Contributors:Jahnavi Narayanan, MBBS
So, pituitary apoplexy is a disorder where there is either severe bleeding, or loss of blood flow to the pituitary gland, resulting in cell death and sudden loss of function.
Normally, the pituitary is a pea-sized gland, hanging by a stalk from the base of the brain.
It sits just behind the eyes near the optic chiasm, which is where the optic nerves cross.
The anterior pituitary, which is the front of the pituitary gland, contains a few different types of cells, each of which secretes a different hormone.
The second largest cell group are the corticotrophs which secrete adrenocorticotropic hormone, or ACTH, which stimulates the adrenal glands to secrete cortisol, a hormone that controls the stress response, blood pressure, and metabolic regulation.
A smaller cell group are the lactotrophs which secrete prolactin.
There are also thyrotrophs which are cells that secrete thyroid stimulating hormone, or TSH, that stimulate the thyroid gland.
And finally, there are the gonadotrophs which secrete two gonadotropic hormones - luteinizing hormone, or LH, and follicle-stimulating hormone, or FSH, both of which go on to stimulate the ovaries or testes.
ADH acts on the kidneys to decrease the amount of water lost in the urine.
The pituitary gland gets blood through two arteries - the superior hypophyseal artery, which forms a part of the hypophyseal portal system, a web of capillaries linking the hypothalamus to the anterior pituitary, and the inferior hypophyseal artery, which supplies the posterior pituitary.
Pituitary apoplexy can develop as a result of hemorrhage or infarction. The more common way is a hemorrhage, or profuse bleeding, into the pituitary gland.
Larger tumors demand more blood, and increased blood flow means increased pressure in the vessels, eventually causing them to rupture.
The blood collects in the interstitium, or the space between the cells, which makes the pituitary gland swell up.