Adrenocortical function and responsiveness to tetracosactrin infusions after intra-articular treatment with triamcinolone acetonide and hydrocortisone acetate.

The urinary free cortisol (UFC) output, considered a parameter of the action of the exogenous corticosteroid on the hypothalamo-pituitary axis, was followed in five patients who received a total of 12 intra-articular (i.a.) injections of 40 mg of triamcinolone acetonide (TCA) distributed over eight treatment sessions. The effect of intra-articular TCA injections on UFC output was null after three treatment sessions, transient (48 hr) after another three, and more prolonged (6 days), although slight, after the remaining two sessions. These results contrast with the lasting and profound inhibition of the UFC output induced either by the same TCA dose given intramuscularly, or by oral administration of dexamethasone to 30 normal subjects, 0.75 mg at 8-hourly periods for 48 hours. Adrenocortical reactivity, as measured by the response to synthetic ACTH (tetracosactrin) of both plasma cortisol levels and UFC output, was studied in another five patients prior to and after eight i.a. injections of 40 mg of TCA, and in three patients after six i.a. injections of 25-100 mg of hydrocortisone acetate. No decrease was observed after the i.a. injections of HCA. Considered as a group the response to tetracosactrin after TCA injections was not significantly altered. Two patients showed a decreased response of both UFC and plasma cortisol, although their values remained within the limits of those obtained in 44 normal control subjects. In contrast, profound inhibition of the tetracosactrin induced response occurred in a control group of 30 subjects given 0.75 mg of dexamethasone orally at 8-hourly periods for 48 hours.