How does Alzheimer's disease kill you?

From media reports, ex-Tennessee Women’s Basketball coach Pat Summitt’s final days were difficult, but she did not lack for support.

According to The Associated Press, dozens of  Summitt's former Tennessee players and coaches came to Knoxville over the weekend to say their final goodbyes to the winningest coach in Division I college basketball history.

Summitt, 64, died Tuesday morning, five years after being diagnosed with early-onset Alzheimer’s disease.  While her death was reported as a result of the disease,  Alzheimer’s in and of itself does not kill a person. Yet last year nearly 100,000 people in the United States died because of it.

Here’s a look at how Alzheimer’s kills.

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How does Alzheimer’s lead to a person’s death?

Alzheimer’s disease destroys nerve connections in the brain,  making it progressively more difficult to do ordinary things like move around, swallow and feed yourself. While the disease devastates the brain, it does not kill you. Complications of the decline in brain function is what leads to death. Not being able to swallow properly is particularly dangerous. The vast majority of those with Alzheimer’s die from aspiration pneumonia – when food or liquid go down the windpipe instead of the esophagus, causing damage or infection in the lungs that develops into pneumonia.

Which complications of Alzheimer’s are most likely to kill you?

Aspiration pneumonia

Bedsores

Sepsis infections from undiagnosed urinary tract infections

Infections in general

Injuries from falls

Malnutrition and dehydration

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What happens to the brain of a person who has Alzheimer’s?

Alzheimer’s causes the brain to decline in complicated ways. The changes in brain function happens when abnormal deposits of proteins form amyloid plaques (clusters of protein fragments) and tau tangles (twisted strands of another type of protein) causing neurons (a specialized cell that transmits nerve impulses) to stop functioning and die.

The death of neurons eventually leads to problems with bodily functions, such as swallowing and mobility. This puts the person with the disease at risk for poor nutrition, dehydration, blood clots, falls and infection, according to WebMD. From there, the disease contributes to conditions such as pneumonia and heart failure.

What is the death rate for Alzheimer’s?

It is difficult to know how many deaths are caused by complications of Alzheimer’s disease because of the way causes of death are reported. According to the Centers for Disease Control and Prevention, 84,767 people died from Alzheimer’s disease in 2013. That number is probably low.

The CDC considers a person to have died from Alzheimer’s if the death certificate lists Alzheimer’s as an underlying cause of death. However, death certificates often list the  primary cause of death for a person with Alzheimer’s as pneumonia, heart failure or infection.

According to the Alzheimer’s Association, a recent  study suggested that the number of deaths from complications of Alzheimer's disease may be five to six times higher than what the CDC reports.  Also, older patients with Alzheimer’s disease often have other medical conditions – coronary artery disease, diabetes, congestive heart failure, chronic kidney disease, stroke and cancer – that could cause death if the person was not suffering from Alzheimer’s.

Some Alzheimer’s facts:

• 61 percent of those with Alzheimer's at age 70 are expected to die before the age of 80. Thirty percent of people age 70 without Alzheimer's would be expected to die by age 80.

• Alzheimer's is the only disease among the top 10 causes of death in America that cannot be prevented, cured or even slowed.

• An estimated 5.4 million Americans  have Alzheimer's disease now.

• By mid-century, if a cure is not found, someone in the United States will develop the disease every 33 seconds.

• In 2015, 15.9 million family members and friends provided 18.1 billion hours of unpaid care to those with Alzheimer's and other dementias. That care had an estimated economic value of $221.3 billion.

• Approximately two-thirds of Alzheimer's and dementia caregivers are women. Thirty-four percent are age 65 or older.

• In 2013, Alzheimer's care cost $203 billion in the United States. Costs could surpass the $1 trillion mark by 2050.

Sources: The Alzheimer’s Association;  WebMD; everydayhealth.com; The Centers for Disease Control and Prevention

Cox Media Group