I often hear from thyroid patients who suffer fatigue, body aches, and weight gain.  By themselves, these symptoms can all be markers of an autoimmune thyroid disease–or something else.

While the constellation of symptoms can be similar, the primary complaint in Chronic Fatigue Syndrome (CFS) is the unrelenting fatigue. Even the smallest physical exertion can put the sufferer in bed for days. There is no official clinical test to make a firm diagnosis of CFS.

Instead, doctors typically rule out other underlying illnesses before making a CFS diagnosis.

At one point, the Institute of Medicine (IOM) suggested the collection of symptoms known as “Chronic Fatigue Syndrome,” be referred to as systemic exertion intolerance disease (SERD).  This proposed name showed the condition in a different light.

With Fibromyalgia (FMS), an arthritis-related condition, the primary complaint is the pain, a round-the-clock pain that rarely goes away. FMS can be diagnosed via a detailed 18-point “tender point” examination.

With Hashimoto’s Autoimmune Thyroid disease, the thyroid fails to produce sufficient thyroid hormone to regulate metabolism. Symptoms of the resulting underactive thyroid usually include some complaint of fatigue or depression, but may include a host of other symptoms, including or muscular and joint pain, excessive weight gain, hair loss, dry and coarse, skin, menstrual irregularities, infertility and recurrent miscarriage, low blood pressure, high cholesterol and others.

Diagnosis is most often by the sensitive thyroid stimulating hormone (TSH) test, but some doctors also use the thyrotropin releasing hormone (TRH) test or tests for thyroid antibodies.

Why is Diagnosis Difficult? 

CFS, FMS and Hashimoto’s patients often visit their doctors complaining of a host of symptoms.

Since symptoms are similar, there is a risk of misdiagnosis. Some doctors still fail to even acknowledge the existence of CFS and FMS.

And while medical tests can, in most cases, easily test for thyroid problems, many doctors still fail to diagnose the obvious signs of Hashimoto’s, or rely only on one test to diagnose the condition. Commonly, Hashimoto’s is also often misdiagnosed as depression, stress, or “female” hormonal problems such as premenstrual syndrome, post-partum depression or menopause symptoms, which are often labels applied to CFS and FMS sufferers as well.

Some of the Symptoms Seen in CFS, FMS & Hashimoto’s

  • Widespread pain, fatigue, malaise
  • Muscle cramps and pains
  • Unexplained or excessive weight gain
  • Inability to lose weight
  • Gastrointestinal problems Irritable bowel syndrome
  • Poor sleep
  • Headaches and migraines, difficulty concentrating
  • Constipation, dry skin, dry hair
  • Eczema, acne, rashes
  • Swelling and fluid retention
  • Carpal tunnel syndrome, numbness and tingling in extremities
  • Raynaud’s Syndrome
  • Reduced sexual interest and ability
  • Respiratory difficulties
  • Slow pulse, low blood pressure

Who Gets CFS, FMS and Hashimoto’s? 

The majority of diagnosed cases of CFS occur in women, most of whom are 25 to 45 years old.

FMS strikes mostly women between the ages of 20 and 50. And Hashimoto’s is known to affect women at least seven times more often than men, often women in the same age range. Researchers speculate that the same autoimmune mechanisms may be at work, and hormonal relationships may explain the higher incidence in women.

Are CFS, FMS and Hashimoto’s All Autoimmune Diseases? 

While Hashimoto’s is known to be an autoimmune illness, researchers are beginning to believe that there is a strong autoimmune component to CFS and FMS as well. Ultimately, the three diseases may, in fact, be found to be varying manifestations of the same underlying autoimmune problems.

The autoimmune connection that underlies these three conditions is discussed at length in the book Living Well With Autoimmune Disease.

Research reported in the Journal of Clinical Investigation indicates that there is a clear autoimmune component in chronic fatigue syndrome, and that approximately 52% of chronic fatigue syndrome patients develop autoantibodies indicative of autoimmune reactions.

A German study suggested a relationship between CFS and autoimmune disease, including autoimmune thyroid antibodies. According to the researchers, this suggests that “CFS is associated with or the beginning of manifest autoimmune disease.”

Researchers found that defects in the hypothalamus-pituitary-adrenal axis have been observed in autoimmune diseases (such as thyroid disease), rheumatic diseases, chronic inflammatory disease, chronic fatigue syndrome and fibromyalgia. They also found that levels of thyroid hormone are decreased during severe inflammatory disease.

What Causes CFS, FMS and Hashimoto’s? 

