neuro study well

8/9/2019 Neuro Study Well

1/23


2/23

The carotid and vertebral arteries pass through the neck to

supply blood to the head and brain.

y The two carotid arteries

are located in the frontof the neck on either sideof the throat. Thesearteries supply blood to

the face and cerebrum.

y Thevertebral arteries are

two smaller arteries thatpass through the spineinto the brain. Theyprimarily supply blood to

the brain stem,occipital andcerebellum.

CEREBRAL ARTERY


3/23

Motoneural pathwaysCorticospinal- conduct motor impulses to the

anterior horn from opposite side of brain.

- control voluntary muscle activity

Vestibulospinal- uncrossed; ANS function

Corticobulbar- cross; for voluntary head and facial

muscle movementRubrospinal and reticulospinal- involuntary muscle

movement.


4/23

Peripheral nervous systemy Cranial nerves-

> 12 pairs> 3 sensory, 5 motor, 4 mixed

y Spinal nerves> 8-cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Rootsy

Dorsal- sensory from specific areas of bodyy Ventral- motor; from spinal cord to body; either somatic or

visceral- ANS.


5/23

Basic concepts in normal

neurologic functiony Oxygen supply- brain requires 20% ofO2 in the body

y Glucose supply- brain requires 67 to 70% of glucose in

the bodyy Blood supply- brain requires 1/3 of cardiac output

y CSF- 100-150 ml


6/23

y Full consciousness. The patient is alert, attentive, and follows commands. Ifasleep, she responds promptly to external stimulation and, once awake,remains attentive.

y Lethargy. The patient is drowsy but awakensalthough not fullytostimulation. She will answer questions and follow commands, but will do so

slowly and inattentively.

y Obtundation. The patient is difficult to arouse and needs constantstimulation in order to follow a simple command. She may respond verballywith one or two words, but will drift back to sleep between stimulation.

y Stupor. The patient arouses to vigorous and continuous stimulation; typically,

a painful stimulus is required.1 She may moan briefly but does not followcommands. Her only response may be an attempt to withdraw from or removethe painful stimulus.

y Coma. The patient does not respond to continuous or painful stimulation. Shedoes not moveexcept, possibly, reflexivelyand does not make any verbalsounds.

The single most important assessment

Evaluation of level of consciousness (LOC) and mentation are the most important

parts of the neuro exam. A change in either is usually the first clue to a deteriorating

condition.


7/23

Assessing Cerebral Functiony M

ental Status-appearance and behavior, speech,orientation (Frontal, Parietal, temporal)

y Intellectual Function- count, interpretation ofsaying/proverb (Frontal, Temporal)

y Thought content- insights, ideas, illusions (Frontal)

y Emotional Status- affect/mood appropriate (Frontal)

y Perception- interpretation ability (Temporal)

y Motor ability- perform skilled activity (frontal)

y

Language ability(Frontal, Temporal)


8/23

TO ASSESS MOTOR FUNCTIONAND CEREBELLAR FUNCTION

1. Resistance (place muscle at disadvantage)2. Point to point testing/ rapid alternating

movement (coordination)upper- pronate-supinate, finger touchlower- heel to tibia

ataxia- uncoordinated voluntary muscle

coordination= cerebellar disease3. Rombergs test + vestibular dysfunction

heel to toe walk, hop in place (balance)


9/23

ASSESSING SENSORY FUNCTION

Begin with the feet and move up the body to the face,comparing one side with the other. Refer to figure 60-11for dermatome distribution of sensory nerves.

1. Tactile- cotton wisp touch, compare proximal and distal2. Pain and temperature

3. Vibration- use of tuning forks signal when vibrationceases

4. Proprioception- toe up and down determine direction.5. Integration of sensation- 2 point discrimination

Stereognosis-objects and describe


10/23

Other reflexes

yCorneal- blink (CN V and VII)y

Abdominal reflexyGag-swallowing (CN X)yPlantar- toe flexionyCremasteric reflexyOculocephalic- (-) no eye movement(CN III,IV,VI)yOculovestibular- caloric ice reflex

assess intact brain stem


11/23

Causes of altered level of

consciousnessy Structural: brain lesions that destroy tissue or occupy space that is

normally occupied by thebrain Epilepsy Tumors Trauma

y Cardiovascular: temporary or permanent interruption to the blood supply

to the brain Vasovagalresponse C VA TIA Hypertensiveencephalopathy Shock Dysrhythmias

y Metabolic: abnormally high or low levels of circulatingmetabolites Hypoxia Hypoglycemia HyperglycemiaRenal failure (uremia) Liver failure Infection (sepsis)

y Environmental: external factors that cause deterioration of centralnervous system function Overdose Toxins

y Behavioral: abnormal mental status that results from internalfactors Psychiatric disorders


12/23

Mnemonic for Causes of Altered Levelof Consciousnessy A- alcohol, acidosis, anoxia

y E - epilepsy, environment

y I - insulin (diabetes)

y O - overdose

y U - uremia (metabolic), underdose

y

y T - trauma, toxins, tumors

y I - infection (sepsis)

y P - psychiatric disorders

y S - stroke (CVA)


13/23

3 compensatory mechanisms-

ICPy Autoregulation- depends on cerebral perfusion

y CSF regulation- production and reabsorption

depends on intra-cerebral volume.yMetabolic regulation-

O2 CO2 = vasodilation =perfusion = ICP (ifother 2 compensatory mechanisms are notfunctioning properly)


14/23

Need to know:y ICP -measure ofCSF pressure.

