NERVOUS SYSTEM DISEASESKevin Yocum

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Learning Outcomes6.1 Identify key structures of the neurological

system6.2 Discuss the roles of structure and function

played by the neurological system6.3 Define and spell terms related to neurology6.4 Identify characteristics of common neurological

diseases and disorders, including description, incidence, etiology, signs and symptoms, diagnosis, treatment, and prognosis

Structures of the Nervous System• Neurons

• Sense changes• Transmit messages• Facilitate movement

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Structures of the Nervous System• Dendrites

• Extensions of the cell body, receive information and send impulses

• Axons• Transmit nerve impulses away from the cell body

• Myelin sheath• Provides insulation to axon• Along with nodes of Ranvier, enables axon to conduct

impulses at rapid rate

Central Nervous System• Brain • Cerebrum• Cerebellum• Brainstem • Spinal cord

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Central Nervous System• Meninges

• Provide supportive structure for small blood vessels on the brain’s surface

• Protect the brain and spinal cord by housing cerebrospinal fluid (CSF)

• CSF• Circulates and provides a cushion to protect against injury from impact

Peripheral Nervous System• 31 pairs of spinal

nerves• Each named for and

corresponds to vertebra above it

• Associated areas of skin: dermatomes

Peripheral Nervous System• 12 cranial nerves

• Originate in brain and brainstem

• Innervate eyes, ears, nose, face, tongue, and throat and neck muscles

• Nerves in arms and legs

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Time for a Checkup!Which of these statements is true regarding stroke?

A. With ischemic stroke a vessel in the brain ruptures and bleeds

B. Risk factors for hemorrhagic stroke include atrial fibrillation and clotting disorders

C. Physical effects are usually on the opposite side of the body as the stroke area in the brain

D. Hypotension is a risk factor

Peripheral Nervous System• Autonomic nervous system (ANS)• Controls involuntary

functions• Is divided into

sympathetic and parasympathetic nervous systems

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Autonomic Nervous System• Controls involuntary functions• Divided into sympathetic nervous system and parasympathetic nervous system

• Responsible for fight-or-flight response• Parasympathetic nervous system has the opposite response• Dominates during nonstressful times

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Stroke• Etiology

• Hemorrhagic stroke: blood vessel in the brain ruptures and bleeds• Risk factors

• Hypertension• Aneurysms• Arteriovenous malformations (AVMs)

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Stroke• Etiology

• Ischemic stroke: deficiency in blood supply• Thrombotic stroke: blood clot• Embolic stroke: substance in bloodstream becomes lodged in blood vessel• Risk factors

• Cerebrovascular disease• Atrial fibrillation• Tobacco use• Alcohol abuse• Clotting disorders

Stroke• Signs and Symptoms

• Variable• Opposite-side effect

• Paralysis or weakness• Paresthesia

• Vision loss or changes• Dysphasia• Dysphagia

• Severe headache• Dizziness• Confusion• Altered consciousness• Gait and balance

changes

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Transient Ischemic Attack• Etiology

• Emboli• Vascular spasm• Risk factors

• Cerebrovascular disease• Tobacco use• Alcohol abuse• Hypertension• Clotting disorders

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Transient Ischemic Attack• Signs and Symptoms

• Variable and temporary• One-sided weakness• Paresthesia• Vision changes or loss• Dysphasia• Dysphagia• Dizziness• Confusion• Altered consciousness• Gait and balance difficulties

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Transient Ischemic Attack• Diagnosis

• MRI • CT scans• Carotid Doppler studies

• Treatment• Anticoagulant medication• Antihypertensives• Surgery to remove carotid-artery plaque• Reduction/elimination of modifiable risk factors

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Encephalitis• Etiology

• Viruses carried by insects• Some types of fungi and protozoans

• Signs and Symptoms• Seizures• Fever• Abnormal reflexes• Muscle weakness• Paralysis• Confusion• Coma

