Hypopituitarism Flashcards
definition of hypopituitarism
deficiency of one or more of the hormones secreted by the anterior pituitary
panhypopituitarism is a deficiency of all pit hormones
aff ected in this order: growth hormone (GH), gonadotropins: follicle-stimulating hormone (FSH) and luteinizing hormone (LH), thyroid-stimulating hormone (TSH), and adreno corticotrophic hormone (ACTH), prolactin (PRL)
aetiology of panhypopituitarism
irradiation
surgery
pit tumour
what is pituitary apoplexy
haemorrhage or infarction of a pituitary tumour
what is sheehan’s syndrome
pit infarction, haemorrhage and necrosis following post-partum haemorrhage
epidemiology of hypopit
annual incidence and prev of pit adenomas - 1 in 100000, and 9 in 100000 respectively
signs and symptoms of hypopit
depends on the hormones missing and aetiology (eg bitemp hemaniopia if from pit mass, tumour secreting hormones eg acromegaly, cushings or prolactinoma)
lack of ACTH and TSH as in adrenal insufficiency and hypothyroidism
signs and symptoms from lack of GH
Children: Short stature (< 3rd centile/not keeping with parental height)
adults:
- low mood
- fatigue
- reduced exercise capacity/muscle strength
- increased centripedal obesity
- atherosclerosis
- dry, wrinkly skin
- reduced balance
- low CO
- osteoporosis
- low glucose
signs and symptoms of lack of LH FSH
delayed puberty
females:
- loss of secondary sexualr hair
- breast atrophy
- menstrual irregularities - oligomenorrhoea or amenorrhoea
- dyspareunia
- loss of libido
- infertility
- osteoporosis
males
- loss of secondary sexual hair
- gynaecomastia
- small or soft testes
- reduced ejaculate volume
- reduced spermatogenesis
- loss of libido
- impotence
- loss of muscle bulk
signs and symptoms of lack of prolactin
abscence of lactation
signs and symptoms of pituitary apoplexy
life threatening hypopit with ehadache, visual loss, CN palsy
invesitgations for hypopit
pit func tests
- basal tests - 9am cortisol, LH FSH (L/N), testosterone oestradiol (L), IGF-1 (L), prolactin (may be H - loss of dopamine inhibition), free T4 (L) and TSH (L/N)
- dynamic tests:
- insulin induced hypoglycaemia done in the morning (CI in epilepsy, IHS, hypoadrenalism) - give 0.15 U/Kg IV insulin
- in hypopit GH and cortisol are <30mU/L and <550nmol/L respectively
- short synacthen test
- arginine + GHRH tets
- glucagon stimulation test when insulin is CI
- insulin induced hypoglycaemia done in the morning (CI in epilepsy, IHS, hypoadrenalism) - give 0.15 U/Kg IV insulin
MRI/CT brain - investigate the cause
visual field testing
UE - low Na from dilution, low Hb (normochromic, normocytic)
management for hypopit
hormone replacement:
hydrocortisone before other hormones - 20mg in morning, 10mg evening (double for febrile illness, IM hydrocortisone for surgery). Medicalert bracelet and steroid card
levothyroxine - 100ug daily (after hydrocortisone to avoid addisonian crisis)
sex hormones - testosterone enanthate 250mg IM every 3 weeks, daily topical gels or buccal muco adhesive tablets. Patches (eg Testogel®) in males,
oestrogen (transdermal oestradiol patches, or contra ceptive pill) +- progesterone ± testosterone or dehydroepi androsterone (DHEA, in hypo androgenic women; a small amount may improve well-being and sexual function, and help bone mineral density and lean body mass) in females
gonadotrophin therapy needed for fertility
GH - SC 1.2unit/day in adults. somatotrophin mimics GH children need specialist supervision
posterior pit deficiency (damage to pit stalk) - desmopressin (vasopressin analogue) 10-20ug/day intranasally
complications for hypopit
adrenal crisis
hypoglycaemia
myxoedema coma
infertility
osteoporosis
dwarfism (children)
complications of pit mass causing hypopit
optic chiasm compression
hydrocephalus - 3rd ventricular compression
temporal lobe epilepsy
prognosis of hypopit
