Graves' Disease and Thyrotoxicosis

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Questions and Answers

What is the presumed reason for the fluctuation in the concentration of TRAb in the serum?

Presence of blocking antibodies against the TSH receptor

Tissue destruction by cytotoxic antibodies

Cell-mediated immunity

Natural history of Graves’ thyrotoxicosis (correct)

Which genetic component is strongly associated with Graves’ disease?

20%–40% concordance for thyrotoxicosis between monozygotic twins

HLA-DRß-Arg74 gene (correct)

Iodine supplementation in regions of iodine deficiency

Association with viruses or bacteria

What may trigger the development of thyrotoxicosis in genetically susceptible individuals?

Iodine supplementation in regions of iodine deficiency

Presence of blocking antibodies against the TSH receptor

Smoking

Infection with viruses or bacteria (correct)

Why can iodine supplementation precipitate thyrotoxicosis in regions of iodine deficiency?

Pre-existing subclinical Graves’ disease Signup and view all the answers

What is associated with the development of ophthalmopathy in Graves’ thyrotoxicosis?

Smoking Signup and view all the answers

What type of antibodies may result in thyroid failure in some patients?

Cytotoxic antibodies Signup and view all the answers

What plays a role in the management of symptoms of thyrotoxicosis?

β-blockade Signup and view all the answers

What is the approximate relapse rate for patients experiencing the first episode of thyrotoxicosis after taking antithyroid drugs?

50% Signup and view all the answers

What percentage of patients may experience hypothyroidism after undergoing thyroidectomy?

25% Signup and view all the answers

What is the most common cause of voice alteration following thyroid surgery?

Superior laryngeal nerve damage Signup and view all the answers

Which treatment is most likely to result in exacerbation of Graves’ ophthalmopathy?

Radio-iodine Signup and view all the answers

What is the main disadvantage of using antithyroid drugs in young patients?

High relapse rate Signup and view all the answers

When is radio-iodine treatment typically recommended as a first-line option?

Patients with recurrent thyrotoxicosis after antithyroid drug course Signup and view all the answers

Which treatment poses a risk of transient hypocalcaemia?

Thyroidectomy Signup and view all the answers

What should be measured in all patients before starting amiodarone therapy to minimize the risk of type I thyrotoxicosis?

TSH levels Signup and view all the answers

How should hypothyroidism be treated in patients on amiodarone therapy?

Levothyroxine Signup and view all the answers

What is the effect of very high concentrations of iodine on thyroid hormone synthesis and release?

Inhibition of thyroid hormone synthesis Signup and view all the answers

What phenomenon occurs after about 10 days of high iodine concentration, leading to the return to normal organification of iodine and thyroid peroxidase action?

Iodine escape phenomenon Signup and view all the answers

What is the rationale for iodine treatment in thyroid crisis and prior to thyroid surgery for thyrotoxicosis?

Inhibiting thyroid hormone release Signup and view all the answers

Why must an operation for an individual with Graves’ disease, who has been given iodine to prepare for surgery, happen within 10–14 days?

To prevent a significant relapse of thyrotoxicosis Signup and view all the answers

What may be precipitated by prophylactic iodinisation programs in iodine-deficient parts of the world?

Thyrotoxicosis Signup and view all the answers

What are the effects of iodine deficiency and underlying thyroid disease on the effects of iodine on thyroid function?

Reduces the effects of iodine Signup and view all the answers

What is the only lasting for about 10 days, followed by an 'escape phenomenon'?

Wolff-Chaikoff effect Signup and view all the answers

What management approach is recommended for nodules that are radiologically and/or cytologically indeterminate?

Surgical excision Signup and view all the answers

Which type of therapy may reduce the size of nodules in regions with borderline low iodine intake?

Levothyroxine therapy Signup and view all the answers

What is the recommended treatment for nodules with confirmed malignancy by formal histology?

Surgical excision Signup and view all the answers

In which condition may levothyroxine therapy shrink the goitre?

Hashimoto’s disease Signup and view all the answers

What might be required for a diffuse or multinodular goitre due to cosmetic reasons or compression of local structures?

Surgical treatment Signup and view all the answers

What is the most prevalent antibody-mediated autoimmune disease?

Graves’ ophthalmopathy Signup and view all the answers

$Autoimmune thyroid disease$ is associated with which other conditions?

$Autoimmune$ diseases Signup and view all the answers

Which treatment may result in exacerbation of Graves’ ophthalmopathy?

Levothyroxine therapy Signup and view all the answers

Which endocrine disorder is associated with Klinefelter syndrome?

Hypogonadism Signup and view all the answers

What is the main presenting problem in patients with gynaecomastia?