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Encephalitis• Diagnosis

• History• Signs and symptoms• CSF examination• CT scan • MRI

• Treatment• Herpesvirus: antiviral medication • Rabies: rabies immune globulin and vaccine• Management of intracranial pressure (ICP)

• Diuretics• Corticosteroids

Meningitis• Etiology

• Viruses• Bacteria• Fungi• Amoebas• Chemical irritation

• Signs and Symptoms• Headache• High fever• Nuchal rigidity • Nausea

• Vomiting• Photophobia • Confusion• Fatigue• Seizures• Less obvious in infants:

• Poor appetite• Vomiting• Irritability• Lethargy

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Meningitis• Diagnosis

• Examination of CSF• Positive Kernig sign• Brudzinski sign• Increased deep-tendon reflexes (DTRs)

• Treatment• Antibiotics• Intravenous steroids • Analgesics• Antipyretics• Anticonvulsants• Darkness and quiet

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Time for a Checkup!All of the following are possible symptoms of brain abscess EXCEPT:

A. Nuchal rigidityB. HeadacheC. HemiparesisD. Seizures 

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Brain Abscess• Etiology

• Infection• Head injuries• Head-surgery sites• Ear, sinus, or teeth infection• Infections within lungs, heart, or kidneys

• Fungi or bacteria enter brain tissue, usually through the bloodstream

• Inflammation brings WBCs, which collect along with dead microorganisms and debris, and abscess grows

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Brain Abscess• Signs and Symptoms

• Slow or sudden onset (over 1 to 2 weeks)• Headache• Aching or stiffness in neck, shoulders, or back• Vomiting• Seizures• Vision changes• Fever and chills• Weakness• Hemiparesis 

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Brain Abscess• Signs and Symptoms

• Changes in movement and coordination• Mental-status changes

• Confusion• Irritability• Lethargy• Possible coma 

• Dysphasia• Changes in movement and coordination

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Brain Abscess• Diagnosis

• Head CT• MRI• CBC• Blood cultures• Needle biopsy

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Brain Abscess• Treatment

• IV antibiotics• Surgery• Needle aspiration• Increased ICP may be treated with:

• Corticosteroids• Diuretics

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Poliomyelitis• Etiology

• Poliovirus enters through nose or mouth, multiplies in intestines, is absorbed into bloodstream, and travels to CNS

• Direct contact with infected respiratory secretions or feces

Poliomyelitis• Signs and Symptoms

• Most people are asymptomatic

• Nausea and vomiting• Anorexia• Abdominal pain• Fever• Headache• Paralysis• Respiratory failure

• Postpolio syndrome up to 40 years later• Recurrence of fatigue and

weakness • Back and leg pain• Nuchal rigidity• Severe headache• Meningitis

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Poliomyelitis• Diagnosis

• Signs and symptoms• Neurological-examination findings• Stool and throat cultures• Serum and CSF analysis

• Treatment• Analgesics for head and body aches• Respiratory support as needed• Physical therapy • Nutritional support• Promotion of bowel and bladder function

Guillain-Barré Syndrome (GBS)• Etiology

• Exact cause not understood• 60% of the time, viral infection

precedes the disorder by 2 to 4 weeks

• Signs and Symptoms• Develop over 2 weeks• Weakness• Paresthesia• Ascending paralysis • Dysphasia• Dysphagia• Urinary retention

• Rapid or slow heart rate• Altered blood pressure• Severe pain in back, buttocks,

thighs, or shoulders• Peak within 3 to 4 weeks,

plateau for several days, then slowly improve

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Guillain-Barré Syndrome (GBS)• Diagnosis

• CSF analysis• Electromyography (EMG)• Nerve conduction velocity (NCV) studies• Respiratory function tests • Possible muscle biopsy

• Treatment• Plasmapheresis• IV immunoglobulin• Possible respiratory and nutritional care• Physical therapy

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Time for a Checkup!Which of these is true regarding Parkinson disease?

