As I look back on the lectures that we were given on the thyroid hormones and the thyroid hormone system in medical school, I can remember the general consensus among the students being that the lectures on thyroid hormone physiology were among the most confusing lectures in medical school. There was a complete review of all available thyroid hormone testing procedures and how the values of these tests would change under various conditions. Some of this information was comprehensible, especially the part relating to the expected thyroid hormone level changes found in the different glandular abnormalities of the thyroid system. For example, learning the changes in the levels of T4, T3, TSH, and TRH, in primary and secondary hypopituitarism, hyperpituitarism, hypothyroidism, and hyperthyroidism. However, much of the other material presented was considered by the students to be quite confusing.

I will present at this time, very briefly, some of the information that was incomprehensible. Note to the reader: If you find this information confusing and hard to understand, don’t feel badly. Doctors do too. Just quiz a few. Even doctors who do understand it, usually can’t use it to best resolve the symptoms of DTSF in the most effective and predictable manner. “Even when clinicians suspect hypothyroidism [one cause of DTSF], correctly interpreting thyroid function tests is a difficult challenge. For example, a reliable means of directly measuring serum thyroxin (T4) is still not routinely available. And indirect measures of estimating free T4 are prone to misinterpretation….” (Overcoming Diagnostic and Therapeutic Obstacles in Hypothyroidism, Emergency Medicine Reports; Vol. II, Number 23, November 5, 1990).

We often try to “guesstimate” how much T4 is floating freely in the bloodstream (as if knowing that amount exactly would necessarily permit an adequate evaluation of thyroid system function!). We do this by measuring the total T4 in the blood. But we know that the results of this test can be affected by the level of Thyroid Binding Globulin or TBG (the globulin to which T4 is often bound in the bloodstream). Increased TBG levels can display decreased T4 levels. TBG levels can be increased in pregnancy, the new-born state, birth control use, and other conditions.

TBG concentrations can be decreased when male steroids are used, cortisone is used, there is chronic liver disease, there is other severe illnesses, and under other conditions. One can see how the interpretation of a T4 test would be difficult because of the effect of TBG.

A test was devised, called the T3 resin uptake (T3RU) test, in an attempt to help one estimate the effect of TBG on the value of the T4 test to help one better “guesstimate” how much T4 is floating freely in the bloodstream (even though knowing this amount exactly still would not necessarily correlate with thyroid system function). These preceding tests are not even considered to very adequately reflect thyroid gland function, much less system function. For this reason, thyroid stimulating hormone is considered to be a more sensitive indicator of thyroid gland function (which many mistakenly equate to thyroid system function).

Since the purpose of the glands is to secrete hormones into the bloodstream as influenced by the levels of other hormones present, measurements of the levels of these hormones can well reflect the function of the glands (thyroid gland, pituitary gland, and hypothalamus). The function of these glands is quite important in maintaining adequate available levels of the raw material, T4, in the bloodstream. However, T4 is not the physiologically active thyroid hormone. T3 is the physiologically active thyroid hormone. Most of T3 is produced from the peripheral conversion of T4. It is called peripheral because it takes place outside any gland.

Knowing What We Don’t Know
Many people (even doctors) mistakenly assume that doctors know everything, and that if a doctor doesn’t know everything, then he should know everything, because everything is known.

However, medicine is far less of an exact science than some people make it out to be. If it were exact, doctors could fix 100% of the people 100% of the time. It must be remembered that not everything that is written in the medical literature is correct. We have often seen how opinions in medicine can vary tremendously, even in a short number of years. For example, most people are aware of the controversy surrounding female hormones. In the beginning, it was suggested that they should be taken to prevent symptoms, then it was feared that they should not be taken due to an increased risk of cancer. Then it was recommended, again, that they should be taken to prevent osteoporosis, and still the controversy continues. The same can be said about the amount of fiber in a person’s diet. We have seen wide shifts in recommendations from the medical community. First, fiber should be taken in the diet, then a person should eat no fiber in the diet, and then again that they should eat fiber, etc.

While I was in medical school, I heard it said that if one doctor were to read everything that was printed in the field of medicine in the year of 1978 alone, that it would take 54 centuries to read. Of course, since the year of 1978, the situation has grown far more formidable. So, of course, it would be impossible for a doctor to absorb, comprehend, and analyze even a fraction of the available information in an entire lifetime, much less within four years, or twelve years, or even twenty years of medical training and practice. Nevertheless, there are some unfortunate doctors who seem to suffer from the misconception that they do know everything that there is to know about the human body in any of its areas.

