Hypothyroidism Flashcards
What is hypothyroidism?
When the thyroid gland is not producing enough thyroid hormone.
What is the most common cause of hypothyroidism in the DEVELOPED world?
Hashimoto’s thyroiditis.
What is hashimotos thyroiditis?
An autoimmune condition where antibodies attack the thyroid gland.
Initially the thyroid gland enlarges but soon atrophies
Which antibodies are commonly found in hashimotos thyroiditis?
Anti thyroperoxidase (Anti-TPO) = 90-95%.
Anti thyroglobulin 35-60%.
Anti TSH receptor blockers 10% (also often positive in grave’s disease).
What is the most common cause of hypothyroidism in the developing world?
Iodine deficiency
Which countries have a high risk of iodine deficiency?
Middle East
Nepal
South America
What are the main symptoms of hypothyroidism?
Bradycardia Constipation Cold intolerance Brittle Hair Hair loss Fatigue Weight gain (despite loss of appetite) Dry skin Oedema Ascites Amenorrhoea Macroglossia Puffy face Goitre (Especially in hashimotos)
What are the investigations for hypothyroidism?
TFT (thyroid function tests). TSH T3 + T4 Anti TPO Anti thyroglobulin Anti TSH receptor
What will TFT show in primary hypothyroidism?
Low T3 and T4
High TSH
What will TFT show in secondary hypothyroidism?
Low TSH
Low T3 and T4
What is the hormones released in the pathway for thyroid hormone release?
Hypothalamus secretes Thyrotropin releasing hormone
Anterior pituitary releases thyroid stimulating hormone
Thyroid gland releases T3 and T4
What are other causes of hypothyroidism?
Treatment of hyperthyroidism: Carbimazole Thyroid surgery RAI Propyhthiouracil
Medications:
Lithium
Amiodarone
Secondary: Tumour in AP or (tertiary) in hypothalamus. Sheehans syndrome Infection Vascular pathology
What are the complications of congenital hypothyroidism?
Shortened height
Delayed growth
Intellectual disabilities
Mental retardation
What is the treatment for hypothyroidism?
Levothyroxine
What are the complications of levothyroxine?
Osteoporosis
Cardiac arrhythmias.