A. It is caused by a deficiency of endorphins

B. Pill-rolling hand tremor is a common symptom

C. Patients often complain of dry mouthD. It is usually treated with

corticosteroids

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Parkinson Disease• Etiology

• Deficiency of dopamine• Neurotransmitter released by axon terminal to inhibit or excite a

target cell• Critical to nerve-impulse transmission

• Signs and Symptoms• Gradual onset of aching and fatigue in extremities• Resting hand tremor• Generalized muscle rigidity• Pill-rolling hand tremor• Masklike facial expression

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Parkinson Disease• Signs and Symptoms

• Soft, quiet voice• Bradykinesia • Shuffling gait that speeds out of control• Stooped posture• Difficulty initiating movements• Dysphagia• Drooling• Possible dementia

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Parkinson Disease• Diagnosis

• Signs and symptoms • Neurological-evaluation findings• Decreased urine dopamine levels

• Treatment• Dopamine agonists: levodopa-carbidopa (Sinemet)• Medications to reduce:

• Oral secretions• Tremor• Muscle rigidity

Multiple Sclerosis• Etiology

• Autoimmune response• Inflammation and

degeneration of myelin sheath

• Episodic disruption of nerve-impulse conduction

• Triggers• Infections• Viruses• Pregnancy

Multiple Sclerosis• Signs and Symptoms

• Weakness• Fatigue• Muscle spasms• Altered gait• Tremors• Bowel and bladder

dysfunction• Sexual dysfunction• Vertigo• Tinnitus• Hearing loss

• Visual changes• Altered sensation• Dysphasia• Dysphagia• Anxiety• Mood fluctuations• Deficits in short-term

memory • Inattentiveness• Impaired judgment

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Multiple Sclerosis• Diagnosis

• Other disorders must be ruled out• MRI and CT scans indicate reveal MS plaques

• Treatment• Administer corticosteroids• Protect immune system

• Regular, moderate exercise• Good nutrition• Adequate rest• Stress management

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Amyotrophic Lateral Sclerosis (ALS)• Etiology

• 90% unknown• Hereditary cause in 10% of cases

• Signs and Symptoms• Affects motor nerves • Muscle weakness and fatigue • Begins in extremities• Progresses to trunk and head• Progressive paralysis • Dyspnea• Dysphasia• Dysphagia

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Amyotrophic Lateral Sclerosis (ALS)• Diagnosis

• EMG • NCV• Muscle biopsy

• Treatment• Riluzole (Rilutek)• Palliative care• Protection of respiratory function• Medication to:

• Decrease muscle spasticity• Relieve pain• Reduce oral secretions

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Time for a Checkup!All of these are possible causes of dementia EXCEPT:

A. Pick diseaseB. Huntington diseaseC. Parkinson diseaseD. Guillain-Barré syndrome

Dementia• Etiology

• Neuritic plaques• Neurofibrillary tangles• Contributors

• Advanced age• Genetics• Some viruses• Previous brain injuries• Cardiovascular disease• Vitamin B12 or folate

deficiency• Brain infection• Diabetes

• Decrease in neurotransmitters

• Other causes of dementia• Vascular: multiple strokes• Alcoholism• Pick disease• Huntington disease• Parkinson disease• Hypothyroidism• Syphilis• AIDS

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Dementia• Signs and Symptoms

• Pattern of onset depends on type and cause• Alzheimer dementia begins gradually and progresses

slowly• Three stages

• Stage I: progressive short-term memory loss• Stage II: deterioration of intellectual ability, personality changes,

speech and language problems, impaired judgment, and continued worsening of memory, as well as possible paranoia, delusions, hallucinations, seizures, and depression

• Stage III: total dependence on others for care; may also display paranoia, delusions, hallucinations, seizures, and depression

