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Bitemporal hemianopsia. Bitemporal hemianopsia is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field. It is usually associated with lesions of the optic chiasm, the area where the optic nerves from the right and left eyes cross near the pituitary gland.
Nelson's syndrome is a disorder that occurs in about one in four patients who have had both adrenal glands removed to treat Cushing's disease. [1] In patients with pre-existing adrenocorticotropic hormone ()-secreting pituitary adenomas, loss of adrenal feedback following bilateral adrenalectomy can trigger the rapid growth of the tumor, leading to visual symptoms (e.g. bitemporal hemianopsia ...
Pituitary adenomas are tumors that occur in the pituitary gland. Most pituitary tumors are benign, approximately 35% are invasive and just 0.1% to 0.2% are carcinomas. [ 1] Pituitary adenomas represent from 10% to 25% of all intracranial neoplasms and the estimated prevalence rate in the general population is approximately 17%. [ 1][ 2]
Pituitary apoplexy is regarded by some as distinct from Sheehan's syndrome, where the pituitary undergoes infarction as a result of prolonged very low blood pressure, particularly when caused by bleeding after childbirth. This condition usually occurs in the absence of a tumor. [4] Others regard Sheehan's syndrome as a form of pituitary apoplexy.
birnlex_1416. Anatomical terms of neuroanatomy. [ edit on Wikidata] Chiasmal syndrome is the set of signs and symptoms that are associated with lesions of the optic chiasm, manifesting as various impairments of the affected's visual field according to the location of the lesion along the optic nerve. Pituitary adenomas are the most common cause ...
Craniopharyngioma is a rare, usually suprasellar [ 15] neoplasm, which may be cystic, that develops from nests of epithelium derived from Rathke's pouch. [ 16][ 17] Rathke's pouch is an embryonic precursor of the anterior pituitary. [citation needed] Craniopharyngiomas are typically very slow-growing tumors.
The visual pathway consists of structures that carry visual information from the retina to the brain. Lesions in that pathway cause a variety of visual field defects. In the visual system of human eye, the visual information processed by retinal photoreceptor cells travel in the following way: Retina → Optic nerve → Optic chiasm a (here the ...
One important variety of bilateral scotoma may occur when a pituitary tumour begins to compress the optic chiasm (as distinct from a single optic nerve) and produces a bitemporal paracentral scotoma, and later, when the tumor enlarges, the scotomas extend out to the periphery to cause the characteristic bitemporal hemianopsia.