Endo 9.5 Flashcards
Causes of thyrotoxicosis?
Graves 50-60% toxic multinodular goitre acute phase subacute de Quervains thyroiditis acute phase postpartum thyroiditis acute phase Hashimoto's thyroiditis amiodarone Rx
triiodothyronine thyrotoxicosis - small subset who have isolated T3
Rx?
carbimazole
Drivers on insulin/sulfonylureas - who can drive?
HGV: - no severe hypo in 12m - full hypo awareness - has adequate control/monitoring - understands risks of hypo Car: - hypo awareness, not more than 1 hypo episode requiring assistance, no relevant visual impairment
Hypothyroidism Rx
- starting dose of thyroxine?
- therapeutic goal?
- in pregnancy?
- when is levothyroxine & liothyronin (T3) used?
- 50-100mcg OD but lower at 25mcg OD if elderly/have IHD and slowly titrate up
- check TFTs 8-12wks after a change in thyroxine
- TSH 0.5-2.5 i.e. normalisation of TSH
- increase dose by at least 25-50mcg thyroxine in pregnancy, monitor carefully
- Myxoedema coma: T3 has a greater biologic activity & faster onset than T4 so can be used until there’s clinical improvement (can also give steroid as often there’s coexistent adrenal insufficiency)
Side-effects of thyroxine Rx?
Interactions?
- osteoporosis
- worsening of angina
- AF
- hyperthyroid due to over-Rx
- iron reduces absorption of thyroxine - give 2h apart
Pathophys of DKA?
Dx criteria?
- uncontrolled lipolysis -> XS free fatty acids -> ketone bodies
- BM >11
- pH <7.3
- HCO3 <15
- ketones >3
Rx of DKA?
- isotonic saline
- correction of hypokalaemia
- FRII 0.1unit/kg/hr - start 5% dextrose once BM<15
- continue long-acting insulin
- may need to be slower rate in young as at risk of cerebral oedema - usually occurs 4-12h after starting but can occur at any time - if any suspicion, needs CT head & senior R/V
- If K 3.5-5.5 give 40mm KCl
- if <3.5 needs urgent senior R/V
Complications of DKA and its Rx?
- gastric stasis
- thromboembolism
- arrhythmias 2ry to high K/low K
- iatrogenic due to incorrect fluid Rx: cerebral oedema, low K, hypoglycaemia
- ARDS
- AKI
Congenital adrenal hyperplasia:
- autosomal rec disorders affecting adrenal steroid biosynthesis
- low cortisol -> high ACTH -> adrenal androgens -> virilise female infant
- enzyme deficiencies?
21-hydroxylase deficiency (90%) -> reduced cortisol & aldosterone -> high ACTH -> adrenal hyperplasia -> XS androgen: ambiguous genitalia, salt wasting, hypovolaemia, shock
-> can also be aSx with androgen XS a problem in later childhood: premature pubarche, accelerated bone age, acne, hirsutism, oligomenorrhoea, mimicking PCOS
11-beta hydroxylase deficiency (5%) - raised BP, raised androgens
17-hydroxylase deficiency (very rare) - raised aldosterone, low androgens
Hypopituitarism - adult GH deficiency - low peak GH levels in response to insulin-induced hypoglycaemia
- features?
- low ACTH: tired, postural hypotension
- low gonadotrophins: amenorrhoea
- low TSH: constipated
- can happen after e.g. pituitary mass removal
- assess dynamic pituitary function: insulin stress test (measure cortisol surge) BUT inducing hypoglycaemia in some is C/I
- next best test = glucagon stimulation test which mimics hypoglycaemia causing fake stress on pituitary
Onset/peak/duration of rapid-acting insulin analogues?
Onset 5mins Peak 1h Duration 3-5h - insulin aspart Novorapid - insulin lispro Humalog
Onset/peak/duration of Short-acting insulin?
Onset 30mins
Peak 3h
Duration 6-8h
- Actrapid, Humulin S
Onset/peak/duration of Intermediate-acting insulin?
Onset 2h
Peak 5-8h
Duration 12-18h
- isophane insulin
Onset/peak/duration of Long-acting insulin analogues?
Onset 1-2h Flat profile Duration upto 24h - insulin determir Levemir - insulin glargine Lantus
BM aim for T1DM?
5-7 on waking
4-7 pre-meal
5-9 90mins post-meal
Acromegaly Rx
1st line?
Drugs?
What may be used in older pts or if the above fails?
- trans-sphenoidal surgery
- Somatostatin analogue e.g. Octreotide directly inhibits GH release effective in 50-70% may be used as adjunct
- DA agonist eg Bromocriptine effective in only a minority
- SC PEGVISOMANT OD = GH receptor antagonist prevents dimerisation of GH receptor - v effective at decreasing IGF-1 levels in 90% to normal, but doesn’t reduce tumour volume
- external irradiation in older
- monitor IGF-1 every 6months (long half-life)
Addison’s Rx?
