Hypothyroidism - Undiagnosed and Treatment Failures

By Lisa Wells, RN

Hypothyroid at the cellular level

The thyroid gland is a butterfly shaped gland located over the trachea (wind pipe) just below the larynx (voice box). It is responsible for regulating the metabolism of the body.

The thyroid gland normally releases T1, T2, T3, T4 and calcitonin. T4 is the storage hormone (thyroxine) that must be converted into the active hormone T3 (triiodothyronine) by the body. T3 is about five times more potent than T4 and only T3 can bind to the cell nucleus and provide biological activity.

Hypothyroidism is caused by insufficient production or absorption of thyroid hormone. This may be caused by adrenal dysfunction, vitamin and/or mineral deficiencies, autoimmune diseases such as Hashimoto's thyroiditis, or the aging process.

Those with hypothyroidism may look and feel older than their age because it can exaggerate the conditions associated with aging. Adequate levels of active T3 are needed to regulate the body's blood sugar and so cellular hypothyroidism may also bring about mature-onset diabetes. Low levels may increase the risk of cardiovascular disease due to increased cholesterol and triglycerides, and may also contribute to high blood pressure.

Other changes due to hypothyroidism include shrinking and weakening of the body's organs, including the heart muscle, and changes in the fat to muscle ratio with the result being more fat and less muscle.

The decrease in lean muscle mass can then interfere with the activity of the enzyme that converts T4 into T3. Also, patients who have high stress levels can have problems converting T4 into T3. Sometimes this is due to adrenal issues which can cause the patient to have either low or high cortisol levels.

Cortisol imbalance can cause problems with the conversion of T4 into T3. Some specialists believe that the T4 is instead converted into inactive reverse T3, which could clog the cell receptors and prevent the active T3 from entering the cell, while others deny this.

A clinical study was done in the 1980's where healthy subjects were given high amounts of reverse T3. That study appeared to show that RT4 does not block cell receptors. However, the test subjects that were used had healthy thyroid and adrenal glands, and the RT4 was not made by their own bodies, so many specialists still believe that high RT4 can play a role in hypothyroidism.

Symptoms of Hypothyroidism
Fatigue and lack of energy Decrease in heart contractility, feeling of heart heaviness
Atherosclerosis Elevated cholesterol and/or triglycerides
Poor sleep quality Depression
Dry, flaky, pale skin Thinning of eye brows
Sensitivity to cold, cold hands and feet Weakness
Weight gain Constipation
Dry, coarse, dull hair, loss of hair Headache
Mental sluggishness with poor memory Bruises easily
Mood swings and emotional instability Stiff joints including mild arthritis
Susceptibility to viruses and colds Persistent low back pain
Frequent respiratory problems Muscle cramps
Labored breathing Irregular menstrual cycles
Brittle nails Decreased libido

About one in 10 women and one in 20 men over age 50 will develop some symptoms of hypothyroidism. Hormone production decreases as we age, however the usual age related decrease is not considered true hypothyroidism by modern mainstream medicine.

Did you know? Some people today are being treated with synthetic T4 products such as Synthroid (levothyroxine) yet they are still hypothyroid at the cellular level due to their inability to convert the T4 into active T3.

The Problem With The TSH Blood Test

Many doctors only order a TSH (thyroid stimulating hormone) level when checking thyroid function. However, even if your TSH blood results show that you are within the normal range you may still be hypothyroid. Doctors who only check this level are most certainly in some cases missing the diagnosis.

I want to mention that the American Association of Clinical Endocrinologists lowered the normal range in 2003. Unfortunately, many doctors and labs still use the old outdated values.

The new TSH values state that any level above 3.0 is considered hypothyroidism. The old value allowed the TSH to be as high as 5.0 and still be considered normal.

Please note, this test only measures a stimulating hormone, so the higher the TSH level the more hypothyroid you are, meaning the more T3 your cells need.

Old Range: 0.5 to 5.0 mIU/L.
New Range: 0.3 to 3.0 mIU/L.

This decrease in the highest normal range has helped more people who are hypothyroid to be diagnosed, however we in functional medicine know that sometimes the TSH can be 3.0 but the patient is still hypothyroid.

