Parathyroidectomy: Surgical Techniques

The majority of Indian patients are symptomatic unlike those frequently encountered in North American and European countries. Hypercalcemia used to be severe among symptomatic patients. Mild hypercalcemia (<12 mg/dl) does not require active correction before surgery. Hypercalcemia above 12 mg/dl requires correction before surgery. Volume expansion by administration of normal saline 200–300 ml/h (4–6 L in 24 h) brings down the calcium and is the first line of treatment. The volume expansion should be carefully monitored in the elderly and in those with cardiac and renal dysfunction. Intravenous bisphosphonates (Zoledronic acid 4 mg slowly over 20 min, or Pamidronate 30–90 mg at 20 mg per h is effective in bringing down the serum calcium level but usually by 3–4 days. The moderate (12–14 mg/dl) and severe hypercalcemia (>14 mg/dl) require close observation in high dependency wards. Subcutaneous calcitonin (4–8 units/kg body weight) administered twice daily or even 6th hourly is effective in controlling hypercalcemia. Calcitonin reduces the serum calcium concentration by increasing renal calcium excretion and, more importantly, by decreasing bone resorption via interference with osteoclast function. Calcitonin brings down the calcium level by 1–2 mg in 4 h and is safe along with intravenous saline. But the effect is short-lived and limited to 48 h indicating the development of tachyphylaxis, perhaps due to receptor downregulation. More sustained but slow control of hypercalcemia is obtained by intravenous administration of Bisphosphonates. Zoledronic acid (4 mg) administered as a slow infusion effectively brings down hypercalcemia. Bisphosphonates are preferentially incorporated into sites of active bone remodeling in conditions characterized by accelerated skeletal turnover. Bisphosphonates inhibit bone resorption by internalization of osteoclasts. But the action is not limited to osteoclasts alone but also bone remodeling also. The effects last for 3–6 months. About one-third of patients may have acute phase reactions of fever, myalgia, and joint pain lasting for a few days.