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Alzheimer's or age? Some tips to make the right diagnosis

From the September ACP Observer, copyright 2003 by the American College of Physicians.

By Jason van Steenburgh

A few years ago, geriatrician Patricia Lanoie Blanchette, FACP, saw a new patient who had been referred to her for out-of-control hypertension. After the patient stumbled through some basic questions about the year and the date, Dr. Blanchette suspected that the patient's medical problems weren't purely physical.

She called the patient's daughter in from the waiting room and asked if her mother had been having any memory problems. Dr. Blanchette also asked the daughter to do some searching at home. Sure enough, the daughter discovered a drawer full of untouched hypertension medications, helping solve the mystery of the patient's uncontrolled high blood pressure.

While Dr. Blanchette wasn't initially sure that the patient was indeed suffering from Alzheimer's, she saw enough clues to suspect trouble. She followed up on those signs, she said, because she knows just how devastating a condition like dementia can be on the rest of a patient's health.

The problem is that Alzheimer's disease, which makes up about two-thirds of all dementia cases, can be difficult to spot, particularly in its early stages.

"Sometimes patients seem so present and in the moment during the visit," said Dr. Blanchette, who is chair of the geriatric medicine department at the John A. Burns School of Medicine in Honolulu. "But they don't remember a thing you said once they step out the door."

As a result, Alzheimer's often goes undetected. While more than four million Americans suffer from the disease, some studies estimate that up to two-thirds of all cases go undiagnosed.

Physicians are often reluctant to make the diagnosis—particularly if they don't have ironclad proof—because of the stigma or emotional turmoil it can produce with patients and their families. Earlier this year, for example, the U.S. Preventive Services Task Force said it couldn't endorse the idea of widespread screening, in part because of concerns about false positives.

While experts may disagree on exactly who to screen for Alzheimer's, they say that physicians need to be on the lookout for the red flags of dementia. They point out that drugs like cholinesterase inhibitors can slow the progression of the disease, and that early diagnosis gives patients time to do some things that they have always wanted to do, as well as make important decisions about advance directives and organizing finances while they are still lucid.

Here are some tips to recognize signs of dementia during patient visits—and some strategies to avoid mistaking common conditions for Alzheimer's.

Spotting signs of trouble

According to Eric G. Tangalos, FACP, co-director of information transfer for the Mayo Clinic Alzheimer's Disease Research Center in Rochester, Minn., a patient's risk of dementia doubles every five years after age 60. Most experts say that by 85, more than half of patients have a dementing illness, which most commonly is Alzheimer's.

The trick is to distinguish dementia from normal age-related cognitive decline. "As most people age, their performance declines in solving novel problems, such as avoiding car crashes or finding their way around a new town," said Dr. Tangalos. Dementia, on the other hand, is characterized by a decline in memory and "executive function" that inhibits daily activities.

Patients who occasionally lose their keys or forget where they parked their car aren't impaired, experts say. Forgetting the names of family and friends, however, or getting lost in a familiar place are the kinds of memory problems and disorientation that plague demented patients.

(In addition to memory loss, Alzheimer's patients typically lose other cognitive functions and may have problems with language, calculations, planning for the future or decision-making.)

You can also differentiate dementia from normal aging by watching for a rapid rate of decline. "There is nothing as good as serial observation," said Eric B. Larson, FACP, director of the Group Health Cooperative's Center for Health Studies in Seattle and Chair-elect of ACP's Board of Regents. "After six months, if the person has Alzheimer's disease, the decline is evident."

Here are other signs of dementia that should cue you to begin a workup:

  • Comments from family members. Alzheimer's patients often don't realize they're forgetting essential facts, so they don't complain about memory lapses. Patients' spouses, family members and caregivers, however, will notice problems and point them out to you, so be willing to listen.

    James R. Webster Jr., MACP, professor of medicine and emeritus director of the Buehler Center for Aging in Chicago, noted one troubling sign your front desk should watch out for: a patient's family calling to make an appointment.

    "Alzheimer's patients frequently lose their ability to plan, make and keep appointments," he said. Once family members decide a patient can't handle his or her own schedule, ask about cognitive problems.

  • Tip-offs from patients. Patients suffering from Alzheimer's may hint that they are under pressure from their families. Maybe they've complained that their driver's license has been taken away, or that family or friends have started insisting that they move into an assisted-living community. These kinds of family interventions are often a response to concerns about cognitive problems.

