Friday, May 13, 2011

What do my tests mean?

In response to a few questions asked by a LH (an online lupus support group) member.


High Calcium:

There are extremely rare manifestations of lupus in which a person's immune system targets the parathyroid. The parathyroid is the place where (unsurprisingly) the parathyroid hormone is produced. This hormone serves to regulate how much calcium is being taken out of or given to the bones. If the parathyroid is targeted then the patient's body may be constantly taking calcium away from the bones. However, there have only been a very few recorded cases of this happening.

A more common reason for high calcium levels in lupus patients is a problem with the kidneys. The kidneys work to regulate fluids and various ions (single atoms that have an electrical charge) in the body. Calcium is one of these ions, so if your calcium levels are high it may mean that the kidney isn't functioning properly and is therefore unable to regulate your calcium levels. A good resource for blood tests commonly run on lupus patients is here.

Increased lymphocyte count while still on methotrexate: 
It is totally possible that an increasing lymphocyte count means that the immune system has found a way to get around the methotrexate. But it could also happen for other reasons; if you're fighting a cold or virus your immune system will be producing more lymphocytes (or trying to do so) even before you feel ill. So the best answer I can give is that it could certainly be a sign of your becoming resistant to methotexate, but there are other things that could cause it as well. Obviously your rheumatologist would be the best person to judge whether it's resistance to methotrexate or something else that is causing the increased count.


MDW: 
This is a test to see how much variation there is in the volume of your red blood cells. The actual size of the red blood cells is not what is being described; rather it's a measurement of how different each cell is in comparison with the average of all the cells. I know that is about as clear as mud, so I offer the following analogy: 

Let's say that your blood cells are represented by soda bottles. The volume of the cell (soda bottle) is how much that cell  (bottle) can hold. If you have ten 2 liter bottles, then you have low variation; each bottle holds about as much as all the other bottles. The same is true if you have ten child-sized cans. However, if you have five 2 liter bottles, three 16 oz individual bottles and two child-sized bottles then your variation is high; the difference between how much each individual  bottle can hold is quite large. 

 This test is performed because the volume of red blood cells can change in different ways for different kinds of anemia. (Which can be caused by low iron, low B12, etc). Different sizes can be associated with different volumes.  Wikipedia has a pretty good description of some of the causes here.

As for why your doctor writes it off as a lab error I have absolutely no idea. You'd really have to ask him, as I'm sure there could be different reasons for his decision. 



 The usual disclaimer applies; I am not a physician, nor do I have any clinical experience whatsoever. I come at it from a research scientist perspective, and no answer I give should be considered a replacement for a doctor's advice. Also, I suffer from serious brain fog, so if I start going on random tangents in the middle of a post, don't be too surprised.

9 comments:

  1. Sam, my hat is off to you! thanks so much for posting this, this help me quite a bit since I just came back from the rheumy and he only addressed the calcium issue and is testing me for parathyroid problems. I value your opinion and I just want to tell you I really, really appreciate your time!!!!! Love Ya! LJK

    ReplyDelete
  2. I'm so glad you found it helpful! I think rheumatologists are some of the worst doctors for not telling us what they believe is going wrong.

    ReplyDelete
  3. In regards to the parathyroid, there are different things that can go wrong. One uncommon but possible thing has a similar mechanism to that of Graves' Disease (except that GD is a thyroid disease). By that I mean your immune system can decide that the parathyroid is foreign, and make autoantibodies in an effort to kill it. Sometimes these autoantibodies fit into a normal hormone receptor so well that they act cause the same effects as the normal hormone would. That is bad because there are feedback mechanisms to keep the normal hormone down to a certain level, but those mechanisms do nothing to reduce the number of antibodies.

    What this amounts to is essentially a permanently "on" switch which causes the parathyroid to keep telling the rest of the body to release calcium from the bones.

    I don't know if that answers your question or if it's just a whole lot of detail that isn't helpful. :)

    ReplyDelete
  4. Sam, I have had a "strange feeling" in my right neck and thought it was just swollen glands... Maybe my parathyroid glands on that side are swollen or maybe there is a mass inside. Although they are small, they could be causing my swallowing issue if they (it) is inflamed or if there is a tumor on one or all. I'll just get the blood test done and see what happens. In the mean time, I am tired, sometimes dizzy and have to sit down RIGHT AWAY or I will just collapse with exhaustion.. My bones hurt, my muscles hurt and my middle finger on the right side is swollen and my cuticle is red and inflamed. My neuropahty in feet, legs, hands and arms are is flaring up so the neurontin is obviously not working like it used to.

    Thanks so much Sam for your help, explanations and research. I wish I could send you a tiny apartment sized air conditioner so you can sit in front of it and cool down. I do not do well either in the 90+ weather..... <3 LJK

    ReplyDelete
  5. I hope that they figure out what's going on. Have you tried Lyrica instead of neurontin? I know that works better for some people. Personally, I can't tolerate either one. I'm a doctor's worst nightmare for side-effects.

    Thanks, I'd love an air conditioner. Every year I debate getting one, but it just seems stupid when I'd only need it for two or (at the most) three months a year. I live in VT, for crying out loud! I should *not* have to be hot and miserable...well, I mean, apart from the *$!$ lupus fever. Luckily I do have a good window fan, so that helps some.

    ReplyDelete
  6. You posted the dreaded "L" med! I was put on Lyrica for sciatica pain years ago and I promptly gained about 40 pounds! It made me crave food...any food! It didn't do a damn thing for my sciatica so when I started seeing my rheumy, he switched me to the neurontin. After the continuous increases in dosage and a trip to the neurologist for the EMG, an added dosage of Cymbalta was prescribed and the relief finally came! The neuropathy has been well under control until just recently. It means another trip to the neurologist which, since I am trying to retire under disability, is an expense I don't need right now....LJK

    ReplyDelete
  7. Lyrica didn't make me gain weight, but it did make me suicidal. It scared the heck out of me and my doctor, and so it's on the bad list now.

    I'm glad that the Cymbalta is helping. One of my relatives has very bad peripheral neuropathy, and he found that it helped for a while. Unfortunately, I think it stopped being as helpful so now they're trying to find something new.

    I hear you on the expenses! Student health insurance is *awful*. My medical bills are far and away my biggest bills (except rent, and even then the med bills still win). Good luck with the disability retirement!

    ReplyDelete
  8. Hi Sam! I just wanted to update you with the results of my labs. My calcium is 10.7 and my PTH is 90. This indicates a tumor from what I have read. I also have low white and red blood counts. Tired, lupie, pain everywhere, gotta get this tumor out of my neck! I am sure now that this is the cause of all of my swallowing issues. Hope you are doing better and your arm is healing nicely. LJK

    ReplyDelete
  9. I am having joint pain and hives and now have high calcium blood test.My liver enzynes keep increasing, does this sound like lupus related?

    ReplyDelete