Hyperthyroidism Flashcards
What age is mainly affected?
20-40 yrs
What are the main causes of hyperthyroidism?
- Graves disease
- Toxic multi nodular goitre
- Toxic thyroid adenoma
- De Quervains’s thyroiditis
- Drug induced - amiodarone
How does hyperthyroidism present?
- palpitations
- diarrhoea
- WL + increased appetite
- Oligomenorrhoea +/- infertility
- Heat intolerance
- Irritability/behavioural change
- Tremor
- Hyperkinesis
- Proximal myopathy + muscle wasting
- Palmar erythema, fine tremor
- Diffuse goitre
- Lid lag + stare
What features can occur in elderly in hyperthyroidism ?
AF
Other tachycardias and/or HF
What features can occur in children in hyperthyroidism?
XS height or growth rate
Behavioural problems - hyperactivity
What signs are specific to Graves disease?
- Eye disease - exophthalmos, ophthalmoplegia
- Pretibial myxoedema
- Thyroid acropachy - clubbing, painful finger + toe swelling, periosteal reaction limb bones
What tests would u do to diagnose hyperthyroidism?
TFTs:
- TSH suppressed
- T3+T4 raised - diagnostic
What tests would u do to differentiate the cause of hyperthyroidism?
US of thyroid - diff between Graves + toxic adenoma
TSH receptor stimulating abs (TSHR-Ab) raised - diagnostic of Graves
What is Graves disease?
autoimmune induced XS production of thyroid hormone
What sex is graves more common in?
females
What age does graves typically present?
40-60
What are the RFs of Graves?
- Female (onset common postpartum)
- Genetic - HLA-B8, DR3 + DR2
- Smoking
Explain the pathophysiology behind Graves disease
TSH receptor stimulating antibodies (TSHR-Ab) - serum IgG abs specific for Graves - bind to TSH receptors in the thyroid
Stimulate T3 + T4 production
Results in XS secretion of thyroid hormones + hyperplasia of thyroid follicular cells -> hyperthyroidism + diffuse goitre
What is toxic multi nodular goitre?
nodules secrete thyroid hormones
What is de quervains thyroiditis?
transient hyperthyroidism resulting from acute inflammation of the thyroid gland
How does amiodarone lead to hyperthyroidism?
high iodine content
What are medical treatments of hyperthyroidism?
- Antithyroid drugs -carbimazole or thiamazole
- Propanolol - control sx
OR - Radioactive iodine
What are surgical options for hyperthyroidism? when are they indicated?
thyroidectomy
I: large goitre, malignancy suspected, mod-severe active Graves
What are the different regimens of medical treatment ?
- Titration
2. Block-replace therapy - oral carbimazole + thyroxine - less risk of hypothyroidism
What is the main SE of carbimazole? what do u need to watch out for
AGRANULOCYTOSIS - severely low WBC, most commonly neutropenia
Watch out for: sore throat, mouth ulcers, fevers
When is radioactive iodine contraindicated?
pregnancy
breast feeding
How Does radioactive iodine therapy work? ow long does it take to work?
iodine needed for thyroid hormone production so readily taken up by thyroid gland
accumulates and results in local irradiation
takes 4-12 weeks
What re SE of radioactive iodine therapy?
discomfort in neck + hyperthyroidism initially
How should you manage patients medically before thyroidectomy?
Stop antithyroid drugs 10-14 days before
Give potassium iodide to reduce vascularity of gland
What are complications of thyroid surgery?
tracheal compression from post-op bleeding
Laryngeal nerve palsy
Transient hypocalcaemia due to removal of parathyroid gland
what is the main hyperthyroid emergency?
THYROID STORM
Rapid deterioration of thyrotoxicosis - rapid T4 increase
What are the features of thyroid storm?
Hyperpyrexia Tachycardia Agitation + confusion coma eventually death
What are the precipitants of thyroid storms/
Recent thyroid surgery Radioactive iodine therapy Infection MI Trauma
What is the management of thyroid storm?
- IV access, fluids, NG if vomiting
- Take bloods for T3, T4, TSH, cultures - don’t wait for results to treat
- Sedate if necessary e.g. chlorpromazine
- Propanolol max IV dose 1mg over 10min, if CI, diltiazem
- CARBIMAZOLE 15-25mg/6hr PO or propulthiouracil, after 4h give Lugol’s solution
- Hydrocortisone 100mg/6hr
- Rx suspected agitation
