Chapter 15 DSN Neurologic System Kevin Dobi, MS, APRN Copyright © 2013 by Mosby, an imprint of Elsevier Inc

Chapter 15

DSN

Neurologic SystemKevin Dobi, MS, APRN

Copyright © 2013 by Mosby, an imprint of Elsevier Inc.

Concept Overview

Intracranial regulation: Mechanisms that facilitate or impair neurologic

function.

Interrelationships: Brain requires oxygenation.

Respiratory and cardiovascular systems impacted by neurologic control.

Extensions of neurologic function: Sensory perception.

Tactile perception.


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Anatomy and Physiology

Nervous system controls body functions through voluntary and autonomic responses to external and internal stimuli.

Structural divisions of nervous system are: Central nervous system (CNS), which

consists of brain and spinal cord Peripheral nervous system (PNS) Autonomic nervous system (ANS)


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Anatomy and Physiology: CNS: Protective Structures

Skull protects brain. Foramen magnum is large oval opening at base of skull

in occipital bone. Spinal cord extends through from

medulla oblongata. Other foramina at base for entrance and exit of paired

cranial nerves and cerebral blood vessels. Meninges, three layers between skull and brain:

Dura mater, outer double layer. Arachnoid, middle meningeal

layer. Pia mater, inner meningeal layer.


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Anatomy and Physiology: CNS: Protective Structures (contd.)

Between arachnoid and pia mater is subarachnoid space where cerebrospinal fluid (CSF) circulates.

Falx cerebri, a fold of dura mater, separates two cerebral hemispheres.

Tentorium cerebelli, another fold of dura mater, supports temporal and occipital lobes and separates cerebral hemispheres from cerebellum.


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Anatomy and Physiology: CNS:Cerebrospinal Fluid

CSF is colorless, odorless fluid containing: Glucose, electrolytes, oxygen, water, carbon dioxide,

and leukocytes.

Circulates around brain and spinal cord. Provides cushion, maintains normal intracranial

pressure, nutrition, and removes metabolic wastes.


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Anatomy and Physiology: CNS:Cerebral Ventricular System

Cerebral ventricular system consists of four interconnecting ventricles producing and circulating CSF: Two lateral ventricles, one in each hemisphere. One ventricle adjacent to thalamus. One ventricle adjacent to brainstem.


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Anatomy and Physiology: CNS:CSF and Cerebral Ventricular System

CSF circulates from lateral ventricles through the interventricular foramen to third ventricle. Through aqueduct of Sylvius to fourth ventricle. Into cisterna magna, a small reservoir for CSF. To subarachnoid space up around brain and down

around spinal cord. Absorbed through arachnoid villi that extend into

subarachnoid space and returned to venous system.


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Anatomy and Physiology: Brain

Brain consists of cerebrum, diencephalon, cerebellum, and brainstem; is composed of: Gray matter (cell bodies). White matter (myelinated nerve fibers).

Carotid arteries supply most of blood to brain, and branch off into posterior cerebral, middle cerebral, and anterior cerebral arteries. Remaining blood flows through two vertebral arteries and

into posterior and anterior communicating arteries that supply blood through circle of Willis.

Blood leaves brain through venous sinuses that empty into jugular veins.


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Anatomy and Physiology: Brain – Cerebrum

Cerebrum is largest part of brain consisting of two hemispheres, each divided into four lobes: Frontal lobe, parietal lobe, temporal lobe, and occipital lobe. Frontal lobe contains primary motor cortex and

functions related to voluntary motor activity. Broca’s area is located in left frontal lobe involved in

formulation of words. Frontal lobe also controls intellectual function,

awareness of self, personality, and autonomic responses related to emotion.


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Anatomy and Physiology: Brain – Cerebrum (contd.)

Cerebrum: Parietal lobe contains primary somesthetic (sensory) cortex that

receives sensory input such as position, touch, shape, and texture of objects.

Temporal lobe contains primary auditory cortex:

Wernicke’s area located in left temporal lobe, responsible for comprehension of spoken and written language.

Also interprets auditory, visual, and somatic sensory inputs that are stored in thought and memory.

