Nervous System Alterations Flashcards
Exam 3
Central Nervous System:
What is it comprised of?
The CNS comprises the brain and spinal cord.
Central Nervous System
Skull (cranium): What does it do?
Protects brain from traumatic injury
Central Nervous System
Meninges: What is it?
Three layers cover brain and spinal cord.
Central Nervous System
Cerebrospinal fluid: What does it do?
Fluid shock absorber
Central Nervous System
Cerebral vasculature: What is it made up of?
Internal carotids and vertebral arteries
Peripheral Nervous System
What is it comprised of?
The PNS consists of 12 pairs of cranial nerves and 31 pairs of spinal nerves.
Peripheral Nervous System
Cranial Nerves: What do they do?
Supply motor and sensory fibers to the head, neck, upper back, and viscera to the level of the waist
Peripheral Nervous System
Spinal Nerves: What is it attached to?
Attached to spinal cord in pairs
Peripheral Nervous System
Spinal Nerves: Dorsal root?
Dorsal root houses nerve cell bodies of sensory neurons.
Peripheral Nervous System
Spinal Nerves: Ventral root
Ventral root houses motor axons.
Cells of the Nervous System
Include:
Neurons
Neuroglia
Cells of the Nervous System
Include: Neuron
Basic functional unit
Cells of the Nervous System
Neuroglia (glia cells)-
Neuroglia (glia cells)-constitute the supportive tissue associated with the neurons
Cells of the Nervous System
Four types of neuroglia:
Microglia
Astrocytes
Ependymal
Oligodendroglia
Cells of the Nervous System
Four types of neuroglia: Microglia
Phagocytic cells
Cells of the Nervous System
Four types of neuroglia: Astrocytes
Supportive cells making up the blood-brain barrier
Cells of the Nervous System
Four types of neuroglia: Ependymal
Line ventricles,
produce and circulate CSF
Cells of the Nervous System
Four types of neuroglia: Oligodendroglia
Found in white matter, produce myelin
Neurological Assessment
Physical Examination includes:
Mental status
Glasgow Coma Scale
Mini Mental State Examination
Neurological Assessment
Physical Examination includes: Mental Status
What is included?
Level of consciousness and arousal
Orientation to the environment
Thought content
Neurological Assessment
Physical Examination includes: Glasgow Coma Scale - When is this done?
if brain injury is suspected
Physical Examination:
Mini Mental State Examination
Cognitive assessment, monitors disease progression in dementia and other neurological disease states
Glasgow Coma Scale:
What is the tool for? What do scores range from?
The Glasgow Coma Scale is a tool for assessing a patient’s response to stimuli.
Scores range from 3 (deep coma) to 15 (normal)
Testing cranial nerves
CN I: What is it?
CN I (olfactory) pertains to smell
Testing cranial nerves
CN II: What is it?
CN II (optic) pertains to vision
Testing cranial nerves
CN III, CN IV, and CN VI: What are they?
CN III, CN IV, and CN VI are assessed together because they pertain to the innervate extraocular muscles involved in eye movement.
Pupil size/reactivity:
What cranial nerve is assessed?
(CNII)
Pupil size/reactivity:
What are the three ways pupils are?
Pinpoint pupils
Dilated pupils
Aniscoria
Pupil size/reactivity:
Pinpoint pupils: What would this indicate?
Opiates
Medications for glaucoma
Nearly dead
Pupil size/reactivity:
Dilated pupils: What would this indicate?
Fear/panic/anxiety
Seizures
Cocaine,
Pupil size/reactivity:
Aniscoria: What is this? What would this indicate?
Unequal pupils
Can be normal, but can indicate neural dysfunction
Types of Abnormal Pupils include:
- Small or Pinpoint Pupils
- Large pupils
- Midposition Fixed Pupils
- One Large Pupil (Aniscoria)
Vital Signs:
Respirations: What does shallow indicate?
problem with maintaining patent airway/need suctioning
Vital Signs:
Respirations:
Snoring or stridor
Obstruction
Vital Signs:
Respirations:
Inability to maintain airway means?
Inability to maintain airway = cervical spinal cord lesion, neurodegenerative disease
Vital Signs:
Respirations:
Cheyne Stokes: What does this indicate?
Cheyne stokes = increased ICP
Vital Signs:
Respirations:
Hypoventilation: What does this indicate?
Hypoventilation = increased CO2, reduced O2- edema
Vital Signs:
Respirations:
Hyperventilation: What does this indicate?
Hyperventilation = respiratory alkalosis, decreased CO2-vasoconstriction- decreased cerebral blood flow
Vital Signs:
Temperature: What is it controlled by?
Control – hypothalamus
Vital Signs:
Temperature: Loss of control leads to?
Loss of control = Hyperthermia
Vital Signs:
Temperature: Hypothermia indicates?
Hypothermia = pituitary damage, spinal cord injury (SCI)
Vital Signs:
HR: What indicates increased ICP?
