Alzheimer’s Disease

May 5, 2004

By Mark Lucianna, MD

As a family physician for over 28 years, I have watched many of my patients grow older. Most have done so gracefully, however, some have suffered from a progressive form of neurological deterioration known as Alzheimer’s Disease. This incurable disease involves a gradual decline in memory, language skills, and perception of time and space. Ultimately patients loose the ability to care for themselves. A German psychiatrist named Alois Alzheimer first described the disorder in 1906. It was initially thought to be two different diseases; one of early onset in the 30’s, 40’s or 50’s and another of onset after 65. Today we know 90 percent of those who develop the disease do so after the age of 60. Indeed, it is believed 50 percent of the population over age 85 is affected by it.

Symptoms of Alzheimer’s disease develop very slowly. Early on, patients have problems learning and retaining new information; short-term memory loss becomes a big problem. They frequently misplace common objects and cannot remember recent events, even the day or month; they often get lost in familiar surroundings. Sometimes the patient becomes irritable and withdrawn because of the frustration they feel. Behavioral traits (such as paranoid tendencies) may become exaggerated and it may be hard for others to be around. Some patients have delusional beliefs (beliefs not based on reality) and even hear or see hallucinations.

With further progression of the disease, the patient may become totally unable to function in even the most basic ways, such as using the toilet and eating food. They do not die directly from the disease, but of complications of pneumonia, falls, or heart attacks (there is an increase in sudden cardiac deaths in Alzheimer’s patients.) The usual time frame from onset to death is seven to ten years.

The only way to definitively diagnose Alzheimer’s Disease is through an autopsy. These patient’s brains show abnormal protein molecules called tangles and plaques. These are present in many, but not all parts of the brain. These tangles and plaques cause the neurons (the basic cells of the nervous system) to shrink and eventually die. As the brain loses these cells, it is unable to connect information from on part of the brain to another. It is as though the “wires” that connect the brain together become disconnected.

In addition, the chemicals that send information from one part of the brain to another become depleted for unknown reasons. The primary neurotransmitter to become depleted is called acetylcholine, a prominent chemical used to store memory. Most of the drugs used today to treat the disease boost levels of acetylcholine in the brain.

The cause of Alzheimer’s Disease is unknown at this time. It is known that there are genetic factors at work, people with a family history are more likely to get the disease. Scientists have learned people who carry the apoE gene are much more likely to develop the disease than others. This gene comes in two types, 3 and 4, with type 4 being much more common in the older-onset group. Gene Mutations have been found to cause the early onset type; these same mutations have been found in Down’s Syndrome patients; indeed the brains of Down’s Syndrome patients show plaques and tangles similar to Alzheimer’s Disease

There are other studies suggesting environmental agents may be implicated in the cause of the disease; for example, one study suggested high levels of aluminum might be involved. This was later proven to be untrue. Zinc, food borne poisons, and viral agents have also all been falsely implicated.

Treatment of Alzheimer’s Disease tends to delay the time when the inevitable deterioration becomes a reality. Thus, the patient preserves function for a longer period of time. The acetylcholinesterase inhibitor drugs currently available increase the levels of acetylcholine in the brain. They are most useful in the early stages of the disease and include Aricept, Reminyl, Cognex and a newer drug called Namenda. The last drug, Namenda, is the first approved to treat later stage Alzheimer’s and has been shown to significantly prolong the length of time patients are able to function.

There is also evidence of inflammation in Alzheimer’s patient’s brains. This inflammation is associated with the production of a protein (amyloid precursor protein), which causes production of amyloid (a chemical involved in the formation of plaques in the brain.) As I explained earlier, these plaques damage the transmission of information between brain cells. New drugs are being developed to block the activity of enzymes involved in amyloid production.

Caring for someone with Alzheimer’s can be a full time job. They must be watched constantly for fear they will wander away or hurt themselves or others when confused. The high degree of stress involved in caring for these patients may cause the caregivers themselves to become ill. If you are a caregiver, you may find the Alzheimer’s Association to be a great source of information and support.