Endocrine complications in intensive care unit patients

Abstract

Summary This review addressed end organ endocrine dysfunction or failure associated with diabetes, thyrid abnormalities, adrenal insufficiency, pheochromocytoma, and pituitary dysfunction, as well as the issue of corticosteroid replacement or pharmacologic application in the critically ill. Diabetes is a common cause that precipitates ICU admission or is a secondary factor in the routine care of the stressed and critically ill medical or surgical patient. Early identification of hypoglycemia is crucial to avoid potentially devastating neurologic sequale. Increasing data on the deleterious effects on immune function, wound healing, and recovery from ischemia has prompted the use of regular insulin infusions in acute and critically ill patients in an attempt to maintain euglycemia. 58 The large Diabetes Mellitus Insulin Glucose Infusion in Acute Myocardial Infarction trial reported the acute and long-term benefits of initial infusions of glucose, insulin, and potassium combined with tighter glycemic control in diabetics with acute myocardial infaretion. 15 DKA and NKHC share several common features and represent severe endpoints of abnormal glucose and fat metabolism. These entities require timely diagnosis and therapy and rapid identification of the inciting cause to limit morbidity and mortality. Cerebral edema is a relatively uncommon development in DKA, occurring most often in children and resulting in severe neurologic sequalae in many patients. Asymptomatic thyroid disease is fairly prevalant in the United States. Extremes of dysfunction may result in thyroid storm or myxedema coma, both requiring rapid identification and therapy. Thyroid hormone synthesis and peripheral metabllism and function are markedly altered in acute illness. The differentiation of thyroid activity has been markedly improved over the past several decades with the wide application of increasingly sensitive tests, such as the TSH, free T4, and free T3. The euthyroid sick syndrome is recognized as a “normal” physiologic response to critical illness. Supplementation with exogenous thyroid hormone in patients with euthyroid sick syndrome is not indicated and may be deleterious. Adrenal homeostasis is crucial for adequate response to life-threatening trauma or critical illness. The body is normally able to increase glucocorticoid release by a factor of roughly 10-fold. As the population ages and the use of corticosteroids increases, AI should be considered in any hemodynamically unstable patient. Relative AI is being recognized more commonly, particularly as a process in sepsis and septic shock. Recent preliminary data from an ongoing multicenter trial supports the short-term administration of physiologic, stress doses of glucocorticoids in such patients. Patients with pheochromocytoma, and uncommon chromaffin cell tumor, present to the ICU on occasion for acute diagnosis and initiation of therapy or for postoperative management. These tumors are most commonly adrenal in origin, secrete excessive norepinephrine, and may be associated with familial endocrinopathies. Alpha blockade is the mainstay of initial therapy followed by intravascular fluid expansion and judicious use of β blockade and calcium channel blockade in select patients. Pituitary pathology should be considered in patients with a period of significant shock; those who have undergone frontal craniotomy or pituitary resection; those who sustained head injury; or those with cerebral thrombosis who develop polyuria, hypothermia, electrolyte abnormalities, or hyperosmolarity. On occasion, nephrogenic DI develops in patients with renal pathology or secondary to medications, such as lithium or amphotericin B. Patients with central DI should be treated with fluids, have their serum sodium corrected, and receive DDAVP. Patients with suspected or known panhypopituitarism should be treated with appropriate doses of adrenal and thyroid hormone replacement.