The term hypopituitarism generally applies to any condition in which more than a single pituitary hormone is deficient This condition may include deficiencies resulting from a lack of hypothalamic-releasing factors, as well as deficiencies of anterior and posterior pituitary hormones Diabetes insipidus (DI), the lack of antidiuretic hormone (ADH), may occur alone or in association with other hormonal defects and is discussed in a subsequent section Adrenocorticotropic hormone (ACTH) primarily affects adrenal glucocorticoid production; generally, it does not affect mineralocorticoid synthesis, which is primarily regulated by the renin–angiotensin system A deficiency of ACTH production manifests as cortisol deficiency Because cortisol plays a role as an insulin counterregulatory hormone, a lack of either ACTH or cortisol may result in hypoglycemia during stress or a prolonged fast Because the only identified role for thyroid-stimulating hormone (TSH) is the stimulation of thyroid hormone production, a deficiency of TSH is most likely to manifest as hypothyroidism Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are involved in gonadal maturation, as well as the regulation of gonadal functions LH and FSH play an important role in testicular descent and penile growth in the male fetus, as well as affecting the onset of puberty in all adolescents The circulating levels of these two pituitary hormones are low in children and have no significant role before onset of puberty Prolactin is primarily involved in the maintenance of lactation and is of minimal significance in childhood under normal conditions Growth hormone is a principal regulator of linear growth and an important insulin counterregulatory hormone The absence of growth hormone may be associated with hypoglycemia, particularly in infants and young children during a prolonged fast Clinical Considerations Clinical Recognition The symptoms and signs of hypopituitarism depend on the deficient hormones The acute presentation of hypopituitarism is most likely to occur when the child is stressed by injury, illness, or fasting The presentation may involve either an unusually rapid decompensation, reflecting the role of cortisol in adaptation to stress, or as hypoglycemia, mirroring the role of both cortisol and growth hormone in opposing the effects of insulin Triage Children with known hypopituitarism are at risk for severe decompensation during illness or other forms of stress Children who are normally on replacement therapy should be assessed for compliance and tolerance of medications Special attention should be given to abnormal vital signs and mental status Initial Assessment/H&P Patients with known hypopituitarism who present to the ED are at risk for decompensation thus it is important to carefully assess for injury, illness, or fasting state that may precede crisis A history of vomiting or noncompliance with taking medications, particularly steroids, should be elicited Questions related to what and how much the patient has been eating and drinking are important Urine output and fluid status (weight trend if known) are helpful in determining total body water status Physical examination should focus on addressing vital sign abnormalities and assessment of mental status, hydration state, perfusion as well as a