Can You Have Hyperparathyroidism with a "Normal" Calcium and/or "Normal" Parathyroid Hormone Level?

By Melanie Goldfarb, MD, MS, FACS and Fred Singer, MD
hyperparathyroidism with normal calcium

Primary Hyperparathyroidism (PHPT) is a condition of hormonal imbalance– too much calcium and/or parathyroid hormone (PTH) in the blood. It is an underdiagnosed and undertreated disease that is caused by a benign tumor in one or more parathyroid glands. In PHPT, a parathyroid gland “‘goes rogue”, continuously producing parathyroid hormone (PTH) and ignoring signals from the body to stop. PHPT is usually sporadic (though about 5% of cases are genetic/familial) and the incidence is about 2% in middle-aged and older individuals but can occur at any age. The only cure, when deemed necessary, is an outpatient surgical procedure.

"The parathyroid glands regulate the calcium levels in the body. There are generally four glands, which are very small (about the size of a grain of rice) that sit behind the thyroid gland."

The parathyroid glands regulate the calcium levels in the body. There are generally four glands, which are very small (about the size of a grain of rice) that sit behind the thyroid gland. Calcium is the fuel, or energy source of all of the body’s cells, and therefore too much or too little can cause a wide range of symptoms. When PTH levels rise, the body thinks that it needs more calcium, so it steals calcium from the bones, which causes a decrease in bone mineral density - osteoporosis. It also steals calcium from the intestines, and sometimes deposits calcium in the kidneys, which causes kidney stones. Other more common symptoms of primary hyperparathyroidism can include fatigue, weakness, mental confusion, difficulty concentrating, depression, anxiety, waking up to go to the bathroom, itching, and sexual dysfunction. It also increases morbidity and mortality in patients who have underlying heart and vascular disease.

“Classic” primary hyperparathyroidism is when both the calcium and PTH levels are significantly elevated. Historically, clinicians did not recommend surgery unless someone had these specific lab values. However, over the past decade, the endocrine community has come to recognize that not all parathyroid disease is created equal, and that the disease manifests itself in different ways, which can still cause harm and side effects. Calcium and PTH work like the scales of a pendulum – if one level goes up, the other is supposed to go down significantly; if it doesn’t, then the body’s normal regulation of calcium is not working as a result of PHPT.

Patients might have seemingly “normal” lab values, but still have primary hyperparathyroidism. This can come in the form of “normocalcemic” (i.e., calcium level is normal or mid-normal but PTH is high), “normohormonal” (i.e., calcium and PTH are in normal range, but usually on the higher end of normal, and patients have symptoms that cannot otherwise be explained), or “inappropriately high PTH” (i.e., calcium is slightly elevated and PTH is either slightly elevated or the high end of normal). Surgical outcomes are equally beneficial in normocalcemic and hypercalcemic patients according to recent studies, but a higher percentage of patients have multi-gland disease (i.e., more than one parathyroid gland will need to be removed).

Patients should be aware of the different presentations of primary hyperparathyroidism. Personalized and individualized treatment plans are necessary and many, but not all, diagnoses of hyperparathyroidism need treatment.