PSAT214 Management of Hyperparathyroidism Associated with Severe Hypercalcemia Presenting During Labour

Abstract

Background Hypercalcemia is a rare pathology in pregnancy, and primary hyperparathyroidism (PHPT) has been described as the most common cause. No guidelines exist concerning treatment of PHPT during pregnancy, although most authors favor surgery as the treatment of choice during the second trimester. Nonetheless, management during the third trimester of pregnancy is challenging due to lack of current guidelines. Clinical case This 29-year pregnant female presenting at 38-weeks gestation with spontaneous rupture of membranes and admitted for latent labor. She was incidentally found to have hypercalcemia. Endocrinology was consulted for asymptomatic hypercalcemia in the third trimester of pregnancy. A diagnosis of primary hyperparathyroidism (PHPT) was suspected based on elevated serum calcium adjusted for albumin (16 mg/dL, normal range 8.5-10.5 mg/dL) and elevated PTH levels (121 pg/mL, normal range 14-65 pg/mL). In addition, parathyroid hormone related peptide (PTHrP) was less than 2.0 pmol/L (normal range <2.0 pmol/L), 25-hydroxy vitamin D was 35.6 ng/mL (normal range 30-50 ng/mL) and urine calcium/creatinine clearance ratio (CCCR) level was 0.02 (<0.01 familial hypocalciuric hypercalcemia is likely, >0.02 PHPT is likely) further supporting the diagnosis of PHPT. No parathyroid imaging was performed as there was no plan for surgical intervention at that time. Conservative management was initiated with aggressive oral and intravenous fluid rehydration. The patient subsequently had an uneventful vaginal delivery with the arrival of a healthy newborn eight hours after treatment was initiated. With continued IV and oral hydration, corrected calcium fell by a total of 5 mg/dL. Given an uneventful postpartum course as well as improving calcium levels with hydration, the patient was discharged on day three of hospitalization with a plan for outpatient endocrinology follow up in preparation for future parathyroidectomy. Conclusion There is no previous case report describing severe hypercalcemia in the third trimester of pregnancy managed conservatively solely with hydration. Calcitonin has been attempted but use is limited secondary to tachyphylaxis. Additionally, some case reports suggest cinacalcet use but this drug crosses the placenta. In this unique and complicated case of severe hypercalcemia diagnosed in the third trimester of pregnancy, conservative management with intensive oral and intravenous fluid rehydration was safe and effective in lowering serum calcium levels and therefore conducive to a positive pregnancy outcome. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.