CNS Degenerative Diseases Notes

Parkinson's Disease

  • A disorder involving dopamine-producing neurons in the brain.

  • A degenerative disorder of the basal ganglia, causing abnormal movement. Voluntary movement is affected.

  • Basal ganglia are a collection of nuclei deep to the white matter of the cerebral cortex.

    • Includes: caudate, putamen, nucleus accumbens, globus pallidus, & substantia nigra.

  • Symptoms:

    • Tremors

    • Rigidity

    • Bradykinesia

    • Akinesia

    • Masklike expression

Pathophysiology

  • Disorder causes degeneration of the dopamine-producing neurons in the substantia nigra in the midbrain.

  • Dopamine influences purposeful movement.

  • Depletion of dopamine results in degeneration of the basal ganglia.

Parkinson’s Disease (PD) / Paralysis Agitans

  • A progressive disorder with degeneration of the nerve cells in the basal ganglia resulting in generalized decline in muscular function.

  • Disorder of the extrapyramidal system (neural network located in the brain that is part of the motor system involved in the coordination of movement).

  • Usually occurs in the older population: symptoms occur during the 5th decade of life; some diagnosed at age 30.

  • Affects men more frequently than women

  • Cause: UNKNOWN; predominantly idiopathic but sometimes disorder is postencephalitic, toxic, arteriosclerotic, traumatic, or drug induced (reserpine, methyldopa [Aldomet], haloperidol [Haldol], phenothiazines)

  • Diagnostic tests: not helpful …PET used only for evaluating levodopa uptake ==diagnosed clinically from patient’s history, presence of 2 of the 3 cardinal symptoms, neuro examinations

Assessment Findings

  • Tremor:

    • Mainly of the upper limbs

    • "Pill-rolling"

    • Resting tremor; most common initial symptom

  • Rigidity: cogwheel type

  • Bradykinesia: slowness of movement

  • Fatigue

  • Stooped posture; shuffling, propulsive gait

  • Difficulty rising from sitting position

  • Masklike face with decreased blinking of eyes

  • Quiet, monotone speech

  • Emotional lability, depression

  • Increased salivation, drooling

  • Cramped, small handwriting

  • Autonomic symptoms:

    • Excessive sweating

    • Constipation

    • Seborrhea

    • Decreased sexual capacity

    • Lacrimation

Nursing Interventions

  • Administer medications as ordered

    1. Antiparkinsonian: Levodopa (Dopar, Larodopa)

      • Increases level of dopamine in the brain; relieves tremor, rigidity, and bradykinesia

      • Side effects: anorexia; nausea and vomiting; postural hypotension; mental changes such as confusion, agitation, and hallucinations; insomnia; renal damage; cardiac arrhythmias; dyskinesias (purposeless involuntary movements that may be hyperkinetic =rapid and repetitive)

      • Contraindications:

        • Avoid multiple vitamin preparations containing vitamin B6 (pyridoxine) and foods high in vitamin B6 (tuna, pork, dried beans, salmon)

        • Avoid Tyramine rich foods (cheese, yogurt, coffee, raisins, sausage, red wine, beer)=may cause hypertensive crisis

        • Administer with food or snack to decrease GI irritation.

    2. Carbidopa (Sinemet): prevents breakdown of dopamine in the periphery and causes fewer side effects.

    3. Antiviral: Amantadine (Symmetrel):

      • Used in early/mild cases to reduce rigidity, tremor, and bradykinesia

      • Acts by releasing dopamine from neuronal storage sites

    4. Anticholinergic: Benztropine mesylate (Cogentin), procyclidine (Kemadrin)

      • Inhibit action of acetylcholine

      • Used in mild cases or in combination with Levodopa

      • Relieves tremor and rigidity

      • Side effects: dry mouth, blurred vision, constipation, urinary retention

    5. Dopamine agonist: Bromocriptine mesylate (Parlodel)

      • Stimulates release of dopamine in the substantia nigra

      • Often employed when Levodopa loses effectiveness

    6. Tricyclic antidepressants given to treat depression

    7. Antihistamines have mild central anticholinergic & sedative effects & may reduce tremors

  • Provide a safe environment.

    • Side rails on bed; rails and handlebars in toilet, bathtub, and hallways; no scatter rugs

    • Hard-back or spring-loaded chair to make getting up easier

  • Provide measures to increase mobility.