Until definitive research is completed on CFS, FMS, Hashimoto’s and other autoimmune diseases, there are many hypotheses as to the causes behind these diseases. Some FMS researchers are looking at abnormally low levels of the hormone cortisol and its relationship to FMS. Other FMS researchers are studying regulation of the adrenal gland (which makes cortisol) in fibromyalgia.

Some medical researchers believe that a virus (such as Epstein-Barr, the mononucleosis virus is at the core of these diseases. And while no single virus or cause has been firmly associated with CFS, FMS or Hashimoto’s, one medical journal reported that 78% of the CFS patients studied in one research effort also tested positive for the Epstein-Barr Virus. Anecdotally, many thyroid patients report having had serious bouts of mononucleosis, or recurrent Epstein-Barr virus, prior to being diagnosed with HAIT.

Other researchers believe bacterial infection, stress, an accident (such as an auto accident) or other trauma may chronically activate the immune system. The immune system, which ordinarily returns to normal after successfully fighting an infection, then remains in a hyperactive state.

Others have suggested the development of one autoimmune disorder, such as rheumatoid arthritis or lupus may then precipitate the onset of CFS, FMS or Hashimoto’s.

And certain researchers are looking to autoimmune thyroid disease itself as perhaps the underlying cause of some CFS and FMS symptoms, or perhaps the root cause of the diseases themselves.

Is Thyroid Function and Hormone Conversion At the Center of the Mystery? 

The late Dr. John C. Lowe was one of the nation’s pioneers in fibromylagia research. He reported in the Clinical Bulletin of Myofascial Therapy, that he found clear relationships between thyroid function and fibromyalgia, and believes that some form of hypometabolism, including thyroid dysfunction, may in part explain FMS.

In studying patients with diagnosed fibromyalgia, Dr. Lowe ran thyroid function tests on each patient.

Those with elevated TSH levels (indicating hypothyroidism) did not undergo TRH stimulation tests. Those who had normal TSH levels were subsequently also given a TRH stimulation test.

Of the patients studied:

  • 10.5% had primary hypothyroidism.
  • 36.8% were diagnosed as euthyroid (in normal thyroid state)
  • 52.6% had results, via the TRH test, that were consistent with central hypothyroidism.

Overall, the results of this analysis suggest that approximately 64% of fibromyalgia patients had thyroid hormone deficiencies. And interestingly, the level of primary hypothyroidism found among FMS patients is 10.5 times higher than what you’d expect to find in the general population.

Dr. Lowe cited unpublished studies which indicated that while euthyroid fibromyalgia patients do not have a thyroid hormone deficiency, they benefit as much from receiving T3 as most hypothyroid fibromyalgia patients do from T4. T3 is one of the two thyroid hormones, known commercially as Cytomel, and also a component in the T4/T3 drugs levothyroxine sodium (Synthroid and others), and the naturally derived Armour Thyroid and Nature-Throid.

Dr. Lowe indicated that a reason for this could be partial cellular resistance to thyroid hormone, as euthyroid fibromyalgia patients resemble patients with thyroid hormone resistance syndromes.

Some Hashimoto’s patients who do not resolve their hypothyroidism symptoms while taking T4-only drugs (and having normal levels on TSH tests) have found that taking the T4/T3 combination drugs relieve their hypothyroidism symptoms.

This suggests some sort of underlying thyroid hormone resistance syndrome or FMS may also be at play in Hashimoto’s patients who do not thrive on the conventional T4 therapies.

Similar linkages between CFS and thyroid hormones have also been suggested. An article published in the journal Medical Hypotheses researchers indicated that “…we believe much of the symptomotology [of chronic fatigue syndrome] can be explained by…disturbances of insulin and T3-thyroid hormone functions.”

How Do Doctors Diagnose Hashimoto’s? 

When Hashimoto’s and hypothyroidism underlies chronic fatigue or fibromylagia, it may not be picked up by the standard thyroid hormone panel, which tests primarily the TSH, (thyroid stimulating hormone).

Most doctor rely on Thyroid Peroxidase Antibodies (TPO) to identify Hashimoto’s disease, and underlying autoimmune thyroid disease.

What are the Treatments? 

Dr. Lowe’s treatments for FMS emphasized inclusion of the T3 thyroid hormone in treatment. Standard treatment for hypothyroidism is thyroid hormone hormone replacement medication, (which is typically a brand name or generic version of levothyroxine sodium, or a natural thyroid drug).

You can also find more detailed information about chronic fatigue syndrome and fibromyalgia here at About.com.