Addison's disease occurs in all age groups, about equally in each sex, and tends to become clinically apparent during metabolic stress or trauma. In Addison's disease, there is increased excretion of Na and decreased excretion of K, chiefly in the urine, which is isotonic, and also in the sweat, saliva, and GI tract. Low blood concentrations of Na and Cl and a high concentration of serum K result. Inability to concentrate the urine, combined with changes in electrolyte balance, produces severe dehydration, plasma hypertonicity, acidosis, decreased circulatory volume, hypotension, and circulatory collapse. Cortisol deficiency contributes to hypotension and produces disturbances in carbohydrate, fat, and protein metabolism and severe insulin sensitivity.
Weakness follows, due in part to deficient neuromuscular function.
Resistance to infection, trauma, and other stress is diminished because of reduced adrenal output. Myocardial weakness and dehydration cause reduced cardiac output, and circulatory failure can occur. Symptoms and Signs Weakness, fatigue, and orthostatic hypotension are early symptoms. Pigmentation is usually increased except in adrenal insufficiency secondary to pituitary failure. Anorexia, nausea, vomiting, and diarrhea often occur.