Occipital lobe contains primary visual cortex, which receives and interprets visual information.


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Anatomy and Physiology: Brain – Diencephalon

Diencephalon is made up of thalamus, hypothalamus, epithalamus, and subthalamus. Thalamus is relay and integration station from spinal cord to cerebral

cortex and other parts of brain. Hypothalamus important in maintaining homeostasis.

Functions include regulation of body temperature, hunger, and thirst; formation of autonomic nervous system responses; and storage and secretion of hormones from pituitary gland.


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Anatomy and Physiology:Brain – Diencephalon (contd.)

Epithalamus contains pineal gland, which causes sleepiness and helps regulate some endocrine functions

Subthalamus is part of extrapyramidal system of autonomic nervous system and basal ganglia.


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Anatomy and Physiology: Brain – Basal Ganglia

Basal ganglia lies between cerebral cortex and midbrain, adjacent to diencephalon. Basal ganglia comprised of six ganglia: Putamen, caudate nucleus,

globus pallidus, thalamus, red nucleus, and substantia nigra. Function is balancing production of two neurotransmitters—

acetylcholine and dopamine—that create smooth, coordinated voluntary movement.


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Anatomy and Physiology: Brain – Brainstem

Brainstem is made up of midbrain, pons, and medulla oblongata.

Ten of twelve cranial nerves (CNs) originate from brainstem.

Midbrain functions to relay stimuli concerning muscle movement to other brain structures. Contains part of motor tract

pathways that control reflex motor movements in response to visual and auditory stimuli.

Oculomotor nerve (CN III) and trochlear nerve (CN IV) originate in midbrain.


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Anatomy and Physiology: Brain – Brainstem (contd.)

Brainstem: Pons relays impulses to brain centers and lower spinal

nerves. CNs that originate in the pons are trigeminal (CN V),

abducens (CN VI), facial (CN VII), and acoustic (CN VIII).


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Anatomy and Physiology: Brain – Brainstem (contd.)

Brainstem: Medulla oblongata contains reflex centers for

controlling involuntary functions such as breathing, sneezing, swallowing, coughing, vomiting, and vasoconstriction.

Motor and sensory tracts from frontal and parietal lobes cross from one side to other in medulla; lesions on right side create abnormal movement and sensation on left side, and vice versa.

Cranial nerves originating in medulla are glossopharyngeal (CN IX), vagus (CN X), spinal accessory (CN XI), and hypoglossal (CN XII).


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Anatomy and Physiology: Brain – Cerebellum

Cerebellum separated from cerebral cortex by tentorium cerebelli.

Functions of cerebellum include coordinating movement, equilibrium, muscle tone, and proprioception. Each cerebellar hemisphere controls movement for

same (ipsilateral) side of body.


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Anatomy and Physiology: Brain – Spinal Cord

Spinal cord is continuation of medulla oblongata that begins at foramen magnum and ends at first and second lumbar (L1 and L2) vertebrae. At L1 and L2, spinal cord branches into lumbar and

sacral nerve roots termed cauda equina. Spinal cord consists of 31 segments, each giving rise to

a pair of spinal nerves. Nerve fibers, grouped into tracts, run through the

spinal cord transmitting sensory, motor, and autonomic impulses between brain and body.


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Anatomy and Physiology: Brain – Spinal Cord (contd.)

Spinal cord: Myelinated nerves form white matter of spinal cord and contain

ascending and descending tracts of nerve fibers. Descending or motor tracts carry impulses from frontal lobe to muscles

for voluntary movement and play a role in muscle tone and posture. Ascending or sensory tracts carry sensory information from body

through thalamus to parietal lobe.


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Anatomy and Physiology: Brain – Spinal Cord (contd.)

Spinal cord: Fasciculus gracilis travels within medial lemniscus in posterior (dorsal)

column carrying sensations of touch, deep pressure, vibration, position of joints, stereognosis, and two-point discrimination.

Lateral spinothalamic tract carries fibers for sensations of light touch, pressure, temperature, and pain.