    If patients admit they've lost interest in activities they once enjoyed, consider that an important clue. Patients who talk about losing interest in reading, for instance, may have stopped reading because they simply forget what they've read in earlier chapters.

  • Noncompliance. Medical noncompliance can be an important sign of dementia, and not just because patients forget to take their medicines. Dr. Blanchette said that patients who experience exaggerated responses to medications may forget that they've already taken their medications and take too much of a drug.

    Patients who fail to fill a prescription (or get too many refills), stop taking their medications or can't adapt to dosing changes—remembering to take one-and-a half tablets of warfarin some days but only one tablet on others—could be having problems.

Weeding out imposters

One of the great ironies of Alzheimer's disease is that while it goes undetected in millions of people, it is also overdiagnosed because physicians fail to identify other conditions that can present as dementia.

Robert C. Green, MD, a neurologist at the Boston University Alzheimer's Disease Center in Boston, said that patients are referred to his clinic all the time with memory problems that physicians have hastily identified as Alzheimer's. Depression or some other issue, however, is often the true cause of the patient's memory loss.

Many geriatricians routinely screen new patients to get a baseline cognitive score, while other physicians make mental status testing part of patients' routine physicals, starting at age 70. (Dr. Blanchette said this is especially important to help prevent tragedies like serious driving accidents.) Earlier this year, however, the U.S. Preventive Services Task Force ruled that there was insufficient evidence to recommend either for or against using cognition tests to screen for dementia in people over age 65.

(The guidelines are in the June 3 Annals of Internal Medicine.)

Malaz Boustani, MD, a researcher at the Regenstrief Institute for Health Care in Indianapolis, Ind., who wrote the report on which the task force based its recommendation, said the task force was concerned that global screening of patients without symptoms would produce too many false positives. In one of his own studies, he said, 20% of those identified by screening as having cognitive impairment were, in fact, normal.

False positives can lead to "potential suicide, discrimination and depression," Dr. Boustani said. And "people who screen positive for dementia might be stigmatized," he added, by losing their driver's license or their ability to buy long-term care insurance.

There is another caveat to screening: While it is a useful first step, experts say that you can't rely on it as the sole tool to diagnose dementia.

Here are some other diagnoses you need to consider—and possibly exclude—to correctly diagnose and treat patients with Alzheimer's:

  • Depression. Experts say that depression is the condition most frequently misdiagnosed as dementia. Depressed patients typically display poor concentration, which makes them think their memory is failing. With depression, however, attention—not memory—is the problem. Depressed patients often forget things because they don't focus on them in the first place.

    As Honolulu's Dr. Blanchette, who is Governor for the College's Hawaii Chapter, pointed out, patients who truly have memory problems often don't know it. Depressed patients usually make specific complaints about forgetting things, while demented patients' complaints are more vague. If demented patients refer to their cognitive difficulties at all, she said, they usually seek to explain them away or conceal them. She warned, however, that up to half of patients with early dementia also have depression, so making a diagnosis of depression does not exclude an underlying dementia.

    Wayne C. McCormick, FACP, associate professor in the department of medicine's geriatrics division at the University of Washington in Seattle, said that a history—taken from either the patient or a reliable source of information—can help distinguish depression from dementia. You may uncover past depressive episodes, which could help explain current cognition problems.

    A history can also help you gauge how rapidly the patient's difficulties have developed. Cognitive problems in depressed patients manifest themselves much more rapidly than in patients with Alzheimer's.

    While cognitive screening can help you separate the depressed from the demented, keep in mind that depression often accompanies dementia and can make it worse. To assess dementia, you must first successfully treat depression and then evaluate the patient.

  • Medication side effects. Like depression, pseudodementia caused by medications develops very rapidly. This time factor can help distinguish it from the insidious progression of Alzheimer's.

    Sleeping pills, benzodiazepines, tranquillizers and sedative hypnotics can all cause cognitive difficulties because they can have very long half-lives in elderly patients, warned Dr. Webster. Not only do many of these drugs lead to a pseudodementia that mimics Alzheimer's, but they can also aggravate the effects of real dementia, causing patients to lose more function than they would if they weren't taking the drugs.

    When you're sorting through patients' prescription medications, don't ignore over-the-counter drugs. Dr. Webster recalled one long-time volunteer who started forgetting her tasks at the hospital. Several physicians suspected Alzheimer's, but the culprit turned out to be much more simple: Tylenol PM.

