Blood tests don’t back parathyroid diagnosis
DEAR DR. ROACH: I’m a 78-year-old woman with many symptoms of parathyroid disease (chronic fatigue, feel “ill,” need naps, less concentration, memory “hesitation,” blurred vision), yet the blood tests are not at the confirmation level.
My blood tests showed: PTH (parathyroid hormone) 71, calcium 9.5, calcium (ionized) 3.94, vitamin D 29. I have just started a vitamin D regimen. I am feeling dreadful, and am unsure how to proceed.
ANSWER: The parathyroid gland controls many aspects of calcium metabolism. Elevations in parathyroid hormone, usually caused by a benign tumor of the gland (which sits on top of the thyroid gland in the neck, hence its name) trigger a rise in body calcium.
Normal calcium levels depend on age, but usually are below 10.2. Ionized calcium levels, the biologically active kind, normally are 4.5-5.4.
These should be high in people with elevated PTH: Your level is slightly below normal (at least according to my reference laboratory).
Vitamin D also is important in calcium regulation, and the interaction between the two is complex.
A high PTH level commonly causes low vitamin D. However, long-term, persistent low vitamin D can cause PTH levels to become higher than expected.
The lab tests you have are most consistent with low vitamin D, not with high parathyroid levels.
The symptoms you describe are nonspecific. Low vitamin D can cause fatigue and poor concentration: I certainly hope the regimen you started will have you feeling back to normal by the time this is published.
However, if you still are not feeling like yourself, you and your doctor should start at square one and review your entire history, do a careful physical exam, review your medications and lab tests, and decide how to proceed. There are many possible causes.
DEAR DR. ROACH: My husband beat small cell lung cancer with chemo and radiation, but after a few months he was walking with a cane.
A few months later, he had a walker; now, since December, he has been in a wheelchair. He has peripheral neuropathy. What can I do to help my husband?
ANSWER: When a new symptom arises in someone with cancer, the clinician should consider whether it is due to the cancer, due to the treatment or unrelated to either.
All of these are possibilities for your husband.
Small cell lung cancer in particular is associated with what we call “paraneoplastic syndromes.”
These are clinical syndromes that are related to the cancer, but not directly due to the tumor. They often are associated with antibodies attacking different parts of the body, and the nervous system is a frequent target. Sometimes, the antibodies can be found in the blood.
I would consider having a discussion with a neurologist who has expertise in paraneoplastic syndromes.
Treatment for the cancer is another likely possibility. I don’t know what chemotherapy your husband received, but platinumbased chemotherapy is typical with small cell lung cancer, and is a very common cause of peripheral neuropathy.
Radiation to the brain is not a usual cause of peripheral neuropathy.
If your husband does not have identifiable antibodies consistent with a paraneoplastic syndrome and did receive platinum chemotherapy, I would think that the chemo would be the likely cause, as his course is very consistent with this condition.
Treatment to relieve symptoms is possible: An antidepressant drug, duloxetine, has been particularly helpful for some people.
However, physical therapy may be the most effective treatment.
You can find some help at www.foundationforpn.org.
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