Gray matter, which contains nerve cell bodies, arranged in a butterfly shape with anterior and posterior horns.


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Anatomy and Physiology: Peripheral Nervous System

12 pairs of cranial nerves: Five pairs have only motor

fibers. Three pairs have only sensory

fibers. Four pairs have both motor and

sensory fibers.


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Anatomy and Physiology: Peripheral Nervous System –Spinal Nerves

Spinal nerves, 31 pairs, emerge from spinal cord: Cervical nerves: 8 pairs

First 7 exit above their corresponding vertebrae; remaining pair exit below corresponding vertebrae.

Thoracic nerves: 12 pairs Lumbar nerves: 5 pairs Sacral nerves: 5 pairs Coccygeal nerves: 1 pair


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Anatomy and Physiology: Peripheral Nervous System –Spinal Nerves (contd.)

Spinal nerve pairs formed by union of efferent or motor (ventral) root and afferent or sensory (dorsal) root. Motor fibers carry impulses from frontal lobe through spinal cord to

muscles and glands; sensory fibers carry impulses from sensory receptors of body through spinal cord to parietal lobe.

Each pair of spinal nerves and its corresponding part of the spinal cord make up a spinal segment and innervate specific body segments.


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Anatomy and Physiology: Peripheral Nervous System –Spinal Nerves (contd.)

Spinal nerve pairs: Dorsal root of each spinal nerve supplies sensory innervation to a

specific area of skin known as a dermatome.

For example, if patient complains of pain with numbness and tingling across right knee, the nurse knows that fourth lumbar spinal segment is involved and perhaps compressed.


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Anatomy and Physiology: Peripheral Nervous System – Reflex Arc

Reflex arcs tested by observing muscle movement in response to sensory stimuli. Deep tendon reflexes are responses to stimulation of tendon that

stretches neuromuscular spindles of muscle group.

Striking a deep tendon stimulates a sensory neuron that travels to spinal cord where it stimulates an interneuron, which stimulates a motor neuron to create movement.

Superficial reflexes tested similarly. Each reflex corresponds to a specific spinal segment.


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Anatomy and Physiology: Autonomic Nervous System

Autonomic nervous system (ANS) regulates body’s internal environment in conjunction with endocrine system.

ANS has two components: Sympathetic nervous system Parasympathetic nervous

system


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Anatomy and Physiology: Autonomic Nervous System – SNS

Sympathetic nervous system (SNS) arises from thoracolumbar segments of spinal cord and is activated during stress (the “fight-or-flight” response).

SNS actions include: Increasing blood pressure and heart rate. Vasoconstricting peripheral blood vessels. Inhibiting gastrointestinal peristalsis. Dilating bronchi.


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Anatomy and Physiology: Autonomic Nervous System – PNS

Parasympathetic nervous system (PNS) arises from craniosacral segments of spinal cord and controls vegetative function. “Helps out the SNS”

PNS actions associated with conserving energy such as: Decreasing heart rate and force of myocardial

contraction. Decreasing blood pressure and respiration. Stimulating gastrointestinal peristalsis.


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General Health History: Present Health Status

Have you noticed any changes in ability to move around or participate in usual activities?

Do you have any chronic diseases? High blood pressure? Myasthenia gravis? Multiple sclerosis?

What medications do you take? Are you taking medications as prescribed?


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General Health History: Past Medical History

Have you ever had injury to head or spinal cord? What changes have you experienced since injury?

Have you had surgery on brain, spinal cord, or nerves?

Have you ever had a stroke? What changes have you had as result of stroke?

Do you have a seizure disorder? How often? What do you do to prevent seizures?


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General Health History: Family History

In your family, has anyone ever had: A stroke?

Seizures?

Tumor in brain or spinal cord?


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General Health History: Personal and Psychosocial History

Have you had changes in your ability to perform personal care?

Do you drink alcohol? Have you ever used recreational drugs? Do you use seat belts?


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Problem-Based History: Headache

Describe your headaches. What do they feel like? Where? Last how long? How often?

Have you had any recent surgeries or medical procedures such as spinal anesthesia or lumbar puncture?


