Thyroid conditions and Graves disease - Q & A

This article lists a range of questions on thyroid conditions and their effects on other metabolic functions which were posted by visitors to the Better Health Channel. Our experts provide the answers.

Q. I developed Graves’ disease after the birth of my first child 13 years ago. Six years ago I had radioactive iodine treatment and now I have an underactive thyroid. I take 200mcg of thyroxine a day to keep my levels reasonable. Since being hypo, there have been some strange things happening to my body including: cholesterol marks on the face (no family history and a low cholesterol count), lactose intolerance, pigmentation changes and anaemia. All blood tests reported normal except iron.
I am not sure what you mean by ‘cholesterol marks on the face’. Hypothyroid patients frequently suffer from elevated cholesterol because their slowed metabolism slows the cholesterol breakdown process more than it slows the production process.

Allergies (for example lactose intolerance) and vitiligo (white patches on the skin) are much more common in people with autoimmune conditions than in the general population. Graves’ disease is an autoimmune condition and, although the radioactive iodine treatment has stopped it from bothering you (by destroying the active cells in your thyroid), you still have the underlying condition.

It is possible that these conditions, while associated with your Graves’ disease and resulting hypothyroidism, are actually linked to the autoimmunity that caused the thyroid problem in the first place, rather than the thyroid problem itself.

There is also a form of anaemia, called pernicious anaemia, which is linked to autoimmunity. With this form of anaemia, the body lacks an intrinsic factor, which it needs to absorb vitamin B12.

If your thyroid hormone levels are too low, your metabolism is slowed and this, in turn, affects most bodily functions including food uptake and processing. The problem with cholesterol mentioned above is one such effect. The rates of absorption, processing and waste removal are all affected in different ways so that the levels of any number of things can get out of line.

The common problem of weight gain is another effect of a slowed metabolism (the body does not use the food intake properly and what is left is stored away). Constipation is another very common food related symptom of hypothyroidism.

Q. Is there a relationship between thyroid problems and anaemia?
There is definitely a link between hypothyroidism (underactive thyroid) and anaemia. This is actually because the metabolism is slowed down due to inadequate levels of thyroid hormones rather than an iron deficiency. The anaemia usually corrects itself when the hypothyroidism is treated.

The anaemia is not a separate condition, but is caused directly by the hypothyroidism. If you are prescribed iron tablets to help correct the problem, you should not take these tablets together with your thyroxine, because the iron affects the way the body absorbs thyroxine.

A much more serious form of anaemia, called pernicious anaemia, is also associated with Graves’ disease and Hashimoto’s thyroiditis. Special cells in the stomach lining are attacked by the immune system. These cells make a substance called ‘intrinsic factor’. This is needed for the absorption of vitamin B12, which in turn is used to make red blood cells. The condition is more common in older people and can be easily treated with vitamin B12 injections.

Q. I have been diagnosed with a simple non-toxic goitre (multinodular). My doctor says no treatment is necessary, but last month I had a miscarriage. Can these be connected?
A non-toxic goitre implies that none of the nodules are ‘hot’ or producing excessive amounts of the thyroid hormones. It is common to leave multinodular goitres untreated and to just keep an eye on them, provided there is no evidence of ‘hot’ nodules, cancer or the thyroid constricting the throat.

I assume you’ve had a thyroid scan to rule out hot or cancerous nodules and that there is no evidence of pressure on your throat. I also assume you’ve had your thyroid hormone levels tested and they are within the reference range. In these circumstances, it is unlikely that your thyroid condition contributed to your miscarriage because you should not have suffered any metabolic disorders.

Q. How often do I need to have a blood test to check my levels?
We recommend that anyone who has been diagnosed with a thyroid condition have a thyroid function test (TFT) to test their TSH (thyroid stimulating hormone), free T4 (thyroxine) and free T3 (triiodothyronine) levels at least once a year.

However, if there has been a change in dosage of thyroxine or the antithyroid drugs (neomercazole or propylthiouracil PTU), a TFT should be done about a month to six weeks afterwards to check that levels are within the correct ranges for the patient.

Sometimes other drugs can interfere with thyroxine medication. We recommend that anyone taking thyroxine hormone replacement have a blood test done about four to six weeks after starting to take any of the following drugs:

• Anticoagulants such as Warfarin, used to treat blood clots.
• Antidepressants, used to treat depression.
• Medicines used to treat diabetes such as insulin.
• Beta blockers such as propranolol, used to treat high blood pressure and heart conditions.
• Anion exchange resins such as cholestyramine, used to decrease plasma cholesterol.
• Corticosteroids such as prednisolone.
• Oral contraceptives and oestrogen hormone replacement therapy (HRT).
• Hepatic enzyme inducers such as phenytoin.
• Medicines used to treat heart failure such as digoxin.

• Your doctor
• Endocrinologist
• Thyroid Australia Tel. (03) 9888 2588