Degenerative Diseases and Dementias

  • Dementia, defined as the development of memory impairment and other cognitive deficits with preservation of a normal level of consciousness.
  • It is emerging as one of the most important public health issues in the industrialized world.

regardless of etiology, dementia is not part of normal aging and always represents a pathologic process.

Causes of Dementia:

  • Neurodegenerative Disorders

  • Infections

  • Vascular and Traumatic Diseases

  • Metabolic and Nutritional Diseases

  • Miscellaneous

  • Alzheimer disease (AD) is the most common cause of dementia in the elderly.

  • Incidence

  1. 3% for 65 to 74 years old
  2. 19% for 75 to 84 years old
  3. 47% for 85 years or more
  • Alterations in mood and behavior
  • Disorientation
  • Memory loss
  • Aphasia (Aphasia indicate severe cortical dysfunction)
  • Profoundly disabled
  • Mute
  • Immobile
  • Death (intercurrent pneumonia or other infections)

Pathogenesis of Alzheimer’s disease:

  • Genetic factors
  • Deposition of a form of amyloid
  • Hyperphosphorylation of the protein tau
  • Expression of specific alleles of apoprotein E (apo E)

Morphology of Alzheimer’s disease :

Grossly:

  • Cortical atrophy

–widening of the cerebral sulci, most pronounced in the frontal, temporal, and parietal lobes.

  • Ventricular enlargement

–secondary to loss of parenchyma

Grossly the brain shows a variable degree of cortical atrophy with widening of the cerebral sulci that is most pronounced in the frontal, temporal, and parietal lobes.

With significant atrophy, there is compensatory ventricular enlargement (hydrocephalus ex vacuo) secondary to loss of parenchyma.