SAN FRANCISCO – Primary hyperparathyroidism was detected in 7% of 742 patients with recurrent kidney stones at a single tertiary care clinic, and the patients’ primary care physicians may have missed the diagnosis because several affected patients’ calcium levels were in the high normal range.
Of the 53 patients diagnosed with primary hyperparathyroidism (hPTH), 72% had high normal serum calcium levels. After examining the charts of those patients, researchers found that 11 of the 53 patients (21%) had been tested for parathyroid hormone and serum calcium levels and could have been identified by their primary care physicians.
None of the 742 patients with kidney stones in the study had vitamin D deficiency or gastrointestinal malabsorption. All were tested for serum calcium and intact serum PTH, and those with hypercalcemia or high normal calcium (greater than 10 mg/dL) and elevated intact serum PTH were diagnosed with primary hPTH.
The findings emphasize “the importance of [looking] for not just outright primary hyperparathyroidism, but the ratio between PTH and calcium levels,” said Mr. Boyd.
The study received no funding. Mr. Boyd declared no relevant financial relationships.
SOURCE: Boyd C et al. AUA 2018, .