Hypothyroidism Flashcards
What is Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis is an autoimmune disorder of the thyroid gland, typically associated with hypothyroidism.
What is a notable characteristic of Hashimoto’s thyroiditis?
It is 10 times more common in women.
What are the features of hypothyroidism in Hashimoto’s thyroiditis?
Features include a firm, non-tender goitre and the presence of anti-thyroid peroxidase (TPO) and anti-thyroglobulin (Tg) antibodies.
What other conditions are associated with Hashimoto’s thyroiditis?
It is associated with other autoimmune conditions such as coeliac disease, type 1 diabetes mellitus, and vitiligo.
What type of lymphoma is associated with Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis is associated with the development of MALT lymphoma.
Can Hashimoto’s thyroiditis present with thyrotoxicosis?
Yes, there may be a transient thyrotoxicosis in the acute phase.
What percentage of women in the UK are affected by hypothyroidism?
Hypothyroidism affects around 1-2% of women in the UK.
How much more common is hypothyroidism in females than males?
Hypothyroidism is around 5-10 times more common in females than males.
What is the most common cause of primary hypothyroidism?
Hashimoto’s thyroiditis is the most common cause of primary hypothyroidism.
Hashimoto’s thyroiditis is an autoimmune disease associated with IDDM, Addison’s, or pernicious anaemia.
What may occur in the acute phase of Hashimoto’s thyroiditis?
Hashimoto’s thyroiditis may cause transient thyrotoxicosis in the acute phase.
What are other causes of primary hypothyroidism?
Other causes include subacute thyroiditis (de Quervain’s), Riedel thyroiditis, after thyroidectomy or radioiodine treatment, drug therapy (e.g. lithium, amiodarone, or anti-thyroid drugs such as carbimazole), and dietary iodine deficiency.
What is secondary hypothyroidism?
Secondary hypothyroidism is rare and results from pituitary failure.
What are some conditions associated with secondary hypothyroidism?
Associated conditions include Down’s syndrome, Turner’s syndrome, and coeliac disease.
What are general features of hypothyroidism?
Weight gain, lethargy, cold intolerance.
What skin features are associated with hypothyroidism?
Dry (anhydrosis), cold, yellowish skin; non-pitting oedema (e.g. hands, face); dry, coarse scalp hair, loss of lateral aspect of eyebrows.
What gastrointestinal feature is common in hypothyroidism?
Constipation.
What gynaecological feature is associated with hypothyroidism?
Menorrhagia.
What neurological features are seen in hypothyroidism?
Decreased deep tendon reflexes; carpal tunnel syndrome.
What vocal feature may be noted in hypothyroidism?
A hoarse voice is also occasionally noted.
What is the initial starting dose of levothyroxine for elderly patients and those with ischaemic heart disease?
The initial starting dose should be 25mcg od for patients with cardiac disease, severe hypothyroidism, or patients over 50 years. Other patients should be started on a dose of 50-100mcg od.
When should thyroid function tests be checked after a change in thyroxine dose?
Thyroid function tests should be checked after 8-12 weeks.
What is the therapeutic goal for TSH levels in hypothyroidism treatment?
The therapeutic goal is ‘normalisation’ of the TSH level, preferably aiming for a TSH in the range of 0.5-2.5 mU/l.
How should the levothyroxine dose be adjusted for women with established hypothyroidism who become pregnant?
The dose should be increased by at least 25-50 micrograms due to the increased demands of pregnancy, with careful monitoring of TSH aiming for a low-normal value.
Is there evidence to support combination therapy with levothyroxine and liothyronine?
There is no evidence to support combination therapy with levothyroxine and liothyronine.
