Dysfunction of the Adrenal Gland: Physiologic Considerations and Nursing Problems

Abstract

The adrenal gland, actually comprised of two glands, exerts widespread, and at times, critically important physiologic effects. The adrenal cortex, by secreting glucocorticoids, mineralocorticoids, and sex hormones has an impact upon intermediate metabolism, extracellular fluid balance, and secondary sexual characteristics, respectively. Adequate function of the adrenal cortex is essential for the body to adequately cope with stress. By secreting the catecholamines epinephrine and norepinephrine, the adrenal medulla reinforces the function of the sympathetic nervous system, thus facilitating physiologic readiness for the “fight or flight” response. Adrenocortical insufficiency (Addison's disease) predisposes the patient to physiologic collapse (addisonian crisis) in the presence of seemingly minor insults. An inability to maintain blood glucose and hypotension reflect a deficiency in glucocorticoid secretion, whereas the depletion of extracellular fluid and hyperkalemia are the result of a deficient output of mineralocorticoids. Cushing's syndrome occurs as a result of excessive plasma levels of glucocorticoid. Protein catabolism is pronounced and produces thin, weak extremities and osteoporosis. Abnormal distribution of fat leads to the characteristic signs of truncal, facial (“moon-faced” appearance), and interscapular (“buffalo hump”) obesity. The accompanying hyperglycemia and the increased risk for the development of diabetes mellitus are caused by the anti-insulin and gluconeogenic effects of glucocorticoids. Excessive secretion of mineralocorticoids (aldosteronism) produces an expanded extracellular fluid volume with hypertension and hypokalemia. Hypernatremia occurs because of a true excess of sodium coupled with deficit of free water. This deficit of free water occurs because of hypokalemic nephropathy with resultant loss of renal concentrating ability. Pheochromocytomas are autonomous, secreting tumors of the adrenal medulla that produce inappropriate and excessive levels of circulating catecholamines. The clinical picture commonly involves severe hypertension of either a constant or paroxysmal nature. Hypermetabolism and hypercatabolism, which are characteristic of the stress response, also occur. The problems encountered in the care of individuals with adrenal dysfunction are direct outgrowths of the physiologic effects of insufficient or excessive adrenal hormones. The diffuse nature of the physiologic abnormalities produces a wide variety of disorders. A thorough understanding of normal adrenal physiology greatly facilitates the anticipation of and the appropriate nursing intervention in these problems.