Neurology powerpoint snagit

Chapter 31
Neurology

Copyright © 2007, 2006, 2001, 1994 by Mosby, Inc., an affiliate of Elsevier Inc.

Objectives
 Describe nervous system anatomy and
physiology

 Outline pathophysiological changes in the
nervous system that may alter cerebral
perfusion pressure

 Describe assessment of patients with central
nervous system disorders


Objectives
 Describe pathophysiology, signs and
symptoms, and management techniques for:
 Coma
 Stroke
 Headache
 Seizure disorders
 Brain neoplasm
 Brain abscess
 Degenerative disease
 Intracranial bleeding


Scenario
Your patient is a 58-year-old man who awoke
with drooping on the right side of his face and
slurred speech. He has a history of seizures
and high blood pressure. He is very anxious
and crying as you begin your assessment and
care.


Discussion
 What additional assessments should you
perform on this patient?

 List some possible causes of his facial drooping

 What is the significance of his medical history?

 Describe some interventions that you will
consider for this man

Nervous System Anatomy
 Two parts
 Central nervous system
(CNS)
 Peripheral nervous system
(PNS)

 CNS
 Brain
 Spinal cord
• Both encased in and
protected by bone


Peripheral Nervous System
 43 pairs of nerves
originate from CNS to
form PNS
 12 pairs of cranial nerves
• Originate from brain
 31 pairs of spinal nerves
• Originate from spinal cord


Cells of the Nervous System
 Neurons—fundamental units

 Neuroglia—connective tissue cells
 Protect and hold neurons together

 Neurons
 Cell body—single nucleus and nucleolus
 Dendrites—branching projections
 Axon—single, elongated projection



Neuron with dendrites,
cell body, axon

Segment of myelinated axon

Neuron


 Dendrites transmit impulses to neuron cell
bodies

 Axons transmit impulses away from cell
bodies
 Bundles of parallel axons with sheaths are white
• White matter


 In PNS, bundles of axons and their sheaths
are called nerves
 Collections of nerve cells are gray
• Gray matter
 Gray matter is integration site within nervous
system


Types of Neurons
 Classified by impulse transmission direction:
 Sensory neurons
 Motor neurons
 Interneurons


Impulse Transmission
 Nervous system transmission similar to
electrical impulse conduction in heart

 Unmyelinated axons

 Myelinated axons


Nerve Impulse Conduction

Unmyelinated fiber

Myelinated fiber


Synapse
 Membrane-to-membrane contact

 Separates axon endings of one neuron (presynaptic
neuron) from dendrites of another neuron
(postsynaptic neuron)
 Presynaptic terminal
 Synaptic cleft
 Plasma membrane of postsynaptic neuron

 Presynaptic terminals have synaptic vesicles
containing neurotransmitter chemicals

 Neurotransmitters


Components of a Synapse


Reflexes
 Receive stimulus and generate response
 Unidirectional impulse conduction
• Sensory receptor
• Sensory neuron
• Interneurons
• Motor neuron
• Effector organ

 Vary in complexity


Neural Pathway Involved in
Patellar (“Knee Jerk” ) Reflex


Blood Supply
 Arterial blood supply to brain
 Vertebral arteries
 Internal carotid arteries

 Circle of Willis
 Safeguard to ensure blood supply to all parts of
the brain if vertebral or internal carotid arteries are
blocked


Blood Supply


Veins
 Veins that drain blood from head form venous
sinuses

 Drain into internal jugular veins

 Internal jugular veins join subclavian veins on
each side of the body


Venous Sinuses Associated
with the Brain


Ventricles of the Brain
 Lateral ventricle

 Space in cerebral
hemispheres is filled
with cerebrospinal fluid


Divisions of the Adult Brain
 Brain stem
 Medulla
 Pons
 Midbrain

 Cerebellum

 Diencephalon
 Hypothalamus
 Thalamus

 Cerebrum


Neurological Pathophysiology
 Cerebral blood flow (CBF) interrupted by:
 Structural changes or damage
 Circulatory changes
 Alterations in intracranial pressure (ICP)

 Three structures in intracranial space:
 Brain tissue
 Blood
 Water


Intracranial Space
 Brain tissue
 Mostly water, intracellular and extracellular

 Blood
 Major arteries in base of brain
 Arterial branches, arterioles, capillaries,
venules, veins within brain substance
 Cortical veins and dural sinuses


Intracranial Space
 Water in:
 Ventricles of brain
 Cerebrospinal fluid
 Extracellular and intracellular fluid


Cerebral Perfusion Pressure (CPP)
 Cerebral blood flow depends on cerebral
perfusion pressure
 Pressure gradient across brain


