Hypocalcemia following Thyroid Surgery: Incidence and Prediction of Outcome

Abstract

Postoperative hypocalcemia is a common and most often transient event after extensive thyroid surgery. It may reveal iatrogenic injury to the parathyroid glands and permanent hypoparathyroidism. We prospectively evaluated the incidence of hypocalcemia and permanent hypoparathyroidism following total or subtotal thyroidectomy in 1071 consecutive patients operated during 1990-1991. We then determined in a cross-sectional study which early clinical and biochemical characteristics of patients experiencing postoperative hypocalcemia correlated with the long-term outcome. Postoperative calcemia under 2 mmol/l was observed in 58 patients (5. 4%). In 40 patients hypocalcemia was considered severe (confirmed for more than 2 days, symptomatic or both). At 1 year after surgery five patients (0.5%) had persistent hypocalcemia. We found that patients carried a high risk for permanent hypoparathyroidism if fewer than three parathyroid glands were preserved in situ during surgery or the early serum parathyroid hormone level was </= 12 pg/ml, the delayed serum calcium levels </= 8 mg/dl, or the delayed serum phosphorus level >/= 4 mg/dl under oral calcium therapy. When one or more of these criteria are present, long-term follow-up should be enforced to check for chronic hypocalcemia and to avoid its severe complications by appropriate supplement therapy.

Parathyroid hormone: an early predictor of symptomatic hypocalcemia after total thyroidectomy

“…Similar to other studies, we did not find a relationship between patient demographic characteristics and development of hypocalcemia (15,(18)(19)(20)(27)(28)(29), and although several authors have reported a relationship between hyperthyroidism and hypocalemia (1,7,28), our study (like those of Lombardi and cols. (29), Higgins and cols.…”

“…We used only the symptoms of hypocalcemia because we believe that mixing two parameters (biochemical hypocalcemia and symptomatic hypocalcemia) can introduce a bias. Postoperative serum calcium level can take up to four days to reach its lowest value (20) and, like Richards and cols., we also found that almost all patients have calcium levels below reference range after total thyroidectomy (27). Furthermore, the speed of decrease in calcium levels appears to be more important that the absolute value itself (4,20).…”

“…Pattou and cols. reported that a postoperative PTH level of 12 pg/mL or less was a good predictor of hypocalcemia, but did not state how long after surgery PTH values were obtained (20). A group of Australian surgeons found that normal postoperative PTH levels accurately predicted normocalcemia after total thyroidectomy, and the optimal time to make the measurement was four hours after the surgery (21).…”

Prevention of postoperative hypocalcemia with routine oral calcium and vitamin D supplements in patients with differentiated papillary thyroid carcinoma undergoing total thyroidectomy plus central neck dissection

“…In most patients, reductions in total calcium and iPTH were found to be secondary to the impairment of parathyroid function. 8,[21][22][23] Several days after surgery, serum calcium and iPTH concentrations began to recover in parallel. Prophylactic supplementation with calcium and vitamin D contributed to preventing the initial drop in serum calcium levels as well as to preventing the subsequent development of major hypocalcemic symptoms after total thyroidectomy and CND.…”

Hypocalcemia – the most common complication after total thyroidectomy

“…Patients must undergo close postoperative observation and laboratory evaluations. The reasons for postoperative hypoparatyroidism that leads to hypocalcemia are injury or devascularisation of a parathyroid gland, accidental removal of 1 or more parathyroid glands, hematoma formations (3,4,5,6). Hospital stay must be often extended due to this complication (7,8).…”