Severe Symptomatic Hypercalcemia Due to Primary Hyperparathyroidism and Hyperthyroidism in Pregnancy, a Management Challenge Case Report

Presentation Number: MON 320
Date of Presentation: April 3rd, 2017

Krishna Chalasani*1, Dania S Assad1, Julie Samantray2 and Wael Taha3
1Detroit Medical Center, Detroit, MI, 2Division of Endocrinology, Diabetes, and Metabolism. Wayne State University, Detroit, Michigan, United States, 3Wayne State University, Detroit, MI

Abstract

Intro: Prevalence of hypercalcemia in pregnancy is about 0.03%. (1) Diagnosis of primary hyperparathyroidism (pHPT) in pregnancy carries significant risks to mother and fetus, including severe hypertension, pancreatitis, nephrolithiasis, or neonatal hypoparathyroidism. (2) Few drugs are available for the treatment of pHPT in pregnancy. Parathyroidectomy is the only definitive treatment if calcium (Ca) levels reach 11.4 mg/dl to prevent fetal loss. We describe a rare case of pHPT complicating pregnancy managed with cinacalcet after 2 failed parathyroidectomies.

Case:  A 22 year old African American woman at 12 weeks gestation with twins presented with intractable nausea and vomiting. Workup revealed pHPT: Corrected Ca of 14.6 mg/dL (8-10.6 mg/dL), PTH of 127 pg/mL (15-69 pg/mL), ionized Ca of 1.44 (1.13-1.32 mMol/L), PTHrp < 2 pmol/L (0-3.4 pmol/L), Phosphorous of 2.1 mg/dL (2.3-5.0 mg/dL). Also, she was found to have low TSH and high FT4 which resolved after a short course of methimazole and was likely due to transient gestational hyperthyroid. High resolution ultrasound (U/S) failed to localize parathyroid adenoma. U/S of kidneys showed no abnormalities. Hypercalcemia improved with IV hydration; but then recurred. Lasix therapy was unsuccessful. As she was pregnant and refractory to treatment, neck exploration was pursued. The right superior parathyroid was found to be enlarged intraop and suspected to be the source of hypercalcemia. All glands except the left superior were excised as this gland was not located. Post op Ca and PTH levels were still elevated; therefore a 2nd exploration was performed without success. PTH remained elevated at 144 pg/mL, corrected Ca was 12.3 mg/dL and patient continued to be symptomatic. At this point, she was started on Cinacalcet 30 mg daily and then increased to 30 mg bid. Her corrected Ca improved to 11.1 mg/dL. Patient is currently asymptomatic.

Discussion: Symptoms of pHPT are nonspecific and similar to the complaints of pregnancy. Due to the lack of adequate safety data in pregnancy, localization studies are limited to the U/S of the neck. Cinacalcet use during pregnancy requires further study. Its use is limited by its delayed onset of action (30–40 h) and the lack of data on the fetus and neonate. As Ca sensing receptors are present in the placenta, cinacalcet may alter placental function and potentially induce fetal and neonatal hypocalcemia. So far, studies in pregnant rats and rabbits did not show embryonal or fetal toxicity. Two other cases reported successful and safe use of cinacalcet during pregnancy: one with a diagnosis of pHPT and the second with metastatic parathyroid carcinoma. Our case is of earlier stage of gestation and the patient had remarkable hyperthyroidism which may have contributed to hypercalcemia.

Conclusion: Treatment with cinacalcet should be considered an option in pHPT in pregnancy, if surgery fails or cannot be done.

 

Nothing to Disclose: KC, DSA, JS, WT