Thyroid - Hypothyroidism Flashcards
What will TFTs show in primary hypothyroidism?
TSH- high
T3/T4- low
What will TFTs show in secondary hypothyroidism?
TSH- low or normal
T3/T4- low
What is the definition of hypothyroidism?
Any disorder that results in insufficient secretion of thyroid hormones from the thyroid gland
What is myxoedema coma?
A hypothyroid emergency
In general, hypothyroidism is most common in which sex and of which age group?
Females, 65+
Hypothyroidism has a higher incidence in which race?
White populations
What environmental factor causes a higher incidence of hypothyroidism?
Areas of iodine deficiency
What are 5 causes of goitrous, primary hypothyroidism?
- Hashimoto’s thyroiditis
- Iodine deficiency
- Drug induced
- Maternally transmitted
- Hereditary defects
What 2 drugs have a big effect on thyroid function?
Amiodarone and lithium
How is hypothyroidism maternally transmitted?
If the mother is on anti-thyroid drugs
Is Hashimoto’s thyroiditis always goitrous?
No
What are 4 causes of non-goitrous, primary hypothyroidism?
- Hashimoto’s thyroiditis
- Post-ablative therapy
- Post-radiotherapy
- Congenital defects
What are 3 examples of self-limiting hypothyroidism?
- Following withdrawal of anti-thyroid drugs
- Subacute thyroiditis
- Post-partum thyroiditis
What causes secondary hypothyroidism?
Hypothalamic or pituitary disease
What are 6 causes of hypothalamic-pituitary disease?
- Infiltrative disease
- Malignancy
- Infection
- Cranial radiotherapy
- Congenital disorders
- Trauma
What effects can hypothyroidism have on the hair and skin?
- Vitiligo
- Coarse, sparse hair
- Periorbital puffiness
- Pale, cool, doughy skin
- Hypercarotenaemia
What effect does hypothyroidism have on thermogenesis?
Cold intolerance
What clinical sign appears in hypothyroidism as a result of abnormal fluid balance?
Pitting oedema
What effects can hypothyroidism have on the CV system?
- Decreased HR
- Cardiac dilatation
- Pericardial effusion
- Worsening of heart failure
What metabolic effects does hypothyroidism have?
- Hyperlipidaemia
- Weight gain and decreased appetite
What GI effects can hypothyroidism cause?
- Constipation
- Intestinal obstruction
- Ascites
What respiratory effects can hypothyroidism cause?
- Deep, hoarse voice
- Macroglossia
- Sleep apnoea