Pituitary apoplexy is attached to the hypothalamus, a part of the brain, by a stalk that also contains the blood vessels that supply the gland. It is unclear why pituitary tumors are five times more likely to bleed than other tumors in the brain. There are various proposed mechanisms by which a tumor can increase the risk of either infarction (insufficient blood supply leading to tissue dysfunction) or hemorrhage. The pituitary gland normally derives its blood supply from vessels that pass through the hypothalamus, but tumors develop a blood supply from the nearby inferior hypophyseal artery that generates a higher blood pressure,
Pituitary stalk interruption syndrome Pituitary stalk interruption syndrome Pituitary stalk interruption syndrome (PSIS) is a congenital disorder characterised by the triad of an absent or exceedingly thin pituitary stalk, an ectopic or absent posterior pituitary and/or absent or hypoplastic anterior pituitary. Affected individuals may present with hypoglycaemia during the neonatal period, or with growth retardation during childhood (those diagnosed in the neonatal period appear to be affected by a particularly severe form of the disorder). PSIS is a common cause of congenital hypopituitarism, and causes a permanent growth hormone deficit. Some PSIS-affected individuals may also present with adrenal hypoplasia (5-29%), diabetes insipidus (5-29%), primary