Most of the disorders affecting the pituitary gland originate in the anterior lobe. The effects of pathology on the anterior pituitary gland can be broadly summarized as hyperpituitarism and hypopituitarism [6,7].

Growth hormone, also referred to as somatotropin, is produced in the pituitary gland [19]. An estimated 50% of the cells in the anterior pituitary are somatotrophs (cells that secrete growth hormone) [20]. Secretion of growth hormone by the anterior pituitary gland occurs in a pulsatile manner, and the majority (up to 70%) occurs at night during non-REM (typically stage 3) sleep [21,22]. Therefore, the amount and quality of sleep plays an important role in growth and development.

This condition can be seen in patients with a variety of mental health disorders, including autism, schizophrenia, schizoaffective disorder, and bipolar disorder [53]. Schizophrenia is a common cause, with 11% to 20% of patients with schizophrenia developing psychogenic diabetes insipidus [53].

Transfrontal craniotomy is indicated when the tumor extends beyond the pituitary fossa and is impinging on the optic chiasm, because this procedure provides the best view of the operative field [60]. With this technique, an opening is made in the skull and the pituitary is accessed through the brain, increasing the risk of brain injury [59]. Complications can include brain damage, stroke, blindness, meningitis, leakage of cerebrospinal fluid, bleeding, diabetes insipidus, and adverse reactions to anesthesia [59].

Hyponatremia can be classified as mild (130–134 mEq/L), moderate (125–129 mEq/L), or profound (less than 125 mEq/L) [64]. In patients with mild-to-moderate hyponatremia, the only signs and symptoms may be nausea and malaise [17]. As hyponatremia worsens, patients will develop additional signs and symptoms, and serum sodium levels less than 120 mEq/L can lead to coma and respiratory arrest [17]. The speed at which the hyponatremia develops is correlated with the neurologic manifestations [26]. If the patient develops acute hyponatremic encephalopathy, the condition may be reversible, but it could also lead to permanent deficits [17]. Vomiting is considered an ominous sign [17].

Adults with a growth hormone deficiency may present with fatigue, weakness, obesity, decreased muscle mass, weakened bones, sexual dysfunction, elevated cholesterol levels, and insulin resistance [16,69]. Decreased bone turnover and decreased bone mass are common, and adults with a growth hormone deficiency have a risk for fracture that is two to three times higher than their counterparts without growth hormone deficiency [23]. Early onset of deficiency (i.e., in childhood) and cigarette smoking can further increase this risk [23].

The majority of cases of growth hormone hypersecretion (more than 90%) are caused by benign pituitary adenomas [19]. In the United States, it is estimated that about 16% of the population (more than 50 million people) have pituitary tumors, although most are undiagnosed. Approximately 13,000 people are diagnosed with pituitary tumors each year; 25% of these tumors will lead to acromegaly [21]. It is possible for patients to develop a malignant pituitary adenoma that is responsible for acromegaly, but this occurs in less than 1% of cases [24]. The disorder may also be caused by hypothalamic adenomas that increase the amount of GHRH, which, in turn, increases growth hormone levels [19]. Other types of tumors, such as those found in the hypothalamus, pancreas, lungs, chest, or abdomen, can also lead to acromegaly [80]. These tumors can secrete their own growth hormone, although it is more common for them to produce GHRH [80]. Additional possible causes include pituitary hyperplasia and excess GHRH [16].

Cushing syndrome is further classified as iatrogenic (or exogenous), primary, secondary, or ectopic [24]. Iatrogenic Cushing syndrome is the most common form and is the result of long-term glucocorticoid therapy [21]. Both primary and secondary Cushing syndrome develop as a result of endogenous causes (e.g., adrenal tumor). Primary Cushing syndrome is typically caused by adrenal gland malignancy, while secondary Cushing syndrome (also referred to as Cushing disease) is the result of excessive secretion of ACTH by a pituitary tumor, usually an adenoma [24]. Ectopic Cushing syndrome arises from the endogenous production of ACTH by one of at least 25 different extrapituitary malignancies, including carcinoma of the lung and of several organs in the GI tract. Secondary Cushing syndrome is the most common (66%) endogenous type of the disease. When this condition is seen in infants, it is most commonly caused by an adrenal carcinoma [24].

The greatest postoperative concern after adrenalectomy is adrenal insufficiency. Also important are possible hypotension caused by the rapid withdrawal of mineralocorticoids, electrolyte imbalances, and infection resulting from suppression of the immune system. The surgical hazards associated with adrenalectomy include possible injury to the spleen, liver, duodenum, and common bile duct as well as hemorrhage [54].