Alzhermer’s Disease (AD)

Definition

Alzheimer’s disease (AD) is one of the most common forms of dementia characterized by loss of cognitive functions including memory, attention, understanding, speaking and decision making. The early symptom is loss of recent memory followed by confusion, long term memory loss, trouble with speaking, deterioration of personal and social life (social withdrawal). There are drugs which can improve the quality of life but the condition is incurable.

Symptoms

Symptoms vary according to the stage of Alzheimer’s disease :

  • Forgetfulness: the earliest symptom is loss of recent memory with intact old memory followed by periods of memory lapse, forgetting appointments, name of family members, common items and misplacing them, difficulty with numbers.
  • Language problem: limited vocabulary and loss of fluency (poor writing and speech).
  • Difficulty in performing tasks that require reasoning, memory: driving, filling in cheque books. Patients often get lost while walking or driving (due to forgetting common routes)
  • Personality change be associated with :
    – Confusion
    – Frustration
    – Irritability
    – Mood swing
    – Social isolation
    – Depression
    – Delusion
    – Sleep disturbances
    – Aimless wandering

Finally the patients become totally dependent on caregivers. With complete loss of speech and inability to communicate, defective swallowing, loss of control of bowel and bladder activities, institutionalization may often be necessary as it is difficult to manage the patient in the home environment.

Causes

The exact cause of AD is yet to be known. There are some theories regarding the causation of Alzheimer’s disease.

  • Acetylcholine theory: Most of the current drugs used are based upon this theory. In Alzheimer’s disease,  acetylcholine a chemical substance that maintains connection between nerve cells as a messenger) production is reduced.
  • Amyloid hypothesis: Brain tissues of patients’ of AD show presence of amyloid (proteins having abnormal structure) plaques that can destroy cell to cell communication and damage brain tissue irreversibly.
  • Neurofibrillary tangles: Tau protein is responsible for stabilization of the brain tissue. Abnormal tau proteins (hyperphosphorylated) can entangle with each other and form neurofibrillary tangles resulting into collapse of transport system of the nerve cells.
  • Herpes simplex virus 1 (HSV1) may play a causative role.
  • Oxidative stress.

The final outcome is brain tissue atrophy (shrinkage) and loss connections among of nerve cells.

Risk factors

  • Advancing age: Alzheimer’s disease is not a normal part aging although older people are more vulnerable.
  • Family members of patients with Alzheimer’s disease are at a greater risk.
  • Some patients with genetic disease like Down’s syndrome.
  • Women are more vulnerable.
  • Lifestyle factors such as cigarette smoking and a sedentary lifestyle.
  • High blood pressure.
  • Uncontrolled diabetes mellitus.

It is found that people with increased involvement with social and mental activities are less likely to develop Alzheimer’s disease.

Treatment

Despite a better understanding of the condition, there is no cure for Alzheimer’s disease. The drugs that are commonly used offer some degree of symptomatic relief and may play a role in slowing down the progression of the condition. Unfortunately the disease continues to progress.

  • Cholinesterase inhibitors: galantamine, ravastigmine, donepazil.
  • Memantine.

Supportive therapy includes counseling for family members to cope with living with the patient, a healthy diet, awareness of the dangers that may arise and various measures to ensure a safe environment. Institutionalization is not necessary but has to sometimes be considered.

 

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