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Dilemma: Doubt over thyroxine prescription

A newly registered patient asks you to renew her prescription for thyroxine, but you notice it was started without a diagnosis of hypothyroidism. What do you do?

Set out pointers about how you practise

At this first consultation I would set down pointers to demonstrate how I practise. I feel that if I do not deal with these issues now, it will be much more difficult to change later.

First, I would say that for any condition where medication is lifelong, care has to be taken when making the diagnosis. I would suggest she stops the medication and has blood tests six weeks later, including tests for thyroid antibodies.

Second, I would point out that thyroxine could cause palpitations or diarrhoea, plus unseen side-effects such as osteoporosis.

Third, I would explore other potential causes of her original symptoms – such as anaemia and diabetes – as well as assessing for depression and chronic fatigue syndrome. I would look at any psychosocial issues in follow-up consultations.

Finally, I would discuss that sometimes private doctors look at issues differently from NHS ones. Sometimes NICE guidelines are not adhered to and expensive branded products are prescribed, but I would not be critical of another doctor.

I would say that I always review prescriptions from a private doctor and give examples from my recent practice. If the blood tests confirm she has hypothyroidism then I would prescribe thyroxine on the NHS. If the TFTs are normal then I would look for an alternative diagnosis.

Dr Steve Brown is a GPSI in ENT and a GP trainer in Buckinghamshire

Explain that your medical practice is evidence based

To be diagnosed as hypothyroid, it is essential that thyroid function is tested biochemically alongside a careful clinical assessment of the individual patient. Clinical symptoms or signs alone are insufficient to make a diagnosis. The serum TSH assay is an exquisitely sensitive test for identifying patients with any degree of primary hypothyroidism.

As thyroid hormone production decreases, serum TSH increases. The decrease in thyroid hormone secretion may be small and not sufficient to reduce the T4 concentration below the reference range (subclinical hypothyroidism or mild thyroid failure), followed by a fall in serum T4, at which stage most patients have symptoms and benefit from treatment (overt hypothyroidism).

A normal serum TSH thus excludes primary, but not secondary, hypothyroidism. It would be important to obtain her menstrual history and consider and exclude hypopituitarism.

It will be necessary to explain that your medical practice is evidence based. There are no data to support the use of levothyroxine in patients with normal thyroid function and you should emphasise that you are not prepared to continue this prescription even if she has had an initial improvement. This improvement is unlikely to be sustained as you do not believe thyroid failure is the cause of her symptoms. I suggest slowly withdrawing levothyroxine over two months and re-assessing her, with investigation if her symptoms return.

Dr Mark Vanderpump is a consultant physician and honorary senior lecturer in diabetes and endocrinology at the Royal Free London NHS Foundation Trust

Check the diagnosis with the private physician

It is unclear what diagnosis the private physician made to justify prescribing thyroxine. GPs are responsible for all the prescriptions they issue, so if you are in doubt as to whether she has a condition that would benefit from thyroxine, investigate before prescribing.

This is in line with the GMC’s guidance on prescribing, which says you should prescribe medicines ‘only if you have adequate knowledge of the patient’s health and you are satisfied that they serve the patient’s needs’.

So long as you have no reason to believe that the patient might be harmed by stopping her prescription, you may need to decline this woman’s request until you are able to speak to her private physician.

If the physician is unable to explain the reasons to your satisfaction, explain to the patient you are unable to re-issue the prescription. Discuss with her whether there might be other treatments to help with her symptoms. If she is unhappy with your decision, she can request a second opinion from a local specialist or continue to see the private physician, ideally keeping you informed of any ongoing treatments.

If your conversation with the private physician raises any concerns about patient safety, talk to a senior colleague or your medical defence organisation, as the GMC places a positive duty on doctors to raise such concerns.

Dr Phil Zack is a medicolegal adviser at the Medical Defence Union

Further reading

• NICE. Clinical Knowledge Summaries: hypothyroidism. 2011

• Royal College of Physicians. The diagnosis and management of primary hypothyroidism, 2011

• GMC. Good practice in prescribing and managing medicines and devices, 2013

 

Editor’s Note

For a clinical dilemma article like this, especially one regarding a prescribing decision, we would typically ask the opinion of three people: a GP (preferably one with a relevant clinical specialism), a consultant and someone from a medical defence organisation.

Due to a breakdown in communication, two GPs and a non-medical representative of Thyroid UK were initially commissioned - and so the decision was made to recommission some of the elements. Our medical adviser had expressed a preference for Dr David Lewis’ contribution to be retained but asked for some revisions to be made to it.

Unfortunately Thyroid UK informed us that by that point Dr Lewis was too ill to edit his section, so we chose Dr Steve Brown, a GP with a special interest in ENT medicine, to be the GP voice. Dr Mark Vanderpump, a regular contributor to Pulse’s clinical section, supplied the secondary care perspective and Dr Phil Zack from the MDU provided advice from a medico-legal standpoint.

We understand the subject of subclinical hypothryoidism and its treatment is a very emotive one; however the clinical advice contained in the article is based on current UK clinical guidance. The elements of the article which were originally commissioned but which we were unable to use were not omitted because of any agenda on the part of the Pulse editorial team, but simply because the Dilemmas series follows a very specific format, which the first draft did not fit.

