Transcript The Brain - Cape Breton University

NURSING OF ADULTS 111
Introduction to Neurological Nursing
NERVOUS SYSTEM
 CENTRAL NERVOUS SYSTEM
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BRAIN
SPINAL CORD
 PERIPHERAL NERVOUS SYSTEM
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CRANIAL NERVES---12 pairs
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SPINAL NERVES---31 pairs
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8 CERVICAL
12 THORACIC
5 LUMBAR
5 SACRAL
1 COCCYGEAL
AUTONOMIC NS
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SYMPATHETIC
PARASYMPATHETIC
CENTRAL NERVOUS
SYSTEM
 1. Spinal cord (automatic motor
responses—pathways for messages to
and from the brain)
 2. Lower brain (control of B.P., resp,
equilibrium, muscular movements,
primitive emotions) -basal ganglia,
thalamus, hypothalamus, midbrain,
pons, medulla & cerebellum
 3. Higher brain (cortical function –
memory, reasoning, speech, vision,
hearing, sensation, abstraction &
patterns of responses, ) cerebral
cortex
.
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

The Brain
 Centre of our
thought
 Interpreter of our
external environment
 Origin of control
over conscious
(voluntary) and
unconscious
(involuntary)
movement
FUNCIONAL AREAS OF THE
CEREBRAL CORTEX
Sensory area (pain, touch, etc.)
Motor cortex
Visual interpretation
area
Written
speech
Parietal Lobe
Frontal
Lobe
Occipital Lobe
Temporal Lobe
Motor
speech
Auditory receiving area
Brain Stem
Cerebellum
Auditory interpretation area
Visual receiving
area
Functions of the cerebral cortex:

Frontal lobe – “personality” also contains the
motor cortex – controls voluntary motor activity.
Prefrontal areas controls
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1.
2.
3.
4.
5.
6.
7.
Concentration
Motivation
Ability to formulate or select goals
Ability to plan
Ability to initiate or terminate actions
Ability to self monitor
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 and
awareness 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)
 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
 Animal sounds, train whistles, automobile horn etc.
 Damage to Wernicke’s area causes the inability to
understand spoken or written language or recognize music.
Cognitive Function
Each area of the brain
controls particular
activities. Generally
the outer and forward
areas share more
advanced function; the
inner structures
determine basic
metabolic processes.
Each side of the brain
receives the sensory
impressions and
activates the muscles
of the opposite side of
the body.
WHAT PROTECTS THE BRAIN?
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SKULL
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8 bones encase the brain protecting it (frontal, temporal, parietal, occipital) fuse in
childhood in junctions called sutures.
MENINGES
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Fibrous connective tissue covering the brain the spinal cord providing protection,
support, and nourishment
• Dura Mater, Arachnoid, Pia Mater
CSF
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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.
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Cushions and Shock Absorber
BLOOD-BRAIN BARRIER
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Blocks macromolecules and many compounds from dyes and medications from
reaching the neurons.

Helps keep a stable env. for neurons by regulating ion movement.
NEURONS
 Neurons (specialized
cells), make
complex connections
with one another to
send and receive
messages in the brain
and spinal cord.
 The brain and spinal
cord is like a
computer, the neurons
are like the switches
and circuitry that make
it work.
CEREBRAL CIRCULATION
 Receives 15% of cardiac output
 High metabolic demand and does not store
nutrients – can be critical with diabetics (glucose)
feel shaky, foggy, confused.
 Flows against gravity (arteries fill from below and
veins drain from above)
 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 nerves
come from the brainstem.
The brainstem is the pathway for
all fiber tracts passing up and down
from peripheral nerves and spinal
cord to the highest parts of the brain.
Anatomy of
the
Autonomic
Nervous
System
(Brunner
2000, p. 1618)
What impact
on body re SC
injury?
