A story featured in the New York Times recently caught my attention: an 85 year old woman was diagnosed with early Alzheimer’s Disease due to increasing symptoms of confusion, agitation and memory loss; further testing revealed the actual diagnosis to be anemia due to a deficiency of Vitamin B12.

In comparison, anemia is the better scenario for the patient and her family. Given the patient’s age, B12 deficiency is highly likely. As stomach acid levels decrease with age, our ability to absorb dietary B12 decreases. This is something that I’ve learned several times, in several classes since my first year of medical school. In fact, it would be one of my first rule outs. I have to wonder if the doctor who diagnosed early Alzheimer’s disease truly explored all possibilities. The patient’s symptoms clearly fit the picture of early Alzheimer’s disease; she also clearly fit the picture of Vitamin B12 deficiency.

What is a health care provider to do this situation? Physicians should do what they were trained to. A medical education extensively teaches a Physician the art of differential diagnosis.  I personally feel it is the responsibility of the Physician to have a thorough differential to rule out more serious and less serious conditions. As a student, being able to provide my clinical supervisor with a differential diagnosis based on the presented complaints of a patient forces me to review my knowledge and understanding of pathophysiology, and these are skills that will serve me for the rest of my career.

As a student, this story reminds me of several things:

1. Patients should not be placed in diagnostic boxes based on keynote symptoms. This can be damaging to the well being of the patient as well as the credibility of the doctor.
2. A diagnosis can be simple. It isn’t necessary to always jump to the worst-case scenario, however it is important to rule out the worst-case scenario. As my professors say, remember to “look for horses, not for zebras.”
3. Remember pathophysiology. In this case specifically, if the doctor had considered what physiological and functional deficit might have been occurring (primarily with age), it could have prevented a misdiagnosis. Fortunately in this case, the misdiagnosis was caught and the patient fully recovered with Vitamin B12 injections.

Is it worth the risk to avoid doing a full and extensive work up, differential diagnosis and rule out? Not in my opinion. A misdiagnosis can cause the patient and their family unnecessary stress and fear and that is the last thing any health care provider would want.
 
References:
http://www.nytimes.com/2011/11/29/health/vitamin-b12-deficiency-can-cause-symptoms-that-mimic-aging.html?_r=1&src=me&ref=general