Endocrine Abstracts

The British Thyroid Association executive committee advised in 2015 that there was insufficient evidence that levothyroxine(T4) and liothyronine(T3) combination therapy was superior to levothyroxine monotherapy, which remains the standard treatment of primary hypothyroidism. It was considered an experimental approach in symptomatic patients on T4 therapy with a TSH level within normal range.

We present a 47-year-old lady who had been diagnosed with primary hypothyroidism for three-and-a-half years under the care of her General Practitioner. Despite treatment with levothyroxine 25 and 50 micrograms on alternate days she had ongoing lethargy, generalised weakness, a lack of concentration and ‘brain fog’. She gained over 10 kg in weight over the previous 5 years despite adhering to calorie intake recommendations, increased exercise regimes and seeing a nutritionist.

On clinical examination, she had a body mass index (BMI) of 36 with a slow relaxing phase of bicep reflexes, an otherwise normal examination of all systems with no overt features of Cushing’s Syndrome. She was clinically and biochemically euthyroid with TSH 4.49 mU/l [Normal range (NR) 0.35–5.5], free T4 17.3 pmol/l (NR 10–19.5) and free T3 5.1 pmol/l (NR 3.55–5.44) with positive TPO antibodies. An overnight dexamethasone suppression test excluded a Cushing’s syndrome with an appropriate serum basal cortisol suppression at 24 nmol/l.

She was reviewed a number of times over the following 12 months with ongoing symptoms as per patient; feeling tired, worn out, unable to keep awake and ‘at her wit’s end’. She remained clinically and biochemically euthyroid with free T3 4.3 pmol/l at lower half of the normal range, normal TSH 3.96 mU/l and a normal free T4 15.7 pmol/l, hence no changes to levothyroxine dose were made.

The pros and cons of T3 therapy were discussed in detail and subsequently liothyronine 10 micrograms daily was initiated. At further clinic reviews four and eight months later, she reported a significant improvement in her energy levels, hair growth at her eyebrows and weight reduction of 3 kg with no change in her lifestyle. Liothyronine 10 micrograms daily in combination with levothyroxine 25 and 50 micrograms alternate days was continued with subsequent further improvement in her general wellbeing.

Conclusion: We present a case of significant improvements in a patient’s symptoms, well-being and quality of life on commencement of T3 in addition to T4 despite prior normal thyroid function tests on T4 alone.