2. Hypersecretion of anterior pituitary hormones Flashcards
what can hypersecretion of the anterior pituitary be due to?
- isolated pituitary tumours
- can also be ectopic (from non-endocrine tissue e.g. neuroendocrine tumours)
what is hypersecretion of the anterior pituitary often associated with?
often associated with visual field and other defects (e.g. cranial nerves)
what does an absence of black in an MRI scan mean?
absence of CSF
what is bitemporal hemianopia?
tunnel vision
what is bitemporal hemianopia caused by?
compression of the fibres from the nasal retinae that cross at the optic chiasm, leading to loss of vision from the outer temporal visual fields
what might compress fibres at the optic chiasm?
suprasella tumour
how can visual fields be examined?
perimetry
what does excess ACTH (corticotrophin) result in?
cushing’s disease (if due to anterior pituitary tumour)
what does excess TSH (thyrotrophin) result in?
thyrotoxicosis - high TSH and high T4
what does excess gonadotrophins (LH,FSH) result in?
early puberty in children
what does excess prolactin result in?
hyperprolactinaemia
what does excess GH result in?
gigantism (in children) and acromegaly (in adults)
in which situations is it physiological to have high prolactin?
pregnancy and breastfeeding
what do you get at the end of pregnancy to prepare for breastfeeding?
lactotroph hyperplasia
what are the pathological causes of hyperprolactinaemia?
prolactinoma (often a microadenoma so <10mm in diameter)