Pituitary Hyper and Hyposecretion Flashcards
describe the functions of
hypothalamus
pituitary gland
thyroid gland
parathyroids
adrenal glands
testis
which hormone stimulate and act on thyroid?
TSH
thyroid hormones
which hormones act on adrenal gland?
ACTH
adenocorticosteroids
which hormones act on ovaries?
FSH, LH
estrogen
what hormones act on corpus luteum?
FSH, LH
progesterone
what hormones act on testes?
FSH, LH
testosterone
what hormone stimulates bone and soft tissues?
GH
what hromone stimulates breasts?
PRL
what hormone stimulates kidneys?
ADH
what hormone stimulates breasts and kidneys?
oxylocin
what does hypersecretion of GH cause?
acromegaly (Gitantasism)
what does hypersecretion of ACTH cause?
cushings disease
what does hypersecretion of prolactin cause?
hyperprolactinaemia
what does hyposecretion of anterior pituitary affect?
FSH/LH, GH, ACTH, TSH
what does hyposecretion of posterior pituitary affect
vasopressin
what can a space occupying ptuitary tumour cause?
optic chiasmal compression
bitemporal hemianopia
what are clinical features of acromegaly?
Soft tissue overgrowth
‘spade like’ hands (rings)
wide feet (shoes)
coarse facial features
thick lips & tongue
carpal tunnel syndrome
sweating
what are complications associated with acromegaly?
headache
chiasmal compression
diabetes mellitus
hypertension
cardiomyopathy
sleep apnoea
accelerated OA
colonic polyps & CA
how is acromegaly diagnosed?
can GH be supressed
insulin like growth factor 1 elevated
rest of pituitary function normal
normal vision
pituitary tumour on MRI
what is cushings syndrome?
excess corticosteroids
what type of hormone is cortisol?
catabolic hormone
what bodily functions is cortisol responsible for, therefore what affect might excess have?
Tissue breakdown
causes weakness of skin, muscle & bone
Sodium retention
may cause hypertension & heart failure
Insulin antagonism
may cause diabetes mellitus
what are high value symptoms of cushings syndrome?
skin atrophy
spontaneous purpura
proximal myopathy
osteoporosis
growth arrest in children
what are intermediate value symptoms of cushings syndrome?
pink striae
facial mooning & hirsutism
oedema
what are non-specific symptoms of cushing syndrome?
central obesity
hypertension
diabetes mellitus
not all cases of cushing syndrome are caused by a pituitary tumour
ACTH dependent causes may be…
Pituitary tumour (Cushing’s disease)
Ectopic ACTH secretion (eg lung carcinoid)
ACTH independent causes of cushing syndrome?
Adrenal tumour (adenoma or carcinoma)
Corticosteroid therapy (eg for asthma, IBD)
what are clinical manifestations of hyperprolactinaemia in women?
galactorrhoea 30-80%
menstrual irregularity
infertility
what are clinical manifestations of hyperprolactinaemia in men?
what are physiological causes of hyperprolactinaemia?
Pregnancy, lactation, stress
what are pharmalogical causes of hyperprolactinaemia?
DA depleting and DA antagonist drugs
what are pathological causes of hyperprolactinaemia?
Primary hypothyroidism
- Pituitary lesions (prolactinoma or pituitary ‘stalk pressure’)
what drugs may cause hyperprolactinaemia?
Dopamine antagonists
neuroleptics (eg chlorpromazine)
anti-emetics (eg metoclopramide)
DA-depleting agents
Oestrogens (not in OCP dosage)
Some antidepressants
- Don’t forget to ask about homeopathic or herbal remedies!
what are clinical features of hypopituitarism in adults?
Tiredness, weight gain, depression, reduced libido, impotence, menstrual problems
Skin pallor
Reduced body hair
what are clinical features of hypopituitarism in children?
Reduced linear growth
Delayed puberty
what is a water deprivation test
Diabetes insipidus (DI) involves deficient production or lack of effective action of antidiuretic
hormone (ADH or arginine vasopressin). ADH stimulates the kidney to conserve fluid. Deficient
production of ADH or lack of effective action of ADH causes a high urine output, thirst, dehydration,
and low blood pressure in advanced cases.
Disease of the hypothalamus/pituitary gland leading to a deficiency in ADH production is called
cranial or central DI. Disease of the kidney leading to lack of response of the kidney to fluid
conserving action of ADH is called nephrogenic DI.
The principle of the water deprivation test is to assess the ability of the patient to concentrate urine when
fluids are withheld. Water deprivation should normally cause increased secretion of ADH, resulting in the
production of small volumes of concentrated urine.
what are differential diagnosis of cranial diabetes insipidus?
Idiopathic (autoimmune hypophysitis?)
Post-trauma (including pituitary surgery)
Metastatic carcinoma
Craniopharyngioma
Other brain tumours: eg. germinoma
Rare causes: eg. sarcoidosis