Increased ICP = tachycardia, altered ECG such ventricular or atrial dysrhythmias
Vital Signs:
HR: As ICP continues to rise, what happens?
As ICP continues to rise, bradycardia results indicating impending herniation
Vital Signs:
Blood pressure: WHat is most common?
Hypertension most common… as BP increases, CBF increases, and ICP increases
What is at the root of many neurological problems?
Increased intracranial pressure is at the root of many neurological problems.
As such, any patient who has sustained an injury to the central nervous system is at risk for ?
for increased intracranial pressure.
Signs of Increased Intracranial Pressure
What should be established?
Establish baseline neurologic assessment
Signs of Increased Intracranial Pressure
How does the person behave?
Decreased LOC, restlessness, confusion, combativeness
Lethargy, coma
Signs of Increased Intracranial Pressure
How are pupils?
Sluggish pupils to fixed and dilated, unequal pupils
Signs of Increased Intracranial Pressure
What are there changes in? What is a late finding?
Changes in motor function
Changes in VS are a late finding.
Signs of Increased Intracranial Pressure
What else occurs (triad)
Cushing triad:
increased systolic pressure,
bradycardia,
irregular respirations
Increased Intracranial Pressure:
Diagnostic Procedures include:
Computed tomography (CT) of the head
Magnetic resonance imaging (MRI)
Cerebral blood flow with transcranial
Doppler
Evoked potentials
EEG
Angiography
Intracranial Dynamics
How is the skull?
Skull is a rigid box.
Intracranial Dynamics
Contents include:
Blood vessels,
CSF,
brain parenchyma (tissue)
Intracranial Dynamics
According to the _________, the total volume of these three components remains constant because the skull is rigid and non-expandable. If the volume of one component increases, there must be a compensatory decrease in the volume of another to maintain normal intracranial pressure (ICP).
What is this?
Monro–Kellie doctrine
Intracranial Dynamics
Normal ICP range?
Range 0 to 15 mm Hg
Cerebral blood flow
What is autoregulation?
Autoregulation is the ability of an organ to maintain consistent blood flow despite marked changes in arterial circulatory and perfusion pressures.
Cerebral blood flow
What does the normal brain have the ability to do?
Normal brain has the ability to maintain CBF.
Cerebral blood flow
What is normal CBF maintained by?
Normal CBF maintained by CPP 60 to 100 mm Hg
Cerebral blood flow
To maintain functional autoregulation cerebral vessels, the following must be present: (3 things)
Normal Paco2
CPP greater than 60 mm Hg
MAP less than 160 mm Hg
Cerebral blood flow
To maintain functional autoregulation cerebral vessels, the following must be present:
Normal PaCO2: What is this and what does it do?
Paco2 is a potent vasodilator and will increase ICP.
Cerebral perfusion pressure (CPP)
How is it calculated?
Calculated: MAP – ICP = CPP
Cerebral perfusion pressure (CPP)
A CPP greater than 100mmHg indicates what?
CPP greater than 100 mm Hg indicates hyperperfusion and increased ICP.
Cerebral perfusion pressure (CPP)
CPP less than 60 mm Hg does what?
CPP less than 60 mm Hg decreases blood supply and hypoxia.
Cerebral perfusion pressure (CPP)
When MAP = ICP, what does this indicate?
MAP = ICP would indicate no cerebral blood flow.
Cerebral perfusion pressure (CPP)
CPP of ______ is maintained in critically ill patients.
CPP of 70 mm Hg is maintained in critically ill patients.
Increased Intracranial PressureMedical Management
What is needed?
Adequate Oxygenation
Carbon Dioxide Management
Blood Pressure
Metabolic Demands
Diuretics
Increased Intracranial PressureMedical Management
Adequate Oxygenation:
What is the goal?
Goal: PaO2 > 80 mm Hg
Increased Intracranial PressureMedical Management
Adequate Oxygenation:
What must be done for this?
Airway vigilance
Mechanical ventilation
Increased Intracranial PressureMedical Management
Adequate Oxygenation:
Mechanical ventilation: What is used and how?
Positive end-expiratory pressure (PEEP) – use with caution
Increased Intracranial PressureMedical Management
Carbon Dioxide Management:
PaCO2 35-45 mm Hg
Avoid hyperventilation
Increased Intracranial PressureMedical Management (Cont.)
Blood Pressure: What is the Goal?
Goal: MAP 70-90 mm Hg
CPP: at least 70 mm Hg
Increased Intracranial PressureMedical Management (Cont.)
Blood Pressure: What should be avoided?
Avoid hypertension
Increased Intracranial PressureMedical Management (Cont.)
Blood Pressure: What should be given to stop hypertension?
Nicardipine
Increased Intracranial PressureMedical Management (Cont.)
Metabolic Demands- What is done?
Temperature control
Pharmacological therapy
Seizure prophylaxis