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PARKINSON'S DISEASE�

DEFINITION

CHRONIC AND PROGRESSIVE DEGENERATION OF THE NERVE CELLS WHICH TENDS TO AFFECT THE EXTRAPYRAMIDAL NEURONS MOSTLY.

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EPIDEMIOLOGY

  • AFFECTS ALL AGE GROUPS BUT PROGRESSES VERY SLOWLY WITH MORE MANIFESTATION OF THE TYPICAL FEATURES IN OLDER AGE.
  • PD IS USUALLY PRESENT FOR ABOUT 20 YEARS BEFORE THE TYPICAL CLINICAL FEATURES APPEAR
  • EARLY FEATURES ARE ATYPICAL, HENCE THE DELAY IN DIAGNOSIS.

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PATHOPHYSIOLOGY

  • AGGREGATES OF ALPHA-SYNUCLEIN PROTEIN MISFOLD IN THE NEURONS IN PARKINSON’S DISEASE. THIS IS BELIEVED TO BE THE CAUSE OF NEURONAL DAMAGE IN PARKINSON’S DISEASE.
  • THE PROGRESSIVE DESTRUCTION OF THE NEURONS LEADS TO THE EVENTUAL MANIFESTATIONS OF PD.

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CLINICAL FEATURES

NON MOTOR FEATURES (USUALLY PREDATES THE MOTOR BY MANY YEARS)

  • Cognitive dysfunction
  • Anxiety state – 40%
  • Anosmia
  • Low mood
  • Constipation – 90%
  • Orthostatic hypotension – dizziness, headache, neck muscle ache.
  • Bladder dysfunction
  • Depression
  • Sleep dysfunction
  • Visuo-spatial dysfunction
  • Visual changes
  • Fatigue

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  • Difficulty with language expression
  • Impaired executive abilities
  • Reduced attention span
  • Cloudy memory
  • Dementia – 20 to 30%
  • REM sleep – exaggerated body movements

MOTOR FEATURES

  • Coarse tremors at rest
  • Hypokinesia/Bradykinesia
  • Cog-wheel rigidity

These predominate when the disease is fully developed and usually lead to medical consultation.

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NEUROTRANSMITTERS IN PARKINSON’S DISEASE

DOPAMINE

  • Dopamine is involved in the initiation of movements
  • Mood and personality
  • Coordination of movements
  • Sleep

SEROTONINE

  • Autonomic function

ACETYLCHOLINE

  • Involved in mood , attention sustenance, memory
  • Speech
  • Apathy

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RISK FACTORS

  • Uric acid
  • Age – frequency and prevalence increase with age
  • Head injury
  • REM sleep body movement disorders
  • Slow finger tapping

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ASSESSMENT OF PARKINSON’S DISEASE PATIENTS

  • Good history
  • Physical examination
  • coarse tremors at rest
  • Glabellar Tap Reflex
  • Retropulsion
  • Muscle rigidity
  • Inertia
  • Cog-wheel rigidity
  • Orthostasis – postural hypotension, postural nystagmus

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INVESTIGATION

  • Radiology – CT scan, MRI, DaT scan of the brain.

DaT scan uses isoflurane (cocaine analogue) for nuclear medicine. DaT scan diagnoses Parkinson’s disease and differentiates it from other neurological diseases. It is a SPECT imaging technique for visualizing dopamine transporters and channels.

N.B: DaT scan means dopamine transporter SPECT

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TREATMENT OF PARKINSON’S DISEASE

  • Drugs
  • Dopamine replacement – L.dopa
  • Sinemet – L-dopa + carbidopa
  • Madopar – L-dopa + benserazide
  • Dopa agonists – bromocriptine, etc
  • Cholinergic – benzhexol, benztropine, akinetone
  • Exercises – physiotherapy, occupational therapy, rehabilitation
  • Nutrition
  • Speech therapy (if indicated)