Nervous System Diseases and Disorders - Pathophysiology

Nervous System Diseases and Disorders

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Chapter 15
Nervous System Diseases
and Disorders

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Anatomy and Physiology
•Nervous system
–Brain, spinal cord, and nerves
–Central nervous system (CNS)
•Brain
•Spinal cord
–Peripheral nervous system (PNS)
•Autonomic nervous system
•Cranial and spinal nerves

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Common Signs and Symptoms
•Headache
•Nausea and vomiting
•Weakness
•Mood swings
•Fever

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Common Signs and Symptoms
•Symptoms specific to CNS:
–Stiffness in neck, back, or extremities
–Inability to move any part of body
–Seizures or convulsions
–Paralysis
–Visual difficulties

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Common Signs and Symptoms
•Symptoms specific to CNS: (continued)
–Inability to speak
–Paralysis
–Extreme or prolonged drowsiness
–Stupor, unconsciousnes
–Amnesia or extreme forgetfulness

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Diagnostic Tests
•Cerebrospinal fluid
•Measurement of intracranial pressure
•X-rays of skull and vertebral column
•Myelogram
•Angiogram
•Electroencephalography (EEG)
•CT and MRI

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Infectious Diseases
•Encephalitis
–Inflammation of brain tissue caused by bacteria
and viruses
–Symptoms:
•Headache
•Elevated temperature
•Stiff neck and back
•Lethargy
•Mental confusion
•Coma
–Treatment:
•Treatment is supportive
•Antiviral medication may be effective

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Infectious Diseases
•Meningitis
–Inflammation of meninges or coverings of brain
and spinal cord
–Causes:
•Bacteria
•Virus
•Fungi
•Toxins
–E.g., lead, arsenic

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Infectious Diseases
•Meningitis
–Symptoms:
•High fever
•Severe headaches
•Photophobia
•Stiffness and resistance in neck (nuchal rigidity)
•Drowsiness, stupor, seizures
•Coma

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Infectious Diseases
•Meningitis
–Diagnosis
•Lumbar puncture to find causative agent
–Treatment
•Antibiotics for bacterial infection
•Antipyretics
•Anticonvulsants
•Quiet, dark environment
–

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Infectious Diseases
•Poliomyelitis
–Viral infection affecting brain and spinal cord
–Cause:
•Virus spread by oropharyngeal secretions and infected
feces
–Almost eliminated by vaccine in United States

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Infectious Diseases
•Poliomyelitis
–Symptoms:
•Muscle weakness
•Neck stiffness
•Nausea and vomiting
•Muscles atrophy and become paralyzed
–Diagnosis
•Virus culture from throat, feces, and/or spinal fluid

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Infectious Diseases
•Poliomyelitis
–Supportive treatment:
•Analgesics
•Bedrest during acute phase
•Long-term physical therapy and braces may be needed
•If respiratory system involved, mechanical ventilation
may be needed

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Infectious Diseases
•Tetanus
–Highly fatal infection of nerve tissue
–Cause
•Bacteria Clostridium tetani
–First symptom:
•Jaw stiffness
•Commonly called lockjaw

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Infectious Diseases
•Rabies
–An often fatal encephalomyelitis
–Caused by virus
–Primarily affects animals
•E.g., dogs, cats, raccoons, squirrels
–Transmitted to humans through bite of infected
animal

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Infectious Diseases
•Rabies
–Symptoms:
•Fever
•Pain
•Paralysis
•Convulsions
•Rage
•Spasms and paralysis of muscles for swallowing
•Throat spasms leading to hydrophobia

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Infectious Diseases
•Rabies
–Symptoms:
•Inability to swallow
•Drooling of frothy saliva
–Treatment:
•Immediate washing of area with soap and water
•Anti-rabies injections
–No cure

