Subclinical Hypothyroidism – Causes, Symptoms, Diagnosis and Treatment Options

Subclinical hypothyroidism is a hidden disease – one that sometimes is difficult to diagnose simply because the symptoms of subclinical hypothyroidism are not that evident.

What exactly is subclinical hypothyroidism?

Broken down into layman’s terms, it really means that your thyroid is not producing or secreting the correct amount of thyroid hormones that your body demands…

And “subclinical” means that it is not easily detected because the problem is often “asymptomatic”; in other words, the symptoms are not readily visible or noticeable, and without an actual blood test, you may never even know that you have subclinical hypothyroidism.

How Common is Subclinical Hypothyroidism?

Subclinical hypothyroidism is more prevalent than most people realize; again, because it is asymptomatic. In recent studies performed across the United States, it is estimated that (on average) roughly 4% of all men and 8% of all women men are subclinically hypothyroid. However, these averages rise with age, and it has been estimated that 8% of men over 60 and 15% of women over the age of 60 are subclinically hypothyroid.

In Europe, subclinical hypothyroidism is more prevalent in areas of iodine sufficiency. There are reports of a high of 23.9% in regions surveyed that have a high incidence of iodine intake; while the numbers drop significantly to around 4.3% in iodine-deficient areas. However, these are numbers based on actual blood tests; and doctors estimate that the numbers are probably higher since a significant amount of the population are not regularly tested for subclinical hypothyroidism.

Subclinical Hypothyroidism – Also Known As Underactive Thyroid

While subclinical hypothyroidism is usually not life threatening, it can create a multitude of problems throughout the body. The thyroid is a butterfly shaped gland in the middle of the neck.

The thyroid gland regulates the hormones triiodothyronine (T3) and thyroxine (T4); and these hormones control exactly how your body stores and uses energy… In other words, how your body’s metabolism runs.

In about 90% of cases, hypothyroidism can be traced back to a problem in the immune system which creates auto-antibodies that attack the thyroid gland, causing it to malfunction. However, certain medications and diseases can also cause an underactive thyroid.

The main causes of hypothyroidism include:

  • “Hashimoto’s thyroiditis” or autoimmune thyroiditis – this is a form of thyroid inflammation caused by the patient’s immune system. It leaves a large part of the thyroid’s cells damaged and incapable of producing the T3 & T4 hormones in the correct levels.
  • Any kind of surgical procedure that removes a portion of the thyroid gland (a common treatment that is used to assist with other thyroid problems)
  • Certain infections which can temporarily affect the functioning of the thyroid gland.
  • Goiters and some other thyroid conditions that are usually treated with a radioactive iodine therapy. These radioactive iodine treatments may disrupt the normal production of the thyroid hormones.

Goiters are formed because the body is expecting a certain amount of thyroid hormone. Therefore, the pituitary gland will produce additional thyroid stimulating hormone (TSH) in an attempt to coax the thyroid to produce more hormone.

This constant infusion of high levels of TSH may cause the thyroid gland to become enlarged and form a goiter (often referred to as a “compensatory goiter”); and the most common treatment for these goiters is a radioactive iodine therapy.

The aim of the radioactive iodine therapy (for benign conditions) is to kill a portion of the thyroid to prevent goiters from growing larger or producing too much hormone (hyperthyroidism).

Occasionally, the result of this radioactive iodine treatment will be that too many thyroid cells are damaged so the patient often becomes hypothyroid within a year or two.

  • Problems with the pituitary gland or the hypothalamus; these two glands produce hormones that actually control the operation of the thyroid.

In other words, you could have a completely normal thyroid that is not working to produce the T3 & T4 hormones because of an issue with your pituitary gland.

The pituitary gland produces a “thyroid stimulating hormone” (TSH) that forces the thyroid to produce the correct amount of T3 & T4 hormones; however, if the pituitary gland doesn’t produce enough TSH to get the thyroid working then the thyroid doesn’t go to work.

The Far-Reaching Effects of Subclinical Hypothyroidism – Symptoms

Because this condition is subclinical or asymptomatic, many times people do not even realize that they have hypothyroidism.

Some of the typical symptoms would include:

  • Constant tiredness
  • An increase in weight or exceptional difficulty in losing weight
  • Depression
  • Constipation
  • Coarse, dry hair
  • Dry, scaly pale skin
  • A cold temperature intolerance (you cannot take the cold like people around you)
  • Muscle cramps and frequent muscle aches that won’t go away
  • Irritability
  • Memory loss
  • Abnormal menstrual cycles
  • A general feeling of “fuzziness” or lack of orientation.

You may have these symptoms in combination or no symptoms at all. One of these symptoms may be causing you extreme discomfort while another may be a minor nagging complaint. Or you may not have any symptoms at all or they are simply too minor and they just go unnoticed. And since these symptoms are associated with a myriad of other maladies, without accurate testing, hypothyroidism is quite often simply overlooked. Subclinical hypothyroidism is often not discovered without specific testing simply because the disease is very hard to localize.

