Neurology and Disorders

8/9/2019 Neurology and Disorders

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Anatomy and Physiology of the Brain and Spinal Cord

I. Cerebrum

a. Consists of the right and left

hemispheres

b. Each hemisphere receives sensory

information from the opposite side of the

body and controls the skeletal muscles

of the opposite side.

c. The cerebrum governs sensory and

motor activity

d. The cerebrum governs thought andlearning.

II. Cerebral Cortex

a. The cerebral cortex is the outer gray

layer.

b. The cortex is divided into four lobes.

c. The cortex is responsible for the

conscious activities of the cerebrum

III. Basal Ganglia

a. The basal ganglia are cell bodies in

white matter.

b. The basal ganglia assist the cerebral

cortex in producing smooth voluntarymovements.

IV. Diencephalon

a. Thalamus

i. The thalamus relays sensory

impulses to the cortex

ii. The thalamus provides a pain

gate.

iii.The thalamus is part of the

reticular activating system.

b. Hypothalamus

i. The hypothalamus regulates

autonomic responses of thesympathetic and

parasympathetic nervous

system

ii.The hypothalamus regulatesstress response, sleep,

appetite, body temperature,

fluid balance, and emotions.

iii.The hypothalamus isresponsible for the production

of hormones secreted by the

pituitary gland and

hypothalamus

V. Brainstem

a. Midbrain

i. The midbrain is responsible for

motor coordination.

ii.The midbrain contains visualreflex and auditory relay

centers.

b. Pons

i. The pons contains therespiratory centers.

ii.The pons regulates breathing.c. Medulla oblongata

i. The medulla oblongatacontains all afferent and

efferent tracts.

ii.The medulla oblongatacontains cardiac, respiratory,

vomiting, and vasomotor

centers.

iii.The medulla oblongata controls

heart rate, respiration, blood

vessel diameter, sneezing,

swallowing, vomiting, and

coughing.

VI. Cerebelluma. The cerebellum coordinates smooth

muscle movement.

b. The cerebellum coordinates posture,

equilibrium, and muscle tone.

VII. Spinal Cord

a. The spinal cord provides neuron and

synapse networks to produce

involuntary responses to sensory

stimulation.

b. Allows for control of the number of pain

impulses that pass through the spinal

cord on their way to the brain.c. The spinal cord carries sensory

information to and motor information

from the brain.

d. The spinal cord extends from the first

cervical to the second lumbar vertebra.

e. The spinal cord is protected by themeninges, cerebrospinal fluid, and

adipose tissue.

f. Horns

i. Inner column of gray matter

contains two anterior and two

posterior horns.ii. Posterior horns connect with

afferent (sensory) nerve fibers.

iii.Anterior horns contain efferent

(motor) nerve fibers.

g. Nerve Tracts

i. White matter contains the

nerve tract.

ii. Ascending tracts (sensory

pathway)

iii.Descending tract (motor

pathway)

VIII. Meninges

a. Dura mater is the tough and fibrous

membrane.b. Arachnoid membrane is the delicate

membrane and contains subarachnoid

fluid.

c. Pia mater is the vascular membrane.

d. Subarachnoid space is formed by thearachnoid membrane and the pia mater.

IX. Cerebrospinal Fluid

a. Is secreted in the ventricles andcirculates through the ventricles to the

subarachnoid layer of the meninges,

where it is reabsorbed.b. Cerebrospinal fluid circulates in the

subarachnoid space.

c. Normal pressure is 50 to 175 mm H20.

d. Normal volume is 125 to 150ml.

e. Cerebrospinal fluid acts as a protective

cushion.

f. Cerebrospinal fluid aids in the exchange

of nutrition and wastes.

X. Ventricles

a. Four ventricles

b. The ventricles communicate between

the subarachnoid spacesc. The ventricles produce and circulate

cerebrospinal fluid.

XI. Blood Supply

a. Right and left internal carotids

b. Right and left vertebral arteries

c. These arteries supply the brain via ananastamosis at the base of the brain

called the circle of Willis.

XI I. Neurotransmitters

a. Acetylcholine

b. Norepinephrine

c. Dopamined. Serotonin

e. Amino acids

f . Polypeptides


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XIII. Neurons

a. The cell body contains the nucleus.

b. The neuron contains the axons and

dendrites

c. Neurons carrying impulses to the central

nervous systems (CNS) are called

sensory neurons.

d. Neurons carrying impulses away from

the CNS are called motor neurons.

e. Synapse is the chemical transmission of

impulses from one neuron to another.

