Hypothyroidism Flashcards
What is primary hypothyroidism
problem with thyroid gland itself - autoimmune disorder affecting thyroid tissue
What is secondary hypothyroidism
due to disorder with pituitary gland - lesion compressing pituitary gland
What is congenital hypothyrodism
due to a problem with thyroid dysgenesis or thyroid syhormonogenesis
What are causes of hypothyroidism
Hashimotos - most common in DEVELOPED world and autoimmune
Subacute/De Quervains thyroiditis
Riedel thyroiditis- chronic inflammation and fibrosis of thyroid gland
postpartum thyroiditis
drugs-lithium
iodine deficiency - most common in DEVELOPING world
What is seen on history and examination
weight gain
lethargy
cold intolerance
dry. cold. yellowish skin
non-pitting oedema
dry, coarse hair, loss of lateral aspect of brows
contispation
menorrhagia
carpal tunnel syndrome
What investigations are required
Thyroid function
primary - high TSH, low T4
secondary - low TSH , low T4
Thyroid autoantibodies
anti-TPO - in Hashimotos
Iodine scan - globally reduced uptake in De Quervains thyroiditis
What is the management of hypothyroidism
Levothyroxine 50-100mcg OD
reduce starting does for any patients with cardiac disease, severe hypothyroidism or >50
increase starting dose in pregnant women
TFTs after 8-12 weeks
What are side effects of levothyroxine
hyperthyroidism
reduced bone mineral density
worsening of angina
atrial fibrillation
What are features of Hashimotos thyroiditis
autoimmune disorder of thyroid gland
features of hypothyroidism ]goitre-firm not tender
anti TPO and anti-TG antibodies
What is a myxoedemic coma
a rare and extreme complication of severe hypothyroidism
What symptoms are associated with a myxoedemic coma
hypothermia
hyporeflexia
bradycardia
seizures
periorbital oedema
thin and brittle hair
What is subclinical hypothyroidism
TSH raised but T3,T4 normal
no obvious symptoms
What is the risk of subclinical hypothyroidism
risk of progressing to hypothyroidism
risk increased by presence of thyroid autoantibodies
What do you do for elderly patients with subclinical hypothyroidism
watch and wait
How do you manage subclinical hypothyroidism if patient is >65 and symptomatic
offer trial of levothyroxine
recheck TFTs in 6 months time
