Parkinson’s disease

• May get Parkinsonism from drugs, toxins, a byproduct of heroine synthesis (MPTP), and influenza encephalitis

• Movement d/o characterized by

  • Shuffling gate

  • Stooped over posture

  • Rigidity

  • Expressionless (“mask-like”) face

  • Tremor

• Typical onset at 50 YOA

• Pathogenesis

  • Degeneration of pigmented (dopaminergic) neurons in the substantia nigra of the midbrain

  • These neurons project to the striatum; the lack of dopaminergic input to the striatum causes the movement problems

• Lewy bodies

  • Big, round eosinophilic intracytoplasmic inclusions in neurons of the substantia nigra

  • Not specific for Parkinson’s

  • Alpha-sinuclien is the major component

• Dementia seen in about 10% of patients; some patients have dementia without movement problems – this is called diffuse Lewy body disease

• Postencephalic Parkinsonism

  • Mostly seen after flu epidemic of 1914-1918

  • Starts months to years after initial encephalitis

  • Has been associated (rarely) with western equine, measles, and Japanese B viruses

  • Neuronal degeneration in the substantia nigra with the formation of tangles, not Lewy bodies

• Striatonigral degeneration

  • C/S almost the same as Parkinson’s disease, but resistant to L-Dopa therapy

  • Loss of pigmented neurons of substantia nigra and loss of target cells in the striatum, but no Lewy bodies

Category: Pathology Notes