XIV. Axons and Dendritesa. The axon conducts impulses from the

cell body.

b. The dendrites receive stimuli from the

body and transmit them to the axon.

c. The neurons are protected and

insulated by Schwann cells.

d. The Schwann cell sheath is called theneurolemma.

e. Neurons do not reproduce after the

neonatal period.

f. If an axon or dendrite is damaged, it willdie and be replaced slowly only if the

neurolemma is intact and the cell body

has not died.

XV. Spinal Nerves

a. The human being has 31 pairs of spinal

nerves.

b. Mixed nerve fibers are formed by the

joining of the anterior motor and

posterior sensory roots.

c. Posterior roots contain afferent

(sensory) nerve fibers.

d. Anterior roots contain efferent (motor)

nerve fibers.

XVI. Autonomic Nervous System

a. Sympathetic (adrenergic) fibers dilate

pupils, increase heart rate and rhythm,

contract blood vessels, and relax

smooth muscles of the bronchi.

b. Parasympathetic (cholinergic) fibers

produce the opposite effect.

Diagnostic Test

I. Skull and Spinal Radiography

a. Descriptioni. Radiographs of the skull reveal the

size and shape of the skull bones,

suture separation, in infants,

fractures or bony defects, erosion,

or calcification.

ii. Spinal radiographs identify

fractures, dislocation, compression,

curvature, erosion, narrowed spinal

cord, and degenerative processes.

b. Procedure interventions

i. Provide nursing support for the

confused, combative, or ventilator-

dependent client.

ii. Maintain immobilization of the neck

if a spinal fracture is suspected.iii.Remove metal items from body

parts.

iv.If the client has thick and heavy

hair, this should be documented

because it may affect interpretation

of the x-ray film.

v. Post procedure intervention:

maintain immobilization until results

are known.

II. Computed tomography scana. Description

i. Computed Tomography is a type of

brain scanning that may or may not

require an injection of a dye.

ii.Computed tomography is used todetect intracranial bleeding, space

occupying lesions, cerebral edema,

infarctions, hydrocephalus, cerebral

atrophy, and shifts of brain

structures.

b. Preprocedure interventionsi. Obtain an informed consent if a dye

is used.ii. Assess for allergies to iodine,

contrast dyes, or shellfish if a dye is

used.

iii.Instruct the client in the need to lie

still and flat during the test.

iv.Instruct the client to hold his or her

breath when requested.

v. Initiate an intravenous line if

prescribed.

vi.Remove objects from the head,

such as wigs, barrettes, earrings,

and hairpins.vii.Assess for claustrophobia.

viii.Inform the client of possible

mechanical noises as the scanning

occurs.

ix.Inform the client that there may be

a hot, flushed sensation and a

metallic taste in the mouth when the

dye is injected.

x. Note that some clients may be

given the dye even if they report an

allergy and are treated with an

antihistamine and corticosteroids

before the injection to reduce the

severity of a reaction.

c. Postprocedure interventions

i. Provide replacement fluids becausediuresis from the dye is expected.

ii. Monitor for allergic reaction to the

dye.

iii.Assess dye injection site forbleeding or hematoma, and monitor

extremity for color, warmth, and the

presence of distal pulses.

III. Magnetic Resonance Imaging

a. Description

i. Magnetic resonance imaging is a

non-invasive procedure thatidentifies types of tissues, tumors,

and vascular abnormalities.

ii. Magnetic resonance imaging is

similar to the computed tomography

scan but provides more detailed

pictures.

b. Preprocedure interventionsi. Remove all metal objects from the

client

ii. Determine whether the client has a

pacemaker, implanted defibrillator,

or metal implants such as a hipprosthesis or vascular clips

because these clients cannot have

this test performed.

iii.Remove intravenous fluid pumps

during the test.

iv.Provide precautions for the clientwho is attached to pulse oximeter

because it can cause a burn during

testing if coiled around the body or

a body part.

v. Provide an assessment of the client

with claustrophobia.vi.Administer medication as

prescribed for the client with

claustrophobia


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vii.Determine whether a contrastagent is to be used, and follow the

prescription related to the

administration of food, fluids, and

medications.

viii.Instruct the client that he or she

will need to remain still during the

procedure.

c. Postprocedure interventionsi. Client may resume normal activities

ii. Expect dieresis if a contrast agent

was used.

