Thyroid disorders Flashcards
Primary hypothyroidism causes
Hashimoto’s thyroiditis
surgery (thyroidectomy)
radiation
infiltrative/infectious diseases
congenital defects
drug-induced (amiodarone, lithium)
Central (hypothalamic/pituitary) hypothyroidism
tumour (pituitary adenomas, metastasis, craniopharyngioma)
trauma
vascular
infections (TB, abscess)
TFTs in primary hypothyroidism
high TSH
low FT4
low FT3
Possible antibodies in Hashimoto’s
anti-thyroid peroxidase
anti-thyroglobulin
TFTS in secondary (central) hypothryoidism
low TSH
low FT4
low FT3
Hypothyroidism symptoms and signs
hair loss
dry, brittle hair
excessive fatigue
depressed mood
bradycardia
decreased cardiac output
weight gain
constipation
cool, dry skin
cold intolerance
muscle cramps
myxedema
hyporeflexia
Other laboratory findings in hypothyroidism
low sodium
elevated cholesterol, triglycerides
elevated CK
ECG - low voltage, J wave abnormalities
Hypothyroidism treatment
levothyroxine 1.6-1.8 microgram/kg orally daily
usual dose is 75-150 micrograms
should take one hour before food
What can be used to rapidly correct/for a pt unable to swallow to treat hypothyroidism?
liothyronine T3 5-10mcg 12 hourly orally or down NG
do not use T3 IV - can cause arrhythmias
What TFTs show subclinical hypothyroidism
high TSH
normal FT3
normal FT4
How is subclinical hypothyroidism treated
repeat TFTs in 6 weeks
if TSH>10mU/L then levothyroxine is indicated
if TSH 4-10mU/L and anti TPO +ve then TSH should be checked annually - if symptomatic levothyroxine can be started on a trial basis
Causes of hyperthyroidism
Graves’ disease
Toxic multinodular goitre
Toxic adenoma
Iodine and iodine containing drugs
Painless thyroiditis (post-partum)
Subacute thyroiditis
Ectopic thyroid tissue
Chorionic gonadotrophin-induced
TSH secreting pituitary adenoma
Graves disease symptoms
diffuse goitre
ophthalmology
dermopathy
thyroid acropachy
Graves disease TFTs
low TSH
high FT4
high FT3
What antibodies are present in Graves disease?
TSH receptor antibody (TRAb)
