Glucocorticoid epidural for sciatica: metabolic and endocrine sequelae

Objective. The study was designed to investigate the effect of epidural administration of glucocorticoid on insulin sensitivity. Methods. Ten healthy individuals with sciatica underwent a short insulin tolerance test before and twice following (at 24 h and 1 week) a caudal epidural containing 80 mg triamcinolone. Fasting glucose, insulin and cortisol concentrations were also measured. Results. The rate of glucose disappearance after insulin administration (k(ITT)) fell from 3.6%/min before the epidural to 1.9%/min 24 h afterwards (P=0.001) and returned to pretreatment values by 1 week. Significantly raised fasting insulin and glucose levels also reflected impaired insulin sensitivity immediately after the epidural. Morning cortisol levels were suppressed after the epidural (49 nmol/l at 24 h and 95 nmol/l at 1 week vs 352 nmol/l at baseline; P<0.01). Conclusions. Epidural administration of glucocorticoid results in potent suppression of insulin action and this should be taken into account when patients with diabetes require treatment for sciatica.