Hypothyroid Flashcards
What are the types of causes of hypothyroid?
Subclinical
Primary
Secondary
What is subclinical hypothyroid?
Raised TSH but normal T3 and T4
What is primary hypothyroid caused by?
Thyroid pathology
What are the TSH and T4 levels in primary hypothyroid?
Raised TSH
Low T4
What are the causes of primary hypothyroid?
Congenital- developmental, dyshormogenesis
Acquired- autoimmune, iatrogenic, chronic iodine sufficiency, sub-acute thyroiditis
What is autoimmune hypothyroid?
Hashimotos
Thyroid peroxidase antibodies
What causes secondary hypothyroid?
Pituitary pathology
What are the TSH and T4 levels in secondary hypothyroid?
Low TSH and T4
What are causes of secondary hypothyroid?
Pituitary tumour
Craniopharyngioma
Post pituitary surgery/radiotherapy
Sheehan’s
What is the presentation of hypothyroid?
Weight gain Constipation Heavy periods Feeling cold Lethargy Dry skin/hair Bradycardia Slow reflexes
What are the signs of severe hypothyroid?
Puffy face
Hoarse voice
Large tongue
Coma
What investigations are done for hypothyroid?
TFTs
Autoantibodies
FBC, U&Es
What autoantibodies are present in HAshimoto’s?
Thyroid peroxidase antibodies
What can FBC and U&Es show in hypothyroid?
Hypercholesterolaemia
Hyponatraemia
High creatinine
What is the management of hypothyroid?
Levothyroxine
-start on 50mcg, increase to 100mcg after 2 weeks, monitoring TFTs and increasing dose until normalised
Monitor TFTs annually
In who is management of hypothyroid different?
Elderly, IHD
Pregnancy
Post partum thyroiditis
What are the management principles of hypothyroid in elderly or those with IHD?
Start low and go slow
What are the management principles of hypothyroid in pregnancy?
Higher dose normally required and keep T4 in high range
What are the consequences of hypothyroid in pregnancy?
Increased risk of foetal loss and Low IQ
What is the management of postpartum thyroiditis?
Withdraw levothyroxine for 6 weeks and measure TFTs after 6 weeks
When should treatment of subclinical hypothyroid be considered?
TSH >10
TSH >5 with + antibodies
TSH elevated and symptomatic
What are the possible complications of hypothyroid management?
Osteopenia
AF
Angina in those with IHD
