Hyperthyroidism: What are the symptoms of an overactive thyroid?

The thyroid, located in front of the trachea, is an endocrine gland that secretes the hormones that regulate metabolism. A change in the thyroid gland’s function, such as in hyperthyroidism, thus results in energy being consumed at an abnormal rate, causing symptoms and increasing the risk for severe health conditions.

Here to provide an expert insight into hyperthyroidism, including causes, symptoms, and treatment, is Dr Marc Atkin, esteemed consultant in diabetes, endocrinology and internal medicine.

What is hyperthyroidism? What are its symptoms?

Hyperthyroidism, or thyroid overactivity, is a condition in which the thyroid gland produces too much of the hormone thyroxine.

Hormone levels are normally regulated by a negative feedback loop; a self-regulatory system in which the pituitary gland in the head constantly monitors thyroid levels, and then feeds back to the thyroid gland the exact amount of thyroxine it needs to produce.

This system is broken down in hyperthyroidism, meaning that the gland continues to produce thyroxine despite the pituitary gland telling it that there is already enough thyroxine in the bloodstream. The high levels of thyroxine, and the symptoms that are experienced by people with hyperthyroidism, are a consequence of this broken system.

Common symptoms associated with hyperthyroidism include:

• itchy skin
• itchy or watery eyes
• overactive bowels
• heat intolerance (thyroxine causes metabolism to go overdrive, causing an individual with heat intolerance to constantly feel hot when everyone else is cold)
• feeling on edge or unsettled, anxiety (thyroxine releases adrenaline), tremors or palpitations (racing heart)
• sleep problems, tiredness, fatigue

What can cause hyperthyroidism?

Hyperthyroidism has two main causes.

The first is an autoimmune condition, in which the immune system attacks the thyroid gland. When this occurs, the thyroid gland can either become underactive (the gland does not produce enough thyroxine) or overactive (the gland is stimulated to produce more thyroxine). In hyperthyroidism, an autoimmune condition causes the thyroid gland to produce more thyroxine, breaking down its feedback mechanism.

The other is a multinodular goitre, an enlarged thyroid gland with multiple thyroid nodules. Although the nodules are small in size, they can become autonomous and develop a way to produce thyroxine on their own, to the point of causing hyperthyroidism.

Is hyperthyroidism considered a serious condition?

Hypothyroidism can be quite severe. It often creeps up on people over a long period of time, so it goes unnoticed in many cases. However, what starts off as simple tiredness and ‘feeling under the weather’ can later develop into problems with the bones and with the heart, and in extreme circumstances, even cause heart failure.

Thus, hyperthyroidism is not a condition that should be left untreated, because it can progress and cause people to feel seriously unwell. Thankfully, this does not occur very often, but hyperthyroidism still has that potential.

How is hyperthyroidism treated? Can it be cured?

There are medications available for hyperthyroidism that can be used to put a block and a break on the thyroid gland, slowing down and getting the production of thyroxine back under control. Generally, medication tends to be a short-term measure for hyperthyroidism, but it can be prescribed for some time, to see if the thyroid gland will settle down with medication alone.

If the thyroid gland does not settle down, then there are other more definitive methods that can be recommended to treat hyperthyroidism. One treatment option utilises radioactive iodine, which destroys a bit of the thyroid off using radioactivity. Another option is to surgically remove all or part of the thyroid gland through a thyroidectomy, erasing the source of thyroxine overproduction. After both of these scenarios, people would require thyroid hormone replacement therapy later on to replace the natural production of thyroxine, which would be given in pill form.

Who is most at risk of developing hyperthyroidism?

Certainly, autoimmune conditions tend to be more common in women. The reason for this is unclear, but the risk of having hyperthyroidism caused by an autoimmune condition is 10 times greater in women than in men, and usually develops among women who are between 20 to 40 years of age.

Multinodular goitres, on the other hand, are more common in elderly people who are 60 to 80 years old. Hyperthyroidism in this age group is more worrying, due to the co-existing healthcare conditions that elderly people usually have even without hyperthyroidism. An overactive thyroid gland in this age group can cause atrial fibrillation, increasing the risk of suffering a stroke. This is why hyperthyroidism is especially monitored in this age group.

If you have symptoms of hyperthyroidism and wish to have them assessed by an expert, do not hesitate to visit Dr Marc Atkin's Top Doctors profile today.