Thyroid Disorders

Question 1

Thyroid axis

Answer 1

Thyroid gland secretes predominantly thyroxine (T4) and small amounts of biologically active hormone triiodothyronine (T3). T3 is produced from the conversion of T4

Question 2

Diagnosis of hyperthyroidism

Answer 2

Rise in T3 is greater and happens earlier than the rise in T4.

Question 3

Clinical features of hypothyroidism

Answer 3

• Lethargy and tiredness
• Cold intolerance
• Weight gain
• Dryness and coarsening of skin and hair
• Hoarseness - deep voice
• Bradycardia
• Goitre - swelling of neck due to enlarged thyroid glands
• Constipation

Question 4

Investigations for HYPOTHYROIDISM

Answer 4

• A high TSH

Question 5

Treatment for hypothyroidism

Answer 5

• Replacement therapy with thyroxine (100-200mcg/day)
• Initial dose should not exceed 100mcg, preferably taken before breakfast
• Starting dose is 25mcg in elderly or patients with cardiac disease and increased by 25mcg every 4 weeks until maintenance dose reached (50-200mcg)

Question 6

Severe hypothyroidism

Answer 6

Liothyronine sodium
- Initially 10-20mcg daily increased to 60mcg daily in 2-3 divided doses.
- 20mcg is equivalent to 100mcg of levothyroxine

Question 7

Clinical features of hyperthyroidism

Answer 7

• Weight loss
• Increased appetite
• Tremor
• Sweating and heat intolerance
• Palpitation
• Fatigue
• Diarrhoea
• Goitre
• Irritability
• Lid lag

Question 8

Diagnosis of hyperthyroidism

Answer 8

• Suppressed TSH
• Raised thyroid hormone concentrations

Question 9

Management of hyperthyroidism

Answer 9

• Carbimazole
  5-40mg daily and then gradually reduced to maintenance dose of 5-15mg.
• Beta blockers for rapid symptomatic relief
• Therapy given for 12-18 months
• Rashes and pruritis are common but treated with antihistamines without needing to stop treatment
• Report any sore throats as there may be a rare case of granulocytosis
• Propylthiouracil may be substituted.
  At a dose of 200-400mg daily and then reduced to maintainance dose of 50-150mg.
• Radioactive iodine (CI in pregnancy and breastfeeding)