Thyroid disorders Flashcards
what are the symptoms of hypothyroidism?
weight gain cold intolerance slow reflexes slow speech constipation heavy periods dry skin/hair bradycardia goitre if severe- puffy eyes, swollen tongue, hoarseness, coma
what are the symptoms of hyperthyroidism?
weight loss heat intolerance anxiety/irritability bowel infrequency sweaty palms light periods hyperreflexia / tremor goitre thyroid eye disease
if there is raised TSH and low T3, T4 what is this?
primary hypothyroidism
if there is low TSH and normal T4,T3 what is this?
subclinical (compensated) hypothyroidism
if there is low TSH and low T3, T4, what is this?
secondary hypothyroidism
what are causes of acquired hypothyroidism?
hashimotos autoimmune
iatrogenic;
- post radioactive iodine (treatment for hyperthyroidism)
- radioactive iodine for H & N cancers
chronic iodine deficiency
post partum thyroiditis
what are the causes of secondary hypothyroidism?
pituitary tumour craniopharyngioma post pituitary surgery or radiotherapy sheehans syndrome isolated TSH deficiency
if you suspected hyperthyroidism, what investigations would you carry out?
TSH
Thyroxine
autoantibodies
FBC lipids hyponatraemia increased muscle enzymes hyperprolactinaemia
what is the treatment for hypothyroidism?
levothyroxine tablets
when would you treat subclinical hypothyroidism?
if TSH >10
of if TSH >5 with positive thyroid antibodies
or TSH elevated with symptoms
what are the risks with over treatment of thyroxine?
osteopenia
AF
what are physiological causes of goitre?
puberty
pregnancy
what are the different types of goitre?
diffuse goitre multi nodular solitary nodule cyst adenoma, carcinoma, lymphoma miscellaneous i.e. sarcoidosis
how would you investigate a solitary nodular goitre?
TFT’s
USS
FNA
isotope scanning of low TSH
what are differentiated thyroid cancers?
papillary
follicular
lymphoma
what are the non differentiated thyroid cancers?
medullary
anaplastic
what thyroid cancer spreads via lymphatics?
papillary
where does follicular thyroid cancer spread to?
bone
lung
what is the treatment for differentiated thyroid cancers?
radioiodine
near total thyroidectomy
what is the thyroid cancer marker?
thyroglobulin
what is the treatment for medullary thyroid cancer?
prophylactic thyroidectomy
what is the treatment for anapaestic thyroid cancer?
external radiotherapy
what thyroid cancer arises from parafollicular C cells?
medullary
what thyroid cancer is associated with MEN 2 and what is this associated with?
medullary
phaechromocytoma & hyperparathyroidism
in what thyroid cancer is the serum Ca level raised and why?
medullary
because it is associated with MEN 2 which can cause hyperparathyroidism
does thyrotoxicosis result in hyper or hypothyroidism?
hyper
what are the primary causes of hyperthyroidism?
autoimmune hashimotos
toxic multi nodular goitre
toxic adenoma
what are the causes of thyrotoxicosis without hyperthyroidism?
excessive thyroxine administration
destructive thyroiditis - post partum, amiadorone induced, subacute
what is the presentation of sub acute (de Quervain’s) thyroiditis?
presents with hyperthyroidism for 3-6 weeks then hypothyroidism occurs for the following 3-6 months
often recall having painful goitre +- fever, malaise, myalgia
what is the treatment for hyperthyroidism?
anti thyroid drugs;
- carbimazole & propylthiouracil
(titration regimen)
steroids
radioiodine
betablockers
what are the side effects of anti thyroid drugs?
rash
agranulocytosis
what is the difference in the initial treatment of someone with hypothyroidism and also ischaemic heart disease?
start initial dose at 25mcg/day and slowly titrate up every 2-4 weeks until it reaches 75-100mc/day
(normally would start at 50mcg/day)
when would you treat subclinical hypothyroidism?
if TSH > 10 even with no symptoms
if TSH > 5 if positive thyroid antibodies
always treat if they have definitive symptoms
always treat if they become pregnant
what is the change in treatment of hypothyroidism in pregnancy?
double levothyroxine dose
is thyroxine treatment for post part thyroiditis life-long?
no
trial withdrawal within 6-12 months
what is myxedema coma and how do you treat it?
severe hypothyroidism resulting in a coma
treat with IV T3 and IV steroid
What drugs can cause hypothyroidism?
Amiadorone
Lithium
Interferon
What precipitates sub acute thyroiditis (De Quervains syndrome)
Viral infection
What is the cause(s) of secondary hyperthyroidism?
TSH secreting pituitary adenoma
What can cause thyrotoxicosis without hyperthyroidism?
post partum thyrotoxicosis
sub acute syndrome
Drug induced I.e. amiadorone
Excessive thyroxine administration
what is the action of goitrogens?
goitrogens disrupt the thyroid’s ability to produce thyroid hormones by interfering with iodine uptake in the thyroid gland
this results in the pituitary producing more TSH due to reduced negative feedback
what causes thyrotoxicosis without hyperthyroidism?
post partum thyroiditis
sub acute (De Quervains syndrome)
amiadorone induced
excessive thyroxine administration
what does sheehan’s syndrome cause?
secondary hypothyroidism
post partum haemorrhage or hypotension damages the pituitary
what triggers sub acute (de Quavairns) syndrome and how do you treat it?
triggered by virus i.e. enteroviruses - coxsackie
May require short term steroids NSAIDS