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Problem-Based History: Dizziness

What does it feel like when you are dizzy or lightheaded? Do you feel faint? How often do you experience this dizziness? What makes dizziness worse?

Have you ever had a sensation that room is spinning (objective vertigo), or that you are spinning (subjective vertigo)? Does this happen suddenly or gradually? What makes vertigo worse? What relieves vertigo?


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Problem-Based History: Seizures

Have you ever had a seizure? How often are you having seizures? When was your last seizure? What are they like? Do you become unconscious?

Do you have any warning signs before the seizure starts?

How do you feel after the seizure? Are you confused? Have a headache or aching muscles? Do you spend too much time sleeping?


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Problem-Based History: Seizures (contd.)

When patient loses consciousness during seizures, refer these questions to person who observed patient’s seizure: Describe the seizure movements that you observed. Did you notice any other signs such as a change in

color of the face or lips? Loss of consciousness (if so, how long)? Did the patient urinate or have a bowel movement

during the seizure? After the seizure, how long did it take the patient to get

back to normal?


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Problem-Based History: Seizures (contd.)

Are there any factors that start these seizures? Stress? Fatigue? Activity? Do you take actions to prevent hurting yourself during

seizures?

How have seizures affected your life? Your occupation? Do you wear any identification that indicates you have

seizures?


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Problem-Based History: Loss of Consciousness

When did you lose consciousness or feel you were not aware of surroundings? Did it occur suddenly? What happened just before? Other symptoms? Have diabetes mellitus, liver failure, or kidney failure?


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Problem-Based History: Changes in Movement

How long have you had a change in your mobility? Continuous or intermittent?

Noticed tremors or shaking of hands or face? When did they start? Do they seem worse when you are anxious or at rest? Are they worse when you focus on doing something

(intention)? What relieves tremors—rest, activity, or alcohol? Do they affect your performance of daily activities?


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Problem-Based History: Changes in Movement (contd.)

Have you felt sense of weakness in or difficulty moving parts of your body? Confined to one area or generalized? Associated with anything in particular (e.g., activity)? Does anything help to relieve weakness?

Do you have problems with coordination? Do you have difficulty keeping your balance when you

walk? Do you lean to one side or fall? Which direction? Do your legs suddenly give way?


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Problem-Based History: Changes in Sensation

Where are you experiencing numbness or tingling? How does it feel? Is it associated with any activity?


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Problem-Based History: Difficulty Swallowing (Dysphagia) How long have you had problems

swallowing? Do these problems involve liquids or solids? Both? Do you have excessive saliva or drooling? Do you cough or choke when trying to swallow?


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Problem-Based History: Difficulty Communicating (Aphasia/Dysphasia)

How long have you had problems speaking? Difficulty forming words or finding right words? Difficulty understanding

things said to you? Has handwriting changed? When did that begin? How long did it last?


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Physical Examination


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Examination: Routine Techniqueswith Normal Findings

Assess mental status and level of consciousness.

Evaluate speech for articulation and voice quality and conversation for comprehension.

Note cranial nerve functions (data about expected cranial nerve functions collected during interview). Assessing cranial nerves is not ordinarily performed

during routine examination, but when you suspect an abnormal finding of one or more of cranial nerves.


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Examination: Routine Techniques with Normal Findings (contd.)

Observe gait for balance and symmetry.

Evaluate extremities for muscle strength.


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Examination: Special Circumstances and Advanced Practice

Assess individual cranial nerves: Test nose for smell (olfactory nerve CN1). Test eyes (visual acuity optic nerve CN II) for visual

acuity using Snellen’s chart and an ophthalmoscopic examination of eyes.

Test eyes for peripheral vision. Observe eyes for extraocular muscle movement;

oculomotor (CN III), trochlear (CN IV), and abducens (CN VI) nerves are tested together because they control eye movement.


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Examination: Special Circumstances and Advanced Practice (contd.)

