Hyper/Hypothyroidism Flashcards
What is hypothyroidism
A decrease in the level of thyroid hormone in the blood
What can hypothyroidism lead to
SAN and automaticity are reduced, leading to bradycardia
What occurs when noradrenaline and adrenaline bind to alpha receptors
causes blood vessels to constrict, which increases TPR
What are the symptoms of hypothyroidism
- Weight gain, reduced appetite, decreased body temperature, cold intolerance
- Bradycardia, hypertension, decreased Beta receptors or increased alpha receptors
- constipation
- fatigue, depression, impaired memory, impaired concentration
- dry skin, hair loss, brittle hair
- thin nails, brittle nails
What are the causes of hypothyroidism
HARRISMD
1. hormone resistance syndrome- TRH resistance
2. autoimmune thyroiditis- autoimmune destruction of thyroid gland (Hashimoto’s thyroiditis)
3. Radiation therapy- radio iodine ablation and tradition radiotherapy to the neck
4. Reidel thyroiditis- an infiltrative thyroid disorder
5. Iodine deficiency- lack of iodine required for thyroid hormone synthesis
6. Surgery- total thyroidectomy
7. Malignancy- lymphoma, metastatic disease to the thyroid, thyroid malignancy
8. Drugs- amiodarone, lithium, immune checkpoint inhibitors
What is Hashimoto’s disease
autoimmune destruction of thyroid gland
- may or may not be associated with hypothyroidism
- most common cause of hypothyroidism but in some patients, doesn’t necessarily lower thyroid levels
Outline the treatment of hypothyroidism
- Replacement therapy with thyroxine
- monitor effectiveness by measuring TSH
- sufficient T4 will suppress TSH secretion by negative feedback so TSH levels will drop in blood - Typically also need calcium and vitamin D therapy
- thyroid hormones also produce calcitonin, which regulates Ca metabolism in body, so need to supplement
which drugs can induce goitre
- Lithium- used in treatment of bipolar depression
- Iodides- contained in vitamin preparations and some cough remedies
- Amiodarone- used for treatment of AF
What is hyperthyroidism
Elevated levels of thyroid hormones in the blood than is needed in the body
What is another name for hyperthyroidism
Overactive thyroid, thyrotoxicosis
How else can hyperthyroidism occur
can also occur when too much replacement thyroxine (levothyroxine) is taken as a treatment for underactive thyroid
What are the symptoms of hyperthyroidism
- weight loss, increased appetite, increased body temperature, heat intolerance
- tachycardia, palpitations, arrhythmias, hypertension
- diarrhoea
- anxiety, nervousness, irritability, insomnia, tremors
- sweating, hair growth, fine soft hair
- nail growth, onycholysis
What is Graves disease
Most common condition that drives hyperthyroidism
- autoimmune condition where the body attacks the thyroid, making it overactive
- affects 0.5% of people
- 7.5x more prevalent in females
- typified by low TSH and high T4
What would the TSI level be like in a patient with Graves disease
TSI level would be abnormally high
What is TSI
A form of immunoglobulin G (IgG) that can bind to thyrotropin (TSH) receptors on the thyroid gland
- mimics action of TSH, causing excess secretion of T4 and T3