Dementia vs Delirium

Dementia is a slow progressing disease. When you think about your loved one, you should be seeing a decline in abilities that has occurred over a period of several years or months. If you only see your loved one over holidays, then you can almost count backwards from Thanksgiving events and see a steady loss of ability.

Delirium on the other hand, causes a rapid decline in abilities, or the sudden onset of lethargic (slow, sleepy) behavior, or aggressive (agitated, verbal or physical) behavior. It is considered an acute brain dysfunction. The key is your loved one begins behaving much differently than she was only a few hours or days before. Just remember this, dementia is slow, but delirium is rapid and deadly.

Frequently, the cause of delirium is some form of infection. The most common infection in a a person with dementia is a Urinary Tract Infection (UTI). Delirium is considered a life-threatening condition for persons with dementia because their systems can be rapidly overwhelmed by the infection. Oftentimes, the changes will take place in a matter of hours.

Think about delirium like this, a UTI won’t kill you or me but it can cause death in a person with dementia. If you notice your loved one behaving differently, look for causes and call 911 or her physician.

Physicians recognize the danger of delirium and will respond immediately to your concerns When you notice sudden changes in behavior , review the delirium mnemonics and match each letter to the sudden change in your loved on. A mnemonic (new-mon-ic) is a way of using an unusual saying or phrase or work to review symptoms of an illness.


D (Drugs) Has your loved one had any mediation changes or received any new medications, including over the counter drugs?

E (Eyes, ears and other sensory deficits) Has anything happened to change the way your loved one is seeing or hearing in her environment? Or does she have an infection in either her ears or eyes?

L (Low oxygen) Does she have any condition affecting her intake of oxygen? These can include heart attack, stroke, and pulmonary embolism.

I (Infection) Remember UTIs are the most common infection, but also remember colds, flu, etc.

R (Retention of urine or stool Restraints) Again look for UTI or constipation as a cause for suddenly different behavior. Restraints, either chemical (meaning medications) or physical restraints can cause a person to have behavior changes.

I (Ictal) Has there been a change in glucose, thyroid, or lytes levels?

U (Underhydration or Undernutrition) Remember to check for dehydration in an older person; press firmly with your thumb between her eyebrows. When you remove your thumb if you can see the whitish outline of your thumb, then she is dehydrated.

M (Metabolic) This could be caused by a post-operative state or sodium abnormalities.

S (Subdural hematoma or Sleep deprivation) She may have a brain bleed from a fall or ruptured blood vessel or she may be exhausted.

Knowing what to watch for and insist your loved one be thoroughly checked when you see a change in behavior is critical as you move forward in caregiving. Treat the symptoms, but seek the cause is a good rule of thumb. Not only for her immediate health, but because truly terrible events can happen as a result of delirium.

Sally’s Story

A few year ago, a woman was admitted from a DC hospital to a locked memory care community in Northern Virginia. She was in her late 80s and very weak.

This woman had no driver’s license, or any other identification when she was taken to the ER after a shopkeeper notified 911 when she was spotted stumbling outside of his store.

A physician then diagnosed her with dementia when she couldn’t give her physical or recent history. The doctor quickly prescribed antibiotics to treat her urinary tract infection, kidney infection, and pneumonia. She was given an IV to treat dehydration and, within a few days, was eating all of her meals. She quickly gained five pounds and was sent to my unit, a locked memory care floor.

Sally was pleasant and exhibited the correct social skills when I met her the Monday following her admission. Over the next two weeks, she completed her antibiotics and continued to gain weight. She politely declined to join the activities for the other residents and spent her time resting in her room. About two weeks after her admission, she met me in my office and inquired as to why she was in a secured dementia facility.

What was startling about our conversation was that she knew my name. The nature and progression of dementia means that, for the most part, by the time I meet with someone, she probably will not be able to recall my name when we meet again. (I don’t generally meet people until they are Stage Five or later.)

Secondly, Sally knew she was in a secured dementia unit, knew the address of the building, knew the date and knew her most previous history. She had no short-term memory loss and for persons with Alzheimer’s, STM loss is one of the defining and first features of the disease.

As it turned out, Sally was actually Dr. Sally, a retired pediatrician. She had no living relatives and had quickly become very ill in her own home. With no family member or friends to tell the ER who she was and explain her normal state, she was given a dementia diagnosis. A mistaken diagnosis meant she had lost her apartment and her belongings. The city had claimed the apartment and her belongings had been given away. As a physician serving a poorer population, she had no savings and lived quietly and simply on her retirement. In the course of a few weeks, she had gone from living independently to living in a nursing home. No family photos, no clothing of her own, no momentoes of her life.

Sally’s case is a textbook example of an ER diagnosis gone wrong. Too many times persons are given a dementia diagnosis without any actual testing for dementia other than the emergency room doctor asking an older and very sick person a series of orientation questions such as “What is your name?” or “Where are you?” or “What is today’s date?” and “What is the year?”

The problem that occurs when a doctor who is not a specialist in geriatric health issues makes a dementia diagnosis in an emergency room is that some patients may actually be suffering from delirium caused by an illness.

Instead of jumping to a dementia diagnosis, the doctor should first look to determine if a fluctuating memory and reduced ability to maintain attention or shift attention appropriately has another medical cause, such as a urinary tract infection or pneumonia. Or as in Dr. Sally’s case, multiple and very serious infections.

Because delirium is not caused by long-term deterioration in the brain, its effects can be reversed with proper medical treatment.

In the end, Sally was moved to the front of the waiting list for a subsidized community in Virginia. She spend the remainder of her life in an apartment complex that overlooked 60 acres of trees and rolling hills. Her diagnosis of dementia was removed from her record and she died peacefully in her sleep several years later.

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