> normal value- 10-20 mmHg> value greater than 20 mmHg intracranial hypertension

> rate ofC

SF production (0.3-0.4 cc/min)>rate ofCSF reabsorption>pressure exerted in the sagittal sinus

as CSF returns to heart.y Normal ICP- 5-15 mmHg

mild elevation- 16-20 mmHg

moderate elevation- 21-30 mmHgsevere elevation- 31-40 mmHg

very severe elevation - 41 mmHg


15/23

y Cerebral Pressure Perfusion=

mean arterial pressure (MAP) ICP =CPP

normal = 70-100 mmHg

y Mean Arterial Pressure=

Systolic BP + (2 x Diastolic BP) 3 =MAP

CPP is inversely proportional to ICP

(e.g. inc. ICP = CBV to brain = CO2 and O2 = hypoxia)


16/23

Types of cerebral Edemay Vasogenic Edema- osmotic pressure in extracellular compartment

-due to head traumatx: osmotherapy, positioning,

diuretics, steroids

y Cytotoxic Edema- failure Na- K pump in intracellular compartment- due to water intoxication, encephalitis, hypoxia

tx: osmotherapy, hyperventilation

yInterstitial Edema- increase CSF, Na and water around ventricles

-due to obstructive hydrocephalustx: temporary drain


17/23

MedsICPy Osmotic diuretic (mannitol) reduce edema, check

hourly urine

y

Anti seizure drugs (dilantin)it crystallize ; providegood oral care and massage gums

y Corticosteroids (decadron)- reduce edema

y H2 antagonist- (tagamet)- reduce acid production

y Stool softeners

y Opiates and sedatives are contraindicated coz ofrespiratory depression and acidosis


18/23

Nursing Care:ICPy Safetyy Maintain head midline to facilitate blood flowy Maintain head of bed 30-45 degreesy Avoid activities that can increase ICPy Treat hyperthermia and avoid infection, dressing carey Decrease environment stimuli- dim lights, speak softly,

touch gently, space interventionsy Maintain fluid balance via accurate I and Oy Monitor electrolyte balancey Monitor hyperventilationy Skin and mouth care


19/23

Primary trauma- types of skull

fractures (pp.1481, table 57-6)y Concussion- transient disorder due to injury in which there

is a brief loss of conciousness due to paralysis of neuronalfunction

yContusion- extravasation of blood cells

y Laceration- tearing of brain tissue or blood vessel due tosharp brain fragment

y Fracture-y Linear- epidural bleeding

y Basilar- (most serious) may result in brain abscess ormeningitisy Ottorhea or rhinorrheay Battles signy Raccoon eyes


20/23

Pathophysiology- head injuryy 1. depressed neuronal activity in RAS depressed

consciousness

y

2. depressed neuronal functioning in lower brain stemand SC depression of reflex activtiy decreased eyemovements, unequal pupils decreased response tolight stimulation widely dilated fixed pupil

y

3. depressed respiratory center altered respiratorypattern decreased rate respiratory arrest

y For signs and symptoms see table 57-7 page 1482


21/23

Asssessmentbrain tumory Frontal lobe

y Personality disturbancesy Imappropriate affect

y Indifference of bodily functions

y Precentral gyrusy Jacksonian seizures

y Occipital lobey Visual disturbances preceeding convulsion

y Temporal lobey Olfactory, visual and hallucinations

y Psychomotor seizures

y Parietal lobey Inability to replicate pictures

y Loss of right-left discrimination


22/23

y Subcorticaly hemiplegia

y Meningeal tumors

y Symptoms are assc with compression of the brain and depend ontumor location

y Metastatic tumorsy H/A, N/V, because of Inc. ICP

y Thalamus and sellar tumors

y H/A, N/V, vision disturbances, papilledema and nystagmus occurfrom inc ICP, DI

y 4th and cerebellar tumorsy H/A, N/V and papilledema from inc ICP; ataxic gait and changes in

coordination

yCerebellopontine tumorsy Tinnitus and vertigo, deafness

y Brainstem tumorsy H/A on awakening, drowsiness, vomiting, ataxic gait, facial muscle

weakness, hearing loss, dysphagia, dysarthria, crossed-eyes


23/23

craniotomyy Excision of a part of the skull (burr hole to several

centimeters)y for exploratory purposes and biopsy

y To remove neoplasms

y Evacuate hematomas or excess fluid

y Control hemorrhage

y Repair skull fractures

y Remove scar tissues

y

Repair or excise aneurysmsy Drain abscesses

neuro study well

Documents