Cerebral Blood Flow
 Cerebral blood flow controls oxygen and
glucose delivery
 Cerebral perfusion pressure (CPP) and cerebral
vascular bed resistance
 CPP determined by:
• Mean arterial pressure (MAP): (Diastolic pressure + ⅓
pulse pressure) minus intracranial pressure


Cerebral Blood Flow
 As ICP approaches MAP:
 Gradient for flow decreases
 Cerebral blood flow restricted

 When ICP increases, CPP decreases
 As CPP decreases, cerebral vasodilation
 Increases cerebral blood volume (increasing
ICP) and further cerebral vasodilation


Goals of Emergency Care
 Airway control

 Stabilization and support of cardiovascular system

 Intervention to interrupt ongoing cerebral injury

 Protection from further harm

 Transport to an appropriate medical facility


Initial Assessment
 Level of consciousness

 Ensure patent airway

 Immobilize cervical spine

 Airway adjuncts if indicated
 Monitor for respiratory arrest

 Ventilatory support and supplemental oxygen for any
neurological emergency


Physical Examination
 Important elements
 Patient history
 History of event
 Vital signs
 Respiratory patterns


History
 History of event from patient, family,
bystanders

 If loss of consciousness, ascertain events prior
to unconscious state:
 Patient position (sitting, standing, lying down)
 Complaints of a headache
 Seizure activity
 Fall


History
 When no history is available, assume the
onset of unconsciousness was acute and that
an intracranial hemorrhage is likely


Vital Signs
 Assess and record frequently
 May change rapidly
 Monitor ECG for dysrhythmias

 Cushing’s triad, if increased ICP:
 Increase in systolic pressure (widening pulse
pressure)
 Decrease in pulse rate
 Irregular respiratory pattern


Respiratory Patterns
 Normal or abnormal

 Abnormal respiratory patterns
 Cheyne-Stokes respiration
 Central neurogenic hyperventilation
 Ataxic respiration
 Apneustic respiration
 Diaphragmatic breathing


Respiratory Patterns


Neurological Evaluation
 AVPU and Glasgow Coma Scale
 Determine baseline neurological status
 Allow comparisons

 Report and record patient information with
specific descriptive terms


Posturing, Muscle Tone, and Paralysis
 Disturbances of posture result from:
 Flexor spasms
 Extensor spasms
 Flaccidity


 Decorticate rigidity
 Flexion
 Abnormal flexor responses of one or both arms
with extension of legs
 Structural impairment of certain cortical regions of
brain


 Decerebrate rigidity
 Extension
 Abnormal extensor response of arms and legs
 Worse prognosis than decorticate rigidity
 Impairment of subcortical regions of brain

 Flaccidity
 Brain stem or cord dysfunction
 Dismal prognosis


Posturing

Abnormal flexion
(decorticate posturing)

Abnormal extension
(decerebrate posturing)


Assessment—Abnormal Reflexes
 Positive Babinski's sign
 Plantar reflex
 Dorsiflexion of great toe
with or without fanning of
toes

 Relaxation of sphincter
tone with evacuation of
bowels and/or bladder


Pupils at Different
Levels of Consciousness


Extraocular Movements
 Conjugate gaze

 Dysconjugate gaze


Conjugate Gaze


Dysconjugate Gaze


Coma
 Abnormally deep state of unconsciousness

 Cannot arouse by external stimuli

 Two mechanisms
 Structural lesions
 Toxic metabolic states


Coma
 Causes
 AEIOU-TIPS

 Assessment

 Management


Stroke and Intracranial Hemorrhage
 Stroke (“brain attack”)

 Sudden interruption in brain blood flow

 Results in neurological deficit
 Incidence
 Morbidity/mortality
 Risk factors


Stroke Pathophysiology
 Blood supply to brain through four vessels
 Carotid arteries
• 80% of cerebral blood flow
 Vertebral arteries
• Form basilar artery
• 20% of cerebral blood flow
 Interconnected at various levels
• Circle of Willis

 Onset and symptoms depend on area of
brain involved

Types of Stroke
 Neurological manifestations of decrease in
blood flow to brain

 Ischemic and hemorrhagic strokes
 Both can be life threatening
 Ischemic stroke rarely causes death in first hour
 Hemorrhagic stroke can be rapidly fatal


Ischemic Stroke
 85% of strokes are ischemic

 Cerebral thrombosis due to:
 Atherosclerotic plaques
 Extrinsic pressure brain mass

 Thrombotic stroke
 Slower to develop than cerebral hemorrhage


Cerebral Embolus
 Intracranial vessel occluded by foreign
substance from outside CNS

 Sources of cerebral emboli

 Signs and symptoms
 Similar to thrombotic stroke
 Usually develop more quickly
 Often have identifiable cause


Hemorrhagic Stroke
 Incidence

 Morbidity/mortality

 Causes
 Cerebral aneurysms
 Arteriovenous (AV) malformations
 Hypertension



Transient Ischemic Attacks
 Focal cerebral dysfunction lasting from minutes
to several hours

