Endocrinology Flashcards
(30 cards)
Tests for acromegaly
Serum IGF1 (GH acts via IGF1) OGTT - failure to suppress GH (false positive in anorexia, wilson's, opiate addicition) Pituitary function test MRI brain
Rx for acromegaly
Somatostatin analogues - octerotide, lanreotide
Dopamine agonists - bromocriptine, cabergolien –> more for tumours co-secreting prolactin
transphjenoidal hypophysectomy (remove pituitary)
Symptoms of hyperprolactinaemia & Rx
Decreased libido, irregular periods Impotence hypogonadism galactorrohea gynaecomastia
All because reduced GnRH release in hypothalamus –> feedback
Rx = Cabergoline or bromocriptine (dopamine agonist)
causes of Adrenal insufficiency
Primary
Autoimmune = Addison’s disease
TB, meningococcal septicaemia, CMV, infiltration w/ mets or amyloidosis, infarction, bilateral adrenelectomy,
2º = pituitary disease 3º = hypothalamic disease
iatrogenic = steroid therapy
Signs and symtoms of Adrenal insufficiency
Dizziness, anorexia, wt loss, D&V, abdo pain, weakness, depression
Postural hypotension
Increased pigmentation - scars, buccal mucosa, skin creases
Loss of body hair in women
Addisonian crisis - hypotensive shock, tachycardia, pale, clay, oliguria, precipitated by infection or surgery
Adrenal insufficiency Ix
9am cortisol <100 = diagnostic,
if 100-550 do short synthACTHen test –> serum cortisol <550 after 30 mins = adrenal failure
Rx for addisonian crisis
Rapid IV fluid resus
50ml of 50% dextrose
200mg IV hydrocortisone bolus followed by 100mg 6hrly until BP stable
Treat cause
Rx for chronic adrenal insufficency
Hydrocortisone 3x a day –> double dose if illness or stress
Mineralocroticoid replacement w/ fludrocortisone
if also have hypothyroidism, replace hydrocortisone first or will get an addisonian crisis
Carcinoid symptom Hx and Ex
Usually small bowel carcinoma secreting serotonin –> appendix, rectum
hormones release are metabolised in liver, so don’t usually have symptoms until hepatic mets (release hormones into veins), or release into systemic circulation from bronchial or retroperitoneal tumours
Paroxysmal flushing telangiectasia diarrhoea crampy abdo pain whjeeze sweating palpitations Right sided murmurs - TS, TR or PS Nodular hepatomegaly if metastatic Dietary tryptophan defiecency = niacin deficiency= pellagra --> diarrhoea, dementia, dermatitis
Carcinoid crisis - profound flushing, bronchospasm, tachycardia, fluctuating blood pressure
Ix for carcinoid syndrome
24h urine 5-HIAA (false positive w/ bananas, avocados, c caffeine, paracetamol)
Blood - plasma chromogranin A and B, fasting gut hormones
CT/MRI to localise tumour
Radiolabelled somatostatin analogue
Rx for carcinoid syndrome
If crisis - octerotide infusion, IV antihistamine and hydrocortisone
Avoid precipitating factors
Octerotide inhibits hormone release and tumour growth
Interferon α can be used alone or with octerotide
Supportive = ondansetron and cyphrohepatadine (5HT antagonists)
Surgery if resectable
21-hydroxylase deficency
Decreased aldosterone, decreased cortisol, increased androgens
Salt losing crisis - hypotension, hyponatraemia, hyperkalaemia –> give saline, dextrose, hydrocortisone
Males - precocious puberty
Female - ambiguous genitalia, hirtuism
High 9am follicular phase 17OH progesterone and high testosterone
ACTH stimulation = inappropriate elevated 17OH progresterone after IM synthactetin
Rx - dexamethasone/hydrocrotisone + fludrocortisone
11ß hydroxylase
raised 11 deoxycorticosterone, a mineralocorticoid –> hypertension, hypokalaemia
Raised androgens
raised 9am follicular phase 17OH progesterone and testosterone
Congenital adrenal hyperplasia
AR disease
Defect in one of the enzymes in steroidogenesis
Decreased cortisol –> Inceeaaed ACTH –> hyperplasia and build up of precursors (usually androgens)
This causes infertility, especially in women, if not treated w/ steroids to suppress ACTH and androgen formation
If pursuing fertility - give steroids, can use cloiphine to women
If not pursuing fertility - oral contraceptives or cyproterone acetate (anti-androgen)
