Lithium induced hypercalcemia: an expert opinion and management algorithm

Lithium-associated primary hyperparathyroidism:: An evaluation of screening and referral patterns in a southeastern veteran population

BACKGROUND

Long-term lithium therapy has a well-established but under-recognized association with primary hyperparathyroidism. Rates of hypercalcemia, screening for primary hyperparathyroidism, and referral for parathyroidectomy were evaluated among United States veterans on long-term lithium therapy.

METHODS

Patients undergoing chronic long-term lithium therapy (>12 months) were identified from 1999 to 2022. Demographics, long-term lithium therapy duration, post-treatment calcium, parathyroid hormone, creatinine, and vitamin D levels were abstracted. Rates of screening for hypercalcemia (calcium ≥10.2 mg/dL), primary hyperparathyroidism (parathyroid hormone ≥30 pg/mL in the setting of hypercalcemia), referral for parathyroidectomy, and outcomes were evaluated.

RESULTS

A total of 1,356 patients underwent long-term lithium therapy, 514 of whom received chronic long-term lithium therapy. Baseline characteristics of patients with and without post-treatment hypercalcemia were compared. Of 148 patients with post-treatment hypercalcemia, 112 (74.7%) underwent no further evaluation for primary hyperparathyroidism, while 36 (25.3%) patients had a parathyroid hormone level recorded. Although 33 (91.7%) hypercalcemic patients screened positive for primary hyperparathyroidism, only 5 (13%) were referred for parathyroidectomy. Of the 4 patients who underwent parathyroidectomy, mean calcium was 11.2 mg/dL (range 11.1-11.4), and mean parathyroid hormone was 272 pg/mL (range 108-622). Three patients were localized on preoperative imaging, 2 of whom underwent unilateral exploration with cure, with 1 experiencing recurrence at 31 months. The remaining patient who localized preoperatively underwent bilateral exploration and had 2 ipsilateral glands resected and persistence. The patient who did not localize preoperatively underwent bilateral exploration with 3 gland resection and cure.

CONCLUSIONS

Screening for primary hyperparathyroidism and referral for parathyroidectomy are underutilized in United States veterans undergoing chronic long-term lithium therapy. Institutional protocols to standardize screening, surveillance, and referrals to endocrinology/endocrine surgery could benefit this population at increased risk for primary hyperparathyroidism.

The true effect of lithium is hard to determine

Lithium is the primary choice for preventing bipolar disorder relapses, endorsed by guidelines. A recent systematic review by Ulrichsen et al. showed limitations in assessing its specific impact, but data supports lithium's effectiveness in managing symptoms and preventing relapse. Comprehensive guidelines and research are crucial for its continued use.