Parkinson disease

Background

• Degenerative neurological disorder characterized by progressive bradykinesia, rest tremor, rigidity, and postural instability

Pathophysiology

• Destruction of substantia nigra

Clinical Manifestations

• Rest tremor at 4-6 Hz, inhibited by movement and sleep, worsened by stress
  • Pill-rolling
• Rigidity, with increased tone and cog-wheeling
  • No spasticity
  • Often worse with repeated flexion
• Bradykinesia
  • Short, shuffling gait with festination
  • Loss of arm swing
  • Micrographia
• Postural hypotension
• Glabellar tap reflex, normally stops after 5-10 taps

JAMA Rational Clinical Exam

• Change in speech (LR+ 2.6, LR- 0.73)
• ...

Differential Diagnosis

• See Parkinson syndrome

Management

Non-Motor Symptoms

Psychosis

• Usually worsened by antiparkinson medications
• Evaluate and treat any triggers
• Consider decreasing any anticholinergic drugs, followed by amantadine, dopamine agonists, monoamine oxidase type B inhibitors, and COMT inhibitors, and finally levodopa (as a last resort)
• For refractory symptoms, consider quetiapine, pimavanserin, and clozapine
  • Other antipsychotics have higher risk of exacerbating Parkinson disease

Orthostatic Hypotension

• May be caused by the underlying disease or by medications (including levodopa and MAO B inhibitors) that are used to treat it
• Non-medical management includes increased oral fluid (possibly with boluses), salt supplementation, physical counter-maneurvers, abdominal banding, stockings, and elevating the head of the bed
• Pharmacologic treatments include droxidopa, fludrocortisone, and midodrine