 Return to normal <24 hrs

 No permanent neurological deficit
 Indication of impending stroke



Differentiating between Ischemic and
Hemorrhagic Stroke
Ischemic Stroke Hemorrhagic Stroke
Most common Least common
Atherosclerosis or tumor within Cerebral aneurysms, AV
brain malformations, hypertension
Slow onset Abrupt onset
Long history of vessel disease Stress or exertion

Valvular heart disease and atrial Cocaine and other
fibrillation sympathomimetic amines
Hx of angina, previous strokes May be asymptomatic before
rupture


Assessment
 Emergency care priorities
 Maintain patent airway
 Provide adequate ventilatory support
 Oxygen
 Thorough history

 Management
 Time in field must be reduced
 Establish time of symptom onset (if possible)
 Supportive measures


Cincinnati Prehospital Stroke Scale
 Evaluates three physical findings:
 Facial droop
 Arm drift
 Speech


Los Angeles Prehospital Stroke Screen
(LAPSS)
 Age
 History
 Symptom duration
 Baseline disability
 Identifies asymmetry in:
• Facial smile/grimace
• Grip
• Arm strength

 Asymmetry in any category indicates a possible stroke


Prehospital Stroke Management
 Rapid transport
 Determine time of symptom onset
 Manage airway
 Oxygen if SaO2 <92%
 Monitor vital signs and ECG
 Initiate IV en route
 Assess blood glucose
 Control seizures with benzodiazepines


Seizure Disorders
 Temporary alteration in behavior or consciousness

 Caused by abnormal electrical activity of neurons in brain

 Incidence


 Causes


Types of Seizures
 All seizures pathological
 Arise from almost any region of brain
• Have many clinical manifestations
 Most common types
• Generalized
• Partial (focal)


Generalized Seizures
 No definable origin (focus) in brain

 May progress to generalized seizure

 Petit mal (absence seizures)

 Grand mal (tonic-clonic) seizures


Petit Mal Seizures
 Often in children 4-12 y/o

 Brief lapses of consciousness without loss of posture

 Often no motor activity although may have:
 Eye blinking
 Lip smacking
 Isolated clonic activity


Grand Mal Seizures
 Common

 Associated with significant morbidity and
mortality

 May be preceded by an aura (olfactory or
auditory sensation)
 Warning of imminent convulsion


Grand Mal Seizure—Characteristics
 Sudden loss of consciousness with loss of
organized muscle tone
 Tonic phase
 Clonic phase
 Postictal phase

 If prolonged or recur before patient regains
consciousness:
 Status epilepticus


Partial Seizures
 Arise from identifiable cortical lesions

 Simple or complex


Simple Partial Seizures
 Seizure activity in motor or sensory cortex

 Simple motor seizures

 Simple sensory seizures

 Jacksonian seizure


Complex Partial Seizures
 Focal seizures in temporal lobe (psychomotor)

 Manifest as changes in behavior

 Classic complex partial seizure
 Preceded by aura
 Abnormal repetitive motor behavior
 Typically less than 1 minute
 Regains normal mental status quickly
 May progress to tonic-clonic seizure


Hysterical Seizures (Pseudoseizures)
 Mimic true seizure

 Psychological causes
 Not considered true seizures
 No organic origin
 Do not respond to normal treatment

 Usually terminated by sharp commands or
painful stimuli


History and Physical Exam
 History of seizures
 Frequency
• Medication compliance

 Description of seizure
 Duration
 Pattern of seizure
 Aura
 Generalized or focal
 Incontinence
 Tongue biting


History and Physical Exam
 History
 Recent or past history of head trauma
 Recent history of fever, headache, nuchal rigidity
 Significant past medical history

 Physical examination


Syncope versus Seizure
 May be difficult to determine
 Differentiating characteristics are in symptoms
before and after event


Management
 Prevent physical injury

 Oxygen via nonrebreather mask

 Move away from onlookers

 Transport for physician evaluation


Status Epilepticus
 Seizure activity >30 min or recurrent seizure
without intervening period of consciousness

 Emergency

 Causes

 Associated complications


Status Epilepticus
Management
 Secure airway, ventilate, oxygenate

 Protect from injury

 Initiate IV

 Benzodiazepines to control seizures


Headache
 Categorized by underlying cause:
 Tension headaches
 Migraines
 Cluster headaches
 Sinus headaches

 Common medical complaint


Tension Headaches
 Muscle contractions of face, neck, scalp

 Causes


 Management


Migraines
 Severe, incapacitating headaches

 Often preceded by visual or GI disturbances

 Intense, throbbing pain on one side of head
 May spread
 Often nausea and vomiting

 Constriction and dilation of blood vessels
 Imbalance of serotonin or hormone fluctuations


