Pituitary disorders Flashcards
what is the clinical presentation of pituitary tumours?
- compression effects due to increasing mass : visual loss due to pressure on optic chiasm which leads to tunnel vision, headache, left sided eye compressive problems.
- abnormal pituitary function : hyper/ hypo-secretion where GH, LH, FSH, TSH, ACTH falls and prolactin increases.
what effects can be seen due to abnormal pituitary function?
- hypo-secretion where GH, LH, FSH, TSH, ACTH falls and prolactin increases.
- GH: short stature, sex hormone problems.
- Gonadotropin : delayed puberty, loss of secondary sexual characteristics.
- TSH : low thyroid and non elevated TSH.
- ACTH : low cortisol, tired, dizzy MOST DANGEROUS.
*hyper : high prolactin, GH, ACTH leading to cushings and TSH, LH, FSH rarer cases.
how is pituitary disease assessed?
- basal blood test to see TSH, LH, FSH, sex hormone levels.
- HPA axis cortisol reading.
- MRI, assess visual field.
how is HPA + GH axes dynamically tested?
- stimulation test if deficiency suspected.
- adrenal : direct stimulation of adrenals by ACTH see if cortisol rises. using insulin stress test.
- GH : insulin stress test.
- suppression test for suspected excess.
- adrenal : suppressing ACTH with steroids.
- GH : suppress with glucose load, a glucose tolerance test.
what is a prolactinoma?
- prolactin secreting pituitary micro/ macro tumour.
- larger the tumour higher prolactin.
- TREATED WITH TABLETS no need for surgery.
- dopamine INHIBITS prolactin so dopamine agonist given which shrinks tumour.
eg: bromocriptine and cabergoline. - anti-sickness and anti-psychotic drugs cause high prolactin as they are dopamine antagonists. check medication and pregnancy status before.
what is hyperprolactenaemia and what are its symptoms?
- prolactin directly inhibits LH causing menstrual disturbance, fertility problems, galactorrhea in women.
- symptoms much later in men, usually macro-adenomas, low testosterone symptoms like loss of sex drive, visual loss.
- if prolactin <5000 then due to disinhibition and may need surgery.
what are the features of non-functioning pituitary adenomas?
- no secretion of biologically active hormones, so inactive ACTH, LH, FSH.
- mass effect symptoms, or low pituitary symptoms.
what are the features of acromegaly? and how is it clinically confirmed?
- ‘large extremities’
- GH-secreting pituitary tumour, leading to gradual changes over time.
- oral glucose tolerance test with high GH response.
- failure to suppress GH, elevated IGF-1, elevated mean GH on gH day curve.
what are the long-term complications of untreated acromegaly?
what are the treatments?
- premature CVS death.
- increased risk of colonic tumours.
- increased thyroid cancer risk.
- body disfiguration might be irreversible.
- hypertension, diabetes, unpleasant symptoms.
*surgical removal of tumour, dopamine agonist to suppress GH secretion, somatostatin analogues, GH receptor blocker.
what are the features of cushing’s disease?
- ACTH secreting pituitary tumour.
- appearance : ‘moon face’ , purple striae, buffalo hump, round abdomen, high BP, diabetes, osteoporosis.
how does cushing’s disease differ from cushing’s syndrome?
- disease id due to a pituitary tumour whereas syndrome due to other pathologies like adrenal tumour, ectopic ACTH, steroid medication.
what is diabetes insipidus?
- defined so due to extreme thirst due to fluid loss.
- posterior pituitary secretes ADH which increases urinary output.
whats the difference between cranial DI and nephrogenic DI?
- cranial is an ADH deficiency pituitary disease whereas nephrogenic is resistance kidney disease.
- cranial : inflammation, infiltration, malignancy, infection.
*untreated DI : severe dehydration, hypernatraemia, coma. (cranial responds well to synthetic vasopressin).
what is pituitary apoplexy?
- stroke, sudden vascular event in pituitary tumour.
- haemorrhage or infarction.
- presents as sudden headache, double vision, cranial nerve palsy, hypopituitarism.
