Thyroid Disease

Question 1

Thyroid function testing

Answer 1

TSH elevated & T4 suppressed –> primary hypothyroidism

TSH elevated & T4 normal –> do not treat unless Sx, goiter or pregnancy

Question 2

Treating clinical hypothyroidism

Answer 2

T4 - levothyroxine: 1.6 mcg/kg/day
start low and slow in elderly
final required dose 50-200mcg
in those with cardiac risk: start 12.5-25 mcg daily
titrate to obtain normal TSH

Question 3

How often should we test TSH?

Answer 3

Retest TSH and T4 in 4-8wk then periodically until normal
once normal retest q6mo then annually
take blood level before dose

Question 4

Administration of levothyroxine

Answer 4

Take 30-60 min b4 breakfast or at bedtime 4 hours after the last meal. consistency is key 4 hours before taking calcium

Question 5

AEs of levothyroxine

Answer 5

palpitations
anxiety
angina (cardiac disease)
wt loss
tachycardia
diarrhea
a fib
bone loss

Question 6

Methimazole

Answer 6

blocks synthesis of hormones via inhibition of TPO
recommended drug except for 1st trimester
CBC and LFTs needed
initial: 10-20 mg daily
maintenance: 5-10 mg daily

Question 7

PTU

Answer 7

blocks synthesis of hormones via inhibition of TPO
good for 1st trimester
CBC and **LFTs needed**
initial: 50-150 mg tid
maintenance: 50 mg bid-tid

Question 8

Monitoring for hyperthyroidism

Answer 8

measure free T4 at 4 wk
monitor q4-8wk until euthyroid
once euthyroid eval q2-3mo