    • Physical therapy: active and passive ROM exercises; stretching exercises; warm baths

    • Assistive devices If client "freezes," suggest thinking of something to walk over.

  • Improve communication abilities: instruct client to practice reading aloud, to listen to own voice, and enunciate each syllable clearly.

  • Maintain adequate nutrition.

    • Cut food into bite-sized pieces.

    • Provide small, frequent feedings.

    • Allow sufficient time for meals, use warming tray.

Multiple Sclerosis (MS)

  • Abnormal immune response that damages myelin sheath.

  • Only affects nerves in the CNS.

  • Visual problems

  • Decreased hearing

  • Numbness

  • Vertigo

  • Facial nerve problems

  • Weakness

  • Depression

  • Caused by patchy areas of plaque that damage the covering of the nerves.

  • Remissions and exacerbations develop as the condition progresses.

  • Results in impaired transmission of nerve impulses

Multiple Sclerosis (MS)

  • An immune-mediated progressive demyelinating disease of the CNS which results in impaired transmission of nerve impulses

  • Typically present in young adults 20-40

  • Affects women more than men

  • More frequent in cool or temperate climates

  • Cause UNKNOWN; may be a slow-growing virus or possibly of autoimmune origin

  • Characterized by remissions and exacerbations

Pathophysiology

  • Sensitized T cells that would typically cross the blood-brain barrier to check for antigens in the CNS and then leave; in MS would remain in the CNS

  • Promote infiltration of other agents that damage the immune system

  • Immune system attack leads to inflamm that destroys myelin and oligodenroglial cells

Major Types

  1. Relapsing-remitting MS (RRMS)=85%of cases

    • Relapses develop over 1-2 weeks & resolve over 4-8 months then returns to baseline.

    • 50% may develop secondary progressive MS within 10 yrs; 90% develop it within 25 yrs

  2. Progressive-relapsing MS (PRMS)=5% of cases

    • Absence of remission & client’s condition does not return to baseline

    • Progressive, cumulative symptoms & deterioration occur over several years

  3. Primary progressive MS (PPMS)=onset tend to be between 40&60 years of age

    • Steady, gradual neurologic deterioration without remission of symptoms

    • Progressive disability with no acute attacks

  4. Secondary progressive MS (SPMS)

    • Begins with RRMS course that later becomes steadily progressive

    • Attacks & partial recoveries may continue to occur

Diagnostic Tests

  • CSF studies: increased protein and IgG (immunoglobulin)

  • EEG: abN

  • CT scan: increased density of white matter

  • MRI: shows areas of demyelination

Symptoms

  • 1st symptom: visual disturbances: blurred vision, scotomas (patchy blindness), diplopia

  • Impaired sensation: touch, pain, temperature, or position sense; numbness, tingling

  • Impaired motor function: weakness, paralysis, spasticity

  • Impaired cerebellar function: scanning speech, ataxic gait, nystagmus, dysarthria, intention tremor

  • Euphoria or mood swings

  • Bladder: retention or incontinence

  • Constipation

  • Sexual impotence in the male

Nursing Interventions

  • Promote optimum mobility.

    • Muscle-stretching and strengthening exercises

    • Walking exercises to improve gait: use wide-based gait

    • Assistive devices: canes, walker, rails, wheelchair as necessary

  • Administer medications as ordered.

    • For acute exacerbations: corticosteroids (ACTH [IV], prednisone) to reduce edema at sites of demyelinization

    • For spasticity: baclofen (Lioresal), dantrolene (Dantrium), diazepam (Valium)

    • Beta interferon (Betaseron) for relapsing-remitting MS patients

  • Prevent injury related to sensory problems.

    • Test bath water with thermometer. Avoid heating pads, hot-water bottles. Inspect body parts frequently for injury. Make frequent position changes.

  • Prepare client for plasma exchange (to remove antibodies) if indicated

Plasmapheresis

  • This treatment — also known as plasma exchange — is a type of "blood cleansing" in which damaging antibodies are removed from your blood.

  • Plasmapheresis consists of removing the liquid portion of your blood (plasma) and separating it from the actual blood cells.

  • The blood cells are then put back into your body, which manufactures more plasma to make up for what was removed.

