Delayed Calcium Normalization after Successful Parathyroidec
A 38-year-old man with a personal history of hypertension, primary hypothyroidism, and hydronephrosis secondary to urolithiasis was evaluated for hypercalcemia in an endocrinology department of a tertiary health center. There were no familial antecedents of hypercalcemia, lithiasis, or hyperparathyroidism. The patient reported weakness, lack of energy and strength, and mental and physical fatigue. The patient was given levothyroxine 100 mcg and candesartan 16 mg daily. In the biochemical evaluation, laboratory features included creatinine of 1.4 mg/dL, serum calcium of 13.5 mg/dL, albumin of 4.7 g/dL, albumin-corrected calcium of 12.94 mg/dL, phosphorus of 1.9 mg/dL, vitamin D of 18 ng/mL, and PTH of 383.7 pg/mL, with evidence of hypercalcemia, hypophosphatemia, deficiency of vitamin D, and hyperparathyroidism; PHPT was diagnosed. Tc-99m sestamibi scintigraphy identified an abnormal uptake in the left inferior thyroid pole, corresponding to parathyroid adenoma.

Neck exploration and parathyroidectomy were performed, with complete excision of a tumor of 27 × 17 × 8 mm, the weight of 2.3 g, and capsule integrity. An intraoperative PTH drop >50% was corroborated after parathyroidectomy, meeting the “Miami criterion.” The histopathological reporting evidenced a well-circumscribed lesion with a thin fibrous capsule contained in a vascular capillary network; most of the neoplastic cells resembled the normal parathyroid cells; there were uniform polygonal cells with small central nuclei and focal cystic changes, with neither atypia nor increased mitotic figures. The final diagnosis was parathyroid adenoma.

During the first 12 hours after parathyroidectomy, a 98% reduction of PTH levels (PTH preoperatory: 383.7 pg/mL vs. PTH postoperative: 6.5 pg/mL) was evidenced; however, persistence of elevated serum calcium (12.1 mg/dl) was observed. Magnesium remained normal during evolution. During the first 48 hours after parathyroidectomy, the patient received 1500 ml of 0.9% sodium chloride solution I.V. and 500 ml of water P.O. After this time, he continued with 2000 ml of water P.O. during his follow-up. In the clinical follow-up, the evidence of hypercalcemia and normal PTH levels persisted up to 96 hours, with a delayed calcium normalization up to 120 hours. After the first month postoperatively, serum calcium remained normal; however, the patient currently continues with strict monitoring of serum calcium and PTH levels.