Thyrotoxicosis - revised guidance from the American Thyroid Association
In August the American Thyroid Association revised their guidance on the management of thyrotoxicosis. It includes many things that many of us in the UK would consider normal practice and the following are 5 major updates.
1. Making the diagnosis of thyrotoxicosis - the use of thyroid receptor antibodies (TRAb).
Perhaps in response to the relative overuse of radioiodine (RAI) uptake scanning and ultrasound in some hands in the diagnosis of thyrotoxicosis this revision highlights the role of TRAb alongside these other modalities, particularly if Graves' disease is suspected and there are no extrathyroidal features such as ophthalmopathy or orbitopathy (thyroid eye disease - TED) to make the diagnosis. A RAI uptake scan may still be indicated if a toxic adenoma or toxic nodular goitre is suspected.
2 The use of TRAb for monitoring the response to antithyroid therapy.
TRAb can be used to monitor the response to therapy, particularly to give information on the chance of remission after a full course of therapy, on discontinuation; if the TRAb remain elevated another 12 - 18 months of antithyroid medication may be warranted, or definitive therapy with surgery or radioiodine.
3.. Long term antithyroid medication is a safe and reliable alternative to surgery or RAI
Long term antithyroid medication with carbimazole and propythiouracil has been offered to many of my own patients over the years if they have relapsed, or at high chance of relapse, after a 12 - 18 month course of therapy and this course of action is now fully supported in the current revision. Indeed the long term outcomes for patients may be better on long term carbimazole than after RAI.
4. Pregnancy and thyrotoxicosis.
Patients are advised to become euthyroid before becoming pregnant. When choosing therapy the long term risks to the mother and fetus of both thyrotoxicosis and therapy must both be considered. The diagnosis should be considered on at least two blood tests conducted a month apart. During pregnancy antibodies can be used to monitor therapy more freely during pregnancy in Graves' disease..
5. Optimise calcium and vitamin D before surgery.
To reduce the risk of post-operative hypocalcaemia, should the parathyroids be damaged or resected, at surgery, patients should be vitamin D and calcium replete. Having treatment with calcium tablets for two-weeks before surgery may reduce post-operative hypocalcaemia in surgery for Graves' disease.
Ross Douglas S., Burch Henry B., Cooper David S., Greenlee M. Carol, Laurberg Peter, Maia Ana Luiza, Rivkees Scott A., Samuels Mary, Sosa Julie Ann, Stan Marius N., and Walter Martin A.. Thyroid. October 2016, 26(10): 1343-1421. doi:10.1089/thy.2016.0229.