Up to 15% of patients with hypothyroidism will suffer from fibromyalgia, a rate three times as high as the general population. Fibromyalgia and hypothyroidism are indistinguishable from one another using on symptoms alone.
A significant percentage of people diagnosed with hyperthyroidism also end up being diagnosed with fibromyalgia. Part of the reason for this association is that both of these disorders are more common in women than men. Both conditions also share and number of symptoms in, including fatigue, depression, difficulty concentrating, memory problems, and varying degrees of muscle and joint pain. Distinguishing fibromyalgia and hypothyroidism is critical to the diagnosis of each disease because they are treated differently. Approximately 15% of patients with primary hypothyroidism will go on to develop fibromyalgia, a rate roughly three times the average.
Fibromyalgia and Hypothyroidism: The Link
A study published in the November 2010 edition of Rheumatology International found that the presence of thyroid disease worsens the symptoms of fibromyalgia. The study also found that there may be a link between thyroid disease and fibromyalgia in that having thyroid disease may predispose individuals to the development of fibromyalgia, even if that occurs at a point in the future.
There is a substantial amount of data to indicate that the hypothalamus and pituitary glands function abnormally in at least a subset of patients with fibromyalgia. The association of fibromyalgia with both of these glands suggests a role for dysfunction of the hormonal system in individuals suffering from fibromyalgia. It is well known that thyroid disease is often associated with dysfunction in multiple areas of the hormonal system, particularly the hypothalamus. The similarities between fibromyalgia and hypothyroidism have led some physicians to speculate that the underlying mechanism that causes both diseases is mitigated by changes in the hormonal system. Both fibromyalgia and hypothyroidism are known wax and wane with the menstrual cycle, providing yet another link to the hormonal system.
Another common link between fibromyalgia and hypothyroidism was revealed in a 2003 study. The thyroid gland produces thyroid hormone, which has a number of effects on the body, including the regulation of metabolism and of growth. A study in the journal Medical Hypothesis suggested that fibromyalgia may result from thyroid hormone resistance. In these patients, thyroid hormone levels would be normal (or even increased), but the body would not be able to respond appropriately. Thus, it would as if these patients had hypothyroidism. Further research is ongoing in this area to determine the merits of such a hypothesis. If it turns out to be correct, the underlying cause of fibromyalgia will have finally been discovered.
Fibromyalgia and Hypothyroidism: Symptoms
Fibromyalgia and hypothyroidism share a number of symptoms in common. Hypothyroidism is characterized by fatigue, generalized pain, difficulty concentrating, anxiety, and changes in hair and fingernails. This is not all that dissimilar from the symptoms of fibromyalgia. In fact, the diagnosis of fibromyalgia cannot be made until hypothyroidism is ruled out through laboratory testing.
The symptoms of the two diseases are so similar that in patients suffering from both fibromyalgia and hypothyroidism, the only way to tell what disease the symptoms are related to is to treat the hypothyroidism. Any symptoms that do not resolve after treatment can be attributed to fibromyalgia because the treatment of hypothyroidism is complete and effective.
Fibromyalgia and Hypothyroidism: Diagnosis
Hypothyroidism can be diagnosed through laboratory studies that measure blood levels of thyroid hormones. If these levels are normal, hypothyroidism can be ruled out and symptoms attributed to fibromyalgia. If these levels are abnormal, then an individual may suffer only from hypothyroidism or may suffer from both fibromyalgia and hypothyroidism.
The only means of making the diagnosis of fibromyalgia in a patient with hypothyroidism is to treat the hypothyroidism. If all symptoms disappear, then the patient does not have fibromyalgia. If symptoms remain after adequate treatment, then the additional diagnosis of fibromyalgia can be made. For these patients, the wait for a final diagnosis can be quite long as it can take up to three months for the symptoms of hypothyroidism to completely resolve. At that point, treatment for fibromyalgia can begin if the disease exists, which means the patient had to wait an additional three months for treatment.
Fibromyalgia and Hypothyroidism: Treatment
The treatments for fibromyalgia and hypothyroidism are different, but treating hypothyroidism can reduce the symptoms of fibromyalgia in patient suffering from both disorders. Hypothyroidism is treated with thyroid hormone taken by pill or my injection. Treatment is highly effective and completely reverses the symptoms of the disease.
In patients with fibromyalgia, treating hypothyroidism can often have tremendous impact on symptoms. In particular, fatigue and muscle aches are very responsive to treatment of concomitant hypothyroidism. When the fatigue lifts, patients often feel motivated to engage in other activities, which additionally reduce the symptoms of fibromyalgia.
Fibromyalgia is strongly linked with hypothyroidism. The two conditions are indistinguishable from one another on the basis of symptoms alone. There is currently research under way to determine if fibromyalgia and hypothyroidism share a similar cause.