Pituitary II Flashcards
What causes Cushing’s syndrome?
Excess cortisol
What do the excess mineralocorticoid and androgen of Cushing’s syndrome cause?
Mineralocorticoid = hypertension, oedema Androgen = virilism, hirsutism, acne, oligo/ammenorrhoea
What does the altered lipid and carbohydrate metabolism that occurs in Cushing’s syndrome cause?
Diabetes and obesity
How can Cushing’s syndrome alter the patient’s psyche?
Psychosis and depression
How does the protein loss that occurs during Cushing’s syndrome manifest?
Myopathy, wasting, osteoporosis, fractures, thin skin, striae, bruising
What symptoms characterise Cushing’s syndrome?
Thin skin, proximal neuropathy, frontal balding in women, conjunctival oedema, osteoporosis
How is Cushing’s syndrome screened for?
Overnight 1mg dexamethasone suppression test = >130nmol/L is diagnostic
Urine free cortisol = total >250, cortisol/creatine ratio >25
Diurnal variation = loss of variation
What is the definitive test for Cushing’s syndrome?
Low dose DST, 2 day 2mg/day dexamethasone suppression test = cortisol >130nmol/L after 6hrs
What is the aetiology of Cushing’s syndrome?
Pituitary (majority) = Cushing’s disease (all other are Cushing’s syndrome)
Adenoma of adrenal
Ectopic ACTH production = thymus, lungs, pancreas
Pseudo = alcohol, depression, steroids
What does the CRH test show in Cushing’s syndrome?
50% increase in ACTH, 20% increase in cortisol (suggestive of pituitary struggle)
What is the treatment of pituitary Cushing’s (Cushing’s disease)?
Hypophysectomy (transsphenoid route) and external radiotherapy if recurs, bilateral adrenalectomy
How are ectopic and adrenal Cushing’s syndrome treated?
Adrenal = adrenalectomy Ectopic = remove source or bilateral adrenalectomy
What drugs are used to treat Cushing’s syndrome?
Metyrapone = if other treatments fail/while waiting for radiotherapy, side effects common
Ketoconazole = hepatotoxic
Pasireotide LAR = 10-20mg monthly
What hormones are affected by anterior hypopituitarism?
GH (growth failure), TSH (hypothyroidism), LH/FSH (hypogonadism), ACTH (hypoadrenal)
What occurs in posterior hypopituitarism?
Diabetes insipidus
What can cause hypopituitarism?
Pituitary tumours, brain tumours, iatrogenic (surgery), TB, histiocytosis X, sarcoidosis, polyarteritis, trauma, secondary metastases, syphilis, meningitis, autoimmune, infection
What are some symptoms of anterior hypopituitarism?
Menstrual irregularities, infertility and impotence, gynaecomastia, abdominal obesity, loss of facial hair, loss of axillary and pubic hair, dry skin and hair, hypothyroid faces, growth retardation
How can hypopituitarism be investigated?
Check anterior pituitary hormones
What is the replacement therapy for hypopituitarism?
Thyroxine = 100-150mcg/day
Hydrocortisone = 10-25mg/day, split 2-3 times per day
ADH = desmospray (nasal) or desmopressin tablets
GH = nightly
Sex steroids
What are the benefits of growth hormone (GH) replacement in hypopituitarism?
Given by daily SC injection = improves well being and quality of life, decreases abdominal fat, increase muscle mass/strength/exercise capacity/stamina, improves cardiac function, improves bone density
How is testosterone replacement given in hypopituitarism?
IM injection every 3-4 weeks (sustanon), skin gel (testogel, tostran), prolonged IM injection 10-14 weeks (nebido)
What are the risks of testosterone replacement?
Prostate enlargement = monitor PR exam and PSA at start
Polycythaema = cause risk of stroke/MI, monitor FBC
Hepatitis (oral tablets only) = monitor LFTs
What are the causes of diabetes insipidus?
Familial = isolated in most cases, DIDMOAD Acquired = idiopathic (50%), trauma, tumour, sarcoid, meningitis
How are water deprivation tests carried out?
For 8-12hrs
Check serum and urine osmolarities for 8h and then 4h after giving IM DDAVP
What do the results of a water deprivation test indicate?
If urine/serum osmol ratio >2 then is normal (otherwise DI)
If low and improves after DDAVP then is due to cranial DI (deficiency of DDAVP and not nephrogenic DI)
How is diabetes insipidus treated?
Desmospray = nasally, 10-60mcg/day
Desmopressin oral tablets = 100-1000mcg per day
Desmopressin injection = 1-2mcg IM per day (emergency or post-pituitary surgery)