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Dementia• Diagnosis

• History• Neurological-examination findings• Presenting signs and symptoms• Cognitive screening tests are used to evaluate short-

term memory and reasoning• Rule out nutritional deficiencies and other treatable

disorders• CT scan or MRI to rule out stroke or brain lesions

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Dementia• Treatment

• Treatment of the underlying cause, if known• Cholinesterase inhibitors to temporarily enhance

cognitive function by preventing breakdown of acetylcholine

• Medications for behavior management• Antipsychotics• Antidepressants• Anxiolytics• Benzodiazepines

• Measures to maximize function and provide safety

Huntington Disease• Etiology

• Inherited• Signs and Symptoms

• Progressively jerky, unpredictable movement

• Gait and balance deficits• Dysphasia• Dysphagia• Memory and judgment

deficits • Eventual dementia

• Psychiatric symptoms • Depression• Anxiety• Irritability• Aggressiveness• Compulsiveness• Worsening of addictive

behaviors (if present)

Huntington Disease• Diagnosis

• Medical history• Neurological

examination• MRI or CT scan• DNA analysis

• Treatment• No cure• Focus on safety and

quality of life • Education and emotional

support for patient and caregivers

• Medications• Antipsychotics• Antidepressants

• Nutritional support

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Cerebral Concussion and Contusion• Etiology

• Head trauma• Contrecoup injury

• Rapid acceleration followed by deceleration throws the brain forward and backward

Cerebral Concussion and Contusion• Signs and Symptoms

• Concussion• Brief loss of consciousness• Confusion• Disorientation• Headache• Drowsiness• Visual changes

• Contusion • Same as with concussion

plus:• More prolonged loss of

consciousness• Vomiting• Memory problems

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Cerebral Concussion and Contusion• Diagnosis

• Neurological evaluation • Report of symptoms• CT scan

• Salt-and-pepper appearance confirms cerebral contusion

• Spinal films

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Cerebral Concussion and Contusion• Treatment

• Rest • Analgesics• Hospitalization for severe concussion and cerebral contusion with aggressive management of ICP

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Time for a Checkup!Treatment of spinal-cord injury includes all EXCEPT:

A. Use of Gardner-Wells tongsB. Epidural steroid injection C. Application of halo traction braceD. Spinal fusion

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Spinal-Cord Injury• Etiology

• Traumatic or violent injury• Signs and Symptoms

• Loss of function• Loss of sensation• Loss of reflexes

• Diagnosis• Neurological-evaluation findings • Spinal x-rays• CT scan• MRI

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Spinal-Cord Injury• Treatment

• Stabilization with Gardner-Wells tongs and traction

• Surgery• Removal of bone fragments and hematomas • Spinal fusion

• Later application of halo traction brace enables increased mobility

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Subdural and Epidural Hematomas• Etiology

• tearing of blood vessels• high-velocity rotational or linear force• hematoma expands for 6-8 hours, strips away dura

• Risk factors • Age• alcohol abuse• anticoagulant medication

Subdural and Epidural Hematomas• Signs and Symptoms

• Epidural hematoma• Loss of consciousness• Abnormal pupil response• Posturing • Possible lucid interval

• Subdural hematoma • Slower onset by as much

as 2 weeks• Recent head injury• Variable levels of

consciousness

• Headache• Irritability• Seizures• Disorientation• Amnesia• Dizziness• Nausea and vomiting• Difficulty walking• Dysphasia

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Subdural and Epidural Hematomas• Diagnosis

• CT scan• MRI• Cerebral  arteriogram

• Treatment• Surgery to remove hematoma and stop further bleeding

Skull Fracture• Etiology

• Head trauma• Signs and Symptoms

• Linear:• May be asymptomatic• May have swelling

• CSF or blood drainage from the ear or nose

• Loss of consciousness

• Temporary or permanent hearing loss

• Facial numbness• Facial paralysis• Ataxia• Vocal-cord paralysis

Skull Fracture• Signs and Symptoms

• Nystagmus• Headaches• Visual disturbances• Nausea• Vomiting• Short-term memory loss• Seizures• Raccoon eyes• Battle sign

Skull Fracture• Diagnosis

• Neurological examination

• Skull x-rays• CT scan• MRI• CSF tested for glucose

• Treatment• Simple fractures:

