Sunday, January 2, 2011

Are You at Risk for Alzheimer's Disease?

The medical profession’s ability to diagnose far exceeds its ability to effectively treat the conditions discovered. Consider arthritis, Parkinson’s disease, irritable bowel syndrome, strokes, emphysema and many cancers.

When a physician orders a diagnostic test, ideally it should be to answer a specific question, rather than a buckshot approach. A chest x-ray is not ordered because a patient has a cough. It should be done because the test has a reasonable chance of yielding information that would change the physician’s advice. If the doctor was going to prescribe an antibiotic anyway, then why order the chest x-ray? Physicians and patients should ask before a test is performed if the information is likely to change the medical management. In other words, is a test being ordered because physicians want to know or because we really need to know the results?

Does every patient with a heart murmur, for example, need an echocardiogram, even though this test would be easy to justify to patients and to insurance companies?

If the test won’t change anything, then it costs dollars and makes no sense. Spine x-rays for acute back strains are an example of a radiologic reflex.

While some tests yield too little information, others provide too much knowledge. I remember as a medical student discussing if healthy patients at risk for Huntington’s Chorea, a progressive and lethal neurologic condition, should be tested to determine if they will develop the disease. Recently, The New York Times reported on a similar ethical controversy regarding testing to determine a person’s risk for developing Alzheimer’s disease, another progressive and incurable condition. Should we make efforts to identify patients with risk, or even certainly, of developing terrible diseases, which have no effective treatments? Would you want to arise each morning knowing that progressive dementia is in your future? Each time you would misplace your keys, or had trouble finding a word, you would wonder if this was the leading edge of the impending meltdown. To me, this knowledge would result in a profound reduction in quality of life, and would also affect relationships with family and others. One could imagine diagnostic panels being run on young couples who are contemplating marriage, a new twist on pre-nuptial agreements. Could life and disability insurance carriers demand access to these results?

Is there a reasonable rebuttal to this view? Of course, folks are entitled to know their genetic predispositions, if they are properly counseled beforehand. These folks, knowing of a dim future, could modify their current priorities so they could enjoy a more satisfying life. These individuals may choose not to wait until retirement to take that trip around the world.

We must also keep in mind that medical tests are not always right. A ‘positive’ Alzheimer’s test result might be dead wrong. Or, the individual might develop a very mild form of the disease. Genetics is a complex and murky universe.

Medical tests that provide too little information are wasteful and unnecessary. Those that provide too much information can be dangerous and destructive. If the plague of Alzheimer’s is in my future, I don’t want to know it now. Sure knowledge is power, but sometimes sweet ignorance is bliss.


  1. I agree with you. I would not want to know now that Alzheimer's is in my future.

    As you mention, I can see specific circumstances in which someone might want to know genetic information, even if it would not change treatment. For instance, my 17-year-old daughter has heterozygous familial hypercholesterolemia, which is caused by an autosomal dominant mutation. If she has children, each of them will have a 50% chance of inheriting it. Statins are an effective treatment, although opinions differ on what age they should be started. No one, however, would put a baby on a statin. I can see testing a baby for the mutation, however, just because you would want to know. You could also get your answer to a certain degree of certainty in many cases by doing a lipid profile. There is an overlap of LDL levels between people with and without FH, so it would depend on how high the child's LDL was.

    Actually, my daughter has never been tested for an FH mutation. Her LDL is so high that we know she has one.

    Marilyn Mann

  2. Marilyn, thanks for the comment. Keep in mind that hypercholesterolemia, unlike Alzheimers, has effective and safe treatment. There would be little controversy in screening for it.

  3. We have years to go before genetic testing can give is more than "hints" about future outcomes. People need to understand that sometimes it requires combinations of different gene loci or environmental input (radiation,mutation,) to trigger expression of a gene.

    Your questions are good ones. Do we want to know something that may never happen? Is maybe a good enough starting point to make life decisions? At this time the mysteries of life are still mysteries.

  4. More info on Alzheimer's diagnostic tests for those interested.