A 39-year-old woman (157 cm, 75 kg, body mass index [BMI] 30.4 kg/m2) was referred to our outpatient clinic for evaluation of an enlarged thyroid. The patient's medical history and family history were unremarkable. Physical examination confirmed a palpably enlarged thyroid. Normal values of free tri-iodothyronine (fT3), free thyroxine (fT4), and thyroid-stimulating hormone (TSH) were congruent with the lack of clinical signs of hyper- or hypothyroidism; antithyroid peroxidase (TPO), antithyroglobuline (TG), and anti-TSH-receptor (TSH-R) antibodies were negative ().
Evaluation of the Thyroid Parameters in our Patient
Ultrasonography revealed a multinodular goiter with a total volume of 62 mL. A thyroid 99mTC-pertechnetate scintigraphy showed a homogenous uptake with a moderate autonomy in the right upper lobe, confirmed by a thyroid scan under exogenous TSH suppression with levothyroxine ().
Thyroid suppression 99mTC-pertechnetate scintigraphy, before (A) and after taking 100 μg levothyroxine daily for 4 weeks (B), showing a homogenous uptake with a moderate autonomy in the right upper lobe.
The patient was informed of the therapeutic options that included thyroid resection versus routine follow-up clinical visits. She decided against surgery, and a short-term control visit was arranged. Furthermore, it was pointed out to the patient to avoid the intake of large amounts of iodine, such as iodinated radiocontrast agents or iodine-containing drugs or food. Two months later, the patient was in good general health and endocrine tests revealed thyroid hormones and TSH plasma levels within the normal range ().
Four months after the initial visit, the patient presented with typical signs of hyperthyroidism, including tachycardia (100 beats/min), palpitations, tremor, nervousness, insomnia, fatigue, increased sweating, diarrhea, secondary amenorrhoea, and weight loss. Laboratory analysis revealed increased levels of fT3 and fT4 as well as a suppressed TSH concentration, anti-thyroid antibodies remained negative (). Ultrasonography showed a multinodular goiter with a total volume of 67 mL. The patient did not report any exposure to medications containing iodine, such as iodinated radiocontrast agents or amiodarone. However, on further questioning, the patient reported that for the last 4 weeks she had been consuming a herbal tea, prescribed by a Chinese alternative practitioner to treat her enlarged thyroid. The prescription of the tea, which is shown in , revealed large amounts of kelp, Sargassum weed, and kombu.
FIGURE 2 Prescription of the medicinal tea containing several species of seaweed (marked by arrows). Sargassum pallidum, a brown algae found in great abundance along the coasts of Japan and China, is, along with Sargassum fusiforme, referred to as sargassum seaweed (more ...)
The patient was advised to discontinue the consumption of the tea and an antithyroid drug therapy with 40 mg thiamazole and 40 mg propranolol daily was initiated. Her follow-up visit, 7 months after the diagnosis of hyperthyroidism, revealed normal laboratory values of fT3, fT4, and just slightly decreased TSH levels () that were congruent with the lack of clinical signs of hyper or hypothyroidism. Her thiamazole therapy was then reduced to 20 mg daily.