Alzheimer's disease – Causes, Symptoms, Diagnosis, Prognosis and Latest Treatment

Alzheimer\'s disease (AD) is an irreversible, progressive brain disorder that occurs gradually and results in memory loss, behavior changes, and a decline in cognitive abilities. These losses are related to the death of brain cells and the breakdown of the connections between them.

The risk of developing AD increases with age.  While it may be that 10of the population aged over-65 has AD, the percentage of people aged 85 and older with AD is greater than 50 percent!  (Table 1)  On average, patients with AD live for 8 to 10 years after they are diagnosed, though the disease can last for up to 20 years.

Causes and Treatments 
In general, clinical assessment is done by a family physician (PCP).  If the diagnostic test, usually Mini-Mental State Exam (MMSE), points to Alzheimer\'s disease, then the patient is referred to a neurologist who will then conduct the entire panel of diagnostic tests to confirm the disease.  The neurologist may then work with a psychiatrist, geriatricians, pharmacist and social worker to develop a treatment protocol for the patients.

For those who are already suffering from the effects of AD, the most immediate need is to control their symptoms, including problem behaviors such as verbal and physical aggression, agititaion, wandering, depression, sleep disturbances, and delusions.

Currently, the FDA approved four medications for treating AD.  All these products act by inhibiting acetylcholinesterase, which breaks down acetylcholine, a neurotransmitter that is important in maintaining cognitive functioning and is lost in patients with AD.(Table 3)  These products, however, only provide symptomatic relief on cognitive symptoms and do not stop or reverse the progression of AD.  When the disease progresses to a certain stage (usually 2 years), its therapeutic effects disappear and the drugs have to be withdrawn from the patients.  Nevertheless, its temporary efficacy has been proven to delay nursing home placement and to reduce deterioration of cognitive performance.

Table 3.  Selected product comparison of the Alzheimer\'s disease category
Cognex®

Aricept®

Exelon®

Reminyl®

Efficacy
Side-effect:Liver toxicity
Dosage
QD w food
OD w/wo food
BIDw food
BID w food
Tablets and Liquid Formulation
No
No
Yes
Yes
Drug interaction
– Strong
– Moderate
– Low