REDUCTION OF CORTISOL-LEVELS AFTER SINGLE INTRAARTICULAR AND INTRAMUSCULAR STEROID INJECTION

BACKGROUND: This study was undertaken to determine the influence of si ngle intra-articular or intra muscular injections of methylprednisolon e acetate on the hypothalamic-pituitary-adrenal axis. PATIENTS AND MET HODS: Twenty-one patients with rheumatic disease who had never been tr eated with systemic glucocorticoids and had not received local injecti ons of these agents for the preceding 2 months, were given 40 mg of me thylprednisolone acetate. Group I (11 patients) received one intra-art icular injection into the knee, and Group II (10 patients) received th e same dose intramuscularly. RESULTS: In Group I, serum cortisol level s were significantly decreased 24 hours after injection (228.2 +/- 8.7 nmol/L versus 193 +/- 16.3 nmol/L; P < 0.05). Serum cortisol levels w ere decreased in 9 of the 11 patients, by an average of 21.5%. Two pat ients' levels were below 138 nmol/L, which is considered to be the low er limit of normal range. Serum cortisol levels were below normal rang e in 3 patients 72 hours after intra-articular steroid injection. In G roup II, serum cortisol levels were significantly decreased at 72 hour s after injection (239.6 +/- 10.3 nmol/L versus 175.6 +/- 21.4 nmol/L; P < 0.01). Three patients' levels were below normal. By 72 hours post injection, serum cortisol concentrations in 9 of 10 patients were decr eased by an average of 31% compared to preinjection values. CONCLUSlON : The present study suggests that decreased adrenocortical secretion, as reflected in depressed cortisol levels, can result from a single, l ow-dose, intra-articular or intramuscular injection of depot corticost eroids.