Alzheimer’s disease – Causes, Stages, Symptoms and Treatments

What is Alzheimer’s disease?

Alzheimer’s disease (AD), a neurodegenerative disorder is the most common form of dementia, accounting for an estimated 60% – 80% of cases. Dementia is a brain disorder that seriously affects a person’s ability to carry out daily activities. AD is an irreversible and progressive brain disease, with the most common early symptoms being memory difficulties and trouble learning new information. It is a progressive impairment of behavioral and cognitive functions including memory, comprehension, language, attention, reasoning, and judgment.

How Alzheimer’s disease affects the brain?

Alzheimer’s disease (AD) was described for the first time in 1907 by the German psychiatrist Alois Alzheimer in performing a histopathologic study of the brain of his patient Auguste Deter, suffering from dementia. He brought to the presence of two types of lesions in the brain; amyloid plaques and neurofibrillary tangles. They are made up of two key proteins; amyloid and tau. Amyloid and tau are present in healthy brains but in AD they function abnormally. Amyloid forms plaques outside cells (neurons) and tau forms tangles inside them. These plaques and tangles damage nerve cells causing them to die. When lots of cells die, this causes the brain to shrink.

Figure 1: Normal healthy brain tissue. (B) Formation of amyloid plaques and neurofibrillary tangles. (C) Massive apoptosis occurs in later stages of the development of AD in the human brain (brain slices).

What are the stages and symptoms of Alzheimer’s disease?

The development and progression of Alzheimer’s disease are classified into three main stages. 

  1. Pre-clinical or pre-symptomatic phase: During this stage amyloid plaques and neurofibrillary tangles start accumulating in the brain. This does not cause any noticeable symptoms. 

2. Mild Cognitive Impairment: 

Impairment starts to be significant but does not interfere with everyday activities. Symptoms become noticeable. 

3. Dementia-stage/Alzheimer’s disease:

The impairment interferes with everyday functioning. Significant loss of intellectual ability occurs which affects memory.  

In Alzheimer’s disease (AD) the first area of the brain affected is the hippocampus. The hippocampus plays a major role in forming memories. So the initial and most common symptom is trouble forming new memories. They may struggle to remember their most recent activities. In Alzheimer’s disease, older memories can remain for a much longer time while more recent memories usually lost first. This short-term memory loss leads to further impairments like problem-solving, judgment, multitasking, lack of motivation, and disorganization. As the disease progresses through the brain it leads to more severe symptoms which include mood and behavior. As more and more nerve cells die and more areas of the brain are affected, the symptoms of Alzheimer’s becomes worse and more numerous.

What are the treatments of Alzheimer’s disease?

Currently, there is no cure for Alzheimer’s disease. For cognitive and behavioral symptoms some drugs are approved. Donepezil, rivastigmine, and galantamine are FDA-approved for the treatment of Alzheimer’s disease. Donepezil can be used in all stages of Alzheimer’s disease. These drugs help to increase the levels of acetylcholine in the brain, are prescribed to treat symptoms related to memory, thinking, language, judgment, and other thought processes. Another drug approved for AD is memantine, which regulates the activity of glutamate, a chemical involved in information processing, storage, and retrieval. It is approved by the FDA for treating moderate to severe Alzheimer’s disease. 

Please reach out to the Guildview Pharmacy Staff if you have questions about Alzheimer’s are anymore questions. 

Written by: Rubina Polara

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