Parkinson's disease

Disease Description (Causes and Symptoms)

• Summary of definition: Parkinson’s disease is a degenerative movement disorder caused by the progressive loss of dopamine-producing nerve cells in the substantia nigra (nigra) of the midbrain, resulting in an imbalance in the function of the basal ganglia circuits. Pathologically, Lewy bodies (α-synuclein accumulation) are observed. It has a prevalence of approximately 1% among people aged 60 and older, and its incidence increases with age.
• Causes: A genetic cause is identified in approximately 5–10% of cases, while most cases are idiopathic. Environmental toxins (e.g., MPTP, certain pesticides such as rotenone and paraquat, and metal exposure), mitochondrial dysfunction, and abnormalities in protein processing have been proposed as related mechanisms.
• Main pathophysiology: Loss of dopaminergic nerve cells in the substantia nigra → dopamine deficiency in the basal ganglia (including the striatum) → impaired regulation of motor function (bradykinesia, rigidity, tremor, etc.) and non-motor symptoms.
• Representative symptoms
  • Motor symptoms: Resting tremor, bradykinesia (delayed movement), rigidity (stiffness that may be asymmetrical), postural instability (balance impairment), gait disturbance (freezing phenomenon, shortened stride), stooped posture, and reduced facial expression (masked face).
  • Non-motor symptoms: Depression, anxiety, visual hallucinations, cognitive decline (possible dementia), autonomic dysfunction (orthostatic hypotension, constipation, urinary and sexual dysfunction, reduced sense of smell), sleep disorders (REM sleep behavior disorder, daytime sleepiness), pain, fatigue, and sensory abnormalities.
• Diagnosis: Typical clinical findings, based on an examination by a neurologist, are central. Imaging tests such as MRI or PET may help with differential diagnosis and supportive diagnosis. There is no single test that confirms the diagnosis.

Treatment Methods (Standard Treatment · Medications · Procedures/Surgery · Lifestyle Management · Precautions)

• Treatment principles: Symptom relief and maintenance of function — medication therapy is the mainstay, combined with rehabilitation (exercise therapy) and, when necessary, surgical treatment (deep brain stimulation, DBS).
• Medication treatment
  • Levodopa: The most effective medication and an essential drug in the early and advanced stages. Long-term use may cause dyskinesia and fluctuations in medication effect (ON/OFF).
  • Dopamine agonists (e.g., pramipexole, ropinirole): Used as initial monotherapy in younger patients or as an adjunct to levodopa. There is a risk of impulse control disorders (such as gambling and hypersexuality).
  • MAO-B inhibitors (e.g., selegiline, rasagiline): Used in the early stages and as adjunctive therapy; they can help reduce the levodopa dose.
  • COMT inhibitors (e.g., entacapone): Extend the duration of levodopa’s effect.
  • Amantadine: Used to relieve early symptoms and dyskinesia.
• Surgical treatment
  • Deep brain stimulation (DBS): Considered when medication-related fluctuations that cannot be controlled with medication or drug-induced dyskinesia occur, or when control of specific symptoms is needed. A detailed discussion with a specialist is necessary regarding indications, side effects, and expected benefits.
• Non-pharmacological treatment (lifestyle management)
  • Regular aerobic, strength, and balance training (physical therapy, peripheral movement exercises, walking, balance training, etc.) is important for maintaining gait, posture, and daily functioning.
  • Nutritional management (prevention of constipation), sleep hygiene, and environmental adjustments to prevent falls.
• Precautions and risk of complications
  • Certain medications can worsen Parkinson’s symptoms and are contraindicated: gastrointestinal motility-promoting drugs (such as metoclopramide), some antipsychotics (typical antipsychotics such as haloperidol), levopride (such as levosulpiride), and others should be avoided or used with caution.
  • Medication side effects: Nausea, orthostatic hypotension, hallucinations and psychosis, impulse control disorders, dyskinesia, and others.
  • Non-motor complications: Depression, cognitive decline (dementia), pneumonia (risk of aspiration), and fractures caused by falls.
• Treatment goals: Minimize symptoms, maintain function and independent living ability, prevent complications, and improve quality of life.

Checklist Before an Outpatient Visit (Including Items to Bring, Records, and Example Questions)

• Items to bring
  • A list of all medications currently being taken (including prescription drugs, OTC medications, herbal medicines, and supplements), along with the times taken and dosages
  • Previous medical certificates, surgical records, and brain imaging results (MRI, PET, etc.), including films or reports if possible
  • Recent blood pressure records, including whether orthostatic hypotension was observed when measured sitting and standing
  • A symptom diary (for the past 1–2 weeks): Start times of tremor, rigidity, and bradykinesia; the effect after taking medication (ON) and patterns of wearing-off (OFF); the frequency of falls and freezing; sleep patterns; digestive and urinary symptoms; etc.
  • Notes related to depression, cognitive, and sleep problems (time of onset, frequency, and severity)
  • Bringing a caregiver or family member is recommended (to help with assessment and explaining symptoms)
• What to show the doctor at the outpatient visit
  • When symptoms began and how they have progressed
  • Effects and side effects when taking medication (e.g., visual hallucinations, drowsiness, impulsive behavior)
  • Any recent falls and changes in the ability to perform daily activities
• Example questions (short sentences the patient can ask independently during the outpatient visit)
  • "I have recorded when I feel most comfortable after taking my usual medication (ON). May I show it to you now?"
  • "Recently, I have been shouting or moving my body a lot while sleeping at night. Could you evaluate me for a sleep problem?"

General Example Questions to Ask the Doctor

• What are the main side effects of this medication (or combination of medications), and what symptoms should prompt me to contact you immediately?
• For my current symptoms (tremor, bradykinesia, balance problems, etc.), how much improvement can I expect from adjusting my medication?
• If the medication wears off or dyskinesia develops, what next-step treatments (surgery or changing the combination of medications) would you consider?
• How and how often should I exercise or receive physical therapy for it to be helpful?
• What should I be careful about in daily life (driving, work, alcohol, taking sleeping pills, etc.)?

Examples of Disease-Specific Questions

• In my case, ON/OFF fluctuations or dyskinesia are occurring after levodopa use. Could you evaluate whether I meet the indications for DBS (deep brain stimulation)?
• I have recently been experiencing frequent falls and freezing of gait. Besides adjusting medication, which should be prioritized: a walking aid, a rehabilitation program, or environmental improvements?