It is clear there is a distinct hormonal disturbance in Chronic Fatigue Syndrome (CFS) patients, with a general suppression of the hypothalamic - pituitary - adrenal axis (HPA axis). It is the pituitary which is the "conductor of the endocrine orchestra.” If the pituitary is malfunctioning like in CFS patients, then this will affect the thyroid gland, adrenal gland, sex hormones, possibly the pineal (produces melatonin for normal sleep), as well as hormones for growth and urine production.
Hypothyroidism symptoms are very similar to the ones experienced by CFS sufferers. Lethargy, sensitivity to cold, heat intolerance, mood swings and depression, poor memory and concentration, joint pains and morning stiffness, headaches, vertigo and deafness, pre-menstrual tension, voice changes, loss of libido and susceptibility to viral infections are all found with both conditions.
Visible signs experienced by hypothyroid sufferers are: weight gain, fluid retention, puffy face, puffy eyes, hair loss (classically the outer third of the eyebrows), cold extremities and dry skin, rashes, eczema and boils and enlargement of the tongue. One may also suffer from hoarse voice, hypoglycaemia, constipation, menstrual problems, skin problems and tendency to infections, slow pulse, goitre, infertility, digestive problems, slowed Achilles tendon reflex and carpal tunnel syndrome.
The Connection Between Chronic Fatigue Syndrome And Low Thyroid
Studies demonstrate that in addition to an increased incidence of primary hypothyroidism in CFS, there is a combination of secondary, tertiary and thyroid resistance in the overwhelming majority of CFS patients, despite having normal thyroid tests. Why is this happening?
These latter forms of tissue hypothyroidism are not detected by standard thyroid function tests. Thus, many CFS patients are erroneously told that their thyroid levels are fine. In fact, standard thyroid tests fail to detect tissue hypothyroidism 80-90% of the time in patients with CFS.
There are multiple abnormalities in CFS that result in undetectable tissue hypothyroidism, such as :
- TSH is secreted by the pituitary and stimulates the thyroid to produce T4, the non-active thyroid hormone. However, hypothalamic dysfunction results in the production of TSH that has diminished biological activity so there are lower T4 and T3 levels for any given level of TSH. T3 is the active thyroid hormone. In addition, the pituitary dysfunction results in a diminished secretion of TSH, masking low tissue thyroid levels as the TSH is usually in the normal range. Very few doctors understand the significance of this and incorrectly state that the thyroid is fine based on a normal TSH level.
- Diminished T4 to T3 conversion and a relatively increased T4 to reverse T3 conversion result in low tissue levels of active thyroid hormone levels despite having a normal TSH.
- Type II deiodinase that converts T4 to T3 is down regulated in CFS, while the type III deiodinase enzyme that increases T4 to reverse T3 (rT3) is unregulated in these conditions.
- There has been shown to be a peripheral thyroid hormone resistance found in these patients, meaning that there is a diminished thyroid effect for a given amount of thyroid hormone in the blood.
As you see, the combination of factors present in CFS, including hypothalamic and pituitary dysfunction, diminished T3/rT3 production ratios and thyroid resistance, results in most, if not all, CFS patients having inadequate tissue thyroid effect.
What Is An Adequate Treatment For Low Thyroid in CFS?
T4 preparations such as Synthroid and Levoxyl rarely work and Armour thyroid, a pig glandular product, is somewhat better, but definitely not adequate for most patients. The treating physician must know when to use a T4/T3 combination or straight T3. T3 works the best for many of these patients, but Cytomel, a very short acting T3 available at normal pharmacies, is also a poor choice, because the varying blood levels can cause significant side effects.
Compounded timed release T3 is usually the best treatment. However, to achieve significant improvement, the treating physician must be very knowledgeable about T3 and must realize that when on T3, standard blood test will lead one to dose incorrectly and not obtain significant benefits. This includes doctors who previously felt that they were thyroid experts and had been using thyroid in CFS patients for a long time.
Ultimately, it is the expertise and dosing of the T3 or T4/T3 combinations and the makeup of the medications that determines the optimal treatment regimen and is one major component in the treatment of CFS.