Non-motor features of Parkinson's disease

Majority of the patients suffer from non-motor features in the latter part of the disease. But certain symptoms may:

• develop at any time throughout the disease (e.g. - depression, anxiety, hypersomnolence)
• precede it (e.g. - sleep disturbance, depression, anxiety) (1)

These include (1):

• Neuropsychiatric symptoms:
  • depression
    • seen in around 45% of the patients (2)
  • dementia
    • around 40% of PD patients will ultimately meet the diagnostic criteria for dementia during the course of the condition (2)
  • psychosis
    • occurs in 40% of the patients who are on dopaminergic therapy
    • visual hallucinations are common (auditory and olfactory hallucinations are less common)
  • anxiety
    • common
    • may present as panic attacks, obsessive-compulsive behaviours, or generalized anxiety (2)
  • apathy
    • occurs independent of depression and fatigue
    • minimal response to dopaminergic drugs (2)
  • Impulse control disorders (ICD)
    • occurs in a small number of patients
    • thought to be due to dopamine agonists
    • may be seen as hypersexuality, compulsive eating and gambling and other compulsive beahviours (2)
• falls
  • two-thirds of the PD patients fall each year
  • early onset of falls may point towards an alternative disease - progressive supranuclear palsy (PSP) (1)
• sleep disturbance:
  • hypersomnolence
    • seen in around 50% of the patients
    • can be due to the disease itself, poor sleep or anti Parkinson's drugs (2)
  • rapid eye movement sleep behaviour disorder
  • restless legs syndrome
  • inverted sleep-wake cycle
  • nocturnal akinesia
• autonomic disturbance
  • bowel dysfunction including constipation
    • affects more than 50% of the patients
  • dysphagia
    • usually relate to disease severity
    • may lead to aspiration pneumonia, malnutrition and dehydration
  • weight loss
    • unintentional weight loss is seen over 50% of the patients (2)
  • dribbling of saliva
    • occurs in 70-80% of the patients
  • bladder dysfunction
    • affects in around 40% of the patients
    • nocturia is the most common earliest symptom
    • urgency, frequency and urge incontinence can also be seen (2)
  • sexual dysfunction
    • in men - erectile dysfunction
    • in women - arousal difficulties, orgasmic difficulty, dyspareunia or vaginismus (2)
  • postural hypotension
    • seen upto 48% of the patients o patient may have - dizziness, visual disturbances, falling or fainting
    • can be caused by central or peripheral autonomic dysfunction, Parkinson's or antihypertensive medications or co-morbidities (2)
  • excessive sweating
    • may experience as an end-of-dose 'off' phenomenon or in the "on" motor state
    • usually linked to dyskinesia (2)
  • pain
    • pain in Parkinson's disease can either be unrelated, such as osteoarthritis, or related pain that can be defined as pain that starts after Parkinson's disease diagnosis, responds to Parkinson's disease treatment, is maximal on the more affected side, and has no clear alternative cause
      • the main types of pain syndromes encountered in Parkinson's disease are central pain, peripheral pain, musculoskeletal pain, and pain due to dystonia and akathisia (3)

Reference:

• (1) Parkinson's Disease.National clinical guideline for diagnosis and management in primary and secondary care. NICE full guideline.2006
• (2) Parkinson's disease society. The professional's guide to Parkinson's disease
• (3) Khan AZ et al. Pain syndromes in Parkinson’s disease: an update for general practice. BJGP 2024; 74 (739): 90-92.