Hypothyroidism Flashcards
What is hypothyroidism?
Insufficient production of the thyroid hormone by the thyroid gland
What is the most common cause of hypothyroidism in the developing world?
Iodine deficiency
What is the most common cause of hypothyroidism in the developed world?
Hashimoto’s thyroiditis
What is Hashimoto’s thyroiditis?
Autoimmune inflammation of the thyroid gland
What are drug causes of hypothyroidism?
Amiodarone
Lithium
What are possible RF for hypothyroidism?
Down’s syndrome
Coeliac
Turner’s syndrome
How does hypothyroidism present?
Weight gain Lethargy Cold intolerance Dry skin Constipation Hoarse voice
What can happen to hair in hypothyroidism?
Dry, coarse scalp hair
Loss of lateral aspect of eyebrows
What antibodies are present with Hashimoto’s?
Anti-thyroid peroxidase antibodies
Anti-thyroglobulin antibodies
What is the TSH and T3, T4 level in Primary hypothyroidism?
High TSH
Low T3 and T4
What is the TSH and T3, T4 level in subclinical hypothyroidism?
High TSH, normal T3 and T4
What is the medical management of hypothyroidism?
Levothyroxine
How would you change the dose of levothyroxine if the patient was elderly?
Reduce the dose
What should you after changing the dose of levothyroxine?
Check TFT’s in 8-12 weeks
How would you change the dose of levothyroxine in someone who was pregnant?
Increase dose by 25-50mg
What is a side effect of over-treatment with levothyroxine?
hyperthyroidism
What can reduce the absorption of levothyroxine?
Iron tablets
Calcium carbonate tablets
(give 4 hours apart)
What is the therapeutic goal of levothyroxine?
A normal TSH
What is secondary hypothyroidism?
Pituitary gland doesn’t produce enough TSH
What are possible causes of secondary hypothyroidism?
Tumours
Infection
Vascular- Sheehan’s
What is a complication of undiagnosed hypothyroidism or poor compliance to medication?
Myxoedemic coma
How does a myxoedema coma present?
Unconscious Overweight Dry skin Hypotensive Thin and brittle hair Periorbital oedema
What is the management of myxoedemic coma
IV thyroxine
IV fluid
IV hydrocortisone (until adrenal insufficiency has been excluded)
What is the TSH, T3 and T4 level in subclinical hypothyrodism?
TSH raised
T3 and T4 are normal
What is there the risk of developing in subclinical hypothyroidism?
Hypothyroidism
What would you do with someone with subclinical hypothyroidism and asymptomatic?
Observe and repeat thyroid function in 6 months
In who would the starting dose of levothyroxine be lower?
Elderly
Ischaemic Heart Disease
What should the initial starting dose be for people with cardiac disease or over 50 be?
25mcg od with dose slowly titrated
What is the normal starting dose of levothyroxine be in other patients?
50-100mcg od
What are the other potential side effects of levothyroxine?
hyperthyroidism: due to over treatment
reduced bone mineral density
worsening of angina
atrial fibrillation
What gynaecological problem can hypothyroidism cause?
Menorrhagia
What neurological probelms can hypothyroidism cause?
Decreased deep tendon reflexes
Carpal tunnel syndrome
What can occur in the hands and face in someone with hypothyroidism?
Non-pitting oedema (puffy face)
What cardiac symptoms can hypothyroidism cause?
Bradycardia
Cardiomegaly
What cancer is hasimoto’s thyroiditis associated with?
Thyroid lymphoma
How can a thyroid lymphoma present?
solitary, painless, hard, immobile nodule at the front of her neck- Doesn’t move on tongue protrusion.
