Week 11- Neurological Disorders Flashcards
1
Q
Initial response to bruising
A
- Vasodilation and increased blood flow to the area of injury
- Pressure surrounding the injury site
- Increased intracerebral pressure - decreased blood flow
- Edema develops over a period of hours
2
Q
Normal Functioning Brain
A
- Adjusts blood flow to your metabolic needs
- Based on O2 & CO2 levels in the blood and Cerebrospinal fluid (chemoreceptors
- Decreased CO2 levels will cause- Hypervenilation- cerebral vasoconstriction and cerebral ischemia (hypoxia)
- Increased CO2 levels will cause- Hyperventilation, vasodilation and edema (hypoxia)
3
Q
Intracranial Pressure
A
- The pressure inside of the cranium as a result of: brain tissues, blood, CSF
- Normal pressure 5-15mm hg
- 15 mm hg upper limit of normal
- Volume changes of any one are at the expenses of the others
- Blood supply can’t be compromised (need oxygen and glucose to survive)
- No room for the tissues to expand
4
Q
What are the different brain pressure?
A
- ICP- Intracranial pressure (<15 m hg)
- CPP- Cerebral Perfusion Pressure- pressure needed to maintain blood flow to the brain (70-80mm hg), No less than 60 mm hg (doubles the patients chances of death)
- MAP-Mean Arterial Pressure (70-100mm hg).<60 can be deadly to main organs
5
Q
Cerebral Perfusion Pressure
A
- CPP= MAP - ICP
- ICP <15 mm hg normally
- With brain swelling or bleeding inside the skull- Increased ICP- Decreased CPP- Cerebral vasodilation, increased ICP-
- When ICP= MAP, BLOOD FLOW STOPS
6
Q
ICP- Early Signs
A
- Shifts CSF to the spinal cavity to compensate
- Decreasing cerebral blood flow
- Effective for a short time until you become hypoxic
- Hypoxia triggers arterial vasodilation in the brain in an attempt to improve blood supply- adds fluid volume
- Bc of these responses, ICP is significantly elevated before apparent
7
Q
Other Early Signs and Symptoms of ICP
A
- Severe headache- stretching of the dural layer and walls of the large blood vessels
- Vomiting- projectile without food intake association- pressure stimulating the emetic centre of the medulla
- Papilledema- swelling of the optic discs and ICP
- Seizures
- Signs increase in severity until ICP is controlled
8
Q
Vital Signs of ICP
A
- If ICP continues to build up, there is a sequence of events that occurs in an attempt to supply oxygen to the brain
- Cerebral ischemia- cushing’s reflex in the vasomotor centre of the brain (decreasing pulse, increasing systolic pressure w widening pulse pressure, irregular respirations)
- Attempt to increase the blood supply to the brain
9
Q
Systemic Vasoconstriction
A
- Increases the BP and forces more blood into the brain to relive the ischemia
- Baroreceptors in the carotid arteries to the increase in BP by slowing the HR
- Chemoreceptors respond to low CO2 levels from accelerated systemic circulation by slow the RR
10
Q
Then…
A
- Improved cerebral circulation relieves the ischemia and the vasoconstriction relaxes…
- Rising ICP causes ischemia to recur and the cycle is repeated
11
Q
Results of Increased ICP
A
- The brain responds to ischemia by one mechanism… but the feedback control for increased BP uses other mechanisms to protect the rest of the body
- The 2 mechanisms are in conflict of interest
- Eventually severe ischemia and neuronal death prevent any circulatory control and BP drops
- Respiratory Centre control is destroyed resulting in abnormal resp patterns
- Death is inevitable of the pressure is not released
12
Q
Cushing’s Response
A
- HTN, Bradycardia, Irregular Respirations
- As the pressure arises- the body’s reflex mechanism cant keep up- Uncompensated
- Pressure increase to a critical point where there is no perfusion- deterioration and death occurs
13
Q
What is Cerebral Herniation Syndrome?
A
- Brain swelling eventually forces tissues downward through the foramen magnum
- Obstruction of blood flow
- Pressure on the brain stem- vital centres that causes death
14
Q
What are the S&S of Cerebral Herniation Syndrome?
A
- Decreased LOC
- Coma
- Dilation of pupil on same side
- Paralysis on the opposite side of the body
- Decerebrate posturing (extension)
- Increased BP
- Bradycardia
15
Q
What is the treatment for Cerebral Herniation Syndrome?
A
- Hyperventilation to reduce swelling 1:3 secs
- Hyperventilation causes vasoconstriction, which causes blood to go to the brain, reducing blood flow
16
Q
Scalp Wounds
A
- Vascular and bleed well
- Vasospasm is inhibited- prolonged and significant bleeding
- Without skull injuries- direct pressure is indicated
17
Q
What are the different Skull Injuries?
