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common conditions

All about thyroid disease

Around half the people who have thyroid disease don’t know they have it. And for those with a diagnosis, treatment can be a balancing act.   

Health Agenda
July 2017

Do you often feel tired, have joint pain, and can’t tolerate the cold? Or perhaps you lose weight easily, feel your heart racing, and swelter in the summer. If this sounds like you, you may be one of the nearly half a million Australians with thyroid disease.

Anna Kelly understands the highs and lows of thyroid disease all too well. She was diagnosed with the condition when she was 16.

“I was really tired all of the time. The doctors didn’t think I’d have an underactive thyroid as I was quite skinny and always had been, but it turned out that I was underactive. The doctor put me on thyroid replacement hormone straight away,” she says.

What your thyroid does

Located just below your voicebox, your thyroid gland produces hormones, in this case tri-iodothyronine (T3) and thyroxine (T4).

Thyroid hormones influence what goes on in just about every organ in your body, telling them to slow down or speed up their function as needed, regulating how much oxygen you use, and helping you generate heat.

Thyroid disease

Thyroid dysfunction is usually caused by underactivity (hypothyroidism) or overactivity (hyperthyroidism). 

Underactive thyroid

According to endocrinologist Roger Chen, Associate Professor of Medicine at the University of Sydney, the most common cause of hypothyroidism in Australia is Hashimoto’s thyroiditis.

“It’s an autoimmune disease where your body’s immune system attacks the thyroid gland,” he says.

Anna has Hashimoto’s disease but it took many years, and multiple doctors, to get the diagnosis.

“I switched doctors and she was the first to tell me that I had Hashimoto’s, which was 19 years after my initial diagnosis. Nobody had mentioned an autoimmune connection before – she was the first doctor to test my antibodies,” she says.

Other causes of underactive thyroid are iodine deficiency (the most common cause worldwide), congenital (where a baby’s thyroid is underdeveloped at birth), some medications, and removal of the thyroid.

Symptoms of underactive thyroid may include:

  • weight gain
  • fatigue
  • intolerance to cold
  • joint pain
  • constipation
  • painful periods
  • dry and coarse skin and hair
  • pallor
  • slow pulse 
  • swelling of the neck (called goitre).

Overactive thyroid

Another autoimmune condition, Grave’s disease, is responsible for 70% of cases of hyperthyroidism. It mostly affects women between the ages of 20 and 40 and is 10 times more common among women than men.

Excess thyroid hormone is produced, resulting in an overactive thyroid. It isn’t clear what triggers this autoimmune response, but it could be excess iodine.

Symptoms of overactive thyroid may include:

  • weight loss
  • heat intolerance
  • palpitations
  • racing pulse
  • breathlessness
  • anxiety
  • diarrhoea
  • tremor
  • muscle weakness
  • bulging eyes
  • goitre.

The challenges of diagnosis

A significant number of people with thyroid disease think their symptoms are caused by other things, such as aging, depression or menopause, or they think they’re just tired. Women with an overactive thyroid may think they’re reaching menopause because they experience light, infrequent periods or stop menstruating altogether.

It can be frustrating for people whose diagnosis is delayed or who are misdiagnosed. Because a lot of the symptoms and signs of thyroid disease are common to other diseases, blood tests are needed to confirm a diagnosis.

Diagnosing underactive thyroid

“When an underactive thyroid is suspected, the blood level of TSH is high and the level of thyroxine or T4 is low, no further tests are needed and treatment should be started,” Associate Professor Chen says.

More commonly, the blood test shows an elevated TSH but a normal T4. In around 50% of cases, the blood levels will go back to normal, so another blood test is done around 6 to 8 weeks later. If the abnormality persists, you may be offered treatment.

Diagnosing overactive thyroid

In patients with overactive thyroid, blood tests show low or undetectable levels of TSH and elevated levels of T4 and/or T3.

If your blood tests look normal but you’re still worried, get a second opinion.

The challenges of treatment

Treating underactive thyroid

People with underactive thyroid are treated with thyroid hormone replacement therapy. Once the TSH level is back in the normal range patients continue on their current dose.

But it’s not a one-size-fits-all approach. For Anna, finding the right treatment has been an ongoing balancing act.

“My results have been quite all over the place – I’m probably a difficult case,” she said. “I think a lot of people go on tablets and their levels stabilise but mine have been quite up and down.

Anna found proactivity to be the key to managing her condition. By working with various specialists, she determined that specific dietary changes were beneficial. She also charts her progress over time.

“I’ve kept a record of all of my blood tests for the past 4 years. It shows which tablets I was on and what the results were so that I can keep track and watch for trends. You have to be your own health advocate.”

Treating overactive thyroid

In about 50% of cases, Graves’ disease resolves without any treatment, according to Associate Professor Chen.

“If it persists, you may be prescribed drugs to control the racing pulse and tremor. You may also be given a drug that interferes with the production of iodine,” he adds.

A 12 to 18-month course appears to offer the best chance of sustained recovery.

Surgery to remove the thyroid gland is sometimes performed if the thyroid is so enlarged it’s pressing on the windpipe, if drug treatment isn’t successful, or the patient is unwilling to take radioactive iodine, another form of treatment.

“However, surgical removal means taking thyroid replacement therapy for the rest of your life,” Associate Professor Chen notes.

Where to find out more

Talk to your doctor if you have any of the symptoms described above.

To learn more about thyroid disease, go to the Australian Thyroid Foundation.

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