Degenerative Diseases and Dementias-2

Degenerative Diseases and Dementias-2

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NOTICE: This article is a pathological discussion on Degenerative Diseases and Dementias.

In previous discussion,in detail we have discussed

  1. Definition of Dementia
  2. ALZHEIMER DISEASE

So now we will continue our discussion with

Parkinson’s Disease

Parkinsonism:


  • It is a clinical syndrome characterized by diminished facial expression, stooped posture(Slowness in initiation and execution of voluntary movements), bradykinesia(progressively shortened, accelerated steps), festinating gait(Increase Muscle Tone and Increase Resistance to Movement (Arms and Legs Stiff)), rigidity, and a “pill-rolling”(Usually Tremor at Rest, When Person Sits, Arm Shakes, Tremor Stops When Person Attempts to Grab Something Movement (Arms and Legs Stiff))tremor.
  • Cause = damage to the nigrostriatal dopaminergic system.
  • Parkinsonism may also be induced by drugs that affect this system, particularly dopamine antagonists and toxins.

Parkinsonism includes:

  • Parkinson disease (PD)
  • Multiple system atrophy
  • Postencephalitic parkinsonism
  • Progressive supranuclear palsy (PSP)
  • Corticobasal degeneration
  • Some cases of Huntington disease

Parkinson disease (PD):

  • The most common movement disorder affecting 1-2 % of the general population over the age of 65 years.
  • The second most common neurodegenerative disorder after Alzheimer´s disease (AD).
  • Characterized by damage of substantia nigra of midbrain.

Morphology of Parkinson disease:

Grossly:

pallor of the substantia nigra and locus ceruleus

Microscopically:

  • Loss of the pigmented, catecholaminergic neurons in these regions associated with gliosis.
  • Lewy bodies may be found in some of the remaining neurons.

Lewy bodies may be found in some of the remaining neurons.

pigmentation with Parkinson's disease

At the left, normal numbers of neurons in the subtantia nigra are pigmented. At the right, there is loss of neurons and loss of pigmentation with Parkinson’s disease.

Lewy bodies

Pathogenesis of Parkinson disease:


Imbalance primarily between the excitatory neurotransmitter Acetylcholine and inhibitory neurotransmitter Dopamine in the Basal Ganglia

Congenital malformations and perinatal brain injury:

  • CNS malformations can cause

–mental retardation

–cerebral palsy

–neural tube defects

  • Incidence 1%-2%
  • Causes

–Gene mutation

–Environmental factors

–Toxic compounds and infectious agents

Classification:

  • Malformation

–Neural Tube Defects

–Myelomeningocele

–Forebrain Malformations

  • Perinatal Brain Injury

–Hemorrhage

–Infarct

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