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Infectious Diseases
•Shingles
–Viral disease caused by herpes zoster (chicken pox
virus)
–Symptoms
•Itchy, painful, red rash and small vesicles on sensory nerve
paths
•Symptoms last 10 days to several weeks
–Diagnosis
•Made based on the appearance of lesions
•Viral culture test

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Shingles
Photo courtesy Robert A. Silverman, MD,
Pediatric Dermatology, Georgetown University

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Infectious Diseases
•Shingles
–Treatment:
•There is no cure
•Treatment is symptomatic
•Antivirals
•Analgesics
•Antipyretics
•Antipruritics
–Vaccine recommended by CDC for adults over age
60

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Vascular Disorders
•Cerebrovascular accident (CVA)
–Also known as stroke
–Is due to a poor blood supply to the brain
–Causes
•Cerebral thrombus
•Cerebral embolism
•Cerebral hemorrhage

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Vascular Disorders
•CVA
–Symptoms: numerous symptoms depending on
the area of the brain affected and the severity of
the CVA
•Sudden loss of consciousness
•Confusion
•Poor coordination
•Dysphasia
•Dysphagia
•Hemiparesis

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Vascular Disorders
•CVA
–Diagnosis
•Physical exam, EEG, CT scan, and MRI
–Treatment:
•Anticoagulant
•Hypertensive medications
•Rehabilitation program

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Vascular Disorders
•CVA
–Risk factors:
•Smoking
•High-fat diet
•Obesity
•Lack of exercise
–Surgical prevention treatment:
•Carotid endarterectomy

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Vascular Disorders
•Transient ischemic attacks (TIAs)
–Also known as mini-strokes
–Due to insufficient blood supply to brain
–Symptoms:
•Weakness of arm and/or leg
•Dizziness
•Slurred speech
•Mild loss of consciousness

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Vascular Disorders
•TIAs
–Symptoms last few minutes to 1 hour
–Diagnosis by angiogram
–Treatment:
•Surgery to improve blood flow

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Functional Disorders
•Degenerative disk disease
•Headaches
•Epilepsy
•Bell’s palsy
•Parkinson’s disease

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Functional Disorders
•Degenerative disk disease
–Degeneration or wearing away of intervertebral
disk
•Allows vertebrae to bump or rub against each other
–Symptoms:
•Difficulty walking
•Radiating pain in back and in one or both legs
–Diagnosis by X-ray, myelogram, CT scan, and MRI

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Functional Disorders
•Degenerative disk disease
–Treatment:
•Rest back and legs
•Back brace
•Analgesics
•Anti-inflammatories
•Exercise to ease pain
•Surgery

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Functional Disorders
•Headaches
–One of the most common disorders in humans
–Usually a symptom of another disease rather than
a disorder in and of itself
–Disorders that typically have headaches as a
symptom include:
•Sinusitis Meningitis
•Encephalitis Hypertension
•Anemia Constipation
•Premenstrual tensionTumors

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Functional Disorders
•Headaches
–Caused by two mechanisms:
•Tension on facial, neck, and scalp muscles
•Vascular changes in arterial size of vessels inside head
–Contributing factors:
•Stress
•Toxic fumes
•Noise
•Lack of sleep
•Alcohol consumption

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Functional Disorders
•Headaches
–Headaches may be acute or chronic
–Pain may be mild to unbearable and incapacitating
–Pain may be constant, pressure, throbbing,
stabbing, or intermittent
–Types:
•Tension
•Cluster
•Following lumbar puncture
•Migraine

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Functional Disorders
•Headaches
–Diagnosis:
•History and physical, X-ray, EEG, MRI, and CT
–Treatment:
•Lifestyle changes – improved diet, sleep, exercise
•Analgesics
•Bedrest
•Muscle massage
•Muscle relaxants
•Warm baths
•Biofeedback

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Functional Disorders
•Epilepsy
–Chronic disease of brain
–Intermittent episodes of abnormal electrical
activity in brain
–Symptoms:
•Seizure
•Convulsions

