Optimum Diagnosis and Treatment of Hypothyroidism With Free T3 and Free T4 Levels
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Diagnosis of Hypothyroidism
The big myth that persists regarding thyroid diagnosis is that an elevated TSH level is always required before a diagnosis of hypothyroidism can be made. Normally, the pituitary gland will secrete TSH in response to a low thyroid hormone level. Thus an elevated TSH level would typically suggest an underactive thyroid.
The traditional tests of thyroid function, the T4 (or total T4), T3-uptake, FTI, 'T7', total T3, and T3-by-RIA tests should be abandoned because they are unreliable as gauges of thyroid function. The most common traditional way to diagnose hypothyroidism is with a TSH that is elevated beyond the normal reference range. For most labs, this is about 4.0 to 4.5. This is thought to reflect the pituitary's sensing of inadequate thyroid hormone levels in the blood which would be consistent with hypothyroidism. There is no question that this will diagnose hypothyroidism, but it is far too insensitive a measure, and the vast majority of patients who have hypothyroidism will be missed.
The clinical symptoms of hypothyroidism are many. Perhaps the most common is fatigue. The skin can become dry, cold, rough and scaly. The hair becomes coarse, brittle and grows slowly or may fall out excessively. There is a sensitivity to cold with feelings of being chilly in rooms of normal temperature. It is difficult for a person to sweat and their perspiration may be decreased or even absent even during heavy exercise and hot weather. Constipation that is resistant to magnesium supplementation and other mild laxatives is also another common symptom. Difficulty in losing weight despite rigid adherence to a low grain diet seems to be a common finding especially in women. Depression and muscle weakness are other common symptoms.
Most patients continue to have classic hypothyroid symptoms because excessive reliance is placed on the TSH. This test is a highly accurate measure of TSH but not of the height of thyroid hormone levels.
The basic problem that traditional medicine has with diagnosing hypothyroidism is the so called "normal range" of TSH is far too high: Many patients with TSH's of greater than 1.5 (not 4.5) have classic symptoms and signs of hypothyroidism.
The alternative to monitor thyroid disease is to use the Free T3 and Free T4 and TSH levels and interpret them with new reference ranges. If one measures the Free T3 and Free T4 levels the only accurate measure of the actual active thyroid hormone levels in the blood, as well as the TSH, one will find out how often a low normal TSH does NOT exclude hypothyroidism. It is relatively common to find the Free T4 and Free T3 hormone levels below normal when TSH is in its normal range, even in the low end of its normal range. When patients with these lab values are treated, one typically finds tremendous improvement in the patient, and a reduction of the classic hypothyroid symptoms.
There are a significant number of individuals who have a TSH below 1.5 but their Free T3 (and possibly the Free T4 as well) will be below normal. These are cases of secondary or tertiary hypothyroidism, so, TSH alone is not an accurate test of all forms of hypothyroidism, only primary hypothyroidism.
This revised method of diagnosing and treating hypothyroidism seems superior to the temperature regulation method promoted by Broda Barnes and many natural medicine physicians.
Treatment of hypothyroidism
After proper diagnosis of hypothyroidism, the next issue is with what substance to treat.. The traditional approach is to use Synthroid/ Levoxyl/Levothroid (levothyroxine) which is only T4. Natural medicine doctors tend to use Armour thyroid which is a mixture of mono and di-iodothryonine and T3 and T4, the entire range of thyroid hormones.
If the Free T3 level is significantly lower than the Free T4 level, it is next to useless to treat with Synthroid/ Levoxyl/Levothroid (T4) only replacements. If the patient could not muster sufficient T3 from their gland (which produces some T3 directly), then they are certainly not going to convert enough T3 from T4 only. Traditional medicine assumes that preparations like Synthroid which are T4 only converts peripherally in the body to T3 in fairly standard amounts and at fairly standard rates. Unfortunately, clinical experience shows this is not true for the majority of patients. Consistent measuring of both free T3 and free T4 blood levels in hypothyroid patients who are on T4 only therapy will very rapidly dispel this myth. A certain percentage of hypothyroid patients do convert enough T4 to T3 at a sufficient rate for T4 treatment to be adequate as a source of T3; but a substantial proportion of patients require some combination of both exogenous T3 and T4.
