The following is not a feature of Alzheimer's disease: (LQ)
|B||Senile (neuritic) plaques|
a. Most common cause of dementia in the elderly
b. In young people occurs in patients of down syndrome (trisomy 21) after 40 yrs.
c. There is cortical atrophy with widening of the cerebral sulci (most commonly in frontal, temporal and parietal lobe)
d. Histology shows:
i. Neurofibrillary tangles ii. Senile angiopathy iii. Granulovacuolar degeneration
iv. Hirano bodies v. Ghost tangles.
e. Plaque and tangles are found extensively in the hippocampus and amygdala.
f. There is relative sparing of the primary motor and sensory cortices and Purkinje cells of cerebellum.
g. Most important biochemical abnormality is deficiency of acetylcholine and associated enzymes.
h. Severe loss of neurons of basal nucleus of meynert (major source of cholinergic input to areas of depletion)
i. Patient presents first with changes in memory for recent happenings.