severe adrenocortical insufficiency when an intercurrent illness or trauma causes an increased demand for adrenocortical hormones in a patient with adrenal insufficiency due to disease or use of relatively large amounts of similar hormones as therapy; characterized by nausea, vomiting, hypotension, and frequently hyperthemia, hyponatremia, hyperkalemia, and hypoglycemia; can be fatal if untreated. Syn: addisonian crisis, adrenal crisis, Bernard-Sergent syndrome.