Inadequate parathyroid response in acute pancreatitis

We studied nine consecutive hypocalcemic patients with acute pancreatitis to elucidate the mechanism of hypocalcemia. Mean serum ionized calcium, 0.97 mM, was below the normal mean of 1.16 mM (P less than 0.001). Seven of eight patients tested had normal parathyroid hormone levels. All responded to parenteral parathyroid extract by increasing serum ionized calcium and urinary cyclic AMP, indicating parathyroid-hormone-responsive target organs. Calcitonin and glucagon concentrations were increased above normal in some patients, but there was no relation with serum ionized calcium. Parenteral glucagon had no significant effect on serum ionized calcium or calcitonin concentrations. These findings suggest that neither glucagon nor calcitonin was primarily responsible for the hypocalcemia, which did not produce expected increases in serum parathyroid hormone concentrations. Relative parathyroid insufficiency may account for the persistent hypocalcemia frequently observed in patients with acute pancreatitis.