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Functional Disorders
•Epilepsy
–Common types of seizures
–Petit mal
–Grand mal
–Status epilepticus
–Diagnosis by EEG, CT scan, cerebral angiogram,
and blood tests
–Treatment:
•Anticonvulsive medications
•Close monitoring and adjusting of medication

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Functional Disorders
•Bell’s palsy
–Affects facial nerve (7th cranial) leading to
unilateral (one-sided) paralysis
–Affects individuals 20 to 60 years of age
–Symptoms:
•Drooping weakness of eye and mouth
•Inability to close the affected eye
•Drooling of saliva

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Functional Disorders
•Bell’s palsy
–Symptoms: (continued)
•Unable to whistle or smile
•Distorted facial appearance
–Diagnosis by history and symptoms
–Treatment:
•Analgesics
•Anti-inflammatories

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Functional Disorders
•Parkinson’s disease
–Slow, progressive brain degeneration
–Cause is unknown, but may be related to a decrease
of brain neurotransmitter – dopamine
–Symptoms:
•Rigidity and immobility of hand
•Very slow speech pattern
•Pill-rolling motion of fingers
•Expressionless facial appearance

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Functional Disorders
•Parkinson’s disease
–Symptoms: (continued)
•Abnormal bent-forward posture
•Short, fast-running steps with shuffling appearance
–Symptomatic treatment:
•Dopamine replacement
•Physical and psychological therapy

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Dementias
•Loss of mental ability due to loss of
neurons or brain cells
•Types of dementia
–Senile (old age)
•Alzheimer’s disease – the most common type of senile
dementia
•Senile and Alzheimer’s disease are often used
synonymously, but they are not the same.
–Vascular
–Head trauma
–Substance induced

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Dementias
•Alzheimer’s disease
–A form of senile dementia
–Usually affects individuals age 70 and older
–Early symptoms:
•Short-term memory loss
•Inability to concentrate
•Slight changes in personality

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Dementias
•Alzheimer’s disease
–Symptoms of disease progression:
•Diminished communication skills
•Meaningless words
•Inability to form sentences
•Increased forgetfulness
•Irritability and agitation

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Dementias
•Alzheimer’s disease
–Diagnosis
•Positive only by autopsy
•Initially, diagnosis may be made by ruling out other brain
diseases
–Treatment
•Supportive, no known cure
•Focused on safety, maintaining nutrition, hydration,
personal hygiene
•Emotional support for family and caregivers

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Dementias
•Vascular dementia
–Atrophy and death of brain cells due to decreased
blood flow
–Atherosclerotic plaque can cause decreased blood
flow
•Common with aging

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Dementias
•Vascular dementia
–Symptoms:
•Changes in memory, personality, and judgment
•Irritability
•Depression
•Sleeplessness
•Lack of personal hygiene

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Dementias
•Vascular dementia
–Diagnosis:
•History and physical, blood flow testing
–Treatment:
•Increasing blood flow to brain
•Carotid endarterectomy

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Dementias
•Head trauma dementia
–Death of brain cells due to head trauma
–Symptoms:
•Decrease in mental intellect and cognitive function
•Loss of ability to reason, remember, or show appropriate
emotions
•Changes in personality

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Dementias
•Head trauma dementia
–Diagnosis:
•History, cranial X-rays, CT scan, and MRI
–Treatment:
•Correct damage, if possible
•Therapy and rehabilitation
–Prevention:
•Is often easy to prevent with proper use of protective
equipment

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Dementias
•Substance-induced dementia
–Brain cell death from drug toxicity and toxins
–Toxic substances include:
•Alcohol Cocaine
•Heroine Lead
•Mercury Paint fumes and thinner
•Insecticides
–Symptoms:
•Mental impairment
•Decreased cognitive ability