Once on hormone replacement, the TSH remains useful until it goes BELOW 0.4. Then one has optimized thyroid function by the TSH yardstick; it then remains to optimize thyroid function by the yardstick of the accurate measures of the 2 thyroid hormones, the Free T4 and Free T3 levels.
So one should use a combination of T4 and T3 which compensates for the inability to convert T4 to T3. This is most frequently done with Armour thyroid. However, Cytomel, which is T3 only, can be used in combination with one of the T4 only preparations. It is important to recognize that T3 should always be prescribed twice daily due to its shorter half life. This is typically after breakfast AND supper for compliance reasons.
Taking the dose at these times overcomes traditional medicine's major objection and resistance to using natural thyroid preparations - its variability in its blood levels. Armour thyroid is desiccated thyroid and has both T3 and T4. Most doctors using Armour thyroid are not aware that Armour thyroid should be used twice daily and NOT once a day. The major reason is that the T3 component has such a short half life and needs to be taken twice daily to achieve consistent blood levels.
Once or twice daily dosing one can then optimize both the T4 and T3 levels, with whatever thyroid preparation is required. This is not possible in most hypothyroid patients with T4 only preparations. It is important to use a preparation with T3 because T3 does 90% of the work of the thyroid in the body. The only exception to pursue optimization of the T3 level without using Armour thyroid is in severe acute cardio-pulmonary conditions, when the metabolic slowing effect of a low FT3 level can actually be life-saving. However, the vast majority of hypothyroid patients do not have acute cardio-pulmonary conditions, such as congestive heart failure.
The most common starting dose for patients with hypothyroidism is Armour thyroid, 90 mg which is cut in half with a razor blade and half is taken after breakfast and the other half after dinner. Taking it after meals also helps to reduce volatility of the blood-level of T3. If the patient has any problem breaking or cutting the pill, they should purchase a pill-cutter at the pharmacy. The TSH, Free T3 and Free T4 are then repeated in one month and the dose is adjusted.
In order to optimize the hormone replacement, the Free T3 and Free T4 should be above the median but below the upper end of the laboratory normal reference range. The goal for healthy young adults would be to have numbers close to the upper part of the range, and for cardiace and/or elderly patients, the numbers should be in the middle of its range. The Free T3 and Free T4 levels should be checked every month and the hormone therapy readjusted until the FT3 and FT4 levels are in the therapeutic range described. A small number of large, overweight, thyroid-resistant women may need 6-8 grains of Armour Thyroid or the equivalent of thyroxine per day (counting 0.1mg of T4 as 1 grain of Armour Thyroid).
If the patient is currently taking Synthroid (thyroxine), their Free T4 level is usually at or above the high end of its normal range and the Free T3 level is below. In this situation, or if a patient is allergic to Armour thyroid or is resistant to taking Armour thyroid, one may then add 5-12.5 mcg Cytomel (pure-T3) after breakfast and supper daily, rather than Armour Thyroid or Thyrolar (synthetic T4/T3 combo). It is important to remember that if the FT4 is being raised by a still-high TSH, the FT4 level will drop some when the TSH drops when adequate T3 is added to the hormone replacement.
Patients need to be warned about the overdosage symptoms which are frequently only temporary during the adaptation stage. The symptoms may include: palpitations, nervousness, feeling hot and sweaty, rapid weight-loss, fine tremor, and clammy skin. There is one exception to the 1.5 level of TSH as the cutoff for treatment. Overweight patients who have classic symptoms of hypothyroidism and have made heroic unsuccessful attempts to lose weight may benefit from thyroid hormone replacement even if their TSH slightly below 1.5 and FT4 and FT3 are not below their normal ranges
Patients who are already on once daily Armour thyroid should split their doses immediately and take half after breakfast and half after dinner. Since the only change will be in the FT3 level, which has a short half-life, the serum FT4 and FT3 levels (and TSH, if indicated) can be measured 48-72 hrs after the splitting of the doses if the patient had been on the hormone for 4-6 weeks before the splitting of the doses. This is because the T4 fraction is the one that takes a number of weeks to build up to its steady-state serum level.
For more Information, read thyroid articles on Mercola.com