Parkinson's Disease Overview

Overview of Parkinson's Disease

• Also known as Parkinson disease, Parkinson's, Idiopathic parkinsonism, Primary parkinsonism, PD, or paralysis agitans.
• It's a degenerative disorder of the central nervous system (CNS).
• It’s a slowly progressive neurological movement disorder, ultimately leading to disability.
• Parkinson's is associated with decreased dopamine levels.
• The degenerative or idiopathic form is the most common type.

Cause and Risk Factors

• Cause is unknown for most cases (idiopathic).
• An imbalance between dopamine and acetylcholine is implicated.
• Age is the biggest risk factor i.e. greater than 50-60 years of age.
• Men are affected 1.5-2 times more often than women.
• Genetics play a role for a small number of individuals with a family history of the disorder.
• Head trauma and illness can be risk factors.
• Exposure to environmental toxins like pesticides and herbicides is a potential risk.

Normal Physiology

• Dopamine acts as a messenger between two brain areas: the substantia nigra and corpus striatum.
• Dopamine is essential for producing smooth and controlled movements.

Basal Ganglia Function

• Voluntary movements are a function of the basal ganglia.
• Routine behaviors are mediated by the basal ganglia.
• Cognition, learning, and emotion are functions of the basal ganglia.

Pathophysiology

• The pathophysiology of Parkinson's starts with the destruction of dopaminergic neuronal cells.
• This leads to depletion of dopamine stores.
• Degeneration of the dopaminergic nigrostriatal pathway takes place.
• An imbalance of acetylcholine and dopamine neurotransmitters occurs in the corpus striatum.
• Leads to impairment of extrapyramidal tracts controlling complex body movements.
• This results in tremors, rigidity, bradykinesia, and postural changes.

Clinical Manifestations : Early Onset

• Early obvious symptoms are movement-related, including shaking.
• Rigidity is an early obvious symptom.
• Slowness of movement is an early sign.
• Difficulty with walking and gait are early signs.

Clinical Manifestations : Later Stages

• Cognitive and behavioral problems manifest.
• Dementia occurs in advanced stages.
• Sensory, sleep, and emotional problems develop.

Four Cardinal Signs

• Tremor is a slow, unilateral resting tremor of fingers, hands (turning motion), arms, feet, legs, jaw, or head.
• Tremors occur when the individual is resting, not while involved in a task.
• Tremors worsen when excited, tired, or stressed.
• Tremors may manifest as a motion of the thumb against the fingers, resembling rolling a pill between the fingers.
• Rigidity involves stiff and resistant limbs and trunk that increase during movement.
• Muscle aches and pain are part of rigidity.
• Handwriting becomes difficult (micrographia), as well as eating.
• Lead-pipe rigidity leads to cogwheel rigidity.
• Asymmetrical presentation in early stages(neck & shoulder muscles prior to the muscles of the face & extremities)
• Bradykinesia is the slowness of voluntary movement.
• It can be difficult to initiate or complete movements
• Bradykinesia together with stiffness affects the facial muscles, leading to a expressionless, "mask-like" appearance.
• Initial signs include problems performing daily tasks requiring fine motor control like writing, sewing, or getting dressed.
• In severe form, "FREEZING PHENOMENON," a transient inability to perform active movement is present, as well as a "glued" sensation while walking are often noticed.
• Postural instability means impaired or lost reflexes.
• Postural and gait problems lead to falls.
• Posture is caused by forward flexion of neck, hips, knees, and elbows.
• Patients may walk faster and faster, trying to move the feet forward under the body’s center of gravity i.e. shuffling gait.
• More progressive Parkinson's disease leads to a distinctive shuffling walk with a stooped position and diminished or absent arm swing.
• Difficulty starting to walk and making turns often occurs.
• May freeze in mid-stride and appear to fall forward while walking.

Other Manifestations

• Psychiatric changes include depression, dementia (progressive mental deterioration), delirium, and hallucinations.
• Mental changes involve cognitive, perceptual, and memory deficits; intellect is not usually affected.
• Dysphonia is characterized by soft, slurred, low-pitched, less audible speech.
• Dysphagia is characterized by drooling and risk for choking and aspiration.

Autonomic symptoms

• Hyperhidrosis, or excessive sweating.
• Orthostatic hypotension, is a form of low blood pressure that occurs when standing up.
• Gastric and urinary retention, plus constipation.
• There is often sexual dysfunction.

Complications

• Patients are at risk for respiratory problems.
• Patients are at risk for UTI.
• Patients are at risk for skin breakdown.
• Patients are at risk for injury from falls.

Diagnostic Testing

• PET & Single Photon Emission Computed Tomography (SPECT) findings show nigrostriatal dysfunction.
• EEG may be performed.
• No single test definitively diagnoses PD.
• Most accepted diagnosis is based on patient history and at least two of the four cardinal signs.

Medical Management

• Treatment aims at controlling symptoms and maintaining functional independence.
• Care is individualized, based on presentation of symptoms, as well as social, occupational, and emotional needs.
• Patients are usually cared for at home, admitted to the hospital only for complications or new treatments.

Pharmacologic Therapy

• Antiparkinsonian medications act by: Increasing striatal dopaminergic activity.
• Antiparkinsonian medications act by: restoring a balance between dopaminergic & cholinergic activities.
• Antiparkinsonian medications act by: Acting on neurotransmitter pathways other than the dopaminergic pathway.
• Levodopa (Larodopa)/ Carbidopa with levodopa (Sinemet) is the most effective agent & mainstay treatment.
• Converted to dopamine in basal ganglia, producing symptom relief.
• Avoid the following with Levodopa: Tyramine rich foods, to prevent hypertensive crisis.
• Avoid B6 (pyridoxine) when taking Levodopa.

Surgical Management

• Surgery is used for symptom relief in selected patients only

Stereotactic Procedures

• Used to interrupt the nerve pathways & alleviate tremors or rigidity.
• Thalamotomy is a stereotactic electrical stimulator that destroys part of the ventrolateral portion of the thalamus to reduce tremor.
• Pallidotomy involves destruction of part of ventral aspect of medial globus pallidus through electrical stimulation in patients with advanced disease.
• Deep Brain Stimulator (DBS) is one in which a pacemaker-like device with electrodes attached to thalamus is inserted to relieve tremors.

Nursing Diagnoses

• Impaired physical mobility is related to muscle rigidity & motor weakness.
• Self-care deficits are related to tremor & motor disturbance.
• Constipation as related to medication & reduced activity.
• Imbalanced nutrition.
• Impaired verbal communication.
• Ineffective coping.

Nursing Interventions

• Improving mobility by progressive program of daily exercise.
• Enhancing self-care activities is key to independence with PD.
• Improving bowel elimination.
• Improving nutrition through high residue, high caloric, soft food .
• Encouraging the use of assistive devices.
• Improving communication by referral to speech therapy.
• Supporting coping abilities through conversation and compassion.
• Support by providing home and community-based care.