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Sleep Disorders
•Insomnia
–The most common form of sleep disorder
–Inability to fall or stay asleep
–Cause:
•Stress, pain, fear, depression, caffeine, alcohol, nicotine,
and bronchodilators
–Treatment:
•Identifying and removing cause

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Sleep Disorders
•Sleep apnea
–Characterized by periods of breathlessness
–Cause:
•More common in men
•Obesity
•Hypertension
•Airway obstruction
•Alcohol ingestion
•Cigarette smoking

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Sleep Disorders
•Sleep apnea
–Symptoms:
•Daytime sleepiness
•Extreme snoring
•Changes in personality
•Depression
•Impotence
–Diagnosis:
•Monitoring affected individual during sleep for apnea
and low blood oxygen levels

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Sleep Disorders
•Sleep apnea
–Treatment:
•Based on cause
•Weight loss
•Surgery to correct nasal obstruction
•Oxygen during sleep
•Medications to stimulate breathing
–Prevention:
•Most cases can be prevented by maintaining a healthy
weight, avoiding alcohol, not smoking, and avoiding
environmental smoke

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Tumors
•Brain tumor
–Classified as primary and secondary
–Primary tumors are called brain tumors
–Secondary tumors are named after the organ of
origin
–Cause:
•Unknown
–Symptoms:
•Headache
•Vomiting
•Seizures
•Changes in mood and personality
•Visual disturbance
•Loss of memory

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Tumors
–Diagnosis:
•Clinical symptoms
•X-ray
•CT scan
•MRI
•Biopsy
–Treatment:
•Surgery
•Radiation
•Chemotherapy

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Trauma
•Concussions and contusions
–Concussion less serious than contusion
–Contusion is a physical bruising of the brain tissue
–Cause
•Blow to head by object, fall, or other trauma
–E.g., automobile accident
–Symptoms:
•Disruption of normal electrical activity in brain –
unconsciousness
•Unconsciousness may last a few seconds to several hours
•Headache
•Blurred vision

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Trauma
•Concussions and contusions
–Symptoms: (continued)
•Irritability
•Draw up knees and begin vomiting
–Contusions can lead to:
•Hematoma
•Increased intracranial pressure (ICP)
•Permanent brain damage
–Coup and contrecoup contusions

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Coup and Contrecoup

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Trauma
•Concussions and contusions
–Diagnosis:
•History of injury, neurologic examination, cranial X-ray, CT scan,
and MRI
–Treatment:
•Bedrest
•Direct observation
–Individual should be checked every 2 to 4 hours
•Monitoring of changes in consciousness, eye pupil size, mood,
and behavior
•Analgesics, stimulants, and sedatives should not be given
•Medications may mask symptoms and make assessment
difficult

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Trauma
•Skull fracture
–A break in a cranial (skull bone)
–Greatest danger:
•Brain tissue damage from bony fragments
•Potential of cutting brain, severing vessels, causing
hematoma
–Brain damage may be temporary or permanent

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Trauma
•Skull fracture
–Symptoms:
•Variety of symptoms depending on location of fracture
•Fracture near base of skull may cause impaired breathing
•Hemiparesis
•Seizures
•Infection
–Treatment:
•Dependent on type and position of fracture
•Craniotomy may be necessary to relieve ICP
•Protective headgear may be necessary until fracture healed

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Trauma
•Epidural and subdural hematomas
–Epidural hematoma is a collection of blood between
the bony skull and dura mater (outer meninges)
–Subdural hematoma is a collection of blood between
the dura mater (outer layer) and the arachnoid
(middle layer)
–Subdural hematoma occurs twice as often as epidural

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Trauma
•Epidural hematoma
–Cause:
•Usually the result of a fight or accident
•Blood vessels rupture and hemorrhage or seep blood
usually rapidly over a period of hours
–Symptoms:
•Usually occur within a few hours
•Headache
•Dilated pupils
•Nausea
•Vomiting

