Thyroid Resistance – A Risk of Misdiagnosis
According to a well-resourced paper, Thyroid Hormone Resistance and Its Management, “the syndrome of thyroid hormone resistance is an inherited condition that occurs in 1 of 40,000 live births characterized by a reduced responsiveness of target tissues to thyroid hormone due to mutations on the thyroid hormone receptor. Patients can present with symptoms of hyperthyroidism or hypothyroidism. They usually have elevated thyroid hormones and a normal or elevated thyroid-stimulating hormone level. Due to their nonspecific symptomatic presentation, these patients can be misdiagnosed if the primary care physician is not familiar with the condition.” What this means is routine lab work only looks at thyroid-stimulating hormone (TSH). So if your physician says your lab work is normal, ask if a full thyroid panel was done and be persistent.
Genetic mutation may not be the only cause of thyroid resistance. Acquired thyroid resistance from drugs, toxins, metabolites (the bi-product of cellular metabolism), and autoimmune antibodies may be more common than genetic thyroid resistance. Suffice it to say, “functional and conventional medicine do not always agree.”
So let’s look at the symptoms of hypometabolism of the thyroid (hypothyroidism), hypermetabolism (hyperthyroidism), and the relationship to symptoms of fibromyalgia.
Thyroid Symptoms Related to Fibromyalgia
Not all symptoms of thyroid disease or thyroid resistance are present in all patients. And, not all symptoms of fibromyalgia point to thyroid disease. For instance, TMJ, bladder problems, repetitive injury, traumatic event, and other criteria from the Centers for Disease Control (CDC) are not associated with thyroid dysfunction. That said, there is research to suggest thyroid autoimmune disease may worsen our symptoms or represent a predisposition for the development of fibromyalgia. And, a high occurrence of autoimmune thyroid disease is prevalent in fibromyalgia. But remember, thyroid resistance is not a problem with thyroid function. Thyroid resistance is characterized by cellular rejection of thyroid hormone, which leads to symptoms of thyroid dysfunction.
Commonly Reported Symptoms of Thyroid Dysfunction
Symptoms of hypometabolism also seen in fibromyalgia:
- Cold intolerance
- Dry skin and mucous membranes
- Weight gain (at risk)
- Muscle weakness
- Muscle aches, tenderness, and stiffness
- Pain, stiffness, or swelling in your joints
- Abnormal menstrual periods
- Slowed heart rate (dysautonomia)
- Impaired memory
- Neuropathy (tingling and numbness)
*Symptoms of hypometabolism not usually associated with fibromyalgia include puffy face, hoarseness, elevated blood cholesterol level, and thinning hair.
Symptoms of hypermetabolism also seen in fibromyalgia:
- Nervousness, anxiety, and irritability
- Changes in menstrual patterns
- Frequent bowel movements
- Muscle weakness
- Difficulty sleeping
- Rapid or irregular heartbeats, heart palpitations (dysautonomia)
*Symptoms of hyperthyroidism not usually associated with fibromyalgia include an enlarged thyroid gland (goiter), weight loss despite increased appetite, tremor (usually hands and fingers), sweating, skin thinning, and fine brittle hair.
Dr. Roy Weiss, M.D., Ph.D., and nationally recognized endocrinologist known for his studies of thyroid disease and other endocrine disorders, tells us not all tissues are equally resistant to thyroid hormone. This might explain why people with thyroid resistance have varying symptoms of metabolic dysfunction. His paper at EndocrinologyAdvisor.com is well referenced and offers a variety of information you may want to share with your physician.
In their heavily referenced 2016 paper, doctors Ana Marcella Rivas, MD and Joaquin Lado-Abeal, MD, PhD say one should concentrate on the patient’s symptoms and clinical picture, and they offer advice on treatment for different presentations of thyroid resistance.
Genomic studies on both fibromyalgia and thyroid resistance and a better understanding of cellular metabolism of thyroid hormones in fibromyalgia will no doubt one day help us unravel the mystery as to why we experience symptoms that are so closely related.