419) A 26-year-old woman presents for an ante-natal check up after her home pregnancy test showed positive result. Her last menstrual period was 5 weeks ago. Her past medical history includes hypothyroidism for which she has been using 125 mcg of levo-thyroxine for the past five years. She did not require any dose adjustment of her thyroid hormone therapy in the past 4 years. Her most recent thyroid stimulating hormone level ( TSH) was performed 2 weeks ago and was 2.5µU/ml ( N = 0.5 to 5.0 µU/ml). She denies any cold intolerance, weakness or constipation. She has gained about 2 lbs weight in the past one month. On physical examination, vitals are stable. There is no goiter. Reflexes are 1+ in bilateral lower extremities and there is 1+ pre-tibial edema. Laboratory investigations reveal :
Thyroid Stimulating Hormone : 2.5 µU/ml( N = 0.5 to 5.0 µU/ml)
Serum Total T4: 13.9 µg/dl ( N = 5 to 12µg/dl)
Serum Free T4 : 1.9 ng/dl ( N = 0.9 to 2.4ng/dl)
Which of the following is the most recommendation?
A) Decrease Levothyroxine and recheck TSH in 4 weeks
B) Continue same dose Levothyroxine and repeat TSH in 4 weeks
C) Increase Levothyroxine and repeat TSH in 4 weeks
D) Repeat TSH in 8 to 10 weeks
E) Check Serum thyroid binding globulin levels
C
E
C. As in pregnancy you need to increase the dosage of peck thyroxine . Thyroid hormone requirements increases in pregnancy , and previously well controlled women can become symptomatic.
e
C) Increase Levothyroxine and repeat TSH in 4 weeks- increased levothyroxine requirement due to increase in thyroxine binding globulin during pregnancy resulting low free T4 (but high Serum Total T4)
b
ans
C.
C-increase Levothyrox due to increase TBG f/u tsh in 4 wks