This section presents current epidemiological and trends data related to pituitary dysfuntion in the United States (US).
Section 1.1 focuses on pituitary dysfunction: anterior hypopituitarism/pituitary insufficiency, which refers to the complete or partial deficit of anterior and/or posterior pituitary hormones.1 While congenital hypopituitarism occurs due to the abnormal prenatal development of either the pituitary or hypothalamus, acquired hypopituitarism may occur either due to or as a response to the treatment of pituitary, non-pituitary, or hypothalamic tumors (i.e., surgery and radiation therapy); traumatic brain injury; subarachnoid hemorrhage; and autoimmune conditions.2
Section 1.2 presents data on posterior pituitary disease, specifically central diabetes insipidus (CDI), and hyponatremia.
Central diabetes insipidus (CDI) is a disease in which large volumes of dilute urine (polyuria) are excreted due to deficiency of arginine vasopressin (AVP), also called antidiuretic hormone (ADH). Known causes of CDI include mass lesions such as germinomas and craniopharyngiomas, infiltrative disease such as Langerhans cell histiocytosis and sarcoidosis, trauma resulting from surgery or an accident, neoplastic metastases, and midline cerebral and cranial malformations. In rare cases, the underlying cause can be genetic defects in AVP synthesis.43 In addition, roughly one quarter of adult cases and half childhood cases are considered idiopathic.44,45 CDI may present as either transient or permanent. Due to the inability to concentrate urine, patients with CDI may develop dehydration and metabolic abnormalities, including hypernatremia, that can be life threatening if not recognized and treated in a timely manner with AVP or the AVP analog, desmopressin, and appropriate fluids.46
Hyponatremia is an electrolyte disorder. Serum sodium concentrations < 125 mmol/L are considered an indication of severe hyponatremia, and serum levels < 115 mmol/L are associated with substantial morbidity and increased mortality.59,60 The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is the most common cause of hyponatremia.61 It’s caused by excess of renal water reabsorption due to inappropriate antidiuretic hormone (vasopressin) secretion.62 Sherlock et al. reported that 62% of cases of hyponatremia resulted from SIADH.63