Hyperthyroidism Flashcards by Holly Grey

What are the signs + symptoms?

Brittle hair/hair loss
Reduced focus
Enlarged thyroid
Increased metabolism (weight loss)
Diarrhoea
Muscle weakness
Sweating

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What can be a result of hyperthyroidism?

Graves’ disease
Nodular disease
Thyroiditis

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What is Graves’ disease?

Eyelids retract
Bulging eyes
Redness

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What is nodular disease?

Thyroid grows nodules
Single or multinodular goiter
Women over 60

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What is thyroiditis?

Inflammation of thyroid follicles

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What is thyroiditis caused by?

Infection, trauma, drug induced or autoimmune
= T3/T4 leak from inflamed cells

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How do you diagnose?

Symptoms
TFTs
- TSH
- FT4
- FT3
TRABs

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What does TFT show if hyperthyroidism of thyroidal origin?

TSH low
BUT FT4 + FT3 raised

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What does a definitive diagnosis require?

2 sets of TFTs taken at least 6 weeks apart

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What does TFT show if hyperthyroidism of extrathyroidal origin (pituitary/hypothalamic disease)?

TSH raised
FT3 + FT4 raised

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What is thyroiditis confirmed with?

TRABs

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What do you conduct if TRABs test comes back negative?

Radioactive iodine uptake scanning

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What are the aims of treatment?

Acute = manage symptoms
Chronic = effectively supress thyroid hormone

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What are the choices for treatment?

Antithyroid drugs
Radioactive iodine
Thyroidectomy

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What is 1st line for Graves’ disease if likely to go into remission?

Thionamides
Carbimazole

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What is 1st line for Graves’ disease if unlikely to go into remission?

Radioactive iodine

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What is 1st line for Graves’ disease if concerns regarding compression/malignancy?

Thyroidectomy

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What is 1st line for multinodular goitre?

Radioactive iodine
2nd line = thionamides/thyroidectomy

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What is 1st line for single nodular?

Radioactive iodine/surgical intervention
2nd line = thionamides

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What is 1st line in pregnancy?

Thionamides/propylthiouracil
2nd line = thyroidectomy

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What is contraindicated in pregnancy + breastfeeding?

Radioactive iodine
= potentiate thyroid hormone release = precipitate thyroid crisis = teratogenic

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What is 1st line for children with Grave’s disease?

Thionamides/carbimazole

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What is 1st line for children with MNG/SN?

Thionamides
Long term = risk/benefits of radioactive iodine/thyroidectomy

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What are the most common antithyroid (thionamides) drugs?

Thionamides
Carbimazole (1st line unless pregnant)
Propylthiouracil

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How long does it take to see therapeutic effect with thionamides?

6-8 weeks

What are the choices for regime with thionamides?

Titration OR Block + replace = high dose = destroy + terminate thyroid hormone = given alongside with levothyroxine

What is carbimazole?

Pro-drug undergoes hepatic metabolism = problem with liver?

How long does carbimazole take to show therapeutic effect?

4-8 weeks

What is the mechanism of action of carbimazole?

Inhibition of organification of iodine + thyroglobulin + coupling of iodothyronine residues = supress synthesis of thyroid hormones

What is the initial dose of carbimazole?

20-60mg daily dose in divided doses

How often should TFTs be checked with carbimazole?

Every 6-8 weeks

What happens once thyroid levels are within reference range, carbimazole?

Choose either "titration" or "block + replace" + continue for 12-18 months

What is the titration for carbimazole?

5-15mg OD Regular TFTs

What is block + replace for carbimazole?

High starting dose till production suppressed Levothyroxine alongside

What are the side effects of carbimazole?

Macropapular rash Bone marrow suppression

What do you do is patient develops macropapular rash?

Generic antihistamine

What do patients on carbimazole need to look out for?

Signs + symptoms of blood dyscrasis - FATAL

What are the signs + symptoms of blood dyscrasias? ANY SYMPTOMS = STOP MEDICATION

Sore throat Bruising Bleeding Mouth ulcers Fever Malaise

What should be done to prevent blood dyscrasias?

Full blood count every 6 months

What are the contraindications of carbimazole?

Severe hepatic impairment pre-existing blood disorders History of pancreatitis (check amylase)

What is the counselling for carbimazole?

Need for additional medications for symptoms 6-8 weeks to work Urgency of reporting symptoms of blood dyscrasias Start contraception = teratogenic Intensify effects of warfarin

What is the mechanism of action of propylthiouracil?

Inhabitation of enzyme peroxidase

What is propylthiouracil used for?

2nd line for contraindications/side effects/with carbimazole/pregnancy

What are the side effects of propylthiouracil?

Macropapular rash Severe hepatic reaction Bone marrow suppression

What are the contraindications of propylthiouracil?

Hepatic impairment Pre-existing blood disorders History of pancreatitis

What is the monitoring for propylthiouracil?

Every 6 weeks (TSH, T4, T3) till in reference range THEN every 3 months until complete

What is the aim of radioactive iodine?

Resolve hyperthyroidism without post-ablation hypothyroidism

What are the physician choices for radioactive iodine?

Fixed dose Adjusted dose dependent on size of thyroid Adjusted dose to administer specific dose of radiation

What problem with radioactive iodine?

Radioactive for up to 6 weeks 14 days after = no close contact Avoid contact with pregnant women + children for 24 days

How long must thionamides be stopped before radioactive iodine?

1 week prior

How long will radioactive iodine take to have an effect?

2-3 months

What happens in severe cases?

Antithyroid medications restarted 3 days post op Normally safe not to restart

What is the monitoring for radioactive iodine?

Measure TSH every 6 weeks until within reference range Stop antithyroid medication once in range

When is a thyroidectomy vital?

Symptoms of windpipe compression

What is the surgical intervention of SND?

Partial or hemi-thyroidectomy

What is the surgical intervention of MND?

Dependent on nodule effected

What must you start post-thyroidectomy?

1.6mcg/kg levothyroxine immediately after

What is a hyperthyroid crisis?

Manifestation of thyrotoxicosis = overproduction of thyroid hormones

What are the symptoms of thyroid crisis?

Hyperthermia Dehydration Tachycardia (>140bpm) Atrial dysrhythmias Hypotension Sweating N/V/D/abdominal pain Confusion/agitation

What are the 4 mechanisms of treatment for thyroid crisis?

Inhibition of thyroid hormone synthesis Inhibition of thyroid hormone release Inhibition of peripheral action of excess thyroid hormone Supplementary management

What is used for inhibition of thyroid hormone synthesis for thyroid crisis?

20-30mg carbimazole every 4-6hrs Oral/NG/rectal

What is used for inhibition of thyroid hormone release for thyroid crisis?

Iodine BUT need to leave at least an hour between anti thyroid medication + iodine

What is used for the inhibition of peripheral hormone action for thyroid crisis?

Propranolol IV 1-2mg every 15mins until HR controlled MAX 10mg Cardioselective if COPD or asthma

What is used for supplementary management for thyroid crisis?

Paracetamol = antipyretic effects Cholestyramine 4g every 6-12hrs = enhance thyroid hormone excretion