  • It's not clear why this treatment works, but scientists believe that plasmapheresis rids plasma of certain antibodies that contribute to the immune system attack on the nerves

Myasthenia Gravis (MG)

  • A chronic autoimmune disease caused by antibodies against acetylcholine receptors, which affect neuromuscular junction.

  • Progressive muscle fatigue

  • Drooping head

  • Diplopia of eyes

  • Affects muscles of mouth and throat

  • Comes without warning, causing difficulty in swallowing, high-pitched voice, and decreased energy that improves with rest. The body literally attacks itself.

Myasthenia Gravis (MG)

  • A neuromuscular disorder in which there is a disturbance in the transmission of impulses from nerve to muscle cells at the neuromuscular junction (PNS), causing extreme muscle weakness

  • Highest between ages 15-35 for women, over 40 for men.

  • Affects women more than men

  • Cause: thought to be autoimmune disorder whereby antibodies destroy acetylcholine receptor sites on the postsynaptic membrane of the neuromuscular junction.

  • Voluntary muscles are affected, especially those muscles innervated by the cranial nerves.

  • The first noticeable symptoms of myasthenia gravis may be weakness of the eye muscles, difficulty in swallowing, or slurred speech.

Assessment Findings

  • Ptosis, diplopia, dysphagia

  • Extreme muscle weakness, increased with activity and reduced with rest (identifying characteristic)

  • Masklike facial expression

  • Weak voice, hoarseness

Diagnostic Tests

  • Tensilon test: IV injection of Tensilon provides spontaneous relief of symptoms (lasts 5-10 minutes)

  • Electromyography (EMG): amplitude of evoked potentials decreases rapidly

  • Presence of anti-acetylcholine receptor antibodies in the serum

Tensilon Test

  1. Performed to diagnose myasthenia gravis

    • Tensilon (edrophonium chloride - anticholinesterase) 2mg are injected IV, if no response after 30 secs, the remaining 8mg are injected

    • (+) test: reveals an ↑ in muscle strength (reduction of eyelid ptosis) within 1 min, weakness returns within 5-30 mins.

    • Tensilon (edrophonium)a medication that blocks the action of the enzyme that breaks down the transmitter acetylcholine is given, muscle function may improve.

    • (-) test: client shows no improvement & strength may deteriorate

  2. To differentiate myasthenic crisis and cholinergic crisis

    • Myasthenic crisis: Tensilon is administered & if strength improves, the client needs more medication

    • Cholinergic crisis: Tensilon is administered & if weakness is more severe, the client is overmedicated, administer atropine sulfate

Medical Management

  • Drug therapy

    • Anticholinesterase drugs: neostigmine bromide (Prostigmin), pyridostigmine bromide (Mestinon), edrophonium chloride (Tensilon)

      • Block action of cholinesterase and increase levels of acetylcholine at the neuromuscular junction

      • Side effects: excessive salivation and sweating, abdominal cramps, nausea and vomiting, diarrhea, fasciculations (muscle twitching)

    • Corticosteroids: prednisone used if other drugs are not effective suppress autoimmune response

Nursing Interventions

  • Administer anticholinesterase drugs as ordered.

    • Give medication exactly on time.

    • Give with milk and crackers to decrease GI upset.

    • Monitor effectiveness of drugs: assess muscle strength and vital capacity before and after medication.

    • Observe for side effects.

  • Promote optimal nutrition.

    • Mealtimes should coincide with the peak effects of the drugs: give medications 30 minutes before meals.

    • Check gag reflex and swallowing ability before feeding.

    • Provide a mechanical soft diet.

    • If the client has difficulty chewing and swallowing, do not leave alone at mealtimes

    • Keep emergency airway and suction equipment nearby.

  • Monitor respiratory status frequently: rate, depth; vital capacity; ability to deep breathe and cough

  • Observe for signs of myasthenic or cholinergic crisis.

  • Provide nursing care for the client with a thymectomy.

Thymus Gland

  • The Thymus is an organ that forms part of the upper part of the chest and consists of two lobes.

  • Thymus tissue contains white blood cells, called lymphocytes, which mature under the influence of hormones produced by the thymus. These white blood cells help to protect the body against disease by attacking invading organisms.

  • The thymus is large and active in children but shrinks with age.