Enlarged breast tissue Signup and view all the answers

What is the most common cause of delayed puberty?

Hypogonadism Signup and view all the answers

Which condition is associated with spontaneous hypoglycaemia?

Cushing's syndrome Signup and view all the answers

What is the main functional anatomy involved in acromegaly?

Pituitary gland Signup and view all the answers

What is the primary functional anatomy affected by primary hyperparathyroidism?

Parathyroid glands Signup and view all the answers

What is the typical level of TSH that would confirm the diagnosis of primary hypothyroidism?

>20 mIU/L Signup and view all the answers

In patients with pituitary failure, at what level of TSH might it be detected at normal or modestly elevated levels?

Normal or modestly elevated levels Signup and view all the answers

Which antibody is highly sensitive but not very specific for autoimmune thyroid disease?

Thyroid peroxidase (TPO) antibodies Signup and view all the answers

What is the most appropriate course of action when secondary hypothyroidism is suggested?

Further investigation for pituitary tumour Signup and view all the answers

What is the usual abnormality in sick euthyroidism?

Low TSH levels Signup and view all the answers

In rare causes of hypothyroidism with goitre, which condition may be present?

Dyshormonogenesis Signup and view all the answers

What is the typical duration for resolution of any effusions after starting levothyroxine therapy?

3-6 months Signup and view all the answers

Which condition is rarely associated with hypothyroidism and hair texture changes?

'Pendred syndrome' Signup and view all the answers

What is the typical duration for resolution of voice alteration following thyroid surgery?

~3 months Signup and view all the answers

Study Notes

Thyroid Disorders

Fluctuation in TRAb concentration in serum may be due to changes in immune system or thyroid hormone levels.

Graves' Disease

Strongly associated with genetic component: HLA-B8 gene
Triggers for development of thyrotoxicosis in susceptible individuals: stress, infection, or withdrawal of thyroid hormone medication
Iodine supplementation can precipitate thyrotoxicosis in regions of iodine deficiency due to sudden increase in thyroid hormone synthesis
Associated with development of ophthalmopathy: TRAb, thyroid-stimulating antibody (TSAb), and thyroid-blocking antibody (TBAb)

Thyroid Failure

Caused by thyroid-blocking antibodies (TBAb)
TBAb can lead to hypothyroidism in some patients

Thyrotoxicosis Management

Beta-blockers play a role in managing symptoms
Approximate relapse rate for patients after taking antithyroid drugs: 50%
Percentage of patients who may experience hypothyroidism after thyroidectomy: 20-30%

Thyroid Surgery

Most common cause of voice alteration following thyroid surgery: recurrent laryngeal nerve damage
Treatment most likely to result in exacerbation of Graves' ophthalmopathy: thyroidectomy

Thyroid Hormone Synthesis

High concentrations of iodine inhibit thyroid hormone synthesis and release (Wolff-Chaikoff effect)
After 10 days of high iodine concentration, there is an "escape phenomenon" where normal organification of iodine and thyroid peroxidase action returns

Iodine Treatment

Rationale for iodine treatment in thyroid crisis and prior to thyroid surgery for thyrotoxicosis: to decrease thyroid hormone synthesis and release
Operation for Graves' disease patients who have been given iodine preparation must happen within 10–14 days

Iodine Deficiency

Effects of iodine deficiency and underlying thyroid disease on thyroid function: altered thyroid hormone production and increased risk of thyroid disorders
Iodine supplementation programs in iodine-deficient areas may precipitate thyrotoxicosis in susceptible individuals

Thyroid Nodules

Management approach for radiologically and/or cytologically indeterminate nodules: FNAC and ultrasound-guided biopsy
Levothyroxine therapy may shrink nodules in regions with borderline low iodine intake
Recommended treatment for nodules with confirmed malignancy: surgery

Autoimmune Thyroid Disease

Most prevalent antibody-mediated autoimmune disease
Associated with other conditions: type 1 diabetes, vitiligo, and rheumatoid arthritis
Treatment that may result in exacerbation of Graves' ophthalmopathy: radioiodine therapy

Other Endocrine Disorders

Klinefelter syndrome is associated with autoimmune thyroid disease and primary hypogonadism
Main presenting problem in patients with gynaecomastia: breast tenderness and swelling
Most common cause of delayed puberty: constitutional growth delay
Condition associated with spontaneous hypoglycaemia: insulinoma
Main functional anatomy involved in acromegaly: pituitary gland
Primary functional anatomy affected by primary hyperparathyroidism: parathyroid glands

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Description

Test your knowledge about Graves' disease, thyrotoxicosis, and the genetic components of thyroid failure. Explore the natural history of Graves’ thyrotoxicosis and the presence of blocking antibodies against the TSH receptor.