Considering that the entire mass of information cannot be comprehended at one time by any human mind, it seems that it would be difficult for any person to determine which, of all that information, is the most significant and what parts of that vast amount of information should be taught in medical school. And even if it were possible, doctors don’t always agree on what is most significant. That’s what second opinions are for. The things that are taught in medical school are extremely small portions of the available medical information, almost like needles removed from the haystack. It may lead one to wonder how it is being determined what needles are the most significant and what needles are not.

It is understandable that the information pertaining to some conditions (especially those that are life-threatening) have gotten more attention than others. But that’s unfortunate for people who happen to be suffering from other conditions. Because, even though their condition may not be life-threatening, they can feel so miserable that they sometimes say that they “would have to die to feel better.” It should be remembered that simply because symptoms are not life-threatening does not necessarily mean that they are mild, or not severe.

Our Technology Only Reaches So Far
It probably should be pointed out at this time why there are some things that are easier to document and test than others. The human body is extremely complex in design. It is a highly organized system and it is organized in various levels. The organism is made up of systems. The systems are made up of organs. The organs are made up of tissues and the tissues are made up of cells. The cells are made up of subcellular organelles which are made up of molecules. Molecules are also involved in the chemical reactions.

In general, the higher the level or organization wherein lies the problem, the more specific and documentable the complaint. The lower the level of organization wherein lies the problem, the more generalized and the more difficult to document the complaint. For example, the highest level of organization is the organism taken as a whole. It is easy to see whether or not an organism is alive or dead. When one goes down to the next level of organization of the body, the systems, it is also not difficult to recognize the problem. For example, if someone suddenly pushed himself away from a steak dinner clutching his throat, turned blue in the face and fainted, it would not be hard to see his problem as being respiratory. Neither is it difficult to recognize when someone has a digestive system problem when they vomit everything they eat, and when they stop having bowel movements.

Things are a little less obvious when one goes down to the level or organization of the body represented by the organs. Nevertheless, certain groups of signs and symptoms are usually easy to recognize as being related to a particular organ. For example, not being able to move the left side of one’s body is consistent with having a stroke in a particular part of the right side of the brain. Severe pain in the right lower quadrant of the abdomen coupled with significantly elevated body temperature often leads one to think of appendicitis or inflammation of the appendix. Shortness of breath and wheezing often leads one to think of asthma

The problems that are related to the next lower level of organization of the body, namely the tissues, are even more difficult to recognize. Problems at this level are somewhat harder to identify and frequently require the technology that is available through various tests to help identify them. For example, different problems at the level of organization of the tissues can cause fatigue. It is known that patients with liver problems, kidney problems, anemia, and even thyroid gland problems can develop fatigue. Blood tests, urine tests, x-rays, and scans can often help us to determine the source.

The even lower levels or organization, such as the function of cells and the chemical reactions among the molecules, are among the most fundamental processes of life. Symptoms that result from problems lying at these levels are that much more difficult to document. Yet that does not mean that they don’t exist. It only means that we have not yet been able to devise tests that can reproducibly and predictively evaluate certain problems and their symptoms. For example, the symptom of depression can be caused by a number of things such as chemical imbalances in the brain that can result from various chemical processes resulting from various causes such as abnormal production or breakdown of neurotransmitters, imbalances brought on by stress, and imbalances that result from substance abuse. It is extremely difficult to measure the levels of neurotransmitters, and the functioning of the cells and chemical reactions within the brain to determine the exact cause of a patient’s depression. Nevertheless, that does not prevent depression from being recognized as a debilitating symptom that often responds well to treatment. And it does not prevent antidepressants from being some of the most widely prescribed medicines in the world.

It is understandable that more easily documented and observed processes should be given a lot of attention by medical science. But some of the more fundamental processes of the body are extremely important also, even if they cannot be easily monitored or measured. Is it any wonder that some of the more fundamental processes of the body have not gained as much attention from the medical profession as other more easily documentable problems? (It is commonly joked, for example, that doctors don’t know much about nutrition.) It should be remembered though, that just because things are not easily documentable or measurable doesn’t necessarily mean that they are not important or that they do not exist.

The assumptions that are made and the theories that are formulated to describe things that aren’t easily documented are worth looking at. However, just because people were not able to see that the earth was round, didn’t necessarily mean that it was flat. In fact, there are still many things in medicine that have been difficult to document and measure, but we don’t have to jump to conclusions.