Thyroid disorders and Osteoporosis

Question 1

What do thyroid hormones do?

Answer 1

Regulate:
- Metabolism
- Growth and development
- Cellular activity

Question 2

What are two thyroid hormones called? Where are they found?

Answer 2

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

Question 3

What are some symptoms of hyperthyroidism?

Answer 3

Bulging eyes, tachycardia, weight loss, tremors

Question 4

What is Grave’s disease?

Answer 4

Most common cause of hyperthyroidism

Symptoms include
- Nail clubbing
- Goiter

Diffuse toxic goitre

Question 5

What is Toxic nodular goitre?

Answer 5

A benign tumour
Second most common cause of hyperthyroidism

Question 6

How is hyperthyroidism managed?

Answer 6

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

Question 7

What are Thioureylenes?

Answer 7

Thioureylenes –> most common treatment
- e.g. Carbimazole, Propylthiouracil
- Inhibit thyroperoxidase
- Act on thyroid gland to decrease action

Question 8

What is Radioiodine?
What cautions come with this drug?

Answer 8

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

Question 9

What are some symptoms of hypothyroidism?

Answer 9

Extreme fatigue, hair loss, muscle aches, thickened tongue

Question 10

What is severe Hypothyroidism called?

Answer 10

Myxoedema
- Can effect the tongue and larynx causing slurred speech and horseness
- Can lead to coma or death

Question 11

What is a possible cause of Hypothyroidism?

Answer 11

Non-toxic goitre / Hashimoto’s thyroiditis
- Autoimmune disease, where the immune system attacks the thyroid gland

Question 12

How can Hypothyroidism be treated?

Answer 12

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

Question 13

What can interfere with Levothyroxine absorption?

Answer 13

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)

Question 14

How is Osteoporosis characterised?

Answer 14

• 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

Question 15

What are some risk factors for osteoporosis?

Answer 15

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

Question 16

How is osteoporosis managed?

Answer 16

• 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

Question 17

Give examples of oral and IV forms of Bisphosponates

Answer 17

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

Question 18

What does Raloxifene do? (Oesteoporisis)

Answer 18

It’s a selective estrogen receptor modulator
- Mimics the action of oestrogen on the bone tissue
- Blocks the effect of oestrogen in other tissue

Question 19

What does calcitonin do? (Osteoporisis)

Answer 19

Secreted by the thyroid gland in response to increased serum calcium
- Antiresorptive activity
- Less commonly used

Inhibits bone resorption which increased bone mass

Question 20

Describe Hormone Replacement Therapy

Answer 20

• 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.

Question 21

Describe Vitamin D and Calcium requirement (Oestroposis)

Answer 21

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