Ask the Doctors

Dear Doctor: I understand that Alzheimer's disease causes memory loss and leads to dementia. But when someone has Alzheimer's, what is the actual cause of death?

Dear Reader: Alzheimer's disease is a progressive disease of the brain in which dementia is the most noticeable of numerous symptoms. Changes within the tissues of the brain slowly destroy vital connections between different regions of the brain, and between the brain and the body. The result is that Alzheimer's disease is the fifth-leading cause of death among adults over 65, and is the sixth-leading cause of death for all adults nationwide.

The disease was first identified in 1906 by Dr. Alois Alzheimer, who connected a patient's dementia to certain physical abnormalities he found when he examined her brain after her death. But the human brain is so intricate and Alzheimer's itself is so complex that more than a century later, scientists are still working to discover both the cause of, and a cure for, the disease.

Although each case of Alzheimer's is different, researchers have identified three general stages of the disease. In the first stage, symptoms of cognitive impairment, such as memory loss or confusion, have either not yet appeared or are quite mild. However, significant changes are taking place within the brain, including nerve death, tissue loss and the buildup of abnormal clumps and tangles of protein.

These changes lead to the second stage of the disease, during which symptoms become more pronounced. Patients begin to experience significant memory loss, confusion, impaired reasoning, poor spatial skills and a loss of language. By the final stage of Alzheimer's, the brain has shrunk dramatically. Patients can no longer communicate, are unable to recognize faces, even of family members and loved ones, and are unable to care for themselves.

Patients with advanced-stage Alzheimer's need 24-hour supervision and help with personal hygiene, dressing and eating. Changes in brain function make it increasingly difficult for them to move about, sit up and even swallow. This leads to complications such as bedsores, skin infections, blood clots and sepsis. Injuries from falls are common. Difficulty in swallowing makes eating and drinking an ongoing challenge, and can lead to weight loss, malnutrition and dehydration.

The most common cause of death among Alzheimer's patients is aspiration pneumonia. This happens when, due to difficulty in swallowing caused by the disease, an individual inadvertently inhales food particles, liquid or even gastric fluids. Because our mouths and throats contain numerous bacteria, these are carried deep into the lungs. There they multiply and grow, which leads to pneumonia. Due to the impaired immune systems of Alzheimer's patients, pneumonia is often fatal.

It's important to remember that Alzheimer's patients are often elderly and thus may have a range of medical conditions associated with advancing age. These include stroke, cancer, heart disease, diabetes, hypertension and stroke, any of which can cause death, whether or not Alzheimer's is present.

(Send your questions to askthedoctors@mednet.ucla.edu, or write: Ask the Doctors, c/o Media Relations, UCLA Health, 924 Westwood Blvd., Suite 350, Los Angeles, CA, 90095. Owing to the volume of mail, personal replies cannot be provided.)

More like Ask the Doctors