Hypothyroidism

• What sex is hypothyroidism more common in?

  Female
• What are some causes of primary hypothyroidism?

  Hashimoto's thyroiditis

  Iodine deficiency

  Surgical removal or radioactive iodine treatment
• What is the most common cause of hypothyroidism?

  Hashimoto's thyroiditis
• What is a cause of secondary hypothyroidism?

  Pituitary disorders e.g. pituitary adenomas
• What is a cause of tertiary hypothyroidism?

  Hypothalamic disease
• What are some risk factors for developing hypothyroidism in general?

  Female

  >60 years

  FHx

  Meds e.g. lithium

  Radiation exposure
• What is the stereotypical patient presentation of someone with hypothyroidism?

  Middle-aged woman presents with fatigue, weight gain, cold intolerance, and constipation.
• What are some symptoms of hypothyroidism?

  Fatigue

  Weight gain

  Cold intolerance

  Dry skin

  Depression

  Hair loss

  Constipation
• What are the first line investigations for hypothyroidism?

  Serum TSH test:

  • Inc TSH = primary hypothyroidism

  Serum free thyroxine (FT4):

  • Low FT4 + high TSH = primary hypothyroidism
  • Normal FT4 + high TSH = subclinical hypothyroidism
• What investigations are done if first line tests = hypothyroidism but cause is unclear?

  Serum thyroglobulin and anti-thyroglobulin antibody test (inc levels - Hashimoto's)

  USS
• What is myxedema coma?

  Severe, life-threatening form of hypothyroidism
• What is myxedema coma characterised by?

  Mental status changes and hypothermia
• What are some lab findings for myxedema coma?

  Extremely low T4

  Significantly elevated TSH
• What is the distinguishing feature of myxedema coma vs hypothyroidism?

  Myxedema coma: altered mental status ranging from confusion to coma
• How is hypothyroidism managed with medication?

  Levothyroxine
• Who should have a lower starting dose of levothyroxine?

  Elderly

  Ischaemic heart disease

  Severe hypothyroidism
• How often should thyroid function tests be checked after a change in thyroxine dose?

  8-12 weeks
• What should happen if patients who are taking levothyroxine become pregnant?

  Dose increase
• What are some side effects of thyroxine therapy?

  Hyperthyroidism (over treatment)

  Dec bone mineral density

  Worse angina

  AF