Week 9: NEUROCOGNITION I

Question 1

Processes

Answer 1

1. Sensory input - receive sensory input from the external environment
2. Integration – Nervous system processes that input, and decides what should be done
   about it
3. Motor output – the response that occurs when your nervous system activates certain
   parts of your brain

Question 2

Central Nervous System

Answer 2

(main control center)

• Composed of – brain, spinal cord
• Contains – relay neurons (interneurons)

Question 3

Peripheral Nervous System

Answer 3

(allow central nervous system to communicate with the rest of the body)

• Composed of – cranial nerves, spinal nerves, peripheral nerves
• Contains:
  Sensory (afferent) neurons

Motor (efferent) neurons:
 Somatic NS – voluntary
 Autonomic NS – involuntary
 Sympathetic (fight or flight), parasympathetic (rest and digest)

Question 4

Neurons

Answer 4

• Nerve cells in the brain and nervous system
• Structure:
  o Cell body – contains organelles
  o Dendrites – receive signals and convey information to the cell body
  o Axon – transmit electrical impulses away from the cell body to other cells

Question 5

Specialized NS Cells: Neurons

Answer 5

Neurons - respond to stimuli and transmit signals

o Sensory (afferent) – transmit impulses from sensory receptors toward the CNS

o Motor (efferent) – impulse moves from the CNS to the rest of the body, mostly multipolar

o Interneurons (association) – impulse moves between sensory and motor neurons

Question 6

Specialized NS Cells: Neuroglia/glial cells

Answer 6

“Glue”

Provide support, nutrition, insulation, and help with signal transmission.

CNS:
 Astrocytes – exchange of materials between neurons and capillaries
 Microglial – immune defence against invading microorganisms
 Ependymal–line cavities; create, secrete and circulate CSF
 Oligodendrocytes – wrap and insulate, form myelin sheath

PNS:
 Satellite – surround and support neuron cell bodies
 Schwann – insulate, help form myelin sheath

Question 7

Cerebral Vasculature

Answer 7

• Brain requires perfusion
• Perfused through internal carotid arteries and vertebral arteries
• The further upstream towards the brain the blockage, the bigger the consequences

Question 8

The Meninges

Answer 8

The Meninges – protective membranes surrounding the brain and spinal cord

• Outer to inner:
  o Duramater
  o Arachnoid
  o Piamater

Question 9

Cerebrospinal Fluid (CSF)

Answer 9

• Clear, bathes our CNS organs
• Produced by specialized cells
• Stored by carotid plexus (3rd and 4th ventricles)
• Travels through the subarachnoid space

Question 10

Intracranial Pressure (ICP)

Answer 10

• Pressure within the cranial cavity (ridged bone)
• Measured in mmHg (normal = 5-10mmHg)
• Impacted by volume:
  o Brain tissue, blood, CSF

Question 11

Causes of increased Intracranial pressure

Answer 11

o Stroke
o Infection – meningitis, encephalitis
o Trauma, aneurysms
o Hypertension – causes change in MAP
o Hypoxemia – inadequate O2 levels, increased CO2 levels in brain o Tumours – space occupying
o Hydrocephalus
o Seizures/epilepsy

Question 12

Nursing assessment: Intracranial Pressure

Answer 12

Health history:
 Any risk factors?
 Headache, nuchal rigidity, blurred vision, changes in LOC
 Early recognition is important!!

Physical assessment:
 Weakness
 Nausea/vomiting (lots, rapid onset)
 Pupil changes/no blinking
 Ataxia, coordination issues
 Seizure
 Hemodynamic instability (increased bp, decreased hr)
 Respiratory distress
 Cushing’s triad

Question 13

Labs and investigations: Intracranial pressure

Answer 13

CT/MRI – visualize the ventricles and brain tissues (can see damage)

Question 14

Nursing management: Intracranial pressure

Answer 14

Peak edema = 3-5 days afer injury
- Monitor ABCs
- Frequent neuro assessments
- Elevate head of bed – 30 degrees, decrease stimuli

• Administer IV hypertonic solutions to decrease cerebral edema (20% mannitol,
  3% normal saline)
• Initiate feeding early – brain has high metabolism, requires lots of protein to heal
• Medical interventions – lower pressure
• VP or LP shunts
• Change vent settings – hyperventilation
• Sx – craniectomy
• Meds – acetazolamide

Question 15

Cushing’s Triad

Answer 15

Late-stage symptom of ICP – close to brainstem herniation

Body’s attempt to save brain tissue during severe lowered perfusion

Bradycardia, low, irregular respirations, hypertension** needs emergent medical
attention!

