Tuesday, December 22, 2009

Doctor: I want a Lyme disease test

A patient comes in to the office. Let's say he or she is 5o years old. Many friends and family members have Lyme disease, he wants to know if he has it too. He is generally well but complains of some aches and pains. His joints hurt occasionally, especially after exercise, but recover quickly. His energy level and sleep are good. When asked about memory and cognitive problems he pauses for a moment: Perhaps his memory is not as good as it used to be. There has been some decline over several years. Word retrieval is a problem at times. His focus is not as good as it used to be. His mathematical abilities are not as good as they once were but they are OK. There are no other neurological symptoms. He functions normally at work and at home. These mild changes in cognition have occurred gradually over a period of years but are not bothersome.His family history reveals than a parent developed Alzheimer's disease at age 86. A recent physical has been done. His exam and routine lab work were fine. Should he be tested for Lyme disease?

No. Many patients have asymptomatic infection. This could be the case; still, I would not test. Positive results would only open a Pandora's box. These symptoms are mild and likely within the range of what might be expected in a 50 year old. The normal brain is sharper at age 25-35: minimal cognitive changes--neuronal fall out, occur in normal people. Alzheimer's disease? His risk may be slightly greater than that of the general population. Perhaps general recommendations would be made: exercise brain and body--eat well--perhaps drink coffee and take extra vitamin D.

The patients would be given a list symptoms to watch for. Treatment: watchful waiting--a term frequently used by doctors.

Monday, December 21, 2009

Vitamin D: A retraction--I got it all wrong

Vitamin D is much more complex than I have indicated earlier. The only thing I can say about the reversed pattern (active D higher than inactive D) is that it appears to be a marker for Lyme disease and/or inflammation--perhaps a very good marker.

Much research has been done on vitamin D. All of it is based on measurement of the inactive form, vitamin D hydroxy 25, which correlates with stored vitamin D. Yes, vitamin D has anti-inflammatory properties, but this may not be a bad thing. It affects cytokines andT-cell activation. But contrary to previous comments, it is active vitamin D that increases production of an anti-microbial peptide: cathelicidin. (Past statements that active D tilts the immune system from Th1 to Th2--causing production of anti-microbial peptides is wrong). The binding of active D to receptors modulates the genetic expression of complex proteins. VDRs (vitamin D receptors) are found in many organs in the body, including: brain, heart, skin, gonads, prostate and breast. Vitamin D receptors are found on a variety of immune cells, including: monocytes, B-cells and activated T-cells. It also has effects on dendritic cells. Vitamin D toxicity is very rare, even in patients with very high levels of active vitamin D, the 1,25 dihydroxy form.

Anti-inflammatory effects of D may lower the risk cancers, autoimmune disease, diabetes, heart disease and others. Recent research has shown that vitamin D is required to activate the histocompatibility gene, HLA-DRB 1501. This activation is necessary for the immune system to differentiate between self and non self in a select group of patients.

A link between vitamin D and MS has been shown. Perhaps the lack of MS in tropical climes
is not related to the absence of Bb and other infectious agents, as some have postulated, but due to higher levels of D from birth on.

The main source of D is sun light. Increased melanin decreases UVB penetration through the skin needed for conversion of D. It has been shown the black skin increases the risk of prostate cancer in the US but not in Africa--perhaps evidence of D's cancer fighting effects.

The Canadian Cancer Society has recommended that all it's citizens supplement with 1000 units of D daily.

D supplements are generally in the form called D3. This is the same form obtained from sun exposure. There are many forms of D and it's metabolism is very complex. Clinically, we only measure D in its stored and active forms.

In these numerous studies, only stored vitamin D is measured. Some doctors on the "cutting edge" have suggested that vitamin D hydroxy 25 levels are optimal at 75 (normal
32 to 100). But they are not looking at lab values I see in my practice. The range for normal active vitamin has been expanded, (10 to 75).

Many of my patients typically have stored vit D levels of 12--very low-- and active vit D levels of 100-- still high even though the range has changed.

In some way, the body--the immune system ostensibly, is trying to rectify the problems related to the infection (maybe). After treatment many patients have D levels in the normal ranges. This varies: some patients have D levels which drop across the board.

It now seems to me that judicious supplementation of D may in fact be very useful. Levels need to be monitored. the use of Benicar to inhibit renal conversion of inactive to active D may be a bad idea. Our bodies are pretty smart: let them balance the levels as needed. If active levels are above 100 I am somewhat hesitant to recommend D supplements. I have no basis for this. Again, vitamin D toxicity is difficult to attain. Reported cases have only been reported in individuals taking 40,000 units daily over a period of time.