Assess individual cranial nerves: Observe eyes for pupillary size, shape, equality,

construction, and accommodation. Evaluate face for movement and sensation; evaluate the

trigeminal nerve (CN V) for facial movement and sensation. Test motor function by having patient

clench his or her teeth, then palpate temporal and masseter muscles for muscle mass and strength; there should be bilaterally strong muscle contractions.


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Assess individual cranial nerves: Test ears for hearing and balance (CN VIII).

• Whisper test, Weber/Rinne. P.166-8 Test tongue for taste (CNs VII, IX).

• Sweet, salty (VII); sour, bitter (IX).• Not done unless problem reported.

Inspect oropharynx for gag reflex and soft palate movement (CNs IX, X).

• Touch posterior pharynx with tongue blade.


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Assess individual cranial nerves: Inspect tongue for movement, symmetry, strength,

absence of tumors (CN XII).

• Have patient protrude tongue, move toward nose, chin, side to side.

• Have patient press tongue against gloved finger.

Test shoulder and neck muscles for strength and movement (CN XI).

• Have patient shrug shoulders and turn head to side against hands.


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Test cerebellar function for balance and coordination. Tests for balance:

Romberg test (patient standing)—feet together, arms at side, eyes open/closed.

Eyes closed, stand on one foot. Tandem walking. Hopping on one foot, then other. Knee bending. Walking on toes and heels.


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Test cerebellar function for balance and coordination: Tests for coordination of upper extremity:

Rapid pronation/supination on thighs. Alternately touching nose with index

fingers (eyes closed). Touching each finger to thumb in

rapid sequence. Moving index finger between nose

and examiner finger. Tests for coordination of lower extremity:

Heel to shin of opposite leg.


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Assess peripheral nerves. Assess for sensation:

Areas routinely assessed are the hands, lower arms, abdomen, lower legs, and feet.

Flex muscles, then resist against opposite force.

Dermatome map to identify spinal nerve providing sensation.

Monofilament for peripheral sensation for peripheral neuropathy.

Light touch with cotton tipped swab. Vibration using tuning fork on bony

prominence; feel vibration and when it stops.


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Assess peripheral nerves Assess for sensation:

Kinesthetic sensation by moving finger and toe up and down.

Stereognosis by identification of familiar object in hand.

Two-point discrimination by touching parts of body simultaneously with two points—how many points felt?

Graphesthesia by identification of number and letter drawn on hand, back, other area.


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Assess peripheral nerves Evaluate extremities for deep tendon reflexes:

Muscle contraction response to direct and indirect percussion of tendon.

Patient relaxed and lying or sitting down; 4+ scoring system.

Triceps reflex: Contraction of triceps muscle, extension of elbow.

Biceps reflex: Contraction of biceps muscle, flexion of elbow.

Brachioradial reflex: Pronation of forearm, flexion of elbow.


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Assess peripheral nerves. Evaluate for deep tendon reflexes:

Patellar reflex: Contraction of quadriceps muscles, extension of lower leg.

Achilles tendon: Contraction of gastrocnemius muscle, plantar flexion of toes.

Plantar: Plantar flexion of toes using end of handle on reflex hammer, stroke lateral aspect of sole of foot from heel to ball, curving medially across the ball of the foot; expected findings should be plantar flexion of all toes.

Ankle clonus reflexes if reflexes are hyperactive: Sharply dorsiflex foot, maintain in flexion; should be no movement.


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Evaluate superficial reflexes (little clinical significance for presence or absence): Abdominal reflexes by stroking abdomen away from

umbilicus. Cremasteric reflexes (men) by stroking upper, inner

thigh; testicle should rise slightly.


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Additional Assessment for Special Cases

Altered level of consciousness (LOC): Nurse can determine if the patient is alert

and oriented by the way questions are answered during interview.

Change in LOC is earliest and most sensitive indicator of alterations in cerebral function. Awareness is higher level function

controlled by reticular activating system.

Wakefulness is controlled by brainstem.


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Additional Assessment for Special Cases (contd.)

Altered LOC Assessing awareness:

Determined by orientation, memory, attention, calculation, recall, and language, as well as judgment, insight, and abstraction.

Awareness—mental status (orientation, memory, attention, calculation, recall, language, insight, abstraction).