Question 16

CPP = MAP – ICP

Answer 16

• MAP = 70-100mmHg
• Blood pressure during a cardiac cycle
• Cerebral Perfusion Pressure (CPP) = 60-80mmHg
• Pressure gradient that drives oxygen delivery to cerebral tissue
• Maintaining normal CPP is vital to ensure that the brain receives enough oxygen
• Increased ICP = decreased CPP = brain ischemia = brain damage and death

Question 17

Brainstem Herniation

Answer 17

• Brainstem begins to protrude out of cranial cavity and into spinal cord
• Brainstem is responsible for lots of autonomic body processes (eg. Breathing)
• Causes the loss of ability to engage in essential body functioning
• Patients become very ill, very quickly
• Cushing’s triad, oculocephalic reflex (eyes do not follow when turning head), babinski’s
  reflex (toes fan up when bottom of foot is stimulated, not down)

Question 18

Stages of Brain Herniation

Answer 18

o Obey commands
o Bilateral Babinski’s reflex
o Hypertonia (cannot relax muscles)
o Grasp reflex
o Decorticate
o Decerebrate
o Flaccidity (no motor response to painful stimuli)

Question 19

Spinal Cord Injury (SCI)

Answer 19

• Damage to the spinal cord resulting in physiologic impacts on strength, motor function,
  bladder/bower function, sensation, reflexes, etc.
• Temporary or permanent
• Damage depends on extent and location of injury
• Injury progression:
  o Primary injury – initial traumatic event/insult
  o Secondary injury – edema and hemorrhage that follows the injury, early intervention prevents further damage
• Prognosis most accurately assessed 72+ hours post trauma – period in which edema/bleeding (hopefully) subsides
• Traumatic cause:
  o MVA, fall, sports, violence
• Non-traumatic cause:
  o Tumour, inflammation, infection
• Highest risk: men 16-30

Question 20

Classifications: Spinal cord injury

Answer 20

Complete transection
 Complete loss of mobility, sensation, reflexes (100%)

Incomplete/partial transection
 Some signals, movement and retention is retained

Question 21

Paraplegia

Answer 21

lower extremity

Question 22

Tetraplegia (quadriplegia)

Answer 22

all extremities

Question 23

Level of injury: Spinal cord injury

Answer 23

Cervical (C1-C8)
 All limbs are affected
 C4 and above: diaphragm, bowel/bladder support

Thoracic (T1-T12)
 Paraplegia
 Control of upper extremeties and trunk

Lumbar (L1-L5)
 Ambulation with assistance
 Hips and legs

Sacral (S1-S5)
 Ambulation with or without assistance

Question 24

Brown-Sequard Syndrome

Answer 24

Partial transection of one half of the spinal cord

One outcome on one side of body, one outcome on other side (contralateral)

Question 25

Central Cord Syndrome

Answer 25

Can cause damage to different parts of body

Question 26

Posterior Cord Syndrome/Anterior Cord Syndrome

Answer 26

Might see damage to only one type of nervous function

Question 27

Systemic Impacts: Spinal Cord Injury

Answer 27

Respiratory - Function of accessory muscles and diaphragm - Mechanical ventilation - Poor muscle control – hypoventilation, atelectasis, pneumonia CV - SNS activation can be compromised, causing bradycardia, vasodilation, hypotension, decreased CO - DVT Pain Thermoregulation Urinary - Retention GI - Hypomobility - Bowel reflexivity Integumentary - Skin breakdown risk Musculoskeletal - Range of motion - Atrophy

Question 28

Emergency Nursing Management: SCI

Answer 28

Immobilize Lay flat, log roll No twisting, turning or sitting Apply immobility devices – board, cervical collar, halo ABCs  Patent airway, supplement O2  Treat shock  Support perfusion (support fluid volume, control hemorrhage) o Pain management

Question 29

SCI Complications: Autonomic Dysreflexia

Answer 29

Autonomic Dysreflexia ONLY above T6 Caused by stimulation of sensory receptors below injury – causes vasoconstriction and HTN – body cannot properly interpret and respond to stimulus

Question 30

Signs and symptoms of SCI complications: Autonomic Dysreflexia

Answer 30

 Pounding/throbbing headache  HTN, bradycardia  Sweating/flushing above site of injury  Goosebumps (piloerection)  Nasal congestion Nurse management:  Notify MRP  HOB 45 degrees  Administer antihypertensives (IV)  Assess GI/GU – catheter, infection, overfull bladder?

Question 31

SCI Complications: Spinal Shock

Answer 31

Occurs immediately post-SCI – presents as quadriplegic, will resolve in 72 hour period Areflexia – motor, bladder, bowel Loss of sensation, paralysis, flaccidity Vital signs: bradycardia, hypotension Can be caused by excessive inflammation Causes:  Hypovolemic (hemorrhage)  Cardiogenic (MI)  Distributive --Neurogenic – SCI --Anaphylactic – severe allergic reaction --Septic – systemic infection

Question 32

SCI Complications: Neurogenic shock

Answer 32

No cardiac compensation Causes: - Autonomic dysfunction – decreased systemic vascular resistance and bradycardia – vasodilation and venous pooling Presentation: - Abrupt fever and perspiration above injury - Warm, dry skin below injury - Bradycardia, severe hypotension Nursing management: - Notify rapid response (code blue)  ABCs  Administer O2  IV access  Administer IV vasopressors  Administer IV Atropine for bradycardia  Document CODE