NursingFile.com Cranial Nerves

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NURSING OF ADULTS 111

Introduction to Neurological Nursing



NERVOUS SYSTEM

l CENTRAL NERVOUS SYSTEMq BRAINq SPINAL CORD

l PERIPHERAL NERVOUS SYSTEMq CRANIAL NERVES---12 pairs

q SPINAL NERVES---31 pairs• 8 CERVICAL

• 12 THORACIC

• 5 LUMBAR

•5 SACRAL• 1 COCCYGEAL

q AUTONOMIC NS• SYMPATHETIC

• PARASYMPATHETIC



CENTRAL NERVOUS

SYSTEMl 1. Spinal cord (automatic motor

responses—pathways for messages toand from the brain)

l 2. Lower brain (control of B.P., resp,equilibrium, muscular movements,primitive emotions) -basal ganglia,thalamus, hypothalamus, midbrain,pons, medulla & cerebellum

l 3. Higher brain (cortical function – memory, reasoning, speech, vision,hearing, sensation, abstraction &patterns of responses, ) cerebralcortex



1. Central Nervous System =

Brain & Spinal Cord

2. Peripheral Nervous System =

12 Cranial & 31 Spinal Nerves

3. Autonomic Nervous System =

Hypothalamus (part of CNS)Sympathetic Nervous System –

important in emergency situations

–”fight or flight” response--increase

in heart rate, dilatation of

bronchioles, dilatation of pupils,vasoconstriction of skin & skeletal

muscles, slowing peristalsis,

secretion of nor/epinephrine

Parasympathetic nervous system –

brings about responses assc. With

restful activites--constriction of

pupil, promotes digestion, slows

heart rate

l



The Brain

l Centre of our

thought

l Interpreter of ourexternal environment

l Origin of control

over conscious

(voluntary) and

unconscious

(involuntary)

movement



Written

speech

Motor

speech

Auditory receiving area

Auditory interpretation area

Motor cortex

Sensory area (pain, touch, etc.)

Visual interpretation

area

Visual receivingarea

FrontalLobe

Parietal Lobe

Temporal Lobe

Brain Stem

Occipital Lobe

Cerebellum

FUNCIONAL AREAS OF THE

CEREBRAL CORTEX



Functions of the cerebral cortex:

l Frontal lobe – “personality” also contains themotor cortex – controls voluntary motor activity.

l Prefrontal areas controls

1. Concentration

2. Motivation

3. Ability to formulate or select goals

4. Ability to plan5. Ability to initiate or terminate actions

6. Ability to self monitor

7. Ability to use feedback



Cerebral Cortex (cont.)

Parietal lobes – have primary receptive areas for

tactile sensations i.e. temperature, touch, pressure.

Also has association areas – spatial orientation andawareness of size & shape & body position

(proprioception).

Occipital lobe – visual receptive & association area.

Visual memories are stored in this lobe – helps

visually recognize & understand our environment.



Cerebral Cortex (cont)

l Temporal lobes – auditory receptive area & secondary

auditory association area. Language memories are stored

on the left side. On the right side all other sound memories

that are not memories

q Animal sounds, train whistles, automobile horn etc.

l Damage to Wernicke’s area causes the inability to

understand spoken or written language or recognize music.



Cognitive FunctionEach area of the brain

controls particularactivities. Generallythe outer and forwardareas share moreadvanced function; theinner structuresdetermine basicmetabolic processes.Each side of the brain

receives the sensoryimpressions andactivates the musclesof the opposite side of

the body.



WHAT PROTECTS THE BRAIN?

l SKULLq 8 bones encase the brain protecting it (frontal, temporal, parietal, occipital) fuse in

childhood in junctions called sutures.

l MENINGESq

Fibrous connective tissue covering the brain the spinal cord providing protection,support, and nourishment

• Dura Mater, Arachnoid, Pia Mater

l CSFq Clear, colorless fluid 100-160 mls circulate b/w the subarachnoid spaces & the

ventricles. Approx. 500 mls produced per day, most is reabsorbed by the bld.Consider pressure on the brain, if not reabsorbed.

q Cushions and Shock Absorber

l BLOOD-BRAIN BARRIER q Blocks macromolecules and many compounds from dyes and medications from

reaching the neurons.q Helps keep a stable env. for neurons by regulating ion movement.



NEURONS

l Neurons (specialized

cells), make

complex connections

with one another to

send and receive

messages in the brain

and spinal cord.

l The brain and spinal

cord is like a

computer, the neurons

are like the switches

and circuitry that make

it work.



CEREBRAL CIRCULATION

l Receives 15% of cardiac output

l High metabolic demand and does not store

nutrients – can be critical with diabetics (glucose)feel shaky, foggy, confused.

l Flows against gravity (arteries fill from below and

veins drain from above)

l Cannot tolerate a decrease in blood flow b/c there

is no collateral circulation.



Brainstem - The lower extension of the brain where it

connects to the spinal cord. Neurological

functions located in the brainstem include those

necessary for survival (breathing, digestion, heart

rate, blood pressure) and for arousal (being awake

and alert).

