Thyroid Disease Flashcards
How much does a normal thyroid gland weigh?
25g
Majority of cases of hypothyroidism in developed world are caused by?
Hashimoto’s thyroiditis (autoimmune)
Causes of hypothyroidism?
Auto immune disease Severe iodine deficiency Dyshormogenesis (inborn errors in the formation of thyroid hormones) Anti thyroid drugs Excessive surgical resection Treatment with radioiodine Hypopituitarism (as causes reduced TSH)
What are you at increased risk of with Hashimoto’s thyroiditis?
B cell lymphoma and at higher risk of other auto-immune diseases
Most cases of hyperthyroidism is due to …
Grave’s disease
Pathogenesis of Graves and Hashimoto’s disease?
In Hashimotos auto antibodies attack the thyroid but in Grave’s they stimulate the function of the gland
Pathology of Hyperthyroid?
Gland is diffusely enlarged, gland is hyper plastic and there are numerous closely packed acini of various sizes, sometimes intra-acinar pailliform growths, colloid is absent and columnar cells
What is non-toxic goitre?
This is a simple enlargement of they thyroid gland not associated with increased secretion of thyroid hormone.
Causes of non-toxic goitre?
Not fully understood
Iodine deficiency
Dyshormonogenesis
Describe the phases of non-toxic goitre?
Diffuse hyperplasia and then nodular hyperplasia where areas of marked hyperplasia cause atrophy of intervening parenchyma.
Most common benign tumour of the thyroid?
Follicular adenoma
How do follicular adenomas usually look?
Discrete solitary masses surrounded by encapsulating collagen cuff
Most common malignant tumour of the thyroid?
Papillary carcinoma
Thyroid Papillary carcinomas spread by ________
lymphatics
Characteristic of papillary carcinomas of thyroid?
Orphan Annie nuclei (clear nuclei) and psammomma bodies
Are adenomas usually functional?
No
Causes of thyroid cancers?
Ionising radiation for papillary
Iodine deficiency for follicular
Second most common thyroid cancer?
Follicular carcinoma
Thyroid follicular carcinomas usually spread by ______
haematogenous spread to the bones and lungs
Thyroid Medullary carcinomas are derived from? So can therefore stain for?
Neuroendocrine from C-cells
Stain for calcitonin
Aggressive rare thyroid cancer?
Anaplastic carcinoma
Difference between hyperthyroidism and thyrotoxicosis?
Thyrotoxicosis- any excessive thyroid hormone production
Hyperthyroidism excessive production of thyroid hormone by thyroid gland
3 causes of diffuse goitre?
Simple- no clear cause
Autoimmune disease- hashimotos or thyrotoxicosis
Thyroiditis- de quervains
2 causes of nodular goitre?
Multinodular- hyper plastic growth common in older patients
Solitary nodules- worry of malignancy but likely to be benign or cystic or largest of multinodular
Describe multi nodular goitre?
hyper plastic growth, patients are usually older and euthyroid but may be border hyperthyroid. Most common cause of tracheal or oesophageal compression and can lead to nerve palsy. Some people may be asymptomatic. Surgery done if a structural problem or significant retrosternal extension but most can be left alone.
Small euthyroid goitres may occur in …..
puberty or pregnancy and often resolve