Firstly, you may not have to do very much. Mild degrees of thyroid overactivity can occur on a self-limiting basis, and may sometimes be left to run their own course, with an informed patient monitoring how they are, and seeking equally well-informed advice if things are not going right.
The first approach is an alert and informed assessment of progress, intervening only when necessary.
The second line of approach is to relieve symptoms until it is clear that the illness is either going to resolve itself in time or will require sterner measures. There are two medical weapons in most common use.
(i) Simple anxiolytics.
These are basically tranquillisers (eg Diazepam), and are acceptable, for a limited time where the degree of overactivity causes nervous tremor, worry, panic and palpitations.
(ii) Along with this or possibly instead, beta-blockers maybe used.
These are a group of compounds which prevent high levels of nervous activity reaching the tissues, and have a general calming effect on anxiety, nervous shaking, rapid pulse, in addition to their other therapeutic effects like reducing blood pressure, slowing down heart action (helping angina) and preventing migraines.
The one most widely used is Propranolol, either 10 or 40 mg two or three times a day, according to need. Even with extensive use there are very little either short-term or long-term side effects. Many doctors have found that a combination of an anxiolytic and a beta-blocker, in really small doses, works better than high doses of either by themselves and may control mild hyperthyroidism for extended periods of time.
When things are getting tougher, the next approach is the use of a chemical block on the production within the thyroid of thyroxine, which prevents the iodine molecules from attaching themselves normally to the thyronine molecule.
Two preparations have been in use for years: the commonest is Carbimazole (Neomercazole) (in multiples of 5 mg and 20 mg), this is usually given in a dose of 20-60 mg daily in two or three divided doses until the patient is euthyroid and then the dose is reduced to a maintenance dose of between 5 and 15 mg per day. When the symptoms have improved sufficiently and the levels of thyroxine have also reduced sufficiently, the dose may be further reduced or discontinued. It may be reintroduced if symptoms reappear.
The other is Propyl-thiouracil (PTU) (50 mg), the normal starting dose is 450 mg per day. Again, this dose is reduced depending on the response until a maintenance dose is found or the condition improves sufficiently for it to be discontinued. There are of course difficulties: they have been found to cause problems with the growth of white blood cells; suddenly and unexpectedly the immune system may be so compromised that a major or minor infection may suddenly appear.
Sometimes, of course, the patient is simply intolerant of the medication and becomes ill.
A variation of treatment is called “block and replace”. Enough antithyroid medication is given to suppress thyroid function completely and then supplemental thyroid hormone, as T4 or T3, to restore a euthyroid state. The reasoning behind this is that thyroid activity should be stopped so completely that when it restarts a year or so later, it remains at normal levels. Some people still feel tired under this regime.
When a regular daily dose is chosen, the amount of thyroid hormone production starts to fall, and the circulation of thyroid hormone starts to decline. The trick, of course, is to ensure the dose is neither too much, nor too little, remembering that thyroid production and thyroid hormone requirement may vary quite a lot. If this isn’t borne in mind, the result will be that the patient may be out of balance, either over or underactive.
Regular blood testing will be done to see if doses need to be adjusted.
This treatment may be used for an extended time – certainly a year or so – so long as the self-monitoring and the advice from an understanding doctor or healthcare practitioner, provides for virtual normality. Most commonly, the overactive state will, with ups and downs, tend to correct itself; the patient may find over time that the medication becomes unnecessary.
A life event or illness may, however, start it all over again, but the patient by now will recognise the symptoms and be able to deal with them. Another common sequel, however, is that having normalised for a while, the thyroid activity may start running below normal.
The problem is that this running down may be slow and insidious; the loss of energy and well-being, the weight gain, may go more or less unnoticed; be put down to age, overwork, worry, bad eating; before it becomes obvious that all is not well. The informed patient will alert themselves to this and seek advice.
If the hyperthyroidism cannot be controlled, a final solution to the problem will be offered to the patient. This final solution is thyroid ablation; which means the thyroid is knocked out finally and forever.
Two approaches are chosen: the first is radioactive iodine. I 131, the radioactive form, is given to the patient as a drink. The radioactive iodine concentrates in the thyroid tissue and ‘nukes it’. And secondly, surgery, where a proportion of thyroid tissue is removed.
The thyroid uses iodine as its main raw material and so this radioactive form concentrates in the colloid (hormone forming) tissue in the thyroid gland.
I 131 concentrates in the cells and its radioactivity destroys them. Depending on how much is given initially depends of course on the severity of cellular damage. The amount given is calculated by body weight and the presumed severity of the over-activity of the thyroid forming cells.
There are three possible scenarios. One is that the calculation was right. The amount of thyroid tissue left is just right to produce the right level of hormones in the bloodstream. Of course, the cells may later partly recover, and then it may have to be done all over again or further damage and loss of function may occur and the thyroid as a whole may become underactive.
The second scenario is that the patient continues to have an overactive thyroid in spite of treatment, and a further dose of radioactive iodine – or doses – may have to be given at once.
The third scenario is a good deal more common. Overkill becomes evident in a few days, and thyroid hormone in the bloodstream falls pretty quickly. Very soon thyroid replacement (usually thyroxine) becomes necessary.
The second approach is thyroid surgery. Let it be said at once that growths or cysts in the thyroid must be treated by surgical removal or a drainage procedure, and a much-enlarged thyroid which interferes with breathing or swallowing leaves no option.
Partial thyroidectomy to reduce the amount of thyroid hormone forming tissue is an option for some endocrinologists.