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Altered LOC: If orientation is a concern during history, determine if

oriented to time, place, and person. Date and time is first orientation to

disappear. Only a problem if remains

disoriented after being reoriented. Place is second orientation to

disappear. Person is last orientation to disappear.

Orientation returns in opposite order in which is lost.


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Additional Assessment for Special Cases (contd.) Altered LOC:

Assessing arousal—modified assessment for unconscious individual who cannot participate. When interacting: Assume ability

to hear. Pupillary reaction: Hold eyelid open

when shining light. Inspect to observe respiratory pattern.

Cheyne-Stokes is alternating periods of apnea with hyperventilation (brainstem compression).

Central neurogenic hyperventilation is sustained hyperventilation (lesions of midbrain/pons).


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Altered LOC: Assessing arousal—modified assessment for unconscious individual

who cannot participate. Smell breath for alcohol.

Pupillary response: CN III oculomotor, which originates in midbrain.

Small, reactive pupils: Bilateral cerebral dysfunction.

Bilaterally dilated pupils: Overdose of hallucinogens or CNS stimulants; pressure in brainstem compressing CN III bilaterally.

Unilateral fixed and dilated pupil: Pressure on ipsilateral CN III.


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When patient’s awareness cannot be assessed because unconscious, awakening is assessed. Glasgow Coma Scale: Assess LOC using 15-point scale. Assess for best response to eye opening, motor

response, and verbal response. Determine stimulation or pain required to elicit

response.

Only time acceptable to inflict pain on patient.


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Assessing awakening: First stimulation is touch, normal voice tone. Shake patient on shoulder or leg; shout. Painful stimuli begin peripherally, move centrally.

Applied until patient responds in some way or for at least 15 seconds, but no more than 30 seconds.

Begin by depressing nail bed at cuticle with your fingernail or length of pen or pencil.


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Assessing awakening: Squeeze trapezius muscle very hard. Push upward on supraorbital notch above eye.

Best motor response describes and assigns arbitrary number to level of movement. 5: Localization of pain: Moves to remove stimulus. 4: Attempt to withdraw from stimulus. 3: Abnormal flexion (decorticate). 2: Abnormal extension. 1: No response.


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Additional Assessment for Special Cases (contd.) Meningeal irritation: Assessed when meningitis

suspected Kernig’s sign: Flexing one leg at hip and

knee, then extending knee: No pain indicates negative Kernig’s sign. If inflammation of meninges, patient

reports pain along vertebral column when leg is extended.

Brudzinski’s sign tested with patient supine. Patient’s neck flexed: Reports no pain or

resistance to neck flexion. Positive Brudzinski’s sign patient

passively flexes hip and knee in response to head flexion; reports pain along vertebral column.


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Age-Related Variations: Infants, Children, and Adolescents There are several differences in

assessment of system for infants and young children. Infants’ sensation and cranial nerves are assessed by

observation. Unique reflexes are assessed in infants. Children’s motor development is compared with

standardized tables of normal age and sequences of motor development.

Assessment of older children and adolescents follows same procedures and reveals similar expected findings.


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Age-Related Variations: Older Adults

Assessing neurologic system of an older adult usually follows same procedures as for younger adults.

Tests for balance and gait are often assessed for older adults to identify those at risk for falls.


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Disorders of the CNS: Multiple Sclerosis

Multiple sclerosis: Progressive demyelination of nerve fibers of brain and

spinal cord Autoimmune disorder initiated by virus attacks on

myelin at various sites of CNS

Symptoms vary depending on areas of central nervous system demyelinated: Symptoms: Fatigue, depression, paresthesias Signs: Clinical findings Signs and focal muscle weakness, ocular changes,

bowel, bladder, sexual dysfunction, gait instability, spasticity


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Disorders of the CNS:Meningitis

Meningitis: Inflammation of meninges that surround brain and

spinal cord. Invasion of bacteria, viruses, fungi, parasites, or other

toxins. Bacterial meningitis most common; death results if not

treated promptly. Viral meningitis: Self-limiting infection with full

recovery.


