Hypothyroidism has been called the “unsuspected illness” because the usual blood tests can be completely normal and the diagnosis can be easily missed. The correct diagnosis depends on noticing symptoms such as:
- low energy
Other symptoms can include:
weight gain, cold hands and feet, slowness of thought, puffy facial swelling, fluid retention, dry skin, brittle nails, constipation, irregular menstrual cycles, and fertility problems.
The body temperature may be low and the patient prefers to set the room thermostat very high.
If the diet is deficient in iodine, the thyroid gland enlarges and forms a goiter along with the usual symptoms of hypothyroidism. In 1924, iodized salt was introduced into the nation which greatly reduced the occurrence of goiter.The recommended daily allowance for iodine in the U.S. is only 150 micrograms. In Japan, the daily intake of Iodine is 10 to 20 times greater and is associated with many health benefits for Japan. This observation led some doctors to suggest that a daily iodine intake closer to the amount in the Japanese diet might also be beneficial for us.
The thyroid gland’s production of thyroid hormone is controlled by the master gland in the brain called the “pituitary gland” which releases TSH (thyroid stimulating hormone). The TSH then travels in the blood stream to the thyroid gland and instructs it to produce more thyroid (T4) hormone. When the thyroid gland has difficulty making T4 due to iodine deficiency or damage to the thyroid gland, then the TSH level can be quite high. High TSH indicates low thyroid function.
So, how is it that hypothyroidism can be missed by today’s conventional medical system?
That’s because many doctors rely exclusively on the TSH test and do not order a full panel of thyroid blood tests to make the diagnosis. The TSH level is an indirect measure of only one kind of thyroid hormone sufficiency and does not correlate well with symptoms. A normal TSH level doesn’t rule out partial secondary hypothyroidism–where the problem is in the pituitary gland or the hypothalamus (brain) itself. This problem is more frequent than currently recognized. It is an often unrecognized cause of depression, obesity, high cholesterol, chronic fatigue, and fibromyalgia. The current practice of excluding a thyroid hormone problem on the basis of a”normal” TSH is scientifically indefensible. A large number of things can go wrong with thyroid hormone production and effectiveness and yet not show up on a TSH test.
The best blood tests for thyroid hormone sufficiency are the levels of the actual free thyroid hormones in the serum: free T4 and free T3. A physician should be concerned when these are below the mid-point of their reference ranges in a symptomatic patient, and especially concerned when they are in the lower third or outside of their population ranges. However, even the free serum hormone levels cannot tell the whole story. Human physiology is much more complicated than that. There are many mechanisms by which a relative resistance to thyroid hormones can occur.
Although many conventional physicians would argue otherwise, the fact is that the thyroid blood tests may be in the reference range even though there is a low thyroid condition. In recognition of this problem the American Association of Clinical Endocrinologists recommended that the normal range for the TSH test be changed to 0.3 up to 3.04 mIU/L. The National Academy of Clinical Biochemistry wants to change them again and says “In the future, the upper limit of the serum TSH reference range will be reduced to 2.5 mIU/L and “a serum TSH result between 0.5 and 2.0 mIU/L is generally considered the therapeutic target for primary hypothyroidism.”
Once the diagnosis is made based on history, physical examination and proper interpretation of lab testing, the next step is a therapeutic trial of thyroid hormone. In the best tradition of clinical medicine, a physician should prescribe thyroid hormones for persons whose symptoms, physical signs, and/or blood tests indicate that they may have inadequate thyroid hormone effects for optimal health and quality of life. If they do not need the thyroid supplementation, they will feel worse instead of better when their levels are increased. Thyroid optimization for those who need it improves mood, energy, and alertness. It reduces risk of a heart attack, helps with weight loss, and lowers cholesterol levels.
Dr. Randy Lundell, DO