7. Thyroid Disease - Hyperthyroidism Flashcards
What would you expect the TFT to show in someone with hyperthyroidism
low TSH
high T3 and T4
what would you expect the TFT to show in someone with primary hypothyroidism
high TSH
low T3 and T4
what would you expect the TFT to show in someone with secondary hypothyroidism
low TSH
low T3 and T4
What antibodies are usually present in graves disease and hashimotos thyroiditis
antithyroid peroxide (anti-TPO) antibodies (against the thyroid gland itself) in hashitmotos Antithyroglobulin antibodies - TSH receptor antibodies in graves disease
what is graves disease
autoimmune condition where TSH receptor antibodies cause primary hyperthyroidism
these are abnormal antibodies produced by the immune system and mimic TSH
In a radioisotope scan to investigate hyperthyroidism and thyroid cancers what conditions give the characteristic clinical finding
- diffuse high uptake of the isotope
- focal high uptake of the isotope
- ‘cold’ areas (ie abnormally low uptake) of the isotope
- graves disease
- toxic multinodular goitre and adenomas
- thyroid cancer
define Hyperthyroidism and what is it also known as
over production of the thyroid hormone by the thyroid gland
aka thyrotoxicity
What is the difference between primary and secondary hyperthyroidism
primary is due to thyroid pathology (the thyroid itself is behaving abnormally)
secondary is as a result of overstimulation by TSH and the pathology is in the hypothalamus or pituitary
what is the most common cause of hyperthyroidism
Graves disease
what is toxic multi nodular goitre (aka plummers disease )
nodules develop on the thyroid gland that act independently of the normal feedback system and continuously produce excessive thyroid hormone
What is exophthalmos
bulging of the eyeball out of the socket caused by graves disease. Due to inflammation, swelling and hypertrophy
what is pre-tibial myxoedema
deposits of mucin under the skin on the anterior aspect of the leg
specific to graves disease and is a reaction to the TSH receptor antibodies
Describe where the thyroid gland is located and the basic structure
- soft gland in the lower neck, anterior to the trachea, below the thyroid cartilage of the larynx, moves when you swallow
- makes thyroxine (T4) and T3 and is composed of 2 lobes and an isthmus
What other conditions could present with weight loss and what questions would you ask
- GI symptoms: anorexia, abdo pain, diarrhoea, symptoms of IBD, coeliac disease, peptic ulcer
- Symptoms of depression: low mood, loss of interest, sleep disturbances
- Symptoms of eating disorder: decreased food intake, self-induced vomiting, over exercise. Anorexia nervosa and bulimia may commonly present in this age group (early 20s)
- Polyuria and polydipsia: type 1 diabetes mellitus may present with weight loss
- Drug use: including alcohol, cocaine, amphetamines, cannabis
- Night sweats or fevers: although malignancy is rare in this age group, lymphomas may present with weight loss. TB and HIV can also present this way
Describe the basic histology of the thyroid gland
- Made up of follicles lines by cuboidal epithelium and parafollicular C cells that secrete calcitonin
- follicles are filled with colloid (looks pink)
- follicular cells make thyroglobulin
what are c cells involved in
the production of calcitonin involved in bone mineral deposition