EFFECTS ON AGING
 Loss of nerve cells therefore slower to receive and send
messages
 Learning , memory and reasoning decline
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Memory loss for recent events
 Takes longer to process thoughts and put them into action
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No change in intelligence but it takes longer to learn
 Decreased ability to hear, see certain colors, decreased
peripheral vision, sense of smell
 Reduced taste buds and sense of touch in fingers and toes
Cognitive and Perceptual
Disorders
 Assessment of the Neurologic System
Neurologic System: History
 Biographical and Demographic Data (is the data reliable)
 Current Health (what brought them to seek care)
 Past Health History
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Childhood & Infectious Diseases – meningitis, herpes
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Major Illnesses & Hospitalizations –diabetis, CVA, liver failure
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Medications – prescribed, OTC, herbal
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Growth and Development – duration of problem
 Family Health History- ALS, MD, Huntington’s
 Psychosocial History – personality changes, sleep patterns, stressors,
exposure to chemicals, pesticide (Agent Orange)
Neurologic System:
Physical Exam
 Cervical spinal cord injury can exhibit dec. B/P, P
& T – (loss of sympathetic nervous system)
 Vital Signs – note changes
 Mental Status – note changes
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Level of Consciousness
Orientation
Memory – long & short term
Mood and Affect- aggression & euphoria
Intellectual Performance – knowledge/calculation
Judgment and Insight – assess reasoning
Language and Communication – fluent & appropriate
Neurologic System:
Physical Exam
 Head, Neck, and Back
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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)
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Palpation
– Nodules, boggy skull, nuchal rigidity
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Percussion
– Gentle percussion – watch for pain response
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Auscultation
– Major neck vessels – turbulent - ? High risk for CVA
Neurologic System:
Physical Exam
 Cranial Nerves
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Olfactory Nerve (CNI): Smell
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Optic Nerve (CN II): Vision
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Oculomotor (CNIII),Trochlear (CNIV), Abdocens (CNVI): Eye control
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Trigeminal Nerve (CNV): Sensations of the face, movement of the mouth
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Facial Nerve (CNVII): Facial muscles
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Acoustic Nerve (CNVIII): Hearing
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Glossopharyngeal (CNIX), Vagus (CNX) Nerves: Palate, Uvula
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Spinal Accessory Nerve (CNXI): Muscles of the Shoulders and Neck
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Hypoglossal Nerve (CN XII): Tongue
Neurologic System:
Physical Exam
 Motor System
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Muscle Size- symmetrical
Muscle Strength - symmetrical
Muscle Tone – rigid/flaccid/normal
Muscle Coordination – repetitive movement
Gait and Station- proprioception
Movement – fine & gross motor
Motor Testing of Unconscious Patients – to test
response to pain – sternal rub, pressure on nail bed,
orbit of the eye.
Neurologic System:
Physical Exam
 Sensory Function
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Superficial Sensations
• Touch and Pain
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Mechanical Sensations
• Vibration – tuning fork
• Proprioception
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Discrimination – stereognosis – distinguish objects,
graphism – trace letters on palm of hand
Neurologic System:
Physical Exam
 Abnormal Reflexes
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Babinski’s Reflex
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Jaw Reflex
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Palm-Chin Reflex
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Clonus
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Snout Reflex
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Rooting Reflex
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Sucking Reflex
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Grasp Reflex
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Chewing Reflex
Posturing
 Abnormal flexion (decorticate) internal
rotation of the arms & wrists
 Abnormal extension (decerebrate) extension
& external rotation of arms & wrists – more
serious than abnormal flexion - midbrain
Neurologic System:
Physical Exam
 Normal Reflexes
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Superficial (cutaneous) Reflexes
Abdominal Reflex
Plantar Reflex
Corneal Reflex
Pharyngeal Reflex - gag
Cremasteric Reflex
Anal Reflex – check with MVA
Deep Tendon Reflexes
Neurologic System:
Physical Exam
 Autonomic Nervous System
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Cannot be examined directly
Clinical Manifestations
• Increase/Decrease Heart Rate
• Vasoconstriction/Dilatation Peripherally
• Bronchoconstriction/Dilatation
• Increase/Decrease Peristalsis
• Pupil Constriction/Dilatation
Neurologic System:
Physical Exam
 Functional Assessment
 Clinical Applications
 Diagnostic Tests-Noninvasive
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Skull and Spinal X-Ray Studies
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Computed Tomography
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Magnetic Resonance Imaging
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Positron Emission Tomography
Neurologic System:
Diagnostic Tests
 Invasive
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Lumbar Puncture
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Myelography
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Cisternal Puncture
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Cerebral Angiography
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Cerebral Perfusion Studies
Neurologic System:Diagnostic Tests
 Noninvasive Tests of Function
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Electroencephalogram
Evoked Potential Studies
Neuropsychological Testing
 Invasive Tests of Function
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Caloric Testing
Peripheral Nerve Studies
Muscle Biopsy
Cellular Assessment
CONSCIOUSNESS
… is a state of general awareness of oneself and
environment.