Migraines
 Also triggered by:
 Excessive caffeine use
 Various foods
 Changes in altitude
 Extremes of emotions

 Management


Cluster Headaches
 Occur in bursts (clusters)

 Often several hours after asleep

 Pain
 Severe
 Usually around one eye
 Often nasal congestion and tearing
 Often lasts 30 min to 2 hrs, and recurs a day or so later
 May occur every day for months before long periods of
remission


Cluster Headaches
 Histamine headaches
 Release of histamine from tissues
 Symptoms
• Dilated carotid arteries
• Fluid accumulation under eyes
• Tearing
• Rhinorrhea

 Management


Sinus Headaches
 Pain in forehead, nasal area, and eyes

 Feeling of pressure behind face

 Inflammation or infection of membranes lining
sinus cavities or allergies

 Management


Brain Neoplasm
 Mass in cranial cavity

 Malignant or benign

 Risk factors


 Management


Brain Abscess
 Accumulation of purulent material (pus)
surrounded by a capsule within brain

 Causes

 Clinical manifestations

 Management


Muscular Dystrophy
 Inherited muscle disorder

 Unknown cause

 Slow, progressive degeneration of muscle

 Different forms classified by:
 Age symptoms appear
 Rate of disease progression
 How inherited

 Duchenne muscular dystrophy
 Most common type


Multiple Sclerosis (MS)
 Progressive CNS disease

 Scattered patches of myelin in brain and
spinal cord are destroyed
 Cause
 Incidence
 Morbidity/mortality
 Clinical manifestations
 Management


Dystonia
 Local or diffuse alterations in muscle tone
 Usually abnormal muscle rigidity

 Causes
 Painful muscle spasms
 Unusually fixed postures
 Strange movement patterns


Dystonia
 Localized dystonia
 Torticollis (painful neck spasm)
 Scoliosis (abnormal curvature of the spine)

 Generalized dystonia
 Parkinson disease
 Stroke

 Also feature of schizophrenia or side effect of
antipsychotic drugs

 Management


Parkinson Disease
 Degeneration or damage to nerve cells within basal
ganglia in brain

 Leading neurologic disability in persons over 60 yo

 Characterized by :
 Muscle rigidity
 Tremors (start on one side)
 Weakness
 Shuffling gait
 May lead to dementia


Central Pain Syndrome
 Infection or disease of trigeminal nerve (cranial nerve
V)
 Tic douloureux (trigeminal neuralgia)
• Common form
• Excruciating pain

 Affects one side of face

 Brief attacks of intense pain

 May be associated with MS in persons under 50 yo


Bell’s Palsy (Facial Palsy)
 Paralysis of facial muscles
 Inflammation of seventh cranial nerve
 Usually one sided and temporary
 Often develops suddenly
 Affects 1 in 60 or 70 people

 Often spontaneous recovery


Bell’s Palsy


Amyotrophic Lateral Sclerosis (ALS)
 Lou Gehrig’s disease

 Rare disorders (motor neuron disease)

 Nerves that control muscular activity degenerate within
brain and spinal cord

 Often begins with weakness in the arms and hands

 Paralysis progresses to include respiratory muscles

 Death often within 2-4 years of diagnosis


Peripheral Neuropathy
 Diseases and disorders affecting peripheral nervous
system, including:
 Spinal nerve roots
 Cranial nerves
 Peripheral nerves

 Damage or irritation of axons or myelin sheaths

 Affect different areas of body

 Many medical causes


Myoclonus
 Rapid and uncontrollable muscular
contractions (jerking) or spasms of muscle(s)
 Occur at rest or with movement

 Associated with:
 Disease of nerves and muscles
 Brain disorder (e.g., encephalitis)
 Seizure disorder

 May occur in healthy persons


Spina Bifida
 Congenital defect

 One or more vertebrae fail to develop completely
 Leaves portion of spinal cord exposed

 Most common in lower back

 Incidence


 Cause is unknown


Types of Spina Bifida
 Severity depends on how much nerve tissue
is exposed after neural tube closure
 Spina bifida occult
 Meningocele
 Myelocele
 Encephalocele


Meningocele


Myelomeningocele


Polio (Poliomyelitis)
 Caused by poliovirus hominis

 Incidence declined in 1950s after vaccine

 Risk if unvaccinated and traveling abroad

 Febrile illness with or without paralysis

 Can cause breathing difficulty


Conclusion
Acute disorders of the nervous system
require rapid assessment and management.
Paramedics can help reduce mortality and
morbidity, and produce maximal potential for
rehabilitation and recovery.


Questions?


Neurology powerpoint snagit

Recomendados

Recomendados

Mais conteúdo relacionado

Semelhante a Neurology powerpoint snagit

Semelhante a Neurology powerpoint snagit (20)

Neurology powerpoint snagit