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Trauma
•Epidural hematoma
– Symptoms: (continued)
•Dizziness
•As the hematoma grows:
–Loss of consciousness
–Increase in ICP
•Subdural hematoma
–Cause:
•Usually result of head hitting stationary object
–As is seen with falls when the head hits the floor

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Trauma
•Subdural hematoma
–Cause: (continued)
•Blood vessels rupture and seep blood slowly, usually over
a period of days
–Symptoms:
•Hemiparesis
•Nausea and vomiting
•Dizziness
•Convulsions
•Loss of consciousness

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Trauma
•Epidural and subdural hematoma
–Diagnosis:
•Cerebral hematoma is made by
–Clinical history
–Cranial X-ray
–CT or MRI
–Treatment:
•Goal is to decrease ICP
•Pressure can be relieved by
–Special craniotomy called burr holes
–Electrical cauterization

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Trauma
•Spinal cord injury
–Usually results when bony spinal column is injured
or fractured
–The cord can be injured at any level
•Neck area is most vulnerable
–Cause:
•Automobile accidents – leading cause
•Gunshot and knife wounds
•Falls and sports injuries

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Trauma
•Spinal cord injury
–Symptoms:
•Varying degrees of injury
•Injury to C1-C3 is usually fatal
•Quadriplegia
–Loss of movement and feeling in trunk and all four
extremities
–Loss of bowel, bladder, and sexual function
–If severe, respiratory ventilation
•Paraplegia
–Loss of movement and feeling in trunk and both legs
–Loss of bowel, bladder, and sexual function

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Trauma
•Spinal cord injury
–Diagnosis:
•History of injury, neurologic exam, spinal X-rays, CT scan,
and MRI
–Emergency treatment:
•Immediate treatment necessary
•Do not move individual unless surroundings unsafe
•Maintain position of spine with special collars and
backboards
–Treatment:
•Realignment and stabilization of bony spinal column
•Decompression or release of pressure on spinal cord
•Prevent further injury

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Rare Diseases
•Amyotrophic lateral sclerosis (ALS)
–Also known as Lou Gehrig’s disease
–Destructive disease of motor or movement neurons
–Atrophy of muscles leading to progressive loss of
movement of hands, arms, and legs
–Supportive treatment
–No cure

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Rare Diseases
•Guillain-Barré syndrome
–Acute, progressive disease affecting spinal nerves
–Begins 10 to 21 days after febrile illness
–Early symptoms:
•Nausea
•Fever
•Malaise

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Rare Diseases
•Guillain-Barré syndrome
–Within 24 to 72 hours, paresthesia, muscle
weakness, and paralysis usually begin
–Symptoms may progress for several days to weeks
–Once progression ceases, recovery begins
–Supportive treatment
–Recovery usually complete

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Rare Diseases
•Huntington’s chorea
–Inherited disease
–Appears during middle age
–Progressive degenerative disease of brain
–Leads to mental deterioration

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Rare Diseases
•Huntington’s chorea
–Symptoms:
•Loss of muscle control and chorea
•Changes in personality mood, and behavior
•Loss of memory and dementia
–Supportive treatment
–No cure

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Rare Diseases
•Multiple sclerosis (MS)
–Causes:
•Demyelination of CNS nerves
•Allows information to leak from nerve pathway
•Leads to poor or absent nerve transmission
–Symptoms:
•Muscle weakness and lack of coordination
•Paresthesia
•Speech difficulty
•Loss of bladder function
•Visual disturbance, especially diplopia

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Rare Diseases
•Multiple sclerosis
–Affects adults between ages 20 and 40
–Periods of remission and exacerbation
–Treatment:
•Physical therapy
•Muscle relaxants to maintain muscle tone and reduce
spastic movement

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Effects of Aging
•Decreased nervous system activity in brain
and spinal cord
•Loss of short-term memory
•Loss of visual acuity and peripheral vision
•Altered sleep patterns