Consciousness has two components:
1. Arousal (wakefulness): concerned with the
person’s wakefulness (Controlled by Cerebral
Cortex Function + Upper Brain Stem)
2. Content/cognition/awareness (cognitive +
affective function or awareness of self): the
sum of cerebral mental functions (Controlled by
Cerebral Cortex Function).
AROUSAL
The mediator of arousal and sensory stimulation is the
RETICULAR ACTIVATING SYSTEM (RAS). The RAS is
located in the Brain Stem and contains projections
between the Thalamus and the Cortex. A network of
neurons in the RAS monitors ascending and descending
stimuli.
Nerve cells run through the medulla, pons, midbrain,
thalamus, and hypothalamus. RAS maintains muscle
tone, keeps the higher brain in a state of alert
wakefulness, and filters incoming messages.
HOW UNCONSIOUSNESS
OCCURS
 Disruption of the ascending reticular
activating system (extending from the
length of the brain stem into the thalamus)
 Disruption in the function of one or both
cerebral hemispheres
 Metabolic depression of the brain (i.e.-----as
with drug overdose)
DISORDERS PRODUCING
UNCONSCIOUSNESS
 Structural lesions in the brain placing pressure on the
brain stem or other structures
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Brain tumors
Head trauma
Cerebral hemorrhage
 Metabolic disorders and diffuse lesions
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Hypoxia/Ischemia
Liver, lung and kidney disorders
Toxins, hypoglycemia, fever, infections, fluid/electrolyte
imbalance, acid-base imbalance
 Psychogenic causes
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Catatonia and Hysteria
 Why is it important to assess LOC?
 How do we do this?
Stages of decreasing LOC
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ALERT
CONFUSION
DISORIENTATION
LETHARGY
OBTUNDATION
STUPOR
COMA
SUSTAINED
UNCONSIOUSNESS
 COMA
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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
 Respiration controlled by cerebrum, pons
and medulla
 Airway obstruction and aspiration common
complications
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Obstructed airways causesCO2
retentionvasodilationcerebral
edemaincreased ICP
Reduced O2 levelsless oxygen to
brainincreased ICP
EYE MOVEMENTS IN THE
UNCONSCIOUS CLIENT
 CN responsible for eye movement exit thru the
brain stem. If compressed eye movement is
impaired.
 Normally gaze straight ahead and track together
 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 CLIENT
 Nuclei of CN11 and 111 located below
cerebrum and in mid-brain
 Assessed for size, equality, reaction,
responsive
 Fixed and dilated late signs of herniation
and severe hypoxia
 Other causes
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Hypothermia, Medications, Lesions
MOTOR RESPONSES SEEN IN
UNCONSCIOUSNESS
 POSTURING
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Decorticate
Decerebrate
Flaccidity (Unilateral or Bilateral)
 OTHER MOTOR SIGNS
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Primitive sucking or snout reflexes
Strong reflexive hand grasps
Restlessness
Resistance to passive movements
Hemiplegia
Hemiparesis
Seizures
CHANGES IN VITAL SIGNS
 Wide variations may be seen with various levels of
consciousness and some changes directly related
to the cause of the unconsciouness
 Cushings (Triad) may develop with increased ICP
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Decreased pulse
Increased systolic BP with same or slightly higher
diastolic resulting in a widened Pulse Pressure
Slow respirations
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ASSESSING CONSCIOUSNESS
The Glasgow Coma Scale
(GCS)
Universally used
Measures eye, verbal, and motor
response
Excellent scale to measure Arousal.
Know the difference b/t
content & arousal
Eyes
Motor
GLASGOW COMA SCALE SCORE (GCS)
1 Closed at all times
2 Opens to pain
3 Opens to voice command
4 Open spontaneously
1 No response
A score of 10 or less
2 Extension (decerebrate rigidity) indicates a need for
3 Flexion posturing
emergency attention
4 Flexion withdrawal
15 (top score)
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
A score less than 7 is
interpreted as coma
CONTENT
Besides orientation to time, place and person the
following cognitive abilities should also be assessed:
•Attention and vigilance
•Memory – short, intermediate, long term
•Language – understanding of spoken and written 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 test for
cognitive function.
Any process that results in ↑ICP
will produce impairment of
content and arousal.
***Remember restless and other
changes in behavior frequently
precede changes in vital signs,
However, changes in LOC will
occur first.