INITIAL AND POSTOPERATIVE HYPONATREMIA ASSOCIATED WITH PITUITARY-ADENOMA - A CASE-REPORT

This 67 year-old man experienced 3 episodes of symptomatic hyponatraem ia. Radiological examination revealed a sellar lesion and the tumour w as removed via the transsphenoidal route. Thereafter, he simultaneousl y developed intractable diabetes insipidus and serious hyponatraemia w ith persistent natriuresis. His level of atrial natriuretic peptide wa s not significantly elevated, however, his plasma aldosterone concentr ation was low. The oral administration oi salt gradually improved his hyponatraemia as well as the coincident symptoms. By the administratio n of a mineralocorticoid, fludrocortisone acetate, we succeeded in mai ntaining his serum sodium level without salt replacement. We discuss t he mechanism(s) and treatment of hyponatraemia associated with pituita ry tumour.