Calcific Tendonitis May Be Complication of Hypoparathyroidism

People with hypoparathyroidism may be at risk of having calcium crystals form in their tendons — a condition called calcific tendonitis — which can cause joint pain and inflammation, a new case report suggests.

The report, “Acute calcific epicondylitis associated with primary hypoparathyroidism: a paradox effect or an adverse event,” emphasizes the need for more research into what causes these crystals, and how it might be related to hypoparathyroidism and its associated treatments. It was published in the journal Rheumatology Advances In Practice.

Calcific tendonitis (or tendinitis) is the term for inflammation caused by calcium crystals in tendons, the tissues that connect muscle to bone. It remains unclear what biological processes lead to calcific tendonitis. Most cases are idiopathic — meaning there is no clear underlying cause — although it has been associated with physical trauma in about a third of cases.

The new case report details the story of a 33-year-old man who went to the hospital with acute pain and swelling of the elbow.

X-ray of the left elbow revealed calcium crystals within the tendons, indicating calcific tendonitis (or acute lateral calcific epicondylitis).

Five-day treatment with celecoxib, a nonsteroidal anti-inflammatory drug, was beneficial. A CT scan of the neck revealed a tiny calcific deposit along the surface of the soft palate (located at the back of the roof of the mouth).

The patient previously had been diagnosed with primary hypoparathyroidism. As expected, his blood levels of parathyroid hormone (PTH) and calcium were low, being treated with high daily doses of calcium carbonate and calcitriol (a synthetic version of vitamin D). His 24–hour urinary calcium was high at 11.8 mmol/24 h (upper normal level is 7.5 mmol/24 h). “Mmol” is an abbreviation for the measurement millimoles.

As of the study’s completion date, the patient had been referred to an endocrinologist to consider PTH replacement therapy to optimize management.

“In our case, given the absence of trauma or any other predisposing factors and given his young age, the calcific tendonitis is most likely to be secondary to the underlying hypoparathyroidism,” the investigators wrote. “However, it is not clear whether his calcific tendonitis is attributable to his primary disease or to the high level of calcium replacement.”

Overall, better understanding of calcific tendonitis is essential for improved prevention and management, the investigators wrote. “In young patients with calcific tendonitis, hypoparathyroidism should be considered as a causative factor,” they added.