Hyperthyroid

Question 1

Definition

Answer 1

excess thyroid hormone, usually T4 thyroxine. Usually due to glandular hyperfunction.
T3 is tri iodothyronine.

Question 2

Aetiology

Answer 2

-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.

Question 3

Symptoms

Answer 3

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.

Question 4

Signs

Answer 4

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.

Question 5

Management

Answer 5

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.

Question 6

Complications

Answer 6

Thyorotoxicosis- rapid irregular HR, high temp, vomiting, diarrhoea, agitation.
Tx with antithyroid drugs and BBs.

Question 7

Diagnosis

Answer 7

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.

Question 8

Thyroid hormones

Answer 8

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

Question 9

Explanation

Answer 9

• 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.