Recommended Thyroid Lab Tests

Due to the TSH issue, if the patient is still symptomatic even with thyroid medication, the lab tests that may tell the story of what is going on are the Free T3 and Reverse T3 tests.

Some doctors may check the Free T4 but remember from above, the body must convert storage T4 into active T3, and only free T3 can be used by the cells. Some people have problems converting T4 into T3.

A few doctors may check a Total T3. However, most T3 in the bloodstream is bound by protein and so is not available for use. We need to know how much of the T3 is "free" and available.

Also, a reverse T3 test should be done at the same time as the free T3 test, since the total and free T3 tests measure all T3, both the active and the inactive reverse T3. If the free T3 level is either low or within the low end of normal limits but the reverse T3 is high or on the high end of normal, that may mean that much of the T4 is being converted into unusable reverse T3. At this point the T3 ratio is very important and should be used for figuring out how much of the free T3 is usable.

Reverse T3 is similar to active T3 and can bind to the cell receptors but it doesn't carry any activity, so it's basically trash. As mentioned above it may then block the cell receptors and prevent the active T3 from entering, which contributes to hypothyroidism. In patients who take large doses of levothyroxin but their TSH and Free T3 are still showing hypothyroidism this could be happening.

Since many doctors do not routinely check the free T3, and some may not be familiar with reverse T3, they may not understand the significance of these tests in diagnosing and treating hypothyroidism.

Other Important Blood and Saliva Tests

Did you know? Thyroid function depends on healthy adrenal glands. Even if the thyroid gland is producing enough of its hormones the body will have trouble using them without proper adrenal function.

Thyroid and adrenal function go hand in hand. For this reason it is my opinion, and it is also the opinion of other functional healthcare practitioners, that those who are suffering with symptoms of hypothyroidism should have their cortisol and DHEA levels checked to help assess adrenal function.

Since cortisol is supposed to change throughout the day the cortisol blood test should be checked at least twice on the same day. The first blood draw should be at 8 AM, and the DHEA level should also be checked at this time. Then the patient should return to the lab on that same day at 4 PM for a repeat cortisol blood test.

A more accurate way to test the adrenal glands is the saliva test that measures cortisol at 8 AM, 12 PM, 4 PM, and 8 PM on the same day in the convenience of your home. The DHEA level is checked along with the 8 AM test.

Unfortunately, at this time there are no insurances that I know of that cover saliva tests. However, cortisol test kits may be purchased online.

Below you will find instructions for the Barnes basal temperature test. It is a very basic home test that can be used by those who are experiencing some of the symptoms listed above.

The Barnes Basal Temperature Test For Hypothyroidism

1. When you go to bed at night place a thermometer next to your bed. Be sure to shake the thermometer down if it is a mercury thermometer.

2. As soon as you awake and before getting out of bed place the thermometer under your arm in your armpit. If using a mercury thermometer leave it in place for about 10 minutes. Be sure to check your temperature before you move around much because an increase in your activity can cause an increase in your temperature.

3. Record your temperature this same way for two days. If your temperature is below 97.8° to 98.2° for two consecutive days, you may possibly be hypothyroid.

4. Women should wait until after the first day of their menstrual period before taking this test.

*If your Barnes Basal Temperature test is positive you should take the results to your private healthcare provider and request he/she check you for hypothyroidism by checking the previously mentioned blood tests.

I also recommend that anyone with thyroid symptoms do more research so they are well informed when they see their doctor.

More Articles By Lisa Wells, RN

Thyroid Autoimmune Disorders - the Most Common Cause of Thyroid Dysfunction

How Human Growth Hormone (HGH) May Affect and Improve Thyroid Function

The Importance of Proper Adrenal Function and Balanced Cortisol

Our Homeopathic Supplement For Thyroid Support

Homeopathic Thyroid Support!


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Datis Kharrazian, "Why Do I Still Have Thyroid Symptoms When My Lab Test Are Normal", Morgan James Publishing, 2010

Stephen B. Edelson, Deborah Mitchell, "What Your Doctor May Not Tell You About Autoimmune Disorders," Wellness General Hachette Book Group, 2003