Most of the cranial nervescome from the brainstem.

The brainstem is the pathway for

all fiber tracts passing up and down

from peripheral nerves and spinalcord to the highest parts of the brain.



Anatomy of

the

Autonomic

NervousSystem

(Brunner

2000, p. 1618)

What impact

on body re SC

injury?



EFFECTS ON AGING

l Loss of nerve cells therefore slower to receive and sendmessages

l Learning , memory and reasoning declineq Memory loss for recent events

l Takes longer to process thoughts and put them into actionq No change in intelligence but it takes longer to learn

l Decreased ability to hear, see certain colors, decreased

peripheral vision, sense of smelll Reduced taste buds and sense of touch in fingers and toes



Cognitive and Perceptual

Disorders

l Assessment of the Neurologic System



Neurologic System: History

l Biographical and Demographic Data (is the data reliable)

l Current Health (what brought them to seek care)

l Past Health History

q Childhood & Infectious Diseases – meningitis, herpesq Major Illnesses & Hospitalizations –diabetis, CVA, liver failure

q Medications – prescribed, OTC, herbal

q Growth and Development – duration of problem

l Family Health History- ALS, MD, Huntington’s

l Psychosocial History – personality changes, sleep patterns, stressors,

exposure to chemicals, pesticide (Agent Orange)



Neurologic System:Physical Exam

l Cervical spinal cord injury can exhibit dec. B/P, P& T – (loss of sympathetic nervous system)

l Vital Signs – note changes

l Mental Status – note changesq Level of Consciousnessq Orientationq Memory – long & short termq Mood and Affect- aggression & euphoriaq Intellectual Performance – knowledge/calculationq Judgment and Insight – assess reasoningq Language and Communication – fluent & appropriate




l Head, Neck, and Back q Inspection –

– raccoon’s eyes – basal skull fx (look for CSF from nares)

– Battle’s sign – middle basal skull fx – bruising over mastoid process (look for CSF

from ears)

q Palpation

– Nodules, boggy skull, nuchal rigidity

q Percussion

– Gentle percussion – watch for pain response

q Auscultation

– Major neck vessels – turbulent - ? High risk for CVA




l Cranial Nerves

q Olfactory Nerve (CNI): Smell

q Optic Nerve (CN II): Vision

q

Oculomotor (CNIII),Trochlear (CNIV), Abdocens (CNVI): Eye controlq Trigeminal Nerve (CNV): Sensations of the face, movement of the mouth

q Facial Nerve (CNVII): Facial muscles

q Acoustic Nerve (CNVIII): Hearing

q Glossopharyngeal (CNIX), Vagus (CNX) Nerves: Palate, Uvula

q Spinal Accessory Nerve (CNXI): Muscles of the Shoulders and Neck

q Hypoglossal Nerve (CN XII): Tongue




l Motor Systemq Muscle Size- symmetricalq Muscle Strength - symmetricalq Muscle Tone – rigid/flaccid/normalq Muscle Coordination – repetitive movementq Gait and Station- proprioceptionq Movement – fine & gross motor q Motor Testing of Unconscious Patients – to test

response to pain – sternal rub, pressure on nail bed,orbit of the eye.




l Sensory Function

q Superficial Sensations

• Touch and Pain

q Mechanical Sensations

• Vibration – tuning fork

•Proprioception

q Discrimination – stereognosis – distinguish objects,

graphism – trace letters on palm of hand




l Abnormal Reflexes

q Babinski’s Reflex

q Jaw Reflex

q Palm-Chin Reflex

q

Clonusq Snout Reflex

q Rooting Reflex

q Sucking Reflex

q Grasp Reflex

q Chewing Reflex



Posturing

l Abnormal flexion (decorticate) internal

rotation of the arms & wrists

l Abnormal extension (decerebrate) extension

& external rotation of arms & wrists – more

serious than abnormal flexion - midbrain




l Normal Reflexesq Superficial (cutaneous) Reflexesq

Abdominal Reflexq Plantar Reflexq Corneal Reflexq Pharyngeal Reflex - gagq

Cremasteric Reflexq Anal Reflex – check with MVAq Deep Tendon Reflexes




l Autonomic Nervous Systemq Cannot be examined directlyq

Clinical Manifestations• Increase/Decrease Heart Rate

• Vasoconstriction/Dilatation Peripherally

• Bronchoconstriction/Dilatation• Increase/Decrease Peristalsis

• Pupil Constriction/Dilatation




l Functional Assessment

l Clinical Applications

l Diagnostic Tests-Noninvasive

q Skull and Spinal X-Ray Studies

q Computed Tomography

q Magnetic Resonance Imaging

q Positron Emission Tomography



Neurologic System:Diagnostic Tests

l Invasive

q

Lumbar Punctureq Myelography

q Cisternal Puncture

q Cerebral Angiography

q Cerebral Perfusion Studies



Neurologic System:Diagnostic Tests

l Noninvasive Tests of Functionq Electroencephalogramq

Evoked Potential Studiesq Neuropsychological Testing

l Invasive Tests of Functionq Caloric Testing

q Peripheral Nerve Studiesq Muscle Biopsyq Cellular Assessment



CONSCIOUSNESS… is a state of general awareness of oneself

and environment.

