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Alzheimer's disease - First Symptoms, Progression and Prognosis



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Alzheimer's disease is one of the most devastating brain disorders of elderly humans. Alzheimer disease is the most common cause of a decline in cognitive ability.
It causes degeneration of the cells in the brain.
Resulted progressive impairment of behavioral and cognitive functions: including memory, comprehension, language, attention, reasoning, and judgment.
It begins with insidious onset, Mild Cognitive Impairment, Commonly after 65 years of age.
In this stage, patients have impairment in either memory or in nonmemory domains, such as executive ability or language function.
These individuals continue to work, socialize, and function independently.
Short-term memory impairment is followed by impairment in problem-solving, judgment, executive functioning, lack of motivation and disorganization. leading to problems with multitasking and abstract thinking.
Symptoms worsens over time.
incapacitating memory impairment. Language changes include anomia, the person can not recall the names of everyday objects.
paraphasic errors, using the wrong words, a tendency for use of many words , to avoid forgotten words. It is called circumlocution.
Impairment of visuospatial abilities leads to wandering in the familiar surroundings and constructional apraxia which means Inability of patients to copy accurately drawings or three-dimensional constructions.
A decline in cognitive ability severe enough to interfere with activities of daily living is called dementia.
Alzheimer's disease is the most common type of dementia.
Neuropsychiatric symptoms like apathy, social withdrawal, disinhibition, agitation, psychosis, and wandering are also common in the mid to late stages.
parkinsonian symptoms also occur late in the disease.
They eventually become mute, fail to respond to verbal requests, remain confined to bed, and frequently slip into a persistent vegetative state.
This is followed by primitive reflexes, incontinence, and total dependence on caregivers.
20-40% of patients will have delusions. Visual hallucinations are more common.
Risk Factors:
Increasing age is the most important risk factor for Alzheimer's disease.
Traumatic head injury, depression, cardiovascular and cerebrovascular disease, higher parental age, smoking, family history of dementia. Diabetes mellitus.
While:
Higher education, use of estrogen by women, use of anti-inflammatory agents, leisure activities like reading or playing musical instruments, healthy diet and regular aerobic exercise is known to decrease the risk of Alzheimer's disease.
Intellectual activities like playing chess, reading books also have preventive role.
Having a first-degree relative with Alzheimer's disease increases the risk of developing Alzheimer's disease by 10% to 30%.
The incidence of Alzheimer's disease dramatically increases with age.
For example: prevalence rate increases from, 10% after the age of 65; to 40 % after the age of 85.

Pathophisyology:
Alzheimer's disease is believed to occur when abnormal amounts of amyloid beta (Aβ), accumulating extracellularly as amyloid plaques and tau proteins, or intracellularly as neurofibrillary tangles. form in the brain, affecting neuronal functioning and connectivity, resulting in a progressive loss of brain function.
Alzheimer's disease is a gradual and progressive neurodegenerative disease caused by neuronal cell death. It typically starts in the entorhinal cortex in the hippocampus.
Amyloid deposition causes neuronal toxicity, and it occurs around meningeal and cerebral vessels and gray matter in Alzheimer's disease. This tangles is used to define staging of Alzheimer’s disease.

Diagnosis:
Alzheimer's disease is usually diagnosed based on the person's medical history, history from relatives, and behavioral observations.
In Alzheimer's disease, the neurological exam is usually normal. =
CT brain shows cerebral atrophy and widened the third ventricle. It is suggestive but it's nonspecific because these abnormalities are also present in other illnesses and people with normal age-related changes.
Cerebrospinal fluid (CSF) analysis for low beta-amyloid 42 and elevated tau is helpful in the diagnosis of the preclinical stage.
The most reliable method to detect mild cognitive impairment in early disease is neuropsychological testing.
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Treatment:
Two categories of drugs are approved for the treatment of Alzheimer's disease: cholinesterase inhibitors and partial N-methyl D-aspartate (NMDA) antagonists.
Donepezil is usually preferred of all because of once-daily dosing.

Alzheimer's disease is invariably progressive. Average life expectancy for a person age 65 years or older diagnosed with Alzheimer's disease is about 4 to 8 years. Some individuals with Alzheimer's disease may live up to 20 years after the first signs of disease.
The most common cause of death in Alzheimer's disease is pneumonia
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