If women gets pregnant, check partner for CAH –> if he carries/has it, foetus can have CAH and get virilised (female foetus gets male features wo/ testicles) –> give dexamethasone in all pregnancies
17 α hydroxylase
Increased aldosterone - HTN, hypokalaemia
Decreased androgens
Ambigous male genetalia
Females - failure to develop 2º sexual characteristics at puberty
Low dose dexamethasone test
failure to suppress cortisol = cushing’s
High dose dexamethasone test (and inferior peetrosal sinus sampling )
Not often done any more as can inferior peetrosal sinus sampling
if in inferior peetrosal sinus sampling central ACTH is 2x more than peripheral ACTH (or 3x larger after CRH admission) = pituitary disease –> shows high ACTH release from pituitary
in high dose dexamtheasone test, if there is a pituitary adenoma there will be suppression of cortisol as there’s still some feedback mechanism,
if there is ectopic ACTH release, it will fail to suppress at high dose
Cushing’s disease
1º disease of the adrenals (adenoma or carcinoma) - high cortisol, low ACTH
2º of pituitary (adenoma = Cushing’s disease) - high ACTH, high cortisol
ectopic release e.g small cell lung carcinoma or pulmonary carcinoid syndrome - very very high ACTH, high cortisol
note raised ACTH will cause pigmentation
also glucocorticoids also have a mineralocorticoid effect so might get HTN
Treat the tumour + can use metryapone or keotconazole to suppress cortisol synth
Cranial diabetes insipidus
failure to release ADH Idiopathic tumours - pituitary infiltrative - sarcoidosis Infection - meninigits Vascular - anneyrusm Trauma - head injury
Will fail to concentrate urine (osmolarity >600) on water deprivation, but urine osmolarity will rise >50% when desmopressing given
Rx= desmopressin intransailly
Nephrogenic diabetes insipidus
Kidney does't respond to ADH Idiopathic Drugs (lithium) Post-obstructive uropathy pyelonephritis pregnancy osmotic dieresis e.g DM
Will fail to increase urine osmolarity both with water deprevation and w/ desmopressin
Rx = Sodium + protein restriction, thiazide diuretics
Conn’s syndrome vs other 1º aldosteronism
Conn’s syndrome = adrenal adenoma –> adrenalectoym
Other cause is hyperplasia of the adrenal cortex –> Rx = spironalactone/epleronone
Both cause hypokalaemia (muscle weakness, nephrogenic DI, paraesthesia, tetany) and HTN
Both have low blood K+, high urine K+, high aldosterone concentration and high aldosterone:renin ratio
Both fail to suppress following salt load
CT/MRI helps visualise adrenals
Postural test - test aldosterone, renin and cortisol lying down at 8am, and then after 4hr of being upright
Adenomas are ACTH sensitive which drops after morning so will suppress aldosterone release a bit
Bilateral adrenal hyperplasia responds to posture so will increase renin and aldosterone
Primary hyperparathyroidism vs 2º
Primary = raised calcium, decreased phosphate
2º (chronic renal failure or vit D deficiency) –> low.normla calcium, caused phosphate, decreased vit D
long term 2º can cause 3º - like 1º
raised Ca causes stones bones moans groans.
Rx for hypercalcaemia = IV fluids then avoid thiazide diuretics and maintain hydration
Rx for raised PTH - parathyroidectomy (usually subtotal)
1º vs 2º hypogonadism
1º = hypergonadotrophic (high FSH and LH) –> gonadal dysgenesis (e.g Turners, Kelinfelters, undescended testits), or damage (mumps, torsion, trump, autoimmune, surgery)
2º = hypogonadotrophic (low FSH and LH) —> functional (stress, anorexia), hyperprolactaemia (prolactinoma causes pituitary stalk compression and suppresses GnRH), pituitary tumours, Kallmann;s
Signs of Paget’s disease of bone
Insidious onset pain aggravated by wt bearing and movement
headaches
Bitemporal skull enlargement with frontal bossing
Spinal kyphosis
anterolateral bowing of femur, tibia and forearm
Skin over involved bone is warm
Sensorineural deafness due to compression of vestibulecholear nerve
Increased all phos
X-ray - enlarged deformed bones w/ mixed lytic/scleoritc appearance
Bone scan = hot spots are active areas