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Disorders of the CNS:Meningitis (contd.)

Clinical findings: Meningitis: Symptoms: Severe headache, fever, and generalized

malaise. Signs: Stiff neck, and positive Brudzinski’s and Kernig’s

signs. LOC may decrease (drowsiness and reduced attention

span), may progress to stupor and coma. Confusion, agitation, and irritability may occur.


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Disorders of the CNS:Encephalitis

Encephalitis is inflammation of brain tissue and meninges. Caused by bacteria, viruses, fungi, and parasites; viral encephalitis

most common.

Clinical findings: Symptoms depend on invading organism and part of brain involved. Onset may be gradual or sudden with symptoms of headache, lethargy,

irritability, nausea, signs of fever, nuchal rigidity, and vomiting. May develop decreased consciousness, motor weakness, tremors,

seizures, aphasia, and positive Babinski’s sign over several days.


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Disorders of the CNS:Spinal Cord Injury

Spinal cord injury (SCI): Any traumatic disruption of spinal cord. Vertebral fractures or dislocations—car accidents,

sports injuries, and other violent impacts.

Injury to cervical spinal cord: Quadriplegia—injury to the thoracic or lumbar spinal cord—or paraplegia.


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Disorders of the CNS:SCI (contd.)

Clinical findings: SCI: Symptoms of complete spinal cord transection:

paresthesia or anesthesia. Signs: Paralysis below level of injury; loss of bowel and

bladder control. SCIs damage upper motor neurons causing spastic

paralysis. When injury incomplete, manifestations are variable

and correlates to location and extent of injury.


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Disorders of the CNS:Head Injury

Craniocerebral injury (head injury): Injury to scalp, skull, brain sufficient to alter normal

function. Open-head injuries result from fractures or penetrating

wounds. Closed-head injuries result from blunt head injury:

Cerebral concussion, contusion, laceration.


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Disorders of the CNS:Head Injury (contd.)

Clinical findings: Craniocerebral injury: Depend on severity of trauma and areas of brain

involved (LOC for a few minutes to several weeks) May have residual deficits in memory, cognition, and

motor or sensory abilities.


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Disorders of the CNS:Parkinson’s Disease

Parkinson’s disease: Develops slowly as brain’s dopamine-producing

neurons in substantia nigra of basal ganglia degenerate; second most common neurodegenerative disease after Alzheimer’s disease.

Clinical findings: Resting tremor, bradykinesia, and rigidity. Other manifestations: Masklike facies, trunk-forward

flexion, muscle weakness, shuffling gait, and finger pill-rolling tremor.


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Disorders of the CNS:Cerebrovascular Accident

Cerebrovascular accident (CVA, stroke): When cerebral blood vessels

become occluded by thrombus or embolus, or when intracranial hemorrhage occurs, brain tissues become ischemic, resulting in CVA or stroke.

Hemorrhage can be caused by hypertension or a cerebral aneurysm (a weakened area in an artery that balloons out due to high pressure of blood).


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CVA


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CVA Warning Signs


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Disorders of the CNS: CVA (contd.)

Clinical findings: Signs and symptoms directly related to areas

of brain involved and extent of ischemia. Sudden unilateral numbness or weakness of

face, arm, or leg. Trouble walking, dizziness, or loss of balance. Sudden, severe headache with no known

cause. May be sudden confusion, difficulty

swallowing (dysphagia), difficulty speaking or understanding speech (aphasia), or partial loss of vision.


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Disorders of the CNS:Alzheimer’s Disease

Alzheimer’s disease: Incurable, degenerative neurologic disorder; begins

with decline in memory.

Most common cause of dementia in Western countries.

Cause unknown; theories suggest genetic tendency, environmental toxins, altered neurotransmitter function, autoimmune reaction, or slow virus.

Patients with history of small strokes have tendency to develop Alzheimer disease; stroke-prevention measures may reduce risk of developing disease.


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Disorders of the CNS:Alzheimer’s Disease (contd.)

Clinical findings: Alzheimer’s disease: Three stages of Alzheimer’s disease have been described:

Early stage lasts 2 to 4 years when patient’s memory begins to fail, such as forgetting names and misplacing items.

