Abstract #1406955: Two Parathyroidectomies in the Third Trimester for Severe Primary Hyperparathyroidism (PHPT) Resulting in Distinct Maternal and Fetal Outcomes

Abstract

Parathyroidectomy (PTX) is well-tolerated in the second trimester of pregnancy in women with severe PHPT. We present two women requiring PTX in the third trimester of pregnancy due to the severity of the disease. Case 1: 30 y.o female presented at 33 weeks’ gestation with leg pain and severe PTH-mediated hypercalcemia; serum corrected calcium 4.2mmol/L (NR: 2.15-2.6), PTH 147.9 pmol/L (NR:1.6-6.9). She was symptomatic for 2 yrs prior and had a history of nephrolithiasis; the renal US showed 10-20 non-obstructing renal calculi. Femur X-ray demonstrated an aggressive lesion, identified as a brown tumor, on histopathology with additional bone lesions on skeletal survey. Severe hypercalcemia was managed with IV fluids, calcitonin and cinacalcet 30 mg BID. Neck-CT showed a 4cm parathyroid adenoma with no overt malignant features. Subtotal PTX was performed at 33w2d, and PTH dropped to 4.7pmol/L postop. Histopathology reported atypical parathyroid adenoma. Post PTX patient went into premature rupture of membranes, c-section done at 34 weeks’ gestation. Day 8 post PTX, the patient developed hungry bone syndrome, she also had a mechanical fall and sustained a pathological fracture of the femur, the site of brown tumor. Baby was admitted to NICU with hypoparathyroidism, resolved at 3 months of age. Case 2: 32 y.o female presented at 27 weeks’ gestation with incidental hypercalcemia and high PTH. Nausea and vomiting worsened from the 18th week of gestation. No end-organ involvement. Corrected calcium 3.04 mmol/L, PTH 17.1 pmol/L. Managed with IV fluids, and remained symptomatic with no improvement in hypercalcemia. PTX for parathyroid adenoma was performed at 30 weeks’ gestation with excellent maternal and fetal outcomes. PTH dropped to 2.0 pmol/L postop. Had spontaneous vaginal delivery at 39 weeks’ gestation, no neonatal hypocalcemia. Baby has normal milestones. Biochemical workup for Multiple Endocrine Neoplasia type1 (MEN1) was unremarkable for both patients, DNA testing is outstanding. The duration of PHPT, the severity of hypercalcemia, and the involvement of end-organ damage are critical factors that may influence both maternal and fetal outcomes in women with PHPT who undergo PTX in the third trimester.