- glucocorticoid hydrocortisone eg BD/TDS 20-30mg/day
- mineralocorticoid
- do not miss doses, consider bracelet/steroid card
- sick day rules: double glucocorticoid
- take doses from waking if doing night shift/travelling as cortisol highly linked to diurnal rhythm
Kallmann’s syndrome: hypogonadotrophic hypogonadism -> delayed puberty
- X-linked recessive
- failure of GnRH-secreting neurons to migrate to hypothalamus
Features?
- delayed puberty
- hypogonadism, cryptorchidism
- anosmia
- low sex hormones
- LH, FSH inappropriately low/normal
- typically normal/above average height
- check HCG & FSH then IVF to restore ovulation/try for pregnancy
Features of Addisonian crisis?
hypotension hypothermia hypoglycaemia - classic hyponatraemia/hyperkalaemia doesn't often happen -> give IV hydrocortisone
Causes of hypokalaemia with alkalosis?
- vomiting
- thiazide & loop
- Cushings
- Conns
Hypokalaemia with acidosis?
- diarrhoea
- RTA
- acetazolamide
- partially Rx DKA
DDx with hypokalaemia, metabolic alkalosis & normal-low BP?
Next best Ix?
diuretic abuse
Bartter’s syndrome
Gitelman’s syndrome
- diuretic assay
hypokalaemia, metabolic alkalosis & normal-low BP
- triangular facies, polyuria, polydipsia, renal failure
high renin & aldosterone despite this
- urine calcium may be raised
- renal stones common
Dx?
Bartters syndrome
hypokalaemia, metabolic alkalosis & normal-low BP
- hypomagnaesaemia, hypocalciuria
Dx?
Gitelman’s syndrome
Hypercalcaemia Rx
IV fluids
bisphosphonates - take few days to work, max effect at day 7
(also calcitonin, steroids)
Tests to confirm Cushings syndrome?
- most sensitive is overnight dexamethasone suppression test
- screening 24h urinary free cortisol
Localisation tests for Cushing’s syndrome?
1st line 9am & midnight plasma ACTH & cortisol (if ACTH suppressed then ectopic i.e. non-ACTH-dependent cause likely)
2nd low/high dose dexamethasone suppression test
- if cortisol suppressed by high dose but not by low dose, then Cushing disease
- if cortisol not suppressed by low dose then Cushings syndrome e.g. 2ry to steroids
- if cortisol not suppressed by low/high then ectopic ACTH most likely
CRH stimulation: if pituitary source then cortisol rises
- if ectopic/adrenal then no change in cortisol
- petrosal sinus sampling of acth can help differentiate between pituitary & ectopic ACTH secretion
What is pseudo-cushings?
common in XS ETOH
- idiopathic
- diurnal variation is maintained
- elevated 24h urinary cortisol and will also fail to suppress serum cortisol with a low dose dexamethasone suppression test
Subacute granulomatous de Quervain’s thyroiditis post-viral
4 phases?
Ix?
Rx?
- hyperthyroid, tender goitre, raised ESR, 3-6wks
- euthyroid 1-3wks
- hypothyroid wks-months
- thyroid structure & function normalise
- thyroid scintigraphy: globally reduced uptake of iodine-131
- usually self-limiting, NSAIDs etc, steroids if severe
Pathophys of thyroid eye disease? Prevention? Features? Rx? Monitoring established eye disease?
- autoimmune response against autoAg, possibly TSH receptor -> retro-orbital inflammation -> glycosaminoglycan & collagen deposition in muscles
- stop smoking
- RADIOIODINE WORSENS it
- can be eu/hypo/hyperthyroid at presentation
- exophthalmos, conjunctival oedema, optic disc swelling, opthalmoplegia, exposure keratopathy
- topical lubricants, steroids, RT, surgery
- IV Methylpred if severe
Urgent R/V if:
- unexplained worsening vision, change in intensity/quality of colour vision, subluxation, corneal opacity, cornea visible when eyes closed, disc swelling
MEN type I?
PTH hypeprlasia 95% Pituitary 70% eg prolactinoma Pancreas eg insulinoma/gastrinoma/rec peptic ulcer also: adrenal & thyroid MEN1 gene commonest presentation = hypercalcaemia
MEN type IIa?
Medullary thyroid ca 70%
PTH 60%
Phaeochromocytoma
RET oncogene
MEN type IIb?
Medullary thyroid ca Phaeochromocytoma Neuromas Marfanoid body habits RET oncogene