IV. Lumbar Puncture

a. Description

i. Lumbar puncture is insertion of aspinal needle through the L3-L4

interspace into the lumbar

subarachnoid space to obtain

cerebrospinal fluid (CSF), measure

CSF or pressure, or instil air, dye,

or medications.

ii.Lumbar puncture is contraindicated

in clients with increased intracranialpressure because the procedure

will cause a rapid decrease in

pressure within the CSF around the

spinal cord, leading to brain

herniation.

b. Preprocedure interventionsi. Obtain an informed consent

ii. Have the client empty the bladder

c. Interventions during the procedure

i. Position the client in a lateral

recumbent position and have the

client draw knees up to theabdomen and chin onto the chest

ii. Assist with the collection of

specimens (label the specimens in

sequence).

iii.Maintain strict asepsis.

d. Postprocedure interventionsi. Monitor vital signs and neurologic

signs

ii. Position the client flat as prescribed

iii.Force fluids.

iv.Monitor intake and output

V. Myelogram

a. Description: injection of dye or air into the

subarachnoid space to detect abnormalities

of the spinal cord and vertebra


ii. Provide hydration for at least 12

hours before the test.

iii.Assess for allergies to iodine.

iv.If the client is taking aphenothiazine, hold the medication

because this medication lowers the

seizure threshold.

v.Premedicate for sedation as

prescribed.c. Postprocedure interventions

i. Assess vital signs and neurological

condition frequently as prescribed.

ii. If a water-based dye is used,

elevate the head 15 to 30 degrees

for 6 to 8 hours as prescribed.

iii.If an oil-based, keep the client flat 6

to 8 hours as prescribed.

iv.If air is used, keep the head lower

than the trunk for up to 48 hours as

prescribed.

v. Administer analgesics for headacheor backache as prescribed

vi.Encourage fluids

vii.Monitor intake and output

viii.Assess for bladder distention andvoiding.

VI. Cerebral Angiography

a. Description: injection of contrast through the

femoral artery into the carotid arteries to

visualize the cerebral arteries and assess for

lesions


ii. Assess the client for allergies to

iodine and shellfish

iii.Encourage hydration for 2 days

before the test

iv.Maintain the client on NPO status 4

to 6 hours before the test as

prescribed.

v. Obtain a baseline neurological

assessment.

vi.Mark the peripheral pulses

vii.Remove metal items from the hair.

viii.Administer premedication as

prescribed.

c. Postprocedure interventions

i. Monitor neurological status and vital

signs frequently until stable.

ii.Monitor for swelling in the neck andfor difficulty swallowing, and notify

the physician if these symptoms

occur.

iii.Maintain bed rest for 12 hours as

prescribed.

iv.Elevate the head of the bed 15 to

30 degrees only if prescribed.

v. Keep the bed flat if the femoral

artery is used as prescribed

vi.Assess peripheral pulses

vii.Apply sandbags and a pressure

dressing to the injection site as

prescribed.

viii.Place ice on the puncture site as

prescribed.

ix.Encourage fluids.

VII. Electroencephalography

a. Description: a graphic recording of the

electrical activity of the superficial layers of

the cerebral cortex

b. Preprocedure interventionsi. Wash the clients hair

ii. Inform the client that electrodes are

attached to the head and that

electricity does not enter the head

iii.Withhold stimulants,

antidepressants, tranquilizers, and

anticonvulsants for 24 hours to 48

hours before the test as prescribed.

iv.Allow the client to have breakfast if

prescribed

v.Premedicate for sedation asprescribed

c. Postprocedure interventionsi. Wash the clients hair

ii. Maintain side rails and safety

precautions if the client was

sedated

VIII.Caloric Testing (oculovestibular reflex)a. Description: caloric testing provides

information about the function of the

vestibular portion of the eight cranial nerve

and aids in the diagnosis of cerebellum and

brainstem lesions.b. Procedure

i. Patency of the external auditory

canal is confirmed.


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ii. The client is positioned supine with

the head of the bed elevated 30

degrees.

iii.Cold or warm water is instilled into

the auditory canal to stimulate the

semicircular canals.

iv.A normal response that indicatesintact function of cranial nerves III,

VI, and VIII is conjugate eye

movements toward the side being

irrigated, followed by rapid

nystagmus to the opposite side.

v.Absent or dysconjugated eyemovements indicate brainstem

damage.

