pressure
What is the prognosis of coma under 24hr?
10% chance of recovery
• Absent brainstem reflexes for 24 hours (without sedation) - very little chance of recovery
What is the prognosis of coma after 7 days?
• 3% chance of recovery
• High incidence of death/persistent vegetative state (PVS)
What is Brain Stem Death?
There is no longer any brain stem functions and permanently loss of the potential for consciousness and the capacity to breathe.
When would you diagnose Brain Stem Death?
• Unconscious and no response to outside stimulation
• Heartbeat and breathing can only be maintained using a ventilator
• Clear evidence that serious brain damage has occurred and it can’t be cured
What must be ruled out when diagnosing Brain Stem Death?
an overdose of illegal drugs, tranquillisers, poisons or other chemical agents
• an abnormally low body temperature (hypothermia)
• severe under-activity of the thyroid gland
What must happen when confirming Brain Death
• Diagnosis must be made by two senior doctors.
• Both doctors have to agree on results for a confirmed diagnosis
• Tests are carried out twice to minimise any chance of error.
What happens when someone is in a vegetative state?
The basic brain functions of breathing spontaneously, maintaining the heartbeat and blood pressure, digesting food and producing urine all continue.
• May still be a sleep/wake cycle and spontaneous eye opening, there is no real evidence of consciousness in any meaningful sense and
no response to what is going on in the environment.
How long does a persistent vegetative state last?
4 weeks
How long does a permanent vegetative state last?
1 year
How does a minimally conscious state differ from PVS?
Distinct from PVS, because although it is still a state of profoundly altered consciousness, there is minimal but definite evidence of some limited self-awareness or awareness of the su
What are the signs of minimally conscious state?
Deliberate movements related to cognition
• Track visually
• “inconsistent, erratic responsiveness”
How does locked in syndrome occur?
Damage to the ventral pons
What can locked in syndrome be caused by?
• Stroke
• Head injury
• MS
• Overdose / Sodium problems
What does locked in syndrome result in?
total paralysis with intact consciousness
What is LIS?
Intact eye movements
What is Total LIS?
Loss of eye movement
