Parkinson's Disease
Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by motor symptoms (tremor, rigidity, bradykinesia, postural instability) and non-motor symptoms (cognitive decline, depression, autonomic dysfunction). Management focuses on symptom control and improving quality of life.
Diagnosis
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Clinical Diagnosis:
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Based on the presence of cardinal motor symptoms and response to dopaminergic therapy.
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Supportive Tools:
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DaT-SPECT imaging to assess dopamine transporter loss (if diagnosis is uncertain).
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Medical Management
A. Early Parkinson’s Disease
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Levodopa/Carbidopa (Sinemet):
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Initial therapy for older adults or those with significant motor disability.
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Dose: 25/100 mg orally 2–3 times daily; titrate based on response.
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Controlled-release formulations or extended-release capsules for smoother effect.
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Dopamine Agonists:
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Used as first-line in younger patients (<65 years) to delay levodopa use.
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Pramipexole:
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Initial dose: 0.125 mg orally TID; titrate to 0.5–1.5 mg TID.
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Ropinirole:
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Initial dose: 0.25 mg orally TID; titrate to 1–4 mg TID.
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Rotigotine (Neupro patch):
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Initial dose: 2 mg/24 hours; titrate up to 8 mg/24 hours.
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Monoamine Oxidase B (MAO-B) Inhibitors:
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Mild symptom relief and possible neuroprotection.
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Selegiline:
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Dose: 5 mg orally twice daily.
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Rasagiline:
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Dose: 1 mg orally once daily.
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Amantadine:
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Useful for tremor or early dyskinesias.
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Dose: 100–300 mg orally daily in divided doses.
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B. Advanced Parkinson’s Disease
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Levodopa/Carbidopa Adjustments:
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Increased frequency or addition of controlled-release formulations.
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Levodopa/Carbidopa/Entacapone (Stalevo):
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Combines levodopa with a COMT inhibitor to prolong its effect.
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Dose: Based on levodopa needs (50/200 to 200/200 mg per dose).
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Catechol-O-Methyltransferase (COMT) Inhibitors:
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Reduce "off" time and prolong levodopa effect.
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Entacapone:
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Dose: 200 mg with each levodopa dose (max 8 doses/day).
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Opicapone:
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Dose: 50 mg orally once daily at bedtime.
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Dopamine Agonists and MAO-B Inhibitors:
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Used in combination with levodopa to reduce motor fluctuations.
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Glutamate Antagonists:
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Amantadine ER (Gocovri):
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Dose: 137 mg orally at bedtime for 1 week, then increase to 274 mg daily.
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Reduces dyskinesias.
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Adenosine A2A Receptor Antagonists:
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Istradefylline (Nourianz):
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Dose: 20–40 mg orally once daily.
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Reduces "off" episodes.
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Apomorphine:
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Rescue therapy for "off" episodes.
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Subcutaneous injection: 2–6 mg as needed.
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Sublingual film (Kynmobi): 10–30 mg up to 5
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4. Non-Motor Symptom Management
Depression/Anxiety:
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SSRIs (e.g., sertraline, citalopram).
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Cognitive Decline/Dementia:
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Rivastigmine: 1.5–6 mg orally twice daily.
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Donepezil: 5–10 mg orally once daily.
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Autonomic Dysfunction:
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Orthostatic Hypotension: Midodrine (5–10 mg TID) or fludrocortisone (0.1–0.2 mg daily).
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Constipation: Laxatives or fiber supplementation.
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REM Sleep Behavior Disorder:
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Clonazepam (0.25–0.5 mg at bedtime).
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5. Recent Advances
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Continuous Subcutaneous Levodopa Infusion (Duodopa):
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Delivered via a portable pump for advanced PD with severe fluctuations.
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Improves "on" time and reduces "off" time.
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Focused Ultrasound (FUS):
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Minimally invasive treatment for tremor-dominant PD.
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Targets thalamus for tremor relief.
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Gene Therapy:
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Investigational therapies targeting dopamine production and neuronal repair.
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Stem Cell Therapy:
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Emerging research for regenerating dopaminergic neurons.
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Novel Medications:
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Tavapadon: A selective dopamine D1/D5 receptor partial agonist in trials.
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BTX-A (Botulinum Toxin A):
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Used for drooling or dystonia.
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Digital and Wearable Technologies:
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Devices to monitor symptoms and adjust therapy in real-time.
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Monitoring and Follow-Up
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Assess motor and non-motor symptoms every 3–6 months.
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Monitor for complications of therapy:
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Dyskinesias.
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Impulse control disorders (e.g., gambling, hypersexuality).
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Regular adjustments in therapy to balance efficacy and side effects.