• May require no treatment• Complicated fractures:

• Antibiotics• Anticonvulsants• Surgery

• Remove bone fragments• Elevate depressed bone• Remove hematoma

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Time for a Checkup!All of these are possible causes of spinal stenosis EXCEPT:

A. OsteoarthritisB. Spinal tumorsC. Exertion or fatigueD. Disk herniation

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Spinal Stenosis• Etiology

• Congenital • Degenerative changes• Osteoarthritis• Disk herniation• Ligament changes• Vertebrae misalignment• Spinal tumors• Traumatic injury• Bone-tissue disorders

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Spinal Stenosis• Signs and Symptoms

• Variable depending on severity and specific location• Pain• Numbness• Cramping in the legs, back, neck, shoulders, or arms• Decreased sensation in extremities• Balance problems• Bowel dysfunction• Bladder dysfunction

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Spinal Stenosis• Diagnosis

• Medical history• Signs and symptoms• Spinal examination• Radiological studies

• Spinal x-rays• MRI• CT scan• Myelography• Bone scan

Spinal Stenosis• Treatment

• NSAIDs• Analgesics• Rest• Moderate exercise• Physical therapy• Back brace or corset• Epidural steroid injection • Nerve block

• Surgery• Decompressive laminectomy• Laminotomy• Spinal fusion

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Sciatica• Etiology

• Compression of lumbar-nerve roots or spinal cord • Herniated disks• Tumors• Spinal stenosis• Piriformis syndrome

• Pelvic injury• Active trigger points• Uterine compression

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Sciatica• Signs and Symptoms

• Usually unilateral, but sometimes bilateral• Pain• Aching• Tingling• Burning • Numbness

Sciatica• Diagnosis

• Signs and symptoms • Physical-examination

findings • X-rays• MRI

• Treatment• Analgesics • Corticosteroid injections• Physical therapy

• Acupuncture• Chiropractic• Osteopathy• Stretching• Yoga• Low-dose antidepressants • Anticonvulsants• Surgery

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Migraine Headache• Etiology

• Not fully understood• Familial• Theories include:

• Trigeminal nerve involvement• Imbalances in neurotransmitters (e.g., serotonin)• Vascular dilation and inflammation

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Migraine Headache• Etiology

• Risk factors and triggers• Hormonal changes• Some foods• Stress• Bright lights• Fumes, perfumes, and smoke• Exertion or fatigue• Environmental changes• Some medications

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Migraine Headache• Signs and Symptoms

• Aura• Throbbing• Unilateral or bilateral pain• Nausea with or without vomiting• Photophobia • Phonophobia• Last between 4 and 72 hours• Frequency: from once a year to as often as every week

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Migraine Headache• Diagnosis

• Symptom description• Physical examination• Possible CT scan, MRI, or lumbar puncture

• Treatment• NSAIDS• Nonopiate analgesics• Opiate analgesics• Triptans • Preventive medications

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Time for a Checkup!All of the following are typical of tension headaches EXCEPT:

A. They are usually unilateralB. They may be episodic or chronicC. Pain is typically described as a dull

acheD. Auras are common beforehand

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Tension Headache• Etiology

• Muscle tension in scalp, neck, jaw, or upper shoulders

• Contributors include:• Poor posture• Lack of sleep• Alcohol use• Missed meals• Noise

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Tension Headache• Signs and Symptoms

• Chronic or episodic• Last minutes to days• Bilateral dull, aching sensation• Pressure or a bandlike tightness encircling head• Location

• Forehead• Base of the head• Neck

• Triggered by situational stress

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Tension Headache• Diagnosis

• Medical history • Description of symptoms• Physical examination

• Treatment• OTC analgesics • Relaxation• Massage• Biofeedback• Stress-management activities

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Peripheral Neuropathy• Etiology

• Exact cause unknown• Associated with:

