Hypothyroidism and TSH Levels: Articles by Doctors
Reasons for "normal" test results with hypothyroidism symptoms
Purpose of this compilation
To show that using only the TSH (thyroid stimulating hormone) level as a diagnostic tool can miss many cases of hypothyroidism or result in undertreatment, and that if it is used, the current acceptable range is to be questioned.
See the other compilations of articles by doctors:
1. John C. Lowe, MA, DC: "drlowe.com Most Recent Q&As"
[May 25, 2003] Patients may be suffering from hypothyroid symptoms due to autoimmune thyroid disease, and while thyroid function test results may be "normal," high antibody levels will reveal the disease. In fact, thyroid function test results may be "normal" for years despite patients having autoimmune thyroiditis the whole time.
[November 20, 2002] [Supplemental] T4 is highly effective at one thing: suppressing TSH secretion by the pituitary gland. T4 can suppress pituitary TSH secretion while leaving the metabolism of other tissues so slow that the patient continues to suffer from hypothyroid symptoms. Consequently, the doctor concludes (from the lowered TSH) that the patient is well; in the mean time, the patient suffers from continuing hypothyroid symptoms. Even worse, if the T4 dose is too low, the patient's symptoms may actually worsen.
2. John C. Lowe, MA, DC: "What Your Hypothyroid Patients Should Know about Synthroid"
The pituitary is highly sensitive to T4, and small dosages of T4 decrease the pituitary release of TSH, lowering it into the reference range. Tissues other than the pituitary are comparatively insensitive to small dosages of T4. Much higher dosages are required to normalize the metabolism of these other tissues....when T4 therapy normalizes TSH blood levels of many patients, it leaves their metabolism subnormal. These patients remain symptomatic despite their normal TSH levels.
3. Ralph J. Luciani, DO, MS, PhD, MD: "Hypothyroidism: An Undertreated Illness"
Most physicians rely solely on the TSH level to determine whether the thyroid gland is producing enough T3 and T4. This test can be exceedingly misleading if someone is taking thyroid hormone as therapy for low thyroid function, or if the quality of the T3 produced by the thyroid gland is not normal.
4. Richard Shames, MD, with Karilee Halo Shames, PhD, RN, HNC: "Avoiding the 'Tyranny of the Test': Finding Your Optimal Dose of Thyroid Medicine"
Many physicians are wrongly seeking to have their patients arrive at a TSH level that is in the mid-normal range. In actuality, the mid-normal range is a great target goal for most blood test results. However, it is not generally the most sensible goal of therapy for thyroid patients taking thyroid pills. Instead, for most thyroid sufferers, the goal of therapy should be to achieve a TSH near the low end of the normal range....
This immune attack [from thyroid antibodies] is often lessened when the thyroid gland is stimulated as little as possible by TSH. Recall that TSH means "thyroid STIMULATING hormone". Rather, the person generally does better when her body runs on thyroid hormone pills, allowing the gland to be in a mostly unstimulated, resting state.
5. Jacob Teitelbaum, MD: "Highly Effective Treatment of Fibromyalgia and Chronic Fatigue Syndrome: Results of a Placebo Controlled Study and How to Apply the Protocol"
As physicians, we are trained to interpret a low-normal TSH — that is, 0.5 to 0.95 as a confirmation of euthyroidism. The rules, however, are different with CFIDS/FMS [Chronic Fatigue and Immune Dysfunction Syndrome / Fibromyalgia Syndrome]. In this setting, hypothalamic hypothyroidism is common and the patient's TSH can be low, normal, or high.5 This is why I recommend an empiric therapeutic trial of thyroid-hormone treatment if the TSH and T4 are both low normal. Also, if sub-clinical hypothyroidism is missed, the patient's fibromyalgia simply will not resolve.
6. Kenneth N. Woliner, MD, ABP: "Combined T4/T3 Therapy: Placebo or Tomato?"
There are many possible reasons for why patients may have resistance to thyroid hormone and exhibit symptoms despite having a normal TSH. Thyroid Peroxidase and Thyroglobulin Antibodies can interfere with the thyroid hormone function in the peripheral tissues while not affecting the suppressive effect of thyroid hormone on the TSH.14 The T3 receptor has 4 different gene variants with different types of receptors expressed in the brain than in the peripheral tissues.15 Lastly, there are some patients who have difficulty converting T4 to the active T3 hormone because of selenium deficiency or other conditions that interfere with human iodothyronine selenodeiodinases.16 In any of these cases, the TSH might appear normal despite clearly abnormal thyroid hormone function.
7. Kenneth N. Woliner, MD, ABP: "Understanding Thyroid Lab Tests"
Despite being called 'ultra-sensitive,' the 'TSH' blood test has its limitations....It isn't accurate for everyone.
To prevent too many 'false positives,' too many people from being called 'Hypothyroid' when they are indeed normal, the lab makes a cutoff at some point. Unfortunately, their cutoff point cuts off many patients from getting proper treatment. We call them 'false negatives.'
There is no way to know how much of a negative effect those thyroid antibodies are having, we just know that they are there. The presence of thyroid antibodies throws off every thyroid test, including the TSH.
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