Hyperthyroidism Flashcards
secondary hyperthyroidism is due to?
excess stimulation by TSH
graves disease
autoimmune disease, TSH receptor antibodies, mimic TSH and cause secretion of thyroid hormone- most common cause
what is plummer’s disease?
toxic multinodular goitre, nodules act independently from feedback system and continuously produce thyroid hormone
exopthalmos?
bulging of eyeball due to Graves, inflammation swelling and hypertrophy of tissues behind eyeball
pretibial myxoedema?
deposits of mucin under skin on legs- discoloured waxy oedematous. Graves- reaction of tissues to the TSH receptor antibodies
pretibial myxoedema?
deposits of mucin under skin on legs- discoloured waxy oedematous. Graves- reaction of tissues to the TSH receptor antibodies
features of hyperthyroidism?
anxiety irritability, sweating, heat intolerance, fatigue, tachycardia, weight loss, frequent loose stools, sexual dysfunction, palpitations, high output cardiac failure, thyroid acropathy (extremities), clubbing, oligomenorrhoea, diarrhoea
graves disease features?
diffuse goitre no nodules
exopthalmos
pretibial myxoedema
toxic multinodular goitre features?
goitre with firm nodules
> over 50 years
second most common cause of thyrotoxicosis
solitary toxic thyroid nodule?
benign adenoma, treated with surgery
de quervain’s thyroidits features?
hyperparathyroidism, viral infection, fever, dysphagia, neck pain and tenderness
what is special about de quervain’s thyroiditis?
hyperthyroid phase followed by hypothyroid phase (TSH fall due negative feedback) then back to normal
what is special about de quervain’s thyroiditis?
hyperthyroid phase followed by hypothyroid phase (TSH fall due negative feedback) then back to normal
treatment of de quervain’s thyroiditis?
supportive self limiting, NSAIDs and beta blockers for symptomatic relief
thyroid storm?
acute severe hyperthyroidism causing pyrexia, tachycardia and delerium
thyroid storm treatment?
admit, supportive care: fluid, anti-arrhythmic drugs and beta blockers
side effect of propythiouracil?
small risk hepatic reactions- death
management of hyperthyroidism?
carbimazole 12-18months. Usually 4/8 weeks maintenance normal levels titration block or block all production and then replace levothyroxine
side effect of carbimazole?
acute pancreatitis
carbimazole and propylthiouracil can both cause?
agranulocytosis (low white cell count) which makes patient vulnerable to severe infection- (sore throat)
radioactive iodine remission can take?
6 months, may require levothyroxine
rules of radioactive thyroxine?
not get pregnant and breastfeed within 6 months of treatment
men should not father children within 4 months of treatment
limit contact with people after dose 3 weeks
what should be given for hyperthyroidism for adrenalin-related symtoms?
propanolol
what is definitive option for thyroid storm?
thyroidectomy, patient will require levothyroxine after
causes of thyrotoxicosis?
Graves’ disease
toxic nodular goitre
acute phase of subacute (de Quervain’s) thyroiditis
acute phase of post-partum thyroiditis
acute phase of Hashimoto’s thyroiditis (later results in hypothyroidism)
amiodarone therapy
contrast (elderly patients with existing thyroid disease)
what do you find in thyrotoxicosis?
TSH down, T3/4 up
thyroid autoantibodies
isotope scanning
De Quervain’s thyroiditis ?
hyperthyroidism following viral infection
4 phases of subacute thyroiditis?
- 3-4 weeks hyperthyroidism, painful goitre raised ESR
- 1-3 weeks euthyroid
- weeks-months hypothyroidism
- thyroid structure and function goes back to normal
investigation for subacute thyroiditis?
thyroid scintigraphy (globally reduced uptake of iodine 131)
treatment of de quervains thyroiditis?
NSAIDs, steroids if severe
thyroid eye disease affects what percent of people with graves?
25-50%
pathophysiology of thyroid eye disease?
autoimmune response against an autoantigen, TSH receptor to retro-orbital inflammation. inflammation results in glycosaminoglycan and collagen deposition in the muscles
prevention of thyroid eye disease?
smoking is a risk factor
radioiodine treatment may increase inflammatory symptoms , prednisolone may help reduce the risk
features of thyroid eye disease?
eu-hypo, hyperthyroid
exopthalmos
optic disc swelling
opthalmoplegia
conjunctival oedema
sore, dry eyes, because cant close
keratopathy
management of thyroid eye disease?
topical lubricant prevent corneal inflammation
steroids
radiotherapy
surgery
urgent referral to opthalmologist witht hyroid eye disease if?
unexplained deterioration in vision
awareness of change in intensity/quality of colour vision
history of eye suddenly popping out
obvious corneal opacity
cornea still visible when eyelids are closed
disc swelling
thyroid storm is not usually seen in?
iatrogenic thyroxine excess
precipitating events of thyroid storm?
thyroid/non thyroid surgery
trauma
infection
acute iodine load CT contrast media
clinical features of thyroid storm?
fever over 38.5
tachycardia
hypertension
heart failure
n/v
abdnormal LFTs, jaundice
confusion and agitation
management of thyroid storm?
symtomatic- paracetamol
treatment of underlying event
beta blockers - iv propanolol
anti thyroid drugs- methimazole, propylthiouracil
lugol’s iodine
dexamethasone- 4mg IV qds- blockks conversion of t4 to t3
sick euthyroid syndrome?
TSH,T3 or T4 low or TSH may be within normal range.
no treatment is needed ad changes are reversible on recovery
carbimazole?
Used for thyrotoxicosis. High doses for 6 weeks until patient is euthyroid then reduced.
mechanism of action for carbimazole?
blocks thyroid peroxidase from coupling and iodinating tyrosine residues on thyroglobulin hence reducing thyroid hormone production.
what is mechanism of action of propylthiouracil?
blocks thyroid peroxidase from coupling and iodinating the tyrosine residue on thyroglobulin and hence reduced thyroid hormone production.
ALSO inhibits 5’ deiodinase which reduced peripheral conversion of T4 to T3
adverse effects of carbimazole?
agranulocytosis
crosses placenta
What is pretibial myxoedema due to?
accumulation of excess glycosaminoglycans in the dermis and subcutis of the skin. The main glycosaminoglycans hyaluronic acid made by fibroblasts
