Alzheimer's Disease

KEY POINTS: A Alzheimer’s disease is far and away the most common neurodegenerative disease leading to nursing home placement. A Microscopically, there are increasing numbers of extracellular amyloid plaques in patients with Alzheimer’s disease

                                        Alzheimer's Disease

                  Comparison of a normal aged brain (left) and the brain of a person with Alzheimer's (right). Differential characteristics are pointed out.                             

ABSTRACT:

Alzheimer's disease (AD) is a slowly progressive disease of the brain that is characterized by impairment of memory and eventually by disturbances in reasoning, planning, language, and perception. Many scientists believe that Alzheimer's disease results from an increase in the production or accumulation of a specific protein (beta-amyloid protein) in the brain that leads to nerve cell death.

                     In Alzheimer's disease, brain tissue degenerates in a particular way. Nerve cells are lost. Tangles (neurofibrillary tangles) form in nerve cells, and clumps (senile or amyloid plaques) form between nerve cells. People with Alzheimer's disease also have a low level of acetylcholine in the brain. Acetylcholine is a chemical that helps nerve cells communicate with one another.

Risk Factors for Alzheimer’s Disease

While scientists know that Alzheimer’s disease involves the failure of nerve cells, why this happens is still not known. However, they have identified certain risk factors that increase the likelihood of developing Alzheimer’s.

Other risk factor are:-

Ø  The biggest risk factor for Alzheimer's disease is increased age.  

Ø  Possibly head trauma, low education, and environmental factors.

Ø  Down syndrome.

Ø  Aluminum and mercury toxicity may contribute.

Ø  The apoE4 form of the gene has been associated with increased risk of Alzheimer's disease.

Ø  Family history and genetics.

Ø   Heart disease

Signs and symptoms of Alzheimer's disease.

1. Memory loss

2. Difficulty performing familiar tasks                                                    

3. Problems with language

4. Disorientation to time and place

5. Poor or decreased judgment

6. Problems with abstract thinking

7. Misplacing things

8. Changes in mood or behavior

9. Changes in personality

10. Loss of initiative.
11. Depression.
12. Seizures.
13. Insomnia or disturbance in sleep/wake patterns.
14. Accusatory behaviors.
15. Agitation, anxiety.

Diagnosis

Alzheimer's disease is usually diagnosed clinically from the patient history, collateral history from relatives, and clinical observations, based on the presence of characteristic neurological and neuropsychological features and the absence of alternative conditions. Advanced medical imaging with computed tomography (CT) or magnetic resonance imaging (MRI), and with single photon emission computed tomography (SPECT) or positron emission tomography (PET) can be used to help exclude other cerebral pathology or subtypes of dementia. Moreover, it may predict conversion from prodromal stages (mild cognitive impairment) to Alzheimer's disease.               

                                                                                                                     

NEUROPATHOLOGY AND PATHOPHYSIOLOGY:-

In patients with AD, atrophy starts in the entorhinal cortex and hippocam-pus, and as the illness worsens clinical-ly, loss of brain volume increases and spreads more globally to involve most areas of the cortex except the occipital poles.

·        Diffuse atrophy of the cerebral cortex; secondary enlargement of the ventricular system.

·        Neuritic plaques- containing a beta amyloid and Apo E; which accumulates in the cerebral blood vessel walls; testing of Apo E is controversial, however Apo E epsilon 4/4 homozygotes diagnose AD at about 97% accuracy.

                                                                        

                                                                         

                                                                                           

                                                                                         

Treatment

Alzheimer’s Treatments:

 Primary Medications
some of the most commonly used medicines are:

Cholinesterase inhibitors. Such drugs as donepezil (Aricept), rivastigmine (Exelon), and galantamine (Razadyne) prevent the breakdown of acetylcholine, a brain chemical that is important for memory and thinking. By preserving high levels of this chemical messenger, the person may retain cognitive function longer. About 50 percent of patients on these medications see a modest improvement in cognitive symptoms.

Moderate-Affinity NMDA-Receptor Antagonist. The first of a new class of Alzheimer’s medications, memantine (Namenda) is approved for the treatment of moderate-to-severe Alzheimer’s disease. It seems to work by regulating glutamate, a chemical messenger in the brain that triggers certain receptors to allow calcium into the nerve cells so the cells can produce the necessary chemical environment to process and store information.

Vitamin E: This nutrient helps brain cells defend against free radicals, a type of oxygen molecule that is a byproduct of chemical reactions in the cells. These molecules can damage cells and genetic material in a process called “oxidative stress,” which may play a role in the progression of Alzheimer’s disease.

Alzheimer’s Treatments: Daily Care Suggestions

In addition to medications to slow disease progression, Alzheimer’s patients may receive non-medical interventions. These may include:

• Altering the person’s living arrangements and/or caregiver
• Revamping the person’s physical environment, such as furnishings, or improving lighting to reduce confusion and nighttime restlessness
• Simplifying daily tasks and routines. For example, laying out clothing or labeling items to help the person manage more effectively
• Fine-tuning communication by maintaining a non-confrontational tone with the person and redirecting their attention from whatever is upsetting them
• Providing for adequate rest between events that stimulate the person
• Changing the person’s surroundings through travel and other activities

Alzheimer’s Treatments: Controlling Behavioral and Psychiatric Symptoms

Medications can be prescribed to target specific symptoms. Physicians usually start with a low dose of a single drug to better monitor effectiveness and spot side effects. Alzheimer’s patients are prone to more serious medication side effects, including a slightly higher risk of death from anti-psychotic drugs, so the potential risks and benefits of any medication should be carefully considered.

Some medications used to treat behavioral and psychiatric symptoms are

• Anti-depressants (for mood and irritability)
• Anxiolytics (for anxiety, restlessness, disruptive behavior, and resistance)
• Anti-psychotics (for hallucinations, delusions, aggression, hostility, and uncooperativeness)
• Anti-convulsant/mood stabilizer (for hostility or aggression)
• Sedatives (for symptoms of insomnia or disturbed sleep)

In addition, Alzheimer’s patients with behavioral or psychiatric symptoms can be unpredictable, so safety precautions should be taken, such as equipping doors and gates with safety locks and locking up or removing guns or other dangerous items.