Clinical presentation: A 24-year-old woman was referred for evaluation of typical complaints of hyperthyroidism including nervousness, anxiety, tachycardia but no symptoms of endocrine orbitopathy. She gave birth two month ago. The gave suggested daily 30 mg methimazole but the patient has not started with the therapy, yet.

Palpation: no abnormality.

Result of blood test: TSH undetectable, FT4 51.9 pM/L, FT3 11.8 pM/L.

Ultrasonography. The thyroid was echonormal and inhomogeneous and presented hypoechoic areas. The echogenicity index was around 30-35%. The vascularity was decreased on Doppler mode.

Additional laboratory tests: Final report. TSAb 3.9 U/L (normal value below 1.5), aTPO 107 U/mL.

Suggestion: repeat thyroid tests in 5 weeks, as much as possible rest. We did not recommend stop breastfeeding.

Essence of follow-up.

Clinical presentation. At the first follow-up at six weeks, the patient felt better, instead of increased heart rate, she had sometimes palpitations. Thereafter, her complaints have ceased except for fatigue. She regained her weight two months later and then gained an extra 5 kg of weight 18 months after giving birth. This time, the administration methimazole was stopped, and no further thyroid medication was administered.

Laboratory test:

• Six weeks later: the TSH was 0.21 mIU/L, FT4 9.0 pM/L, FT3 3,49 pM/L.
• Three months later: TSH was 37.3 mIU/L, FT4 7.8 pM/L.
• One year after delivery: TSH 5.64 mIU/L, FT4 13.0 pM/L.
• 18 months after delivery: TSH 2.57 mIU/L, FT4 14.4 pM/L

Comments.

1. Except for early phase of a recurrent hyperthyroidism, the vascularity is almost always increased in the event of overproduction, i.e. in Graves' disease. In the event of hyperthyroidism caused by thyroiditis, the vascular pattern is not characteristic, it can be either increased or decreased.

2. In our practice, the results of vascularity and TSAb test are controversial in around 15% of cases, and ultrasound appears to be better at judging the condition than antibody testing.

3. We did not recommend breastfeeding or medical examination of the baby. Consider that the amount of thyroxine transferred to the infant via the human lactating breast is around 1% of the total daily requirement. Thus, maternal transfer of thyroid hormone does not have a meaningful impact on the infant's thyroid hormone status not even in significant degree of hyperthyroidism. For ATA guideline, click here.