This is part of an article in Pulse and if you want the whole article email Louise.Warvill@Thyroiduk.org to send to your GP before your appointment
Part Answer to question 2.
The combination of a normal serum T4 and raised serum TSH is known as subclinical hypothyroidism. If measured, serum T3 will also be normal. Repeat the thyroid function tests in two or three months in case the abnormality represents a resolving thyroiditis.2
But if it persists then antibodies to thyroid peroxidase should be measured. If these are positive – indicative of underlying autoimmune thyroid disease – the patient should be considered to have the mildest form of hypothyroidism.
In the absence of symptoms some would simply recommend annual thyroid function tests until serum TSH is over 10mU/l or symptoms such as tiredness and weight gain develop. But a more pragmatic approach is to recognise that the thyroid failure is likely to become worse and try to nip things in the bud rather than risk loss to follow-up.
Treatment should be started with levothyroxine in a dose sufficient to restore serum TSH to the lower part of its reference range. Levothyroxine in a dose of 75-100µg daily will usually be enough.
If there are no thyroid peroxidase antibodies, levothyroxine should not be started unless serum TSH is consistently greater than 10mU/l. A serum TSH of less than 10mU/l in the absence of antithyroid peroxidase antibodies may simply be that patient’s normal TSH concentration.