Thyroid disorders and Osteoporosis Flashcards
What do thyroid hormones do?
Regulate:
- Metabolism
- Growth and development
- Cellular activity
What are two thyroid hormones called? Where are they found?
Triiodothyronine (T3)
- Found mainly intracellularly in target organs
- Small pool in body
- Fast turnover rate
Thyroxine (T4)
- Found in circulation
- Large reservoir in body
- Low turnover rate
What are some symptoms of hyperthyroidism?
Bulging eyes, tachycardia, weight loss, tremors
What is Grave’s disease?
Most common cause of hyperthyroidism
Symptoms include
- Nail clubbing
- Goiter
Diffuse toxic goitre
What is Toxic nodular goitre?
A benign tumour
Second most common cause of hyperthyroidism
How is hyperthyroidism managed?
Thioureylenes –> most common treatment
- e.g. Carbimazole, Propylthiouracil
- Inhibit thyroperoxidase
- Act on the thyroid gland to decrease action
- Side effects include nausea
Radioiodine
- Single dose orally
- Gradually destroy thyroid tissue over 6 weeks to 6 months - reduce size of the thyroid gland
Not suitable for pregnant or breast feeding women. Women should also avoid getting pregnant after taking it. Men shouldn’t father until 4 months after.
Avoid contact with pregnant women
Surgery
- Subtotal or total thyroidectomy
- Hypothyroidism as a side effect with need treating with levothyroxine
What are Thioureylenes?
Thioureylenes –> most common treatment
- e.g. Carbimazole, Propylthiouracil
- Inhibit thyroperoxidase
- Act on thyroid gland to decrease action
What is Radioiodine?
What cautions come with this drug?
Radioiodine
- Single dose orally
- Gradually destroy thyroid tissue over 6 weeks to 6 months - reduce size of the thyroid gland
Not suitable for pregnant or breast feeding women. Women should also avoid getting pregnant after taking it. Men shouldn’t father until 4 months after.
Avoid contact with pregnant women
What are some symptoms of hypothyroidism?
Extreme fatigue, hair loss, muscle aches, thickened tongue
What is severe Hypothyroidism called?
Myxoedema
- Can effect the tongue and larynx causing slurred speech and horseness
- Can lead to coma or death
What is a possible cause of Hypothyroidism?
Non-toxic goitre / Hashimoto’s thyroiditis
- Autoimmune disease, where the immune system attacks the thyroid gland
How can Hypothyroidism be treated?
Levothyroixine (Synthetic T4)
- Take daily
- Life long
- With water on an empty stomach, 30 minutes before eating
- Avoid calcium carbonate (in supplements with antacids) within 4 hours to avoid absorption
- Avoid iron supplements within two hours
- Orlistat may reduce absorption
- Also ciproflaxin (antibiotic), and raloxifene (osteoporosis) may interfere with absorption
What can interfere with Levothyroxine absorption?
Orlistat/ Alli
- Can reduce absorption
Food
Iron supplement (to be taken 2 hours after)
Calcium carbonate (antacids) (4 hours after)
Ciprofloxacin (antibiotic)
Raloxifene (for osteoporosis)
How is Osteoporosis characterised?
- Decreased bone mass
- Alteration of bone architecture
- Increases in bone fragility and fracture risk
- Spinal deformity and height loss
- Peak bone mass 3rd decade
- Bone loss starts 4th decade and continues
What are some risk factors for osteoporosis?
Endogenous
- Age
- Female
- Family history
- Caucasian / Asian
Exogenous
- Steroids
- Low body weight (eating disorders)
- Previous fragility fracture
- Cigarette and alcohol
- Low calcium, low vitamin D, immobilisation
How is osteoporosis managed?
- Bisphospahtes
- HRT (menopause)
- Vitamin D and Calcium
- Raloxifene
- Calcitonin
Treatment is slow to take effect but reduction in fracture risk is often seen after 6-12months
Give examples of oral and IV forms of Bisphosponates
Oral
- Etidronate, Alendronate, Risedronate, Ibandronate
- Daily, weekly or monthly forms
Risks of oesophageal reaction and pain on swallowing
Tablets to be taken whole with at least 200ml water on and empty stomach immediately after getting up in the morning
Patients to stay upright fully for at least 30-60minutes after taking tablet and before taking food, drink or medicine
Intravenous
- Ibandronate
- Once every three months
Associated with renal toxicity
What does Raloxifene do? (Oesteoporisis)
It’s a selective estrogen receptor modulator
- Mimics the action of oestrogen on the bone tissue
- Blocks the effect of oestrogen in other tissue
What does calcitonin do? (Osteoporisis)
Secreted by the thyroid gland in response to increased serum calcium
- Antiresorptive activity
- Less commonly used
Inhibits bone resorption which increased bone mass
Describe Hormone Replacement Therapy
- Provides oestrogen and some progestogen
- Slows the rate of bone loss and fractures
- Not first choice for long term treatment due to increased risks of stroke, blood clots and some cancers
- When taken over the age of 50, benefits outweighs the risks than for younger women who have had an early menopause for preventing osteoporosis.
Describe Vitamin D and Calcium requirement (Oestroposis)
Ca and V D supplementation is a key component of the prevention and treatment of osteoporosis unless calcium intake and V D status are optimal
- Must be taken together
RNI
- Calcium –> 700mg/day
- Vitamin –> 10ug/day
With decreased absorption (e.g. when taking steroids) 1200mg calcium/day is recommended
Maximise absorption of calcium tablet but take at meal times or after food
Separate calcium intake from other medications to prevent interference of absorption