SAT251 A Tale Of Two Calcium Disorders: Hypercalcemia In Pregnancy

Disclosure: M. Stezzi: None. C. Hayes: None. M. Misiura: None. E. Skutnik: None. G.A. Perilli: None. S. Koshy: None. Introduction: Hypercalcemia in pregnancy is a rare event that can be difficult to diagnose given nonspecific presentation of symptoms and distinguishing it from typical symptoms of pregnancy. Primary hyperparathyroidism is the leading cause of hypercalcemia in pregnancy. Management presents a challenge as drug treatment and surgery options are limited. We present two cases of the uncommon non PTH mediated hypercalcemia in pregnancy. Case 1: A 31-year-old pregnant female G1P0 with no past medical history presented at 38 weeks from her obstetrician’s office for elevated blood pressures. She was admitted for preeclampsia without severe features. On initial labs, corrected calcium level was elevated 14.6 mg/dl (8.5-10.1). Her PTH was appropriately suppressed at <6.3 pg/mL. The patient’s PTHrP was slightly elevated at 3.6 pmol/L (0.0-3.4). She was treated with calcitonin. Due to her preeclampsia, labor was induced with subsequent cesarian section. The day after, the corrected calcium level markedly improved to 8.7 mg/dL. Her hypercalcemia was secondary to the humoral response of pregnancy caused by PTHrP produced by the placenta. Case 2: A 38-year-old pregnant female G3P1011 with a past medical history of hypertension presented at 35 weeks and 6 days after getting an MRI for back pain which showed evidence of metastases and a burst fracture of the T9 vertebra. A left breast mass was palpable on exam. On arrival, labs showed a corrected calcium 12.5 mg/dL. Further work up revealed appropriately suppressed PTH <6.3 pg/mL and PTHrP elevated at 29 pmol/L (0.0-3.4). Corrected calcium peaked at 14.5 mg/dL. Cesarian section was performed. Treatment was initiated with four doses of calcitonin and a dose of zoledronic acid. After two days of treatment, corrected calcium was 12.2 mg/dL. Corrected calcium measured 9.3 mg/dL at discharge. Biopsy revealed invasive ductal cell carcinoma. She was also found to have diffuse bone metastasis to the spine and liver. Her hypercalcemia was secondary to invasive ductal cell carcinoma with metastasis. Discussion: Hypercalcemia in pregnancy is difficult to diagnose and treat due to nonspecific maternal symptoms and changes in homeostasis of calcium and vitamin D. Management is difficult as medications used in hypercalcemia outside of pregnancy may be contraindicated. Calcitonin has been used safely in pregnancy. Bisphosphonates are used for life threatening cases of hypercalcemia due lack of long-term data on fetal effects. Short term effects of bisphosphonates are transient neonatal hypocalcemia and low birth weight. Denosumab is not used in pregnancy. Cinacalcet is used in primary hyperparathyroidism. Cinacalcet has been safely used in pregnancy in animal studies. In conclusion, hypercalcemia in pregnancy requires prompt diagnosis and treatment with the mainstay acceptable therapies for non PTH mediated hypercalcemia being intravenous fluids and calcitonin. Presentation: Saturday, June 17, 2023