Neurological Assessment

A. Assessment of risk factors

a. Trauma

b. Hemorrhage

c. Tumors

d. Infection

e. Toxicityf. Metabolic disorders

g. Hypoxic conditions

h. Aging process

i. Hypertension

j. Cigarette smoking

k. Stress

B. Assessment of the cranial Nerves

a. Cranial Nerve I (olfactory): sensory,

smell

i. Have the client close eyes and

occlude one nostril with finger.

ii.Ask the client to identifynonirritating odors such as

coffee, tea, cloves, soap,

chewing gum, and peppermint.

iii.Repeat the test on the other

nostril.

b. Cranial Nerve II (optic): sensory, vision

i. Assess visual activity with asnellens chart or newspaper,

or ask the client to count how

many fingers the examiner is

holding up.

ii. Check visual field by

confrontation.

iii.Have the client sit directly in

front of the examiner and start

at examiners nose.

iv.Examiner slowly moves his or

her finger from the periphery

toward the center until the

client says it can be seen.

v.Check color vision by askingthe client to name the colors of

several nearby objects.

c. Cranial Nerve III (oculomotor), cranialnerve IV (trochlear); Cranial nerve VI

(abducens)

i. The motor functions of these

nerves overlap; therefore they

need to be tested together.

ii.First, inspect the eyelids forptosis (drooping); then assess

ocular movements and note

any eye deviation.

iii.Test accommodation and direct

and consensual light reflexes.

iv.Cranial nerve III (oculomotor;motor): Test assesses papillary

constriction, upper eyelid

elevation, and most eye

movement.

v.Cranial Nerve IV (trochlear,motor): Test assesses

downward and inward eye

movement.

vi.Cranial Nerve VI (adbucens):Test assess lateral eye

movement.

d. Cranial Nerve V (trigeminal): sensory

and motor

i. Test assesses sensation to the

cornea, nasal and oral mucosa,

facial skin, and mastication.

ii. To test motor function, ask the

client to close jaws tightly and

then try to separate the

clenched jaw.

iii.Test the corneal reflex by

lightly touching the clients

cornea with a cotton wisp.

iv.Check sensory function byasking the client to close the

eyes; then lightly touch the

forehead, cheecks, and chin,

noting whether the client can

feel the touch equally on both

sides.

e. Cranial Nerve VII (facial): sensory and

motor

i. Test taste perception on the

anterior two thirds of the

tongue

ii. Have the client show the teeth.

iii.Attempt to close the clients

eyes against resistance, and

ask the client to puff out thecheeks.

iv.Place sugar, salt, or vinegaron the front of the tongue, and

have the client identify these

substances by their taste.

f. Cranial Nerve VIII (acoustic): sensory

i. The ability to hear tests the

cochlear portion

ii.The sense of equilibrium teststhe bestibular portion

iii.Check the clients ability to

hear a watch ticking or a

whisper.

iv.Observe the clients balance,

and observe for swaying when

walking or standing.

g. Cranial Nerve IX (glossopharyngeal):sensory and motor

i. Test assesses swallowing

ability

ii.Test assesses sensation to thepharyngeal soft palate and

tonsillar mucosa and tasteperception on the posterior

third of the tongue and

salivation.

h. Cranial Nerve X (vagus): sensory andmotor

i. Test assesses swallowing and

phonation, sensation to the

exterior ears posterior wall,

and sensation behind the ear.

ii.Test assesses sensation to thethoracic and abdominal

viscera.

i. Cranial Nerve IX (glossopharyngeal);cranial nerve X (vague)


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i. Have the client identify a taste

at the back of the tongue.

ii. Inspect the soft palate and

observe for symmetrical

elevation when the client says

ah.

iii.Touch the posteriorpharyngeal wall with a tongue

depressor to eliecit a gag

reflex.

j. Cranial Nerve XI (spinal accessory):

motor

i. Test assesses uvula and softpalate movement and

sternocleidomastoid and

trapezius muscles.

ii.Test assesses upper portion ofthe trapezius muscle, which

governs shoulder movement

and neck rotation.

iii.Palapate and inspect thesternocleidomastoid muscle as

the client pushses the chinagainst the examiners hand.

iv.Palpate and inspect thetrapezius muscle as the client

shrugs the shoulders against

the examiners resistance.

k. Cranial Nerve XII (hypoglossal): motor

i. Test assesses tongue

movements involved in

swallowing and speech.

ii.Observe the tongue forasymmetry, atrophy, deviation

to one side, and fasciculations.

iii.Ask the client to push the

tongue against a tongue

depressor and then have the

client move the tongue rapidly

in and out from side to side.

