Hypocalcemia following pharyngoesophageal ablation and gastric pull-up reconstruction: pathophysiology and management.

Profound hypocalcemia has been observed following surgical ablation of malignancies in the hypopharynx, larynx, cervical trachea, and esophagus. Adequate control of these tumors may require extirpation of the visceral compartment of the neck and upper mediastinum. Preservation of parathyroid glands is sometimes inconsistent with good oncologic principles. Postoperative hypocalcemia develops rapidly, and high-dose intravenous calcium supplementation is required. Clinical observations indicated that requirements for calcium supplementation were reduced dramatically once oral feeding was instituted. It is postulated that dysfunction arising from surgical manipulation of the duodenum, the primary site for active calcium absorption, and bypass of that bowel segment by the feeding jejunostomy are primary contributors to the severity of hypocalcemia. A plan of management is proposed that includes early postoperative administration of 1,25-dihydroxyvitamin D or dihydrotachysterol, active vitamin D metabolites that promote the absorption of calcium. Early oral feeding is encouraged. Other mechanisms of calcium loss, appropriate calcium management, and parathyroid autotransplantation are discussed.