Though approximately 10 per cent of Canadians aged 45 years or older have thyroid dysfunction, it’s estimated that in North America, 50 to 60 per cent of those living with the disease are unaware of it.
Hypothyroidism, which occurs when the thyroid gland is underactive, is the most common of the thyroid disorders, and its prevalence rises with age. Its symptoms, such as fatigue, muscle weakness, weight gain, depression, constipation and poor memory, as well as intolerance to cold, dry skin and brittle hair often begin mild and intensify gradually.
“People should be aware that this is a common condition that is often not diagnosed, so it’s important to be aware of the symptoms and let your doctor know if you have one or more,” says Dr. Ronald Goldenberg, a consultant endocrinologist with North York General Hospital.
Goldenberg points out the fact that the symptoms of this disorder are associated with aging and other diseases, makes them easier to overlook. But for many, the ability to recognize the symptoms and obtain a diagnosis can make an important difference in their quality of life today and prevent complications that could arise in the future.
Hypothyroidism causes such a broad collection of symptoms because the thyroid gland plays a role in so many body systems. This small gland that sits below the Adam’s apple in the neck is responsible for secreting thyroid hormones that control the body’s metabolic rate. Metabolic rate is essentially the speed at which the body’s chemical functions work, from heart rate and the rate at which calories are burned, to skin maintenance, digestion and fertility. Because the thyroid gland plays such a vital role in how our bodies function, hypothyroidism can lead to serious health consequences if not treated.
The most common cause of hypothyroidism is an autoimmune condition called Hashimoto’s Thyroiditis, which causes enlargement of the thyroid gland. Over time, the thyroid gland’s ability to produce thyroid hormones becomes impaired, resulting in hypothyroidism. It is more common in women, especially those with a family or personal history of other autoimmune diseases.
“Because hypothyroidism is so common and so frequently missed, there are very clear recommendations for who should be screened, even if they are not experiencing symptoms,” says Goldenberg. These groups include individuals over age 60, women who are planning a pregnancy or, early in their pregnancy and those with a personal or family history of autoimmune diseases, such as Addison disease, type 1 diabetes, vitiligo, pernicious anemia, rheumatoid arthritis and lupus.
To diagnose hypothyroidism, physicians check the levels of thyroid stimulating hormone (TSH). As the name suggests, this is the hormone that stimulates the thyroid to produce the hormones T3 and T4. When T3 and T4 levels are low, the pituitary gland produces more TSH in an effort to make the thyroid work harder. This is why people with an underactive thyroid will have a high TSH result. Physicians may also look at the levels of the thyroid hormone, T4, which is normally lower in individuals with hypothyroidism.
The degree to which TSH is elevated and T4 is decreased is also important in the diagnosis. “In overt hypothyroidism, you have an elevated TSH and a low T4, but there are also people who have subclinical hypothyroidism, or what I call mild thyroid failure, which is when the TSH is slightly above the normal range and the T4 is at the low end of normal range,” explains Goldenberg.
“Although the term ‘subclinical’ means that the disease is not causing clinical symptoms, careful examination of these patients sometimes reveals that they actually have been experiencing symptoms and may benefit from treatment.”
While not all individuals with subclinical hypothyroidism need to be treated, experts agree that all individuals with overt hypothyroidism require treatment, which is usually with a synthetic form of the T4 hormone, levothyroxine.
The first months of therapy are focused on getting thyroid hormone levels back into the normal range. Because it can take several weeks for levothyroxine to build up in the body, blood tests are usually done between four and eight weeks after treatment begins to determine whether the dose is right, or needs to be adjusted. Once the right dose is determined, followup tests are done every year to ensure levels are still where they should be.
“The goal of treatment is to get TSH in the normal range, which usually happens within weeks to months. At that time, we’ll also look to see whether there has been an improvement in symptoms,” shares Goldenberg. “It’s very gratifying as a physician to see patients who have been experiencing symptoms of hypothyroidism for weeks and sometimes months, begin to see improvements.”
According to Goldenberg, treatment for hypothyroidism, which is usually lifelong, has a high success rate.
A challenge exists in closing the gap on diagnosis, however. Here, there is an opportunity for those who are at risk to advocate for themselves or an elderly loved one, remembering that hypothyroidism risk increases with age. Physicians believe raising awareness of the risk factors and symptoms can be instrumental in helping to close this gap.
Visit thyroidsymptoms.ca for more information about hypothyroidism, as well as helpful self-assessment tool that can help equip you for a discussion with a health care professional.
This story was created by Content Works, Healthing.ca’s commercial content division, on behalf of a research-based pharmaceutical company.