Simplified water loading test in hypoadrenocorticism and hypothyroidism.

Soffer and Gabrilove introduced a simplified water loading test in 1952 to aid in the diagnosis of adrenocortical insufficiency. The present data confirm these findings in 33 patients with primary (Addisonian) or secondary (hypopituitary) hypoadrenocorticism. Thirteen of the 18 patients with hypopituitarism had unequivocal hypothyroidism. After water loading, all patients tested had impaired diuretic responses which showed substantial improvement when the tests were repeated after administration of cortisone. In contrast, the 9 patients with primary hypothyroidism responded normally to water loading. Hypothyroidism associated with an impaired water tolerance which improves distinctly during administration of cortisone, is probably secondary to pituitary failure. Hypothyroidism associated with normal water tolerance is suggestive of primary thyroidal dysfunction.