1 . Most of the disorders affecting the pituitary gland originate in the posterior lobe.
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].
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2 . Growth hormone, also referred to as somatotropin, is produced in the pituitary gland.
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.
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3 . Lithium is associated with decreased urine osmolality.
MEDICATIONS THAT IMPACT SERUM AND URINE OSMOLALITY
Effect | Medications/Drugs |
---|
Increased serum osmolality |
Corticosteroids | Glycerin | Insulin | Mannitol |
|
Decreased serum osmolality |
Carbamazepine | Chlorpromazine | Hydrochlorothiazide | Cyclothiazide | Doxepin | Lorcainide | MDMA/Ecstasy |
|
Increased urine osmolality |
Anesthetic drugs | Furosemide | Mannitol | Octreotide | Vincristine |
|
Decreased urine osmolality |
Captopril | Demeclocycline | Glyburide | Lithium | Octreotide | Tolazamide | Verapamil |
|
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4 . Schizophrenia is an uncommon cause of psychogenic diabetes insipidus.
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].
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5 . Transfrontal craniotomy is indicated when a pituitary tumor extends beyond the pituitary fossa and is impinging on the optic chiasm.
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].
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6 . Profound hyponatremia is defined as a serum sodium level of 135-140 mEq/L.
SYNDROME OF INAPPROPRIATE ANTIDIURETIC HORMONE SECRETION (SIADH)
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].
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7 . 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.
GROWTH HORMONE DEFICIENCY
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].
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8 . The majority of cases of growth hormone hyper-secretion are caused by autoimmune disease.
DISORDERS OF HYPERSOMATOTROPISM
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].
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9 . Secondary Cushing syndrome (also referred to as Cushing disease) is the result of excessive secretion of ACTH by a pituitary tumor, usually an adenoma.
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].
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10 . The greatest postoperative concern after adrenalectomy is adrenal insufficiency.
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].
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