    Many geriatricians and dementia experts are particularly concerned about the effects of diphenhydramine (Benedryl) and other sedating antihistamines in elderly patients. These drugs often cause cognitive impairment and can make patients groggy and confused.

    Dr. McCormick said he tries to eliminate as many drugs as possible from the medication lists of elderly patients presenting with cognitive issues. "Even run-of-the-mill drugs like cardiac medications or antacids can alter cognition," he said. "The secondary or tertiary effects of many medications can result in people not being able to think well."

  • Alcohol-related problems. Elderly people often lose cognitive function to alcohol not because they start drinking more, but because the amount of alcohol they've always consumed hits them harder as they age.

    "Alcohol can really make you stupid as you get older," Dr. Webster said. "If we can get them off the sauce for three to four months, many older patients get a lot smarter."

    Unfortunately, the effects of steady doses of alcohol can build slowly, so you may not be tipped off by a sudden onset of symptoms. Alcohol-related problems can be especially difficult to diagnose because patients and families often deny them. Try easing the discussion by explaining that people's ability to process even small amounts of alcohol changes over time.

The information included herein should never be used as a substitute for clinical judgment and does not represent an official position of ACP.

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Simple screening techniques to detect dementia

When it comes to screening for dementia, you don't have to conduct an exhaustive battery of tests. Asking a few well-placed questions each time you see your elderly patients can go a long way toward helping you spot signs of dementia.

To test short-term recall, many experts suggest asking patients to remember three common objects, such as an apple, a penny and a tree. Or you can use the serial subtraction method and ask patients to count backwards by seven, starting at 100, for example.

(Depending on a patient's education, you might want to ask him or her to count backwards by three or even two, not seven. Experts say that in all these tests, education affects people's baselines.)

You can also screen patients without using standardized cognition tests. In place of a three-item recall, have patients repeat instructions later in the visit that you've given about a medication.

Patricia Lanoie Blanchette, FACP, chair of the geriatric medicine department at the John A. Burns School of Medicine in Honolulu, said before using standardized tests, she often asks patients how they got to the office or what day it is. If they don't know or explode in anger, which is rare, that's a real red flag, she said.

Testing doesn't have to be a long, drawn-out affair. According to Eric B. Larson, FACP, director of the Group Health Cooperative's Center for Health Studies in Seattle and Chair-elect of ACP's Board of Regents, the most sensitive parts of the mini mental state exam for detecting dementia are short-term recall and serial subtraction.

"If patients pass those parts, which are the hardest," he said, "they're not going to fail anything else, so you may not need to do the whole test."

Dr. Blanchette said that total test scores are less important than which questions a patient missed. "If a patient missed only five or six points [out of 30]," she said, "but all the misses were on questions about orientation and short-term memory, I would be more concerned about dementia than if the wrong answers were spread throughout the exam."

Another key, Dr. Larson said, is to test patients at different visits and look for significant decline, which is the hallmark of Alzheimer's disease. "This is where general internists and primary care physicians, who see their patients over time, have a real advantage," he explained.

Regardless of how you test, experts say it's important not to give patients the benefit of the doubt. "It is not OK to give them a few extra points so they don't flunk," said Wayne C. McCormick, FACP, associate professor in the department of medicine's geriatrics division at the University of Washington in Seattle. "Grade honestly, test repeatedly—and if cognitive impairment is there, diagnose it."

And whether patients pass or fail, don't put too much stock in the results of a single evaluation. Patients found to have cognitive impairment on a screening tool may end up being completely normal, and some patients who have dementia will ace the test.

Dr. Blanchette recalled testing one university professor who repeatedly scored 30 out of 30 on the test. More sophisticated neurological tests also failed to show dementia, but the patient kept complaining that his mind was slowing. His rare insight proved to be accurate, Dr. Blanchette said: Within three years, he was so demented he had to be led around by the hand.

When testing for Alzheimer's, keep in mind that many patients with dementia may have spent years creating coping mechanisms. As a result, they may be adept at talking around such questions as how they got to the office or what day it is.

Dr. Blanchette said to watch out for responses like, "Sometimes I drive and other times I take the bus" or "I'm not working, so all my days are pretty much alike." "It may all sound very plausible," she explained, "but remember that they still never gave you an answer."

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