Treatment of adrenal insufficiency replaces the hormones the gland can no longer make and prevents adrenal crisis, the acute state of shock that untreated deficiency can bring.
Hormone replacement
Glucocorticoid deficiency is corrected with a physiological dose of hydrocortisone, usually 15-25 mg per day divided into two or three doses through the day so that the daily exposure roughly follows the natural cortisol rhythm. Prednisolone (3-5 mg per day) is an alternative, but dexamethasone is generally avoided because its long half-life makes the dose hard to titrate (adjust stepwise) and readily produces Cushingoid side effects, the features of glucocorticoid excess.
Mineralocorticoid replacement with fludrocortisone is added for patients with primary adrenal insufficiency who have confirmed aldosterone deficiency; it is not needed in the secondary and tertiary forms, because aldosterone secretion is preserved there. Fludrocortisone is monitored through serum electrolytes and through the symptoms it should relieve or cause — salt craving and light-headedness when the dose is too low, and raised blood pressure or leg swelling when it is too high.
The aim of replacement is to restore normal function without over- or under-treating. Both too much and too little glucocorticoid are associated with worse long-term outcomes, so the dose is reviewed against symptoms, growth in children, and the clinical picture rather than set once.
Preventing and treating adrenal crisis
Every patient needs to know how to raise the glucocorticoid dose during illness and stress, and how to recognize an impending crisis. Because infection and other major stressors are the usual triggers, the patient is taught to increase the oral dose during febrile illness and to use injectable hydrocortisone when oral treatment cannot be kept down. A steroid emergency card and medical alert identification tell any treating clinician that parenteral glucocorticoid is needed in an emergency.
Adrenal crisis is treated at once, without waiting for confirmatory tests. The first step is 100 mg of hydrocortisone by intravenous or intramuscular injection, followed by either 200 mg over 24 hours as a continuous infusion or 50 mg every 6 hours, together with intravenous 0.9% sodium chloride to restore volume. Glucose is given if hypoglycemia is present, and the precipitating cause is treated in parallel.
Prognosis
With reliable replacement, most patients return to a normal daily life, and the outlook for uncomplicated autoimmune Addison’s disease approaches that of the general population. Mortality and morbidity remain higher than in the general population, however, and adrenal crisis is still one of the leading causes of death in patients with adrenal insufficiency. Prevention — patient education, sick-day rules (raising the glucocorticoid dose during illness) and prompt emergency treatment — therefore matters as much as the prescription itself.
Adrenal insufficiency can also be inherited: in congenital adrenal hyperplasia an inherited enzyme defect in the steroid pathway blocks cortisol synthesis, and its treatment has the further task of controlling excess androgen.