Excessive parathyroid hormone raises blood calcium level
DEAR DR. ROACH: I am an 88-year-old man in quite good health. I spend at least 30 hours a week doing yard work. I have had high blood calcium for many years, usually around 10.7. I take pravastatin and triamterene/HCTZ. My doctor has been a little concerned and has been monitoring it. She sent me to an endocrinologist who did the same. Neither suggested treating it in any way.
I recently saw a Veteran's Affairs doctor who is more concerned. My most recent calcium level is 11, and she took me off the triamterene/HCTZ. She also had me do a 24-hour calcium, with a result of 266 mg/24 hours.
I have read on the internet that high blood calcium is more dangerous than high cholesterol. I'm not in favor of surgery unless absolutely necessary, even more so now in these times of the coronavirus. Right now, she is getting me in to see a specialist. -- W.
ANSWER: It is very likely that you have a condition called primary hyperparathyroidism. This is caused by an excess of parathyroid hormone. I suspect one of your doctors has already confirmed this with a blood test. The parathyroid glands (there are usually four) are located, as their name suggests, immediately adjacent to the thyroid glands in the neck, but parathyroid hormone is very distinct from thyroid hormone. Parathyroid hormone is a major regulator of calcium levels in the blood, along with vitamin D. When a gland starts making excess hormone, usually because of a benign tumor, calcium levels in the blood go up. Your VA doctor appropriately stopped the triamterene/HCTZ -- it can raise blood calcium -- and also did the 24-hour calcium test to be sure you don't have an unusual condition called familial hypocalciuric hypercalcemia. The 24-hour calcium is also useful for deciding whether to recommend surgery, which is the only definitive treatment.
There are several indications for surgery. One is a very high blood calcium, greater than a single point over normal (in most labs, 10.3 is the high end of normal, so a point over would be a blood calcium of 11.3). It is true that very high calcium levels put a person at increased risk of heart problems, but the magnitude of the harm is relatively small and the benefit of surgery is not seen until 15 years after surgery.
One way that PTH keeps blood calcium levels high is by drawing calcium out of the bones, so you should have an evaluation of your bone density. Most people don't think of men as being at risk for osteoporosis, but at your age and with high PTH, you are at risk. Osteoporosis is another indication for surgery, but it can also be treated with medication.
Another reason to consider surgery would be a history of kidney stones or progressive worsening of kidney function. Finally, some people have vague symptoms, including weakness, mild depression or memory impairment, which can improve after surgery.
Given your desire to avoid surgery, I suspect your VA doctor and her consulting specialist are likely to evaluate you a little more thoroughly and will recommend surgery only if they think surgery is clearly superior to medical treatment. I suspect you will not require surgery.