Hyperthyroid Flashcards
Definition
excess thyroid hormone, usually T4 thyroxine. Usually due to glandular hyperfunction.
T3 is tri iodothyronine.
Aetiology
-Hyperthyroid causes- Graves MOST COMMON (Ab activation of TSH R). AI. toxic goitre or adenoma iodine exposure struma ovarii metastatic differentiated thyroid CA TSH secreting pituitary adenoma -Non hyperthyroid causes- Exogenous thyroid hormone eg drugs, supplements, meat. Thyroiditis Pregnancy, amiodarone, IFNa.
Symptoms
Weight loss BUT VERY GOOD APPETITE. Diarrhoea or hyperdefecation Restless, nervous, emotional, irritable. Sweats Heat intolerance Palpitations Tremor Oligomenorrhoea infrequent, possible infertility Weaknessm, tiredness Insomnia Atypical CP and SOB on exertion. Rare- psychosis, chorea, panic, itch, alopecia, urticaria.
Signs
Fast irregular pulse Systolic HTN with increased PP. Warm moist skin Fine tremor Hyper reflexive Palmar erythema Thin hair Lid lag and retraction Possible goitre, nodules, bruit. Graves signs- exophthalmos (adipose accumulation), clubbing, goitre.
Management
BB to alleviate SNS manifestations eg palpitations, tremor, anxiety.
Thionamides inhibit thyroid hormone biosynthesis by competitive inhibition of iodine organification and iodotyrosine coupling.
Carbimazole inhibits peroxidase incorporation of iodine into TG.
Radioactive iodine
Saturated solution of K iodide or lugols solution inhibit thyroid hormone synthesis and release ST.
Surgery
For thyroid storm- antipyretics, BB, thionamides, iodinated contrast agents, GCs.
Complications
Thyorotoxicosis- rapid irregular HR, high temp, vomiting, diarrhoea, agitation.
Tx with antithyroid drugs and BBs.
Diagnosis
TSH levels low due to negative feedback high circulating T3 and 4. Screen for serum TSH R Abs. Graves- normocytic anaemia, neutropenia. Can get high ESR, Ca, LFT. Test eye function.
Thyroid hormones
T3 more potent than T4 but shorter t1/2.
Much more T4 is produced than T3 but peripheral conversion.
99% bound to eg TBG in plasma, T4 with higher affinity.
T4 used to treat hypothyroid as longer t1/2
Explanation
- hyperthyroid is when you have too much thyroid hormone in your blood. Most commonly because of your own immune system activated the thyroid gland to make it. Thyroid hormone has many actions on the body but in general it tends to speed things up. So you get symptoms like diarrhoea, sweats, palpitations, tremors.
- if not treated and the hormone levels keep going up it can progress to a condition called thyrotoxicosis which can be very dangerous. You get a very high temperature and heart rate.
- lifestyle treament doesnt play a very big part. Other than compliance with your treatment. It shpould be well controlled. Also look out for signs of toxicosis.
- drug treament ncludes tablets to reduce the amount of hormone produced. We will also give you some tablets to reduce your raised heart rate to stop the palpitations. If this doesnt work we can try things like radioactive treatment and even surgery. But with medication you should be able to manage it quite normally and live a normal life.