Alzheimer's Disease - Causes, Symptoms And Treatment

Alzheimer's disease is the most common form of dementia. It's a degenerative disorder of the cerebral cortex, especially the frontal lobe, which accounts for more than half of all cases of dementia. Although primarily found in the elderly population, 1 % to 10% of cases have their onset in middle age. Because this is primarily a slow but progressive dementia, the
Prognosis for a patient with this disease is poor. The course of the disease varies in each person, but on average, patients with the disease live from 8 to 10 years after diagnosis.

The prevalence of Alzheimer's disease usually begins after age 60 and increases dramatically with age. Its prevalence is highest among those who are age 85 and older. Because women make up 72% of the U.S. population over age 85 and usually live longer than men, they're more likely to develop Alzheimer's disease.

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SPECIAL NEEDS

Alzheimer's disease also appears to be more prevalent among Blacks. Various studies have
found the prevalence rate to be 14% to 100% higher in Blacks than in Whites.

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Causes of Alzheimer's disease

The exact cause of Alzheimer's disease is unknown. Factors that have been associated with its development include:

• neurochemical- deficiencies in the neurotransmitters acetylcholine, somatostatin, substance P. and norepinephrine
• environmental- repeated head trauma; exposure to aluminum or manganese
• genetic - Aprolipoprotein E gene, the autosomal dominant form of Alzheimer's disease associated with early onset and death, as well as family history of the disease or the presence of Down syndrome in the patient.

Other risk factors include:

• age
• vascular disease (Those with hypertension or high cholesterol have found found twice as likely to get Alzheimer's disease. and those with both risk factors are four times as likely to develop dementia.)
• use of hormone replacement therapy in postmenopausal women.

The brain tissue of patients with Alzheimer's disease exhibits three distinct and characteristic features:

• neurofibrillatory tangles (fibrous proteins)
• neuritic plaques (composed of degenerating axons and dendrites)
• granulovascular changes.

Additional structural changes include cortical atrophy, ventricular dilation deposition of amyloid (a glycoprotein) around the cortical blood vessels and reduced brain volume. A selective loss of cholinergic neurons in the pathways to the frontal lobes and hippocampus, areas that are important for memory and cognitive functions, are also found. Examination the brain after death commonly reveals an atrophic brain, usually weighing less than 1000 g (where normal is 1380 g).

Signs and symptoms of Alzheimers disease

Typical signs and symptoms of Alzheimer's disease reflect neurologic abnormalities associated with the disease and include:

• gradual loss of recent and remote memory, loss of sense of smell, and flattening of affect and personality
• difficulty with learning new information
• deterioration in personal hygiene 4 Inability to concentrate
• increasing difficulty with abstraction and judgment
• impaired communication
• severe deterioration in memory,language, and motor function
• loss of coordination
• inability to write or speak
• personality changes, wandering
• nocturnal awakenings
• loss of eye contact and fearful look . signs of anxiety such as wringing of hands
• acute confusion, agitation, compulsiveness, or fearfulness when overwhelmed with anxiety
• disorientation and emotional liability
• progressive deterioration of physical and intellectual ability.

The most common complications include:

• injury secondary to violent behavior, confusion, or wandering
• pneumonia and other infections
• malnutrition
• dehydration
• aspiration
• death.

Diagnosis

Alzheimer's disease is diagnosed by exclusion; that is, by ruling out other disorders as the cause for the patient's signs and symptoms. The only true way to confirm Alzheimer's disease is by finding pathologic changes in the brain at autopsy. However, the following diagnostic tests may be useful:

• Positron emission tomography shows changes in the metabolism of the cerebral cortex.
• Computed tomography (CT) scan shows evidence of early brain atrophy in excess of that which occurs in normal aging.
• Magnetic resonance imaging (MRI) shows no lesion as the cause of the dementia.
• EEG shows evidence of slowed b waves in the later stages of the disease.
• Cerebral blood flow studies show abnormalities in blood flow.

Treatment for Alzheimer's disease

No cure or definitive treatment exist for Alzheimer's disease. Rather, treatment is symptomatic.
Treatment of cognitive symptoms includes:

• N-methyl-D-aspartate (NMDA) receptor antagonist (such as memanthine [Namendal) to treat moderate to severe symptoms of Alzheimer's disease (see Namenda approval)
• cholinesterase inhibitors (such as donepezil [Aricept], rivastigmine [Exelon], galantamine [Reminyl], and tacrine [Cognexl) to help improve memory deficits.
• hyperbaric oxygen to increase oxygenation to the brain
• vitamin E supplements to prevent red blood cell destruction, thereby maintaining oxygen blood flow to the brain
• cerebral vasodilators (such as ergoloid mesylates, isoxsuprine, and cyclandelate) to enhance cerebral circulation
• choline salts,ledthin, physostigmine, or an experimental agent (such as deanol, enkephalins, and naloxone) to attempt to slow the disease process.

Treatment for agitation includes:

• antidepressants, if depression appears to exacerbate dementia
• anxiolytics to decrease anxiety
• psychostimulants (such as methylphenidate) to enhance the patient's mood.

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NAMENDA APPROVAL

In October of 2003, the Food and Drug Administration approved memantine (Namenda), the first drug for the treatment of patients with moderate to severe Alzheimer's disease. Previous treatments have been for patients with mild to moderate Alzheimer's disease.

Namenda's mechanism of action is different from other available drugs. It blocks the activation of N-methyl-D-aspartate receptors, which are thought to contribute to the symptoms of Alzheimer's.

Although the drug doesn't stop or slow the underlying neurodegeneration of the disease, it's been found effective at reducing symptoms and has a low incidence of adverse effects.

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Special considerations

Overall care is focused on supporting the patient's remaining abilities and compensating for those she's lost.

• Establish an effective communication system with the patient and family to help them adjust to the patient's altered cognitive abilities.
• Offer emotional support to the patient and family members. Caring for a person with Alzheimer's is life altering. Behavior problems may be worsened by excess stimulation or change in established routine. Teach them about the disease, and refer them to sodal services and community resources for legal and financial advice and support.
• Anxiety may cause the patient to become agitated or fearful. Intervene by helping her focus on another activity.
• Provide the patient with a safe environment. Encourage her to exercise. as ordered, to help maintain mobility.