Adam Legge
Group clinical editor

Readers' comments (34)

  • The TSH test is an "exquisitely sensitive" marker of TSH levels in serum only. There is no evidence to show that the TSH test measures tissue levels of thyroid hormones. It is a deficiency of thyroid hormone in tissue that leads to symptoms of hypothyroidism.
    http://www.bmj.com/content/326/7384/311

    Vanderpump refers wrongly to a "normal range" yet no such "normal range" exists - there is only a statistically derived reference range. The validity of this reference range is the constant subject of debate and as it stands, the UK has a far wider range than any other Western nation leaving more British patients sick and untreated.
    http://jcem.endojournals.org/content/90/9/5483.full.pdf

    The BTA and RCP are keen on evidence - but only the kind that supports their pre-defined agenda.

    Where is the RCT that finds that NHS endocrinologists and doctors are better able to diagnose and treat symptoms of hypothyroidism than private doctors?

    Why is it acceptable to misdiagnose and mistreat hypothyroid symptoms with statins, orlistat, PPIs, SSRIs, wigs, costly referrals to secondary care etc.?

    What audit has been done to assess the effects of poor treatment and misdiagnosis of hypothyroidism to patients and to NHS budgets?

    How about an approach to hypothyroidism that involves listening to and learning from the patient?

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  • These are the results of a blood test I had this year. The so called " exquisitely sensitive marker, aka TSH blood test, showed my results at 2.78, ref range 0.27 - 4.20
    On this basis, any doctor would have considered me "normal, no action required"
    Fortunately, I also had a Free T3 test, which was
    3.5 , ref range 3.90 - 6.70
    This was under the reference range.
    Free T 4 was 1.1 ref range .12 - 22 also under the ref range.

    Clearly the TSH test has not picked up the low free T4/3
    Why, if it so exquisitely sensitive? I can tell you why but I wonder if any doctor knows the answer.

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  • What happens if you have a male with a mutation in the IGSF1 gene? This prevents the pituary from releasing the correct amount of tsh....

    Also, there are no NICE guidelines for thyroid problems.

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  • What if the patient has Hashimoto's? Why isn't this even mentioned? When I was ill and suffering my TSH test result was 5.89 (0.27 – 4.2), considered normal by my GP and the lab. However after a lot of persistence on my part the TPO antibody test was done, with a result of 258 iu/mL (0-59). I consider I had suffered unnecessarily for 2 years. It really is time to dispel the myth of the TSH test.

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  • My hypothyroidism was diagnosed by an endocrinologist based on symptoms. My TSH was at the upper limit of normal; my T4 and T3 were at the lower end of the normal range. I had already suffered for 5 years with many symptoms. I am lucky enough to respond well to levothyroxine, a cheap and safe treatment, yet I had a battle with my GP to get to an adequate dose. I now live a normally functioning life and hardly ever burden my GP with visits, instead choosing to pay to see my endocrinologist privately who treats me as a human, as the GP does not. Although writing here as a patient, I am also an academic medical researcher. I see no evidence for the TSH test, or the maltreatment of hypothyroid patients as this article suggests.

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  • doctors in this country and indeed the nhs should be ashamed of how they treat people with thyroid problems,its actually a complete lack of treatment, they need to learn to listen not just stick so hard and fast to blood tests. A lot of people are suffering through doctors ignorance and i include myself in this terrible situation, please doctors look at us when we enter your surgery, see in our eyes how hard this is to feel so awful and yet not be taken seriously by the one person we look to for help when we are ill

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  • GP DONT understand thyroid problems they do not examine you or ask any questions if the blood test show to high they drop your dose down and make you feel very unwell treat the patient not the blood test then thyroid sufferers might get a better life.

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  • I can only endorse all the above comments. As a Hashimoto's sufferer, I am extremely familiar with the shocking treatment (or rather, non-treatment) meted out by GP's and so-called expert endocrinologists alike. You could crawl into their offices on your hands and knees, sob uncontrollably and fail to finish a complete sentence and they wouldn't notice a thing, so busy are they assessing your blood tests. This article is dismally unsurprising, and inspires nothing but outrage in the thousands upon thousands of us who must not only continue to suffer the effects of this condition

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  • Because all the medical professionals I saw looked only at the TSH test, it took me nine years' fight to get treated. I had a huge number of symptoms and the majority of the standard physical signs of hypothyroidism, but my TSH was always in range, yo yoing between about 2.5 and 5, with no antibodies, and everyone was keen to diagnose me with CFS and send me away rather than to take note of the fact that FT4 and FT3 were both stubbornly at the bottom of their reference ranges. Being treated makes the difference to me between being effectively disabled and being able to live a full and active life. But, I still don't have a diagnosis. My GP has gone out on a limb for me and we are learning together. If he now starts following Dr Brown's advice, then my wellbeing will be put at risk and I will have no choice but to go private and pay for the treatment I so obviously need. This is a national scandal and it is time that the Department of Health took notice. Thank you.

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  • Some very good posts above and agree with many of them.

    The TSH does not give the whole picture. My experience is that GPs are more interested in dishing out anti-depressants rather than trying to help a patient regain their health.

    Now I avoid GPs as much as possible as I have zero confidence in them.

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