Second stage lasts from 2 to 12 years when patient experiences progressive memory loss and has difficulty with activities of daily living; language skills deteriorate and patient becomes disoriented and confused.

During final stage, patient requires total care and is unable to communicate.


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Disorders of Cranial Nerves:Trigeminal Neuralgia Trigeminal neuralgia:

Trigeminal neuralgia (tic douloureux)—intense paroxysmal pain (1 or all 3 branches of CN V).

Etiology is unknown but trauma to face or head or infection of teeth or jaw are contributing factors.

Many can identify trigger points: Small areas on cheek, lip, gum, forehead that initiate pain.

Clinical findings: Abrupt, intense unilateral pain along tissue innervated

by trigeminal nerve; lasts few seconds.


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Disorders of Cranial Nerves:Bell’s Palsy Bell’s palsy:

Acute unilateral paralysis of facial nerve. 80% of patients recover fully after few weeks or

months.

Clinical findings: History of pain behind ear or face few hours or days

before paralysis. Affected side: Eye does not close, forehead does not

wrinkle; patient is unable to whistle or smile.


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Disorders of Peripheral Nerves:Myasthenia Gravis

Myasthenia gravis: Neuromuscular disease with abnormal weakness of

voluntary muscles; improves with rest and anticholinesterase drugs.

Acetylcholine (Ach) receptor sites destroyed, so fewer receptor sites available to initiate muscle contraction, muscle weakness.

Some cases associated with tumors of thymus gland. Three types: Ocular (eyes); bulbar (swallowing),

generalized (skeletal muscles). Most common in younger women and older men.


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Disorders of Peripheral Nerves:Myasthenia Gravis (contd.)

Clinical findings: Ocular myasthenia: Weakness of muscles of eye (ptosis

and diplopia). Bulbar myasthenia: Aspiration of saliva and fluids

(impaired swallowing). Generalized myasthenia: Weakness of face, limbs,

trunk, including muscles of breathing.


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Disorders of Peripheral Nerves:Guillain-Barré Syndrome

Guillain-Barré syndrome: Widespread demyelinization of nerves of peripheral

nervous system (PNS). Motor component of peripheral nerves; believed to be

caused by cell-mediated autoimmune response to viral infection.

Respiratory or gastrointestinal viral infection weeks before onset.

80% to 90% recover with few or no residual deficits; however, patients may die if respiratory depression develops rapidly.


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Disorders of Peripheral Nerves:Guillain-Barré Syndrome (contd.) Clinical findings:

Ascending paralysis begins with weakness and paresthesia in lower extremities, and ascends to upper extremities and face.

Descending variation: Facial, glossopharyngeal, vagus, hypoglossal CNs downward to hand; can reach feet.

Deep tendon reflexes absent. If paralysis of thorax, respiratory depression may

result.


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Question 1

A patient suffered a head injury, and the neurologist notes a deficit in cerebellar function. As the nurse performs the neurologic assessment, which finding indicates a deficit in cerebellar function?

The patient is unable to count by serial sevens in reverse order.When doing the heel-shin exercise (patient supine), the patient’s heel overshoots shin and oscillates. The patient is unable to identify a paper clip (altered stereognosis).The right patellar deep tendon reflex is diminished.


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Question 2

Three days after a camping trip, a patient is in the hospital with a severe headache and photophobia. The nurse performed a test for Kernig’s sign and documented the results as negative. What best explains this action?

The Kernig’s sign assesses for level of consciousness. A negative finding indicates that the patient is alert and oriented to person, place, and time.The symptoms reported could be a sign of peripheral nervous system damage.The symptoms reported could be a sign of meningeal irritation.The Kernig’s sign is a good test of a patient’s ability to withstand deep tendon reflex assessments.Copyright © 2013 by Mosby, an imprint of Elsevier Inc.

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The End


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Documents

Chapter 15 DSN Neurologic System Kevin Dobi, MS, APRN Copyright © 2013 by Mosby, an imprint of Elsevier Inc