C. Assessment of Level of Consciousness

a. Test assesses cerebral function

b. Test assesses client behaviour to

determine level of consciousness, such

as confusion, delirium,

unconsciousness, stupor, and coma.

D. Assessment of vital signs: monitor for bloodpressure or pulse changes, which may indicate

increased intracranial pressure

E. Assessment of Respirations

a. Cheyne-Stokes

i. Rhythmical with periods ofapnea

ii. Can indicate a metabolic

dysfunction or dysfunction in

the cerebral hemisphere or

basal ganglia

b. Neurogenic Hyperventilationi. Regular rapid and deep

sustained respirations

ii.Indicates a dysfunction in thelow midbrain and middle pons

c. Apneustic

i. Irregular respirations with

pauses at the end of inspiration

and expiration

ii.Indicates a dysfunction in themiddle or caudal pons.

d. Ataxic

i. Totally irregular in rhythm and

depth

ii. Indicates a dysfunction in the

medullae. Cluster

i. Cluster of breaths with irregular

spaced pauses

ii.Indicates a dysfunction in themedulla and pons

F. Assessment of temperature

a. An elevate temperature increases the

metabolic rate of the brain.

b. An elevation in temperature may

indicate a dysfunction of the

hypothalamus or brainstem.

c. A slow rise in the temperature may

indicate infection.

G. Assessment of Pupils

a. Size

b. Equality

c. Reaction to light: described as brisk,

slow, or fixed

d. Unusual eye movements

e. Unilateral pupil dilation indicates

compression of the third cranial nerve

f. Midposition fixed pupil indicates

midbrain injuryg. Pinpoint fixed pupil indicates pontinedamage

H. Assessment of motor function

a. Muscle tone, including strength and

equality

b. Voluntary and involuntary movements

c. Purposeful and nonpurposefulmovements

I. Assessment for posturing

a. Posturing indicates a deterioration of the

condition

b. Flexor (decorticate posturing

i. Client flexes one or both arms

on the chest and may extend

the legs stiffly.ii. Flexor posturing indicates a

non-functioning cortex.

c. Extensor (decerebrate posturing)i. Client stiffly extends one or

both arms and possibly the

legs.

d. Flaccid posturing: client displays no

motor response in any extremity

J. Assessment of reflexes

a. Babinskis Reflex

i. Dorsiflexion of the ankle andgreat toe with fanning of the

other toes

ii. Indicates a disruption of the

pyramidal tract

b. Corneal Reflex

i. Loss of the blink reflex

ii. Indicates a dysfunction of

cranial nerve V

c. Gag Ref lex

i. Loss of the gag reflex

ii.Indicates a dysfunction of

cranial nerves IX and X.

K. Assessment of Meningeal irritation

a. Nuchal rigidityb. Irritabil ity

c. Fever

d. Brudzinskis signi. Flexion of the head causes

flexion of both thighs at the

hips and knee flexion

e. Kernigs Signi. Flexion of the thigh and knee to

right angles and when thelimbs are extended, it causes

spasms of the hamstring and

pain.


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L. Assessment of the autonomic system

a. Sympathetic functions/ adrenergic

responses

i. Increased pulse and blood

pressure

ii. Dilated pupils

iii.Decreased peristalsis

iv.Increased perspiration

b. Parasympathetic function/ cholinergic

response

i. Decreased pulse and blood

pressureii. Constricted pupils

iii.Increased salivation

iv.Increased peristalsis

v. Dilated blood vessels

vi.Bladder contraction

M. Assessment of sensory function

a. Touch

b. Pressure

c. Pain

d. Bladder control

e. Bowel control

N. Glasgow Coma Scalea. The scale is a method of assessing a

clients neurological condition.

b. The scoring system is based on a scale

of 1 to 15 points.

c. A score of less than 8 indicates coma is

present.

d. Eye opening is the most important

indicator.

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Neurology and Disorders