Dec 30, 2015
It Charactarized by memory impairment and other cognitive deficits with preservation of a normal level of consciousness
late features:
Apraxia Short attention span Disorientation language loss (eventually) Depression
Anosognosia*
AL-ZHEIMER’s DISEASE
In AD BOTH short and long term memory are affected
the cases of AD are dividing into 4 main clinical groups :which are
1 -sporadic late onset (most common)2-familial late onset (uncommon)
3 -familial early onset (rare)4 -associated with Down’s syndrome
ETIOLOGY: -It’s the most common age related neurodegenerative
Disease
-4th leading cause of death and the most common cause of Dementia that cause problem with memory among elderly .
- Most cases are sporadic (no known Cause) but 5-10% are familial (rare)!
*The incidence is progressively increased with Advanced age )
familial cases present at 30-40 years old
-Females are affected twice more than males )?( -Down syndrom has been increased the risk of developing AD )?(
Familial forms
EARLY AD : Genetic defect (mutation) in APP (ch 21) or component of gama secretase (presinliin 1(ch14) presinillin 2 (ch1) ,
late AD : apoE4(ch19), SORL1 Ch12 mutation which encodes for alpha-2 macroglobulin
rate of accumlation of AB peptide
Affect the neurons and neuronal function
Small aggregation
1 -neurotransmitter alteration
2 -neurons and synaptic end
toxicity
Large agg. (plaques)
they elicit inflammatory
response leading to
further injury
Neuronal death
Hyperphosphorlation of microtubule
binding protein (tau)
Redisribution of tau from axon to dentrites
and cell body
Aggregation into tangles
Pathogenesis of AD
processing of APP
S APP
Groth factor function
PHYSIOLOGICAL PATHWAY
APP and presenilin mutation
AB40,AB42 formation
AB40 AB42
Aggregation
Amyloid plaques
phosphatase
tau –p ----------- tau ------------<
kinases
Paired helical filaments
Neurofibrillary tangles
NUERONAL DEATH
Morphology :
GROSSLY : brain is reduced in weight ,cortical atrophy with narrowing of gyri and widening of sulci , white matter loss is accompanied by dilatation of the ventricular system ( compensatory hydrocephalus)
MICROSCOPIC ; the cytopathological hallmarks of AD are:1 -intracellular neurofibrillary tangles (hyperphosphrlated form of TAU protein that
normally binds to microtubules ) _2 -extracellular (senile ) amyloid plaques ( core of beta amyloid peptides surrounding
by altered nerve fibers &reactive glial cells ( in hypocampus ) 3 -amyloid angiopathy
4 -granulovacular degeneration : Multiple, small intraneuronal cytoplasmic vacuoles. Some contain dark granules Known as hirano bodies
There is NO CURE for AD but currently drugs are aimed to either improving the cognition and cholenergic transmission
within CNS or preventing excitotoxic actions resulting from over stimulation of NMDA-glutamate receptors in selected
brail areas .
the pharmacological intervention is only palliative and has short term benefit .
TTT of Alzheimer’s disease
•ACHEIs (donepezil , tacrine , velnacrine ِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِِA- • Rivastigmine , glantamine) 1 -DONEPEZIL ; it has no effect on the course of disease but it can improve
cognitive function
2 -TACRINE ; long acting (6-8hrs)
MOA : all of them are non-competitive inhibitors of ACHE in CNS . Except glantamine ;its competitve
Galantamine may also be acting as an allosteric modulator of the nicotinic receptor in the CNS
Tacrine also inhibit MAO -> decrease release of GABA(inhibitory NT in CNS) +increase norepinephrine, serotonin and dopamine from nerve endings
•NMDA- receptor antagonist ( MEMANTINE) •It neuroprotective and can slow the rate of memory loss , used in moderate and
severe cognitive loss . •It is more effective than ACEIs .
MOA : block NMDA receptor associated ion channel (ca+, Na+)
At theraputic dose : partial blockage of channel . It allows limited ca+ flow throuh unbloked channel to preserve other vital processes that depend on ca .+
1-vit.E or other antioxidants - protect neuron from free radical damage
(American journal of nursing 2003, KARGER medical and scientific bublisher 2006)-.
-2-ca+ channel blockers. -protect neurons from ca+ ion -induced injury
-(CMAJ canadian medical association 2003)
3-Cholestrol lowering drugs lower brain concentration of Pubmed 2003, medscape ))APOE4
4-Anti-inflammatory drugs for B amyloid aggregate that induce inflammatoty response
(International weekly journal of science 2010)
-5-drugs used in DM as DM has a risk for developing AD later on
NEW YORK ACADEMY OF SCIENCE 2012).
6-Reverse neurodegeneration with new magnesium (compound prohealth 2013 )
Alzheimer’s disease ; it’s the most common cause of dementi
* Etiology ; most of cases are sporadic , few are familial
*Pathogenesis ; deposition of amyloid beta due to genetic defect in precursor
protein
* Gross and microscopic features : hallmark of AD ?
*TTT of AD : no cure for AD but recently drus aimed to eitherimproving the cognition and cholenergic transmission within CNS or preventing excitotoxic actions from over stimulation of NMDA-glutamate receptors