A
- Linear nondisplaced
- Depressed
- Compound
- Suspected skull injuries with large contusions
- Leave protruding objects in place
- Transport immediately
18
Q
What are the different brain injuries?
A
- Concussion
- Cerebral contusion
- Diffuse axonal injury
- Anoxic brain injuries
- Closed head injuries- countercoup injuries
19
Q
Concussion
A
- History of trauma- Mild blows to the head causing sudden excessive movement of the brain- LOC
- No structural damage to the brain- reversible interference of brain function
20
Q
Brief disruption of neural function:
A
- Period of unconscious or confusion
- Return to normal
- Short term memory loss (amnesia)
21
Q
Concussion Sign and Symptoms
A
- Headache, dizziness, tinnitus (ringing sound), nausea
22
Q
What is a cerebral contusion?
A
- Bruised brain tissue with ruptured small blood vessels (usually from a blow to the head)
- Brain swelling may be rapid and severe
23
Q
What are the sign and symptoms of cerebral contusion?
A
(depends on force):
- prolonged unconscious
- Altered LOC
- Personality changes
- Profound confusion
- Persistent amnesia
- Abnormal behaviour
- Focal neurological signs
24
Q
What are Basilar Fractures?
A
- Occur at the base of the skull
- Often accompanied by leaking CSF through the nose and ears
- Often occur when the forehead hits a car windshield with considerable force
- Diagnosed with dark discolouration around the eyes and behind the ears
25
Q
What is depressed skull fracture
A
- Displacement of a piece of bone below the level of the skull (this compresses brain tissue)
- Blood supply to that area is impaired
- ICP often high
26
Q
What is a Diffuse Axonal Injury?
A
- Most common head injury, Severe blunt head trauma
- Diffuse injury to the brain, stretching, shearing, tearing of nerve fibres, from brain moving back and forth
- Generalized edema
- Subarachnoid bleeding with irritation to the surrounding tissues
27
Q
Signs and Symptoms of Diffuse Axonal Injury?
A
- Seizure activity, Coma, Vomiting
- Herniation syndrome possible
- Often results in permanent vegetative state
28
Q
What is anoxic brain injur?
A
- Lack of oxygen to the cells (cardiac arrest, airway obstruction, drowning)
- Spasm of the cerebral arteries- perfusion is affected to the cortex
- After 4-6 mins to anoxia- irreversible
- Restoring blood pressure and oxygen will not restore perfusion
29
Q
What are closed head injuries?
A
- Occurs when the skull is not fractured in the injury
- Brain tissue is injured from the force exerted against the skull
- Blood vessels may rupture due to force
- Countercoup injury
30
Q
What is countercoup injury?
A
- Rebound of the skull causes the brain to impact the opposite side of the skull
31
Q
What is a spinal cord injury?
A
- Results from fracture of dislocation of vertebrae which stretches, compresses or tears the spinal cord
- May be temporary or permanent
- Nerves in the spinal cord don’t regenerate
- Complete transection results in irreversible loss of function below the level of injury, partial may allow for some recovery
- Bruising is reversible- temporarily impairs nerve function
32
Q
What is the result of a spinal cord injury?
A
- Any compression of the cord must be relieved quickly to maintain blood supply
- As with any trauma, bleeding and inflammation develop creating additional pressure and interferes blood flow
- Initially injury may appear widespread- as edema subsides, may see partial recovery of function
33
Q
How many stages are there to a spinal cord injury?
A
- 2 stages: 1) early stage 2) recovery
34
Q
S&S- Early Stage
A
- During initial period of spinal shock, all neurologic activity ceases at/ below the level of injury
- No reflexes will be present including muscle, sensory and autonomic (bowels, bladder)
- May persists for days or weeks
- At cervical level, this includes loss of control of BP, diaphoresis, body temp, and bowel and bladder emptying
35
Q
S&S- Recovery
A
- Recovery is indicated by gradual return of reflex activity
- Check dermatome response to assess
- May have loss of pain/ sensation
- Permanent- quadriplegia/ paraplegia
36
Q
Intracranial Hemorrhage
A
Types are classified by their location:
- Extradural or Epidural Hematoma- between the skull and the Dura
- Subdural Hematoma- between the Dura and the Arachnoid
- SubArachnoid- between Arachnoid and Pia
- Intracerebral Hematoma- directly into the brain tissues
37
Q
Epidural Hematoma
A
- Bleeding between the Dura and the skull
- Usually from a tear in the middle meningeal artery in the temporal regions
- Results from linear fracture- arterial bleed- quick onset and deadly outcome
