Author, Peter Warmingham, gives a brief summary of an individual approach to thyroid diagnosis and treatment, setting out the new ideas (a paradigm) suggested by Thyroid UK advisers which it is hoped will eventually replace the current ones.
The advisers to Thyroid UK have been working hard to establish a scientific basis for a major change in the diagnosis and treatment of thyroid conditions. To that end, they have published over 30 papers in respected journals over the last decade or so. Their new research takes into account for the first time the close involvement of the thyroid-pituitary system with homeostasis – the way the body keeps internal conditions stable when external influences might otherwise disturb them i.e. temperature and illness.
This enabled the research team to learn a lot more about how the pituitary-thyroid system works, and discredit the prominence currently given to the TSH test. They are now calling for an individual approach to thyroid diagnosis and treatment and have outlined a new set of ideas (a paradigm) which it is hoped will eventually replace the current ones.
The following is a brief summary of those ideas as set out in our paper titled Recent Advances in Thyroid Hormone Regulation: Toward a New Paradigm for Optimal Thyroid Diagnosis and Treatment.1
1. The researchers found that the hypothalamic-pituitary-thyroid system balances the levels of thyroxine (T4), triiodothyronine (T3) and thyroid-stimulating hormone (TSH) in a way that is unique to each individual and each given situation. The final balance is determined by a wide range of factors such as genetics, age, recent illness, etc.
2. As the three main hormones T4, T3 and TSH are closely interrelated it can no longer be assumed that if the TSH level is known the FT4 and FT3 levels are also known. This means that all three test results should be considered together and interpreted in relation to each other.
3. In future, new kinds of reference ranges for combinations of FT3, FT4 and TSH will need to be developed.
4. The current ‘one size fits all’ approach to diagnosis and treatment is no longer justifiable because of the wide variation in hormone levels needed by different individuals to feel well – a much more individual approach is needed.
5. It is now known that as well as controlling how much hormone the thyroid gland produces, TSH also partially controls the conversion of T4 into T3. It is also now known that more T3 is made in the thyroid gland, and less in other parts of the body, than was previously thought.
Furthermore, individuals vary greatly as to how much T3 they are able to make from a given dose of thyroid hormone. This means that when too much thyroid tissue has been lost to thyroid antibodies, some patients may reach a point when they are unable to convert enough T4 into T3 in their liver, and other tissues, to satisfy their body’s needs and will only be able to feel better on liothyronine (L-T3).
6. Research shows that the balance of TSH and FT4 values (referred to by the researchers as either the ’equilibrium’ or the ‘set point’) varies both between individuals and over time, because of homeostatic and other changes. This means that FT4, FT3 and TSH blood test results taken earlier in life can’t be depended on to provide a useful ‘baseline’ for reference later in life.
7. In future, the best levels of TSH, FT4 and FT3 for the patient to feel well first need to be decided by the doctor and thereafter used as a reference against which to interpret the patient’s current levels and to set dose levels of thyroid hormone.
8. TSH is now seen as only being useful for diagnosing overt hypothyroidism or overt hyperthyroidism and, except at extreme levels, can no longer be regarded as a reliable indicator of thyroid health. This is because the reference levels for TSH are much too wide given that each individual’s levels will only ever vary over a small part of that range. Also, a high TSH accompanied by a normal FT4 can no longer be taken to mean subclinical hypothyroidism and FT3 should always be taken into account.
9. A simplistic approach to diagnosis and treatment, i.e. thyroid tests alone, is no longer valid because the process of finding a homeostatic balance is very intricate and it is no longer acceptable to rely on laboratory tests alone.
10. TSH also no longer has an exclusive role in guiding treatment targets – its interpretation should be tied to the clinical signs and symptoms which are the main concern since they reflect both thyroid status and the patient’s well being.
11. The suitable TSH range is different in patients being treated with thyroid hormone to those that are not on treatment because the body reacts differently to receiving a whole day’s dosage in one go instead of being slowly drip-fed with the same dosage over 24 hrs in someone who doesn’t have thyroid disease.
3 elements to a better thyroid diagnosis and treatment
The following is what should happen in an ideal future consultation regarding thyroid diagnosis and treatment with a doctor:
A diagnosis should be made based on three elements:
- the patient’s history and symptoms,
- a complete physical examination including ultrasound of the thyroid gland,
- a complete set of lab tests (TSH, FT4 and FT3).
All of these elements should be considered together in coming to a diagnosis.
Thyroid function tests should be interpreted according to homeostatic principles, by considering the balance between TSH, FT4 and FT3 levels.
At least two criteria should be used to adjust medication dose, these being a) symptoms and b) how far the patient’s test results are from what has been decided are the ideal ones for that patient.
Sadly none of these improvements is available at your GP surgery yet and furthermore, the new NICE guidelines won’t help because the new research has been dismissed by its authors as being ‘beyond the level of detail they would normally consider’.
1.Hoermann R, Midgley JEM, Larisch R, Dietrich JW. Recent Advances in Thyroid Hormone Regulation: Toward a New Paradigm for Optimal Diagnosis and Treatment. Front Endocrinol. Published online December 22, 2017. doi:10.3389/fendo.2017.00364