A rarer condition of hypothyroidism is the so-called “thyroid storm”. While infinitely more serious, it is also much less common; and is usually brought about as a consequence of a stroke, an injury, or a severe infection. Symptoms of a thyroid storm may include fever, jaundice (a condition where the skin turns yellow), a rapid heartbeat, dehydration, agitation, confusion and hallucinations. A thyroid storm demands immediate and urgent treatment as it can lead to coma.

Subclinical Hypothyroidism in Women

Because of the limited visible signs of subclinical hypothyroidism, women are especially cautioned to get tested for subclinical hypothyroidism before or during pregnancy.


Miscarriage Risk and Low IQs

In a recent report in the Journal of Medical Screening, doctors reported that miscarriages could be significantly reduced if screenings for hypothyroidism were performed as a regular part of pre-natal exams.

The study concluded that pregnant women who were discovered to have hypothyroidism are four times more likely to have a miscarriage in the second trimester than women that have normal thyroid functions. The study attributed six out of every 100 late miscarriages to an undiagnosed hypothyroid condition in the mother.

The New England Journal of Medicine also reported its findings on the results of a study of women with hypothyroidism during pregnancy. It found that children born to women with hypothyroidism had below average psychological development.

In addition, they discovered that the children had significantly lower IQ levels, impaired motor skills, and continued difficulties with attention, language, and reading skills.

The study indicated that 19 percent of the children born to mothers with hypothyroidism had IQ scores of 85 or lower; while the baseline for the study showed only 5 percent of children born with a reduced IQ level to mothers without any thyroid problems.

According to the study’s lead author, the range below an 85 IQ level can mean significant impairment for children so they have recommended a full blood workup to specifically check for subclinical hypothyroidism for mothers as part of a comprehensive pre-natal doctrine in addition to the usual pre-natal regimen.

Diagnosing Subclinical Hypothyroidism

Diagnosing hypothyroidism usually requires an in-depth analysis of the patient’s complete medical history in conjunction with a careful physical examination.

The most critical step to the diagnosis of any thyroid condition is a blood test to measure the level of thyroid-stimulating hormone (TSH) (which will show up high in hypothyroidism).

It is also necessary to measure the level of two of the thyroid hormones (both T4 and T3) which are low in hypothyroidism.

Other tests can include…

-The measurement of specific antibodies (TPO-ab and Tg-ab) which detect the origin of a specific thyroid problem

-A thyroid scan or ultrasound, which produces images of the thyroid gland and can help to determine its size, shape and position.

-An iodine scan that is used to measure thyroid function by determining how much iodine is taken up by the thyroid gland

More often than not, any thyroid issues like hypothyroidism or hyperthyroidism can be detected by a simple blood test; and if any thyroid problems are discovered after testing, alternate procedures can be performed to isolate the individual problem.

Subclinical Hypothyroidism Treatment

Many doctors don’t think that subclinical hypothyroidism requires treatment. Usually they would just follow-up with the patient and perform blood tests every few months or so. When TSH becomes elevated, they would give you a prescription for levothyroxine/synthroid in an effort to replace the hormones the thyroid is no longer producing with an orally ingested thyroid supplement. With this type of treatment you would have to take a pill every day for the rest of your life. That doesn’t guarantee, however, that your symptoms would disappear or you’ll restore your health.

Quite the opposite – this type of hormone replacement therapy does not address the main cause of your hypothyroidism problem which in 90% of the cases is AUTO-IMMUNE in its nature. So taking synthroid does nothing to balance your immune system or improve your thyroid function. That’s why it’s very important to get an accurate diagnosis so that you and your doctor could determine the right hypothyroidism treatment for you.

There are several different types of thyroid hormone protocols, and what works well for one patient does not work for another. You can choose the synthetic hormone like synthroid or the natural desiccated hormone like Armour. Some patients prefer to try out both options before choosing one or the other.

Hypothyroidism is different in every patient, and while subclinical hypothyroidism is luckily not life-threatening it can still make you feel completely “out of whack”.

The consensus of endocrinologists is a thyroid blood test every year, especially after 35 years of age.

Tags: hypothyroidism treatment, subclinical hypothyroidism, hypothyroidism symptoms, subclinical hypothyroidism diagnosis




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About Author

Petra Mitova is the author of the best-selling ebook "Overcoming Hypothyroidism: The Ultimate Guide to Recovery." She's dedicated to helping patients empower themselves by providing patient-oriented information about thyroid disease - whether you suffer from hypothyroidism, hyperthyroidism or any other form of thyroid disease, feel free to browse our website and learn about thyroid disease diagnosis, treatment options, natural remedies and more.

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