Pituitary gland abnormalities (week 4) Flashcards
What are the hormones secreted by anterior pituitary gland
Prolactin
ACTH
TSH
GH
LH and FSH
What are the hormones secreted by posterior pituitary gland
Oxytocin
ADH
Function of prolactin
stimulate breast milk production, breast tissue growth
Function of ADH (anti diuretic hormone)
Controls how much water is excreted into urine
Function of GH
growth and development
Function of ACTH
stimulates adrenal cortex to produce cortisol
Function of oxytocin
Stimulates uterine contraction during labour
Promotes breastfeeding
Pituitary pathologies can be
Hyperfunction / hypofunction
Hyperfunction of the the pituitary is caused by
Secreting adenomas
Adenomas can be (function, size)
Secreting / non-secreting
Micro/Macro
How may macro adenomas cause hypopituitarism
Due to large infarction of the pituitary gland tissue
Symptoms of non-secreting adenomas
Headaches
Impaired visual field
Investigation for non-secreting adenomas
MRI
Hormone tests to exclude other causes
Management for non-secreting adenomas
Surgery
Radiotherapy
Types of secreting adenomas
Prolactinoma
GH secreting adenoma
ACTH secreting adenoma
TSH secreting adenoma (very rare)
What does TSH secreting adenoma cause
Secondary hyperthyroidism (very rare)
Most common secreting pituitary adenomas
Prolactinoma
Symptoms of hyperprolactinaemia due to prolactinoma
females - oligomenorrhea/amenorrhea, infertility, vaginal dryness, galactorrhea
Males- erectile dysfunciton, gynaecomastia, reduced facial hair
Both- headaches, low sex drive, impaired visual fields
Investigations for prolactinoma
Serum prolactin level
Serum level of other hormones
MRI
Results of investigations for prolactinoma
Raised prolactin
Decreased level of other hormones
Lesions / tumour seen on MRI
Management for small prolactinoma
Dopamine agonists
Hormone therapy - oestrogen
Management for larger prolactinoma
Surgery
What dopamine agonists are used for prolactinoma
cabergoline
Side effects of cabergoline (dopamine agonists)
Nausea / vomiting
low mood
obsessive compulsive behaviour
If a patient with small prolactinoma has been taking dopamine agonists for over a year and has not experienced any symptoms, what should you do? - continue the treatment ?
Stop dopamine agonist because hyperprolactinaemia is likely to resolve
Start again if hyperprolactinaemia persist
Hormone replacement therapy is used in prolactinoma if
fertility and galactorrhea are not issues
Types of causes of hyperprolactinaemia
Physiological
Pathological - prolactinoma
Physiological causes of hyperprolactinaemia
Pregnancy
Breastfeeding
Anxiety
Use of dopamine antagonists
Use of anti-psychotics
Examples of dopamine antagonists
Risperidone
Metoclopramide
What is SIADH (syndrome of inappropriate ADH production)
Excessive ADH production due to pathology in posterior pituitary / ectopic ADH
What damage to the brain can cause SIADH
subarachnoid haemorrhage (bleeding on the surface of the brain)
What are the non-pituitary cause of SIADH
Small cell lung cancer
Lymphoma
Infections
Pneumothorax
Cystic fibrosis
Chemotherapy
What is a common PMH in patients with SIADH
Lung cancer (small cell lung cancer)