Consciousness has two components:

1. Arousal (wakefulness): concernedwith the person’s wakefulness(Controlled by Cerebral Cortex Function+ Upper Brain Stem)

2. Content/cognition/awareness (cognitive + affective function orawareness of self): the sum of cerebral

mental functions (Controlled by



AROUSAL

The mediator of arousal and sensory stimulationis the RETICULAR ACTIVATING SYSTEM (RAS). The RAS is located in the Brain Stem and

contains projections between the Thalamus andthe Cortex. A network of neurons in the RASmonitors ascending and descending stimuli.

Nerve cells run through the medulla, pons,midbrain, thalamus, and hypothalamus. RASmaintains muscle tone, keeps the higher brain ina state of alert wakefulness, and filters incomingmessages.



HOW UNCONSIOUSNESS

OCCURS

l Disruption of the ascending reticular

activating system (extending from the

length of the brain stem into the thalamus)l Disruption in the function of one or both

cerebral hemispheres

l Metabolic depression of the brain (i.e.-----aswith drug overdose)





l Why is it important to assess LOC?

l How do we do this?



Stages of decreasing LOC

l ALERT

l CONFUSION

l DISORIENTATION

l LETHARGY

l OBTUNDATION

l STUPOR

l COMA



SUSTAINED

UNCONSIOUSNESS

l COMAq A STATE OF SUSTAINED UNCONSIOUSNESS IN

WHICH THE PATIENT DOES NOT RESPOND TO

VERBAL STIMULI, MAY HAVE VARYING

RESPONSES TO PAINFUL STIMULI, DOES NOT

MOVE VOLUNTARILY, MAY HAVE ALTERED

RESPIRATORY PATTERNS, MAY HAVE

ALTERED PUPILLARY RESPONSES TO LIGHT,AND DOES NOT BLINK. (Black, 5th edition)



BREATHING IN THE

UNCONSCIOUS CLIENT

l Respiration controlled by cerebrum, ponsand medulla

l Airway obstruction and aspiration commoncomplicationsq Obstructed airways causes§CO2 retention§

vasodilation§cerebral edema§increased ICP

q Reduced O2 levels§less oxygen to brain§

increased ICP



UNCONSCIOUS

CLIENT

l CN responsible for eye movement exit thru the

brain stem. If compressed eye movement is

impaired.l Normally gaze straight ahead and track together

l In comatose client they are uncoordinated, and

pupillary response is abnormal. (Eyes movements

can be dysconjugate, ocular bobbing, roving,

nystagmus).



PUPILLARY CHANGES IN THE

UNCONSCIOUS CLIENTl Nuclei of CN11 and 111 located below

cerebrum and in mid-brain

l Assessed for size, equality, reaction,responsive

l Fixed and dilated late signs of herniationand severe hypoxia

l Other causesq Hypothermia, Medications, Lesions



MOTOR RESPONSES SEEN IN

UNCONSCIOUSNESS

l POSTURINGq Decorticateq Decerebrateq Flaccidity (Unilateral or Bilateral)

l OTHER MOTOR SIGNSq Primitive sucking or snout reflexesq Strong reflexive hand graspsq Restlessnessq Resistance to passive movementsq Hemiplegiaq Hemiparesisq Seizures



CHANGES IN VITAL SIGNS

l Wide variations may be seen with various levels

of consciousness and some changes directly

related to the cause of the unconsciouness

l Cushings (Triad) may develop with increased ICPq Decreased pulse

q Increased systolic BP with same or slightly higher

diastolic resulting in a widened Pulse Pressure

q Slow respirations



l ASSESSING CONSCIOUSNESS



(GCS)

Universally used

Measures eye, verbal, and motorresponse

Excellent scale to measureArousal. Know the difference b/t

content & arousal

GLASGOW COMA SCALE SCORE (GCS)



( )

Eyes 1 Closed at all times

2 Opens to pain

3 Opens to voice command

4 Open spontaneously

Motor 1 No response

2 Extension (decerebrate rigidity)

3 Flexion posturing4 Flexion withdrawal

5 Localizes painful stimulus

6 Obeys commands

Verbal 1 No response

2 Incomprehensible sounds

3 Inappropriate words

4 Disoriented and converses

5 Oriented and converses

15 (top score)

A score of 10 or less

indicates a need for

emergency attention

A score less than 7 isinterpreted as coma





CONTENTBesides orientation to time, place and personthe following cognitive abilities should also be

assessed:

•Attention and vigilance•Memory – short, intermediate, long term

•Language – understanding of spoken andwritten word•General fund of information

•Construction ability•Sequencing activities

•Problem solving•Abstraction

•Insight and judgement

The Mini Mental Status Exam is an example of a



Any process that results in↑ICP will produceimpairment of content andarousal.

***Remember restless andother changes in behavior

frequently precede changesin vital signs,However, changes in LOC

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