Hypothyroidism ((low thyroid hormone levels) is a very common endocrine disorder, especially in women over the age of 40. There are many causes, the most common being autoimmune and post-partum. The symptoms are numerous and commonly include sensitivity to cold and feeling cold, constipation, depression, fatigue, muscle pain and weakness, hair loss, unexplained weight gain, thinned eyebrows, brain fog, and puffiness of the face, hands or feet.
Hypothyroidism is usually suspected when someone presents to a doctor with several of the above symptoms. A blood test called TSH (thyroid stimulating hormone) is done to confirm the diagnosis. TSH is actually a pituitary hormone that commands or stimulates the thyroid to produce thyroid hormone. The pituitary is sensitive to low levels of thyroid hormone and will produce large amounts of TSH when the thyroid is under producing.
Some people with classic symptoms of hypothyroidism have normal TSH blood tests. These people actually often have true hypothyroidism but are told by their doctors that their fatigue, weight gain, brain fog, constipation and other symptoms are not due to hypothyroidism. They are often dismissed as depressed and offered antidepressant medication, which of course does not work.
There are many reasons that someone may have normal thyroid blood tests but actually have hypothyroidism. For one, the range of normal for TSH, as well as the thyroid hormonesT4 and T3, is very large. From a population standpoint the range is accurate but from an individual standpoint the range may be useless. As an example, the TSH range of normal is generally 0.3-4.2. If an individual’s normal is 0.3 and he is hypothyroid, his TSH may be elevated but only to 2.5-4.2 which appears normal. Again, normal in a population but not for this individual. Another reason is that if the pituitary is not functioning properly, a real concern for people with fibromyalgia and chronic fatigue syndromes, the TSH will appear normal because the pituitary is failing to properly respond to low thyroid hormone levels.
It is also important to understand that, as opposed to the common practice of testing only the pituitary hormone TSH, it is often useful to test levels of the hormones produced directly by the thyroid gland.
The thyroid gland produces thyroxine, commonly called T4. It is active in the body but it is converted into a much more active form called triiodothyronine or T3. T3 is estimated to be 5 times more powerful than T4 in regulating the body’s metabolism. Any “left over” T4 that is not converted into T3 is converted into an inactive form called reverse T3.
Some people with “normal” TSH levels will still have low T4 and/or low T3 levels. These people often benefit from thyroid hormone replacement therapy. Additionally, I have seen many patients with completely normal TSH, T4 and T3 levels who derived enormous benefit from thyroid hormone treatment when their clinical picture strongly suggested hypothyroidism.
If someone has all or many symptoms of hypothyroidism but a normal TSH, it is my opinion that they deserve a therapeutic trial of thyroid hormone to see if they improve. If the trial is done carefully, risks are extremely low and the potential for benefit is great.
Example #1. A 19 year old female college student came to my office requesting treatment for Irritable Bowel Syndrome manifesting as severe constipation for 5 years. On questioning she also had not her menstrual period for 5 years. Further history found that she always felt cold, had cold hands and feet, suffered with brain fog, and was constantly tired despite getting enough rest and sleep. Although her TSH, T4 and T3 were all completely normal, her history strongly suggested hypothyroidism. After 2 weeks of thyroid hormone replacement with natural dessicated thyroid, she was no longer constipated, had a regular menstrual bleed, and found her physical and mental energy greatly improved.
Example #2. A middle aged female mental health professional came to my office for treatment of a 20-25 year history of chronic fatigue syndrome manifested by overwhelming fatigue, depression, low immune functioning, low libido, constipation, and feeling constantly cold. Again, all thyroid blood tests were completely normal. She was treated for hypothyroidism based entirely on her symptoms and clinical picture. After 2 weeks of thyroid hormone replacement with natural dessicated thyroid, all her symptoms improved markedly (except the low libido which had other causes).
For one woman's story and interesting information regarding hypothyroidism go to: http://misslizzy.me/