Systemic Corticosteroid Therapy

Systemic corticosteroids are synthetic glucocorticoids given orally or parenterally to reduce inflammation and suppress harmful immune activity. Common agents include prednisone, prednisolone, methylprednisolone, dexamethasone, and hydrocortisone. Glucocorticoids enter cells and bind cytoplasmic glucocorticoid receptors. The receptor-drug complex changes gene transcription, decreasing production of inflammatory mediators and reducing immune-cell activity. This broad effect can rapidly relieve airway inflammation, autoimmune flares, cerebral edema, transplant rejection, and severe allergic disease. The same broad effect also weakens normal host defenses, raises glucose, impairs tissue repair, and alters mood. Endogenous cortisol is regulated by the hypothalamic-pituitary-adrenal (HPA) axis: 1. The hypothalamus releases corticotropin-releasing hormone (CRH). 2. The pituitary releases adrenocorticotropic hormone (ACTH). 3. The adrenal cortex produces cortisol. Exogenous glucocorticoids signal that the body already has enough cortisol. CRH and ACTH production fall, and the adrenal cortex becomes less able to produce cortisol on its own. With prolonged exposure, the adrenal glands may atrophy. Abruptly stopping therapy can then leave the patient unable to mount a cortisol response during illness, injury, surgery, or other physiologic stress. Clinically meaningful suppression should be assumed when systemic therapy...