Patsy Westcott - The Healthy Thyroid - What you can do to prevent and alleviate thyroid imbalance

Hyperthyroidism, too, can be responsible for menstrual problems, including PMS. Although not as likely to affect fertility as an underactive thyroid, it is nevertheless associated with a number of complications during pregnancy ( see Chapter 9 ).

As with an underactive thyroid, an overactive one can also cause a goitre ( see page 56 ). If the doctor listens through a stethoscope, it may be possible to hear the blood surging turbulently through the vessels in the goitre, a noise known as ‘thyroid bruit’ (a bruit is the sound made in the heart, arteries or veins when the blood flows at an abnormal speed).

The symptoms of hyperthyroidism can often sneak up insidiously. Table 3.5 lists some of the clues that you or others may notice, or that your doctor may detect.

Hyperthyroidism may also be primary, when something goes wrong with the thyroid itself, or secondary, when the fault lies with the hypothalamus or pituitary.

Primary hyperthyroidismcan be due to:

• Graves’ disease, caused by autoimmunity ( see page 50 )

• Thyroiditis (inflammation of the thyroid), caused by autoimmunity ( see page 52 )

• Nodular thyroid disease, for example, toxic multinodular goitre (Plummer’s disease), characterized by the development of multiple lumps, or a ‘hot’ nodule (toxic adenoma), where a single lump becomes overactive ( see page 57 )

• Postpartum thyroiditis, wherein problems develop after giving birth ( see Chapter 9 )

• Excess iodine either from the diet (from food or, in some instances, herbal supplements) or from medications (such as the drug lithium, used to treat manic-depression; amiodarone, a drug used to treat irregular heart beat; and interferon, used to treat certain types of cancer)

Table 3.5 Symptoms suggestive of hyperthyroidism

• Overdosage of thyroxin treatment for hypothyroidism. On rare occasions, hyperthyroidism can be a consequence of people with an underactive thyroid accidentally or intentionally taking too much medication, a condition known as thyrotoxicosis factitia.

Secondary hyperthyroidismcan be brought on by:

• Faulty pituitary function, on rare occasions due to a pituitary tumour, leading to an abnormal production of thyroid-stimulating hormone (TSH), thereby causing the thyroid to produce too much hormone

• Cancer-related problems. In extremely rare instances, hyperthyroidism may be the result of a thyroid cancer that has spread.

In adults, the most common reason for the thyroid to become underactive is autoimmunity. Hashimoto’s thyroiditis (Hashimoto’s disease) – named after Hakuru Hashimoto, the Japanese doctor who originally described it in 1912 – is the most common type of autoimmune hypothyroidism. The other type is called ‘spontaneous atrophic hypothyroidism’, where the thyroid wastes away and shrinks. This is more likely to affect older women.

At first, although you may not feel ill. You may develop a small, painless goitre and, as time goes on, this may become tender and feel uncomfortable when you swallow. Curiously, when the disease first develops, you may develop symptoms of an overactive thyroid ( see page 48 ). This is only temporary, however. As the disease progresses, the thyroid becomes increasingly less active, and the typical signs and symptoms of hypothyroidism eventually set in.

For six to eight out of 10 women, hyperthyroidism is a result of Graves’ disease, another autoimmune condition that is the mirror image of Hashimoto’s disease. It is most common between the ages of 20 and 40, but it can be seen in girls as young as five and, very occasionally, in the infants of sufferers.

Robert James Graves, a charismatic Irish physician, gave his name to the illness. In 1835, he wrote a paper outlining all the symptoms now recognized as Graves’ disease in the UK and USA. In Europe, the same condition is often called ‘von Basedow’s disease’, after Dr Carl A. von Basedow, a private practitioner in Germany, who described the illness in 1840. Graves was the first to make the connection with pregnancy – the women he wrote about were all pregnant ( see Chapter 9 ).

Graves’ disease may be associated with all the classic symptoms of hyperthyroidism but, according to the UK-based endocrinologist Dr Anthony Weetman, these can be extremely variable. Writing in the New England Journal of Medicine , Weetman explains that both age and duration of thyroid overactivity play a part in determining which symptoms predominate. In over half those affected, nervousness, fatigue, rapid heart beat, heat intolerance and weight loss are key symptoms. However, in the over-50s, weight loss and loss of appetite are more common. Atrial fibrilliation is rare among the under-50s, but affects up to a fifth of those over 50. And while 90 per cent of younger women have a firm, diffuse goitre, only 75 per cent of the over-50s do. Glucose intolerance (inability to metabolize glucose) and, more rarely, diabetes can accompany Graves’ disease, and if you have diabetes, the condition will increase your need for insulin.

Graves’ disease has been called the ‘great masquerader’ because it doesn’t always produce the typical symptoms of an overactive thyroid. Confusingly, the condition can take a relapsing-remitting form in which the thyroid swings from overactivity to normal to underactivity and back to overactivity again. Even more curiously, 5 per cent of those with Graves’ disease become hypothyroid over time, sometimes becoming lethargic and passive, and unable to do anything but lie in bed all day. Patricia, 34, who was diagnosed with an overactive thyroid two years ago, recalls:

In the past, I was always a very active person. I love sports and would be out playing tennis or squash or doing aerobics four or five times a week. A couple of years ago, I began to feel completely worn out. I started to put on weight. My muscles ached all over and I felt fluey. I really struggled to get through each day. I was backwards and forwards to the doctor for about six months but, each time, I was diagnosed as having flu or a virus.

My mother suffers from an underactive thyroid so when my neck began to swell, I asked the doctor if I could have a thyroid problem. He said no. He thought it was a problem with my ears, because my job involves a lot of flying abroad. Eventually, I saw an ENT specialist, who felt my neck and said, ‘Are you being treated for your thyroid problem?’ Two days later, I was back at the hospital having tests, which showed I had an overactive thyroid. My symptoms weren’t at all typical, which I guess is why it took so long to get a diagnosis.