Hypopituitarism Flashcards
Define:
Deficiency in one or more of the hormones secreted by the anterior pituitary.
GH –> LH/FSH –> prolactin –>TSH –> ACTH (the order in which they are affected)
Aetiology/Risk factors:
- Hypothalamus affected
- Pituitary stalk
- Pituitary
- Pituitary Masses
Hypothalamus causes:
o Kallman’s Syndrome o Tumour o Inflammation o Infection – meningitis, TB o Ischaemia o Dysfunction due to anorexia, starvation or over-exercise
Pituitary stalk causes:
o Trauma – base of skull fractures o Surgery o Mass lesion – craniopharyngioma (tumour arising from Rathke’s pouch situated between the pituitary and 3rd ventricle floor) o Meningioma o Carotid artery aneurysm
Pituitary causes:
o Tumour – adenoma mostly, cysts
o Irradiation
o Inflammation
o Autoimmunity
o Infiltration – haemochromatosis, amyloid, metastases, sarcoidosis
o Ischaemia – pituitary apoplexy (rapid pituitary enlargement from a bleed into a tumour may cause mass effects, CVS collapse due to mass hypopituitarism and death), DIC, Sheehan’s
o Genetic Mutations - Pit-1 and Prop-1 genes
Pituitary mass causes:
o Most commonly adenomas
o Others include craniopharyngioma, meningioma, glioma, metastases
o Cysts
Epidemiology:
Pituitary adenoma annual incidence: 1/100,000
Signs and symptoms of low GH:
CHILDREN: short stature
ADULTS: low mood, fatigue, reduced exercise capacity and muscle strength, increased abdominal fat mass, dry wrinkly skin, reduced balance and strength, osteoporosis, a therosclerosis, low CO
Signs and symptoms of low LH/FSH:
• Delayed puberty
FEMALES: loss of secondary sexual hair, breast atrophy, menstrual irregularities, dyspareunia, decreased libido, infertility
MALES: loss of secondary sexual hair, gynaecomastia, small and soft testes, decreased libido, impotence
Signs and symptoms of low ACTH:
Signs/symptoms of adrenal insufficiency
Signs and symptoms of low TSH:
signs/symptoms of hypothyroidism
Signs and symptoms of low prolactin:
Lack of lactation
Signs and symptoms of pituitary apoplexy:
o Headache
o Visual loss
o Cranial nerve palsies
Investigations:
• Pituitary Function Tests o Basal Tests • 9 am cortisol • LH and FSH levels • Testosterone levels • Oestrogen levels • IGF-1 levels • Prolactin levels – may be high due to loss of hypothalamic dopamine that normally inhibits its release • Free T4 and TSH levels o Dynamic Tests (rarely performed) • Insulin-induced hypoglycaemic (should cause a rise in GH and cortisol) o Short synacthen test (for adrenal insufficiency) o MRI/CT of brain o Visual field testing
Management:
• Hormone Replacement o Hydrocortisone o Levothyroxine o Sex hormones • Testosterone in males • Oestrogen with/without progesterone in females • Growth hormone • Desmopressin (if central diabetes insipidus as a result of panhypopituitarism)