Do you get numbness or tingling in your hands or fingers?
I’ve been thinking about that recently and wondering if it’s an under-recognized symptom of XLH. I’m just speculating here, but I wonder if we’re more at risk for carpal tunnel syndrome (and other nerve impingements that affect the hand) than the general population.
We all know about spinal stenosis and the nerve issues related to that (generally manifesting in the back or legs). But what about nerve impingements in the arm?
From what I’ve read, there are three major nerves that run down the arm and can be impinged (squeezed): median, ulnar, and radial. The median nerve basically affects your forearm, wrist and thumb side of your hand. The ulnar nerve affects the whole arm and the pinkie-finger side of your hand (and is also responsible for the pain that comes from hitting the tip of your elbow, the “funny bone”). The radial nerve controls the triceps (muscles in the back of the arm) and wrist movement.
The three nerves can be impinged in a variety of locations in each arm (although my reading suggests that radial nerve issues tend to occur more often with an injury rather than with impingement). We hear most often about “carpal tunnel syndrome,” which is when the median nerve is impinged in a narrow space in the wrist. But the nerves can also be impinged at the elbow and the shoulder. When the compression is in the elbow, it’s called “cubital tunnel syndrome.”
The location of the impingement seems to matter less (in terms of symptoms and diagnosis) than which nerve is involved. Somewhat overly simplified: median nerve impingement affects the thumb side of the hand, and ulnar nerve impingement affects the pinkie side of the hand. (Radial nerve damage can affect either side, but is less likely to be due to impingement.)
I haven’t been diagnosed, but suspect median nerve impingement at the elbow, since I get tingling/numbness in my right thumb and first finger, and it goes away if I straighten my arm. Yeah, I know I should check it out, but it’s just a minor nuisance that at least for now is fixed just by remembering to keep my arm straight when I lie down to go to sleep.
In any event, it got me to wondering about how common this kind of nerve impingement is in the chronic hypophosphatemia population. When I was working on the XLH natural history a few years ago, it wasn’t an issue I was aware of, so we didn’t ask about it, as far as I recall, so there’s no data being collected there unless perhaps a participant undergoes surgery and it’s picked up by way of a general question about surgery, but it would miss those who, like me, don’t bother to get a diagnosis or treatment.
I’d love to know if this nerve impingement in the arm occurs at the same rate in XLHers as in the general population, or at an accelerated rate (or in theory it could be slower, but that seems highly unlikely). Not all health issues that any one of us experiences is related to the XLH. We can have a number of unrelated conditions (like the thyroid disease I have or the coronary artery disease that I inherited from my father’s side of the family, nothing to do with my XLH). Still, it seems logical that we would have earlier and more extensive nerve impingement in the arm, since we have known issues with calcification and nerve impingement in the spine.
I can’t recall any mention of carpal tunnel (or the similar impingements at the elbow or shoulder) in medical journals in the XLH context or even among patients. It’s possible that a) it’s no more common, or happens earlier, in XLH than the general population, and that’s why it’s not mentioned, or b) it is more common/earlier in us, but patients don’t think to mention it, or they aren’t asked about it, since both patients and clinicians think of lower limb issues far more than arm issues.
I’m tempted to think it’s the latter, that it’s more common or happens earlier in us, but it goes unnoticed in the same way that, historically, everything about us other than lower limb growth/straightening has been ignored. I mean, I’m about as aware as anyone on the planet of the possible consequences of XLH, and I still didn’t stop to wonder about our rate of carpal tunnel syndrome (and the related impingements) until I started to experience some symptoms myself. It simply wasn’t on my radar, just as I didn’t realize until I was in my fifties that my arms don’t straighten fully, and that permanent bend is a common symptom of XLH. (It makes sense — before we’re weight-bearing on our legs as children, we’re weight-bearing on our arms when we crawl as infants, so the same type of pressure that warps our soft leg bones as toddlers is brought to bear on our arms during the crawling phase).
Yes, I’m as susceptible as anyone to forgetting that XLH is a whole-body, whole-life, whole-family disorder!
So, consider this a shout-out to researchers: we need to study the rate and age-of-onset of nerve impingements in the arms of XLHers (and those with other chronic hypophosphatemias). And another shout-out to XLHers to share your experiences with nerve impingements in the arm (or other less well-known symptoms in the arms). I’d really love to hear from you if you’ve developed one or more of these impingements, whether you got an official diagnosis, how old you were when it happened, how long it took you to seek treatment, and what kind of treatment you had (if any). Drop me a note: Gin at GinJones dot com
And if you know any researchers, ask them if they’d be interested in studying the topic! There are so many medical miracles happening on a daily basis (with far more to come with gene/cell therapy) that it’s easy to forget that science still doesn’t understand some really basic biochemical processes in our bodies, like how, exactly, calcification happens — what triggers it, what proteins (message-carriers that tell the body where to send other substances, like calcium) are involved, and, most especially, how it could be reversed. Every little bit of information we can gather about our susceptibility to calcification might help answer those questions. Research into rare disorders can offer insights into more common conditions!
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Please note that the author is a well-read patient, not a doctor, and is not offering medical or legal advice.
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