What are the symptoms and treatment options for Parkinson's disease?

Symptoms and Treatment of Parkinson's Disease

Parkinson's disease is characterized by both motor and non-motor symptoms, with motor symptoms including bradykinesia, resting tremor, rigidity, and postural instability, while treatment primarily involves dopaminergic medications such as levodopa, along with supportive therapies. 1

Motor Symptoms

• Cardinal Motor Symptoms: The primary motor features of Parkinson's disease include:

  • Bradykinesia (slowness of movement) and akinesia (difficulty initiating movement) 1, 2
  • Resting tremor (typically 4-6 Hz, often described as "pill-rolling") 1, 2
  • Rigidity (increased muscle tone and resistance to passive movement) 1, 2
  • Postural instability (loss of postural reflexes, typically occurring later in the disease) 1, 3

• Additional Motor Manifestations:

  • Gait disturbances (shuffling steps, freezing of gait, festination) 2
  • Impaired handwriting (micrographia - small, cramped handwriting) 2
  • Speech deficits (hypophonia - soft speech, dysarthria, monotonous speech) 2
  • Reduced facial expression (hypomimia or "masked face") 1
  • Difficulty with fine motor tasks 2

Non-Motor Symptoms

• Autonomic Dysfunction:

  • Constipation (often appears years before motor symptoms) 4, 5
  • Orthostatic hypotension (dizziness upon standing) 6, 4
  • Urogenital dysfunction (urinary urgency, frequency, nocturia) 4, 5
  • Excessive sweating 4

• Sleep Disorders:

  • REM sleep behavior disorder (acting out dreams during sleep) - may precede motor symptoms by years 4, 5
  • Excessive daytime sleepiness 6, 4
  • Insomnia 4
  • Restless legs syndrome 4

• Sensory Symptoms:

  • Hyposmia/anosmia (reduced/absent sense of smell) - often an early symptom 1, 5
  • Pain and paresthesias 4, 5

• Neuropsychiatric Symptoms:

  • Depression and anxiety 1, 4
  • Cognitive impairment and dementia (especially in advanced disease) 1, 4
  • Hallucinations (visual more common than auditory) 6, 4
  • Apathy and anhedonia 4, 5
  • Impulse control disorders (often medication-induced) 4

Treatment Approaches

Pharmacological Treatment

• Levodopa Therapy:

  • Most effective treatment for motor symptoms 7, 1
  • Usually combined with carbidopa (inhibits peripheral decarboxylation of levodopa) 7
  • Mechanism: Crosses blood-brain barrier and converts to dopamine in the brain 7
  • Side effects: Nausea, vomiting, orthostatic hypotension, dyskinesias with long-term use 7

• Dopamine Agonists:

  • Direct stimulation of dopamine receptors (e.g., pramipexole) 6, 1
  • May be used as initial therapy or as adjunct to levodopa 1
  • Side effects: Somnolence, hallucinations (especially in older patients), impulse control disorders 6

• Other Medications:

  • MAO-B inhibitors (selegiline, rasagiline) 1
  • COMT inhibitors (entacapone, tolcapone) 1
  • Anticholinergics (primarily for tremor) 1
  • Amantadine (for dyskinesias) 1

Non-Pharmacological Approaches

• Exercise and Rehabilitation:

  • Physical therapy to improve mobility, balance, and prevent falls 1
  • Occupational therapy for activities of daily living 1
  • Speech therapy for dysarthria and hypophonia 1

• Advanced Therapies (for medication-resistant symptoms or complications):

  • Deep brain stimulation (DBS) - typically targeting subthalamic nucleus or globus pallidus 1
  • Levodopa-carbidopa intestinal gel for continuous dopaminergic stimulation 1

• Management of Non-Motor Symptoms:

  • Constipation: Increased fiber and fluid intake, probiotics 8
  • Cognitive symptoms: Cholinesterase inhibitors 1, 4
  • Depression/anxiety: SSRIs and other antidepressants 1, 4
  • Sleep disorders: Sleep hygiene, specific medications for RBD if needed 4

Special Considerations

• Medication Timing:

  • Levodopa absorption can be affected by high-protein meals 7
  • Careful timing of medications is crucial as disease progresses 1

• Disease Progression:

  • Different subtypes have varying progression rates 1
  • Motor complications (wearing-off, on-off fluctuations, dyskinesias) typically develop after 5-10 years of levodopa therapy 1

• Monitoring Side Effects:

  • Watch for excessive daytime sleepiness, especially with dopamine agonists 6
  • Monitor for hallucinations, particularly in elderly patients 6
  • Assess nutritional status regularly, as weight loss is common 8

• Palliative Care:

  • Should be integrated throughout disease course 1
  • Focus on quality of life and symptom management 1