Endocrine Abstracts

A 39-year-old lady with severe primary hypothyroidism was referred to the endocrine clinic. Her past medical history includes intermittent colitis and Irritable Bowel syndrome. There was no history of diarrhoea for the last 1 year. TSH 97.2 mU/l (0.3–5.0) and free thyroxine (T₄) was 5.0 pmol/l (10–22). The dose of levothyroxine was increased gradually from 100 to 300 μg/day. Despite this, TSH level remained high at 96.1 and freeT₄ was 4.0. She felt generally unwell, tired and weak. She denied missing her medications. Weekly supervised thyroxine therapy was started at 1000 μg/week for 1 month. TSH, T₄ and T₃ were monitored closely at 0, 1 and 4 h. Thyroid functions improved dramatically within 1 month (see Table 1). She is now maintained on 150 μg of thyroxine/day and compliance was reiterated.

Discussion: Serum T₄ rose significantly in the first hour but started to drop at 4 h. T₃ did not change much but the TSH levels improved significantly within a month.

Studies were done with biweekly and weekly thyroxine supplementation and doses up to 3 mgms per week were well tolerated. In one study a slightly larger dose than 7 times the normal dose was used for biochemical euthyroidism however in our patient <50% of the total weekly dose was used with good response. Poor compliance is not uncommon in patients with hypothyroid disorder as depression may be a co-morbid state. Supervised weekly thyroxine therapy involves careful monitoring of thyroid functions. Cardiac ischaemia and arrhythmia should be ruled out before starting this treatment.

Conclusion: Weekly supervised thyroxine supplementation may improve compliance in selected group of patients with unexplained severe hypothyroidism.