1(E): Hypothyroidism Flashcards
What is myxoedema
Clinical manifestation of thyroid hormone deficiency
What is the stereotype for hypothyroidism
Women over-40
What is primary hypothyroidism
Defect in thyroid gland: low T3, T4
What is secondary hypothyroidism
Defect in pituitary gland: low TSH
What is tertiary hypothyroidism
Defect in hypothalamus: low TRH
What are the two aetiological categories of hypothyroidism
Autoimmune
Acquired
What are two autoimmune conditions causing hypothyroidism
- Hashimoto’s
- Primary atrophic hypothyroidism
What is primary atrophic hypothyroidism
Diffuse lymphocytic infiltration of the thyroid gland causing atrophy
What is a feature of primary atrophic hypothyroidism
No goitre
What is the most common cause of hypothyroidism in wester civilisation
Hashimoto’s disease
when is Hashimoto’s more common
Women over-60
what is the most common cause of Hashimoto’s in developing countries
iodine deficiency
what are 4 acquired causes of hypothyroidism
- post thyroidectomy
- radio-iodine treatment
- drug induced
- de quervains subacute thyroiditis
- post-partum thyroiditis
what medications can cause hypothyroidism
amiodarone
carbimazole
lithium
explain hypothyroidism in de quervains thyroiditis
after period hyperthyroidism, can lead to hypothyroidism
explain postpartum thyroiditis
after pregnancy can have period of hypothyroidism
what can cause secondary hypothyroidism
pituitary adenoma
what are signs of hypothyroidism
Bradycardia Reflexes diminished Ataxia Defeated demeanour Yawning Cold hands Ascites and non-pitting oedema, pericardial effusion Round puff face Dry hair and skin Immobile/ileus CCF
when does sick euthyroid syndrome occur
In patients who are critically unwell or severe stress
when does sick euthyroid syndrome occur more
ITU patients
explain thyroid function in sick euthyroid
Normal thyroid function - no symptoms of hyper or hypothyroidism, however, cytokines alter circulating thyroid hormone
What is first line investigation for hypothyroidism disease
TFTs
How do TFTs present in primary hypothyroidism
- Low T3, T4
- High TSH
How do TFTs present in secondary hypothyroidism
- Low T3, T4
- Low TSH