• Diabetes• Alcoholism• AIDS• Rheumatoid arthritis• Systemic lupus erythematosus• Ingestion of toxic substances and some drugs• Nerve injury from prolonged immobility or compression

Peripheral Neuropathy• Signs and Symptoms

• Nerve pain • Numbness• Weakness• Muscle twitching• Atrophy• Muscle cramps• Loss of movement• Loss of coordination

• Symptoms related to autonomic nerve damage• Blurred vision• Dizziness• Diarrhea• Constipation• Urinary incontinence• Impotence

Peripheral Neuropathy• Diagnosis

• History • Neurological

examination• EMG• Nerve conduction tests• Nerve biopsy

• Treatment• Physical therapy• Occupational therapy• Emphasis on safety• Pain is treated with:

• Analgesics• Anticonvulsants• Antidepressants

Bell Palsy• Etiology

• Inflammation of seventh cranial nerve

• Possible viral infection• Signs and Symptoms

• Paralysis of one side of face

• Twitching• Weakness• Drooling

• Eye dryness• Impaired taste• Excessive tearing• Headache• Ringing in the ears• Difficulty eating or drinking

Bell Palsy• Diagnosis

• Visual inspection• EMG may reveal nerve

damage• CT scan• MRI• Skull x-rays

• Treatment• Corticosteroids • Antivirals• Analgesics• Warm, moist

compresses • Artificial tears or eye

patch

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Time for a Checkup!Which of these is true about trigeminal neuralgia?

A. It is also called tic douloureuxB. Pain may be triggered by brushing the

teethC. It may be treated with anticonvulsantsD. All of these

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Trigeminal Neuralgia• Etiology

• Various theories• Pain triggers

• Chewing• Shaving• Applying makeup• Talking• Drinking• Brushing teeth• Smiling• Touching the face• Feeling a cool breeze

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Trigeminal Neuralgia• Signs and Symptoms

• Episodes of severe, sudden stabbing, shooting, or shocklike pain in face

• Increase in frequency and intensity• Atypical TN is less severe, causes constant aching or burning pain

• Usually unilateral

Trigeminal Neuralgia• Diagnosis

• Physical-examination findings

• MRI to rule out multiple sclerosis and other disorders

• Treatment• Analgesics• Anticonvulsants• Antidepressants

• Antispasmodics• Injections• Surgery • Heat or cold application• Complementary therapies

• Chiropractic treatments• Acupuncture• Meditation• Hypnosis

Epilepsy• Etiology

• Congenital or acquired • Triggers

• Withdrawal from antiseizure medication

• Head trauma• Illness• Emotional or physical

stress• Fatigue• Specific foods or chemicals• Flickering or flashing lights

• Signs and Symptoms• Depend on type of

seizure • See Table 6-2

Epilepsy• Diagnosis

• History • Description of symptoms • Description of seizure activity• Neurological evaluation • Various diagnostic studies

• Electroencephalogram (EEG)• CT scan• MRI scan• Lumbar puncture (LP) (see Box 6-

7)

• Treatment• Anticonvulsant medication• Surgery may reduce severity

and frequency of seizures and increase responsiveness to medication• Vagal-nerve stimulator implant• Excision of brain tissue • Corpuscallosotomy

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Transient Global Amnesia• Etiology

• Exact cause unknown• Theory includes temporary circulation disruption to parts

of brain • Possible triggers

• Cold-water immersion• Severe emotional or physical stress• Sexual activity• Recent migraine headache• Medical procedures

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Transient Global Amnesia• Signs and Symptoms

• Loss of recent memory with retention of personal identity and distant memory

• Episode lasts less than 24 hours• Absence of neurological deficits • Ability to function normally• Possible headache or anxiety-related symptoms • Symptoms resolve within 12 to 24 hours

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Transient Global Amnesia• Diagnosis

• Witness’s description of event • Description of recent memory loss and other symptoms • Neurological examination • Absence of deficits during or after the event• Tests to rule out other diagnoses

• EEG• CT

• Treatment• None

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