Alzheimer's disease is a progressive disorder that involves the degeneration and death of nerve cells within the brain. Nerve cell death occurs throughout the brain, and this damage eventually hinders several day-to-day functions, leading to memory loss, erratic behavior, loss of muscle control and profound personality changes. In the end stages of the disease, the brain becomes so damaged it is dysfunctional, and Alzheimer's is ultimately fatal.
Malnutrition
Alzheimer's patients may die of malnutrition due to muscle degeneration, according to USF Health. A series of muscles in the face are responsible for chewing, and damage to the parts of the brain responsible for muscle movement in this area can lead to difficulty chewing. Alzheimer's patients also lose the ability of swallow, as the muscles in the throat required for peristalsis--muscle movement that pushes chewed food down the throat and into the stomach--are no longer functional. Eventually, the inability to eat leads to malnutrition, which in turn leads to organ failure.
Brain Death
In the end stages of Alzheimer's disease, a number of nerve cells that have died leads to large regions of the brain without living cells. If enough cells die, the connections between networks of cells become broken, and if enough connections are broken, it can lead to functional brain death.
In late-stage Alzheimer's, there are too few living cells to transmit enough signals within the brain, leading to a breakdown in organ function, as the nerve cells around the body no longer tell the organs what to do. In some cases, a brain-dead Alzheimer's patient may live in a persistent vegetative state, but this is rare, according to a 1997 study published in "Archives of Neurology."
Multiple Organ Failure
Multiple organ failure is a common cause of death in patients with Alzheimer's disease. Throughout the body, nerve input drives organ functioning. In many cases, muscle movement allows for organ functioning: movement of the diaphragm allows for breathing in and out, pumping of the heart muscle allows for oxygen delivery to tissues and movement of muscle lining the digestive tract allows for digestions. In other organs, nerve cells signal for the function of other vital organs, such as the liver and kidneys. As Alzheimer's diseas progresses, the nerve cells that signal for these functions begin to die, so in the late stages of the disease these processes become disrupted, leading to multiple organ failure, which is fatal.
