BACKGROUND: Primary hyperparathyroidism is considered rare in pregnancy, and only about 200 cases have so far been reported in world literature. Severe adverse effects can occur to both the mother and fetus if left untreated. Parathyroidectomy remains the definitive treatment. We present a diagnosed case of primary hyperparathyroidism who underwent a minimally invasive parathyroidectomy with intraoperative PTH monitoring in the third trimester of pregnancy. CASE: A 38 year old female consulted our clinic due to a history of recurrent Urinary Tract Infection (UTI) and bilateral nephrolithiasis. Investigation revealed an ionized calcium level of 1.59mg/dl (normal value 1.05-1.25 mg/dl), and an intact PTH of 257 pg/ml. A parathyroid scintigraphy using Tc99m-sestamibi was done revealing a focal radioavid mass lesion immediately inferior to the left thyroid fossa, consistent with a parathyroid adenoma, approximately measuring 1.6cm x 1.1cm. She was advised surgical excision but opted to postpone surgery and medical therapy instead. After eight months, she followed up in our clinic, 30 weeks pregnant, with symptoms of nausea, vomiting and recurrent UTI. With recent ionized calcium of 1.6mg/dl, she agreed to the removal of the parathyroid tumor. Prior to her scheduled surgery, hydration was done and IV glucocorticoids were given to mature the lung surfactant of the fetus in case of premature labor induced by parathyroidectomy. At 34 weeks of gestation, patient underwent minimally invasive parathyroidectomy which revealed a parathyroid adenoma. Before the excision, intact PTH level was 877 pg/ml and 10 minutes after excision, the intact PTH dropped to 48.8 pg/ml. When the ionized calcium level dropped to 1.03 mg/dl post-operatively, the patient experienced mild transient abdominal contractions and with slight tingling sensation over the face. Calcium supplementation was given which normalized calcium levels. The patient subsequently had an uneventful postoperative recovery and had an uneventful antenatal course.
CONCLUSION: Surgeries for hyperparathyroidism in pregnant women are usually performed in the second trimester of pregnancy, on the other hand there is an ongoing debate regarding the safety performed during the third trimester of pregnancy. We presented a case that was successfully performed during the third trimester with minimally invasive parathyroidectomy. We also present this case due to its rare occurrence and discussed the preoperative management of pregnant patients with proper hyperparathyroidism.