7 - Thyroid disease Flashcards
What to incude in a history of Thyroid disease?
Unintentional wieght loss
Tierdness
GI - anorexia, abdo pain, IBD symptoms
Depression
Eating disorder
polyuria and poly dipsia - exclude T1 DM
Night sweats and fever - exlcude malignancy
What are the symptoms of hyperthyroidism?
Wieght loss with good apetite
Tachycardia with AF
Sweaty and hot
Frequent bowel action
Irritable
sometimes have goiter
Upper eye retraction - superior tarsus (smooth) muscle
Thyroid eye disease
What disease is Thyroid eye disease most commonly seen?
Graves diseas
TSH receptors behind eye
What features of Thyrotoxicosis on examination?
Tremour
Onycholysis - painless detachemnt of the nail bed
Acropachy - soft tissue swelling of hands and feet
Clubbing
What cells produce calcitonin?
C cells
Calcitonin - lower serum [Ca2+] by inhibiting osteoclast and inhibiting reabsoption of renal Ca2+
Describe the process of Thyroid hormone synthesis?
TSH activates TSHR to secrete colloid
sodium iodide symporter imports iodine
organification occurs where thyroid peroxidase (TPO) adds iodine to tyrosine from thyroglobulin to produce T3 and T4
Endocytose from colloid into circulation
T4 is deiodinised in peripheral tissue to become T3
T3 binds to nuclear hormone receptor leading to the transcription of DNA
Describe the Pituituary-thyroid axis
What Treatment of Thyrotoxicosis?
Beta-blockers - treatment of Symptoms
1st line Carbimazole
2nd line Propylthiouracil
Radiotherapy - I131
Thyroidectomy
How is thyrotoxicosis managed with carbimazole?
Titration - start at 40mg then - 15mg.
Block replace - 40mg mainatained and replaced T4 with levothyroixine. Contraindicated in pregnancy
What is Graves disease?
Auto-immune antibiodies which activate TSH-R by molecular mimicry
Common to have exopthalmos and diffuse goitre.
Most common cause of thyrotoxicosis
What is hashimotos disease?
Lymphocyte infilatraiton of the thyroid gland with autoimmune antibodies for TPO and thyroglobulin.
Most common cause of hypothyroidism
Symptoms of hypothyroidism?
Weightloss
Profound lethargy
cold
dry brittle hair
constipaiton and heavy periods
myeodema
Treament of hypothyroidism?
Levothyroxine - start at 50mg and titrate up + 25mg
complications: AF and osteoarthritis
What feature specific to graves disease?
ophthalmoplegia - weakness in extraoccular muscles
Exopthalmos
Thyroid Acropachy - soft tissue swelling of finger and feet and clubbing
What disease cause Goitre?
Graves
Hashimotos
Colloid
Iodine deficiency
Lithium
Which drugs can cause thyrotoxicosis?
INF
amiodarone - arrythmia medication
Solitary nodules of the thyroid can become malignant. Which is most common?
Pappilary thyroid cancer
What is the pathology of post partum hemorrhage thyroiditis?
A form of hashimotos where TPO attack the thyroid leading to a large release of T4. This is followed by subsequent hypothyroidism.
Has a greater ration of T4 compared to T3
What is Sheehans syndrome?
The pituitary (normally anteior) becomes infarcted after post partum heamorrhage leading to 2nd (central) hypothyroidism.
How might a radioactive I131 scan differenciate between post partum heamorrhage thyroidititis and graves disease?
Radioactive scan will be greatest in graves as there is an incraesed uptake in iodine.
How is post partum heamorrhage treated?
No carbimazole/propylthiouracil given.
Popanolol for symptomatic release of thyrotoxicosis.
