There are conditions that occur at the same time as but don't cause each other - they coexist (doctors call such conditions comorbid). With migraine disease, perhaps the most common of those is major depressive disorder (clinical depression). Approximately 47 percent of migraineurs also experience major depressive disorder, but one doesn't necessarily cause the other.
Coexisting conditions can have significant impact on effective treatment of the individual disorders. Thyroid diseases, including hypothyroidism, are among the conditions now known to often coexist with headaches and migraines. A strong connection has been found between hypothyroidism and new daily persistent headache and chronic migraine. Researchers have concluded that coexisting conditions can affect each other in multiple ways, including how they progress and the amount of time it takes to diagnose them and find effective treatments. In addition, it's been shown that coexisting conditions may play a role in headaches becoming and remaining daily or near-daily events. In some cases, the response of migraine to treatment of even borderline hypothyroidism has been dramatic. Dr. Egilius L.H. Spierings, associate clinical professor of neurology at Harvard Medical School in Boston, believes that, "An explanation of the benefit of the treatment, at least with regard to the migraine aura, could lie in the decrease of cerebral excitability associated with the correction of hypothyroidism."
"Thyroid and other endocrine hormones can play a notable role in the development of headache and migraine and in their failure to respond to treatment," stated Dr. John Claude Krusz, an expert in the fields of headache and pain management and vice president of the American Board of Electroencephalography and Neurophysiology. "People tend to look at only reproductive hormones when, in fact, the endocrine hormones can play such a significant role." Dr. Krusz recommends that headache and migraine patients have blood work to check thyroid, cortisol, and other endocrine hormone levels. He also recommends that free T3 and free T4 be checked, saying that the standard TSH test, "doesn't tell the whole story."
Dr. Marcelo E. Bigal, assistant professor of neurology at Albert Einstein College of Medicine in New York, and his colleagues concluded, "Subclinical hypothyroidism may be associated with the development of new daily persistent headaches. Also, hypothyroidism may be associated to refractoriness to treatment in patients with primary headaches, e.g. migraine."
Why headaches and migraines and some other conditions occur together is not well understood, but the connections are there. Taking into account other conditions which may be affecting us can help improve our headache and migraine management. If you question whether thyroid issues may be affecting you, speak with your doctor. For more information about thyroid diseases, be sure to visit About Thyroid Disease.
Bigal, Marcelo E., Sheftell, Fred D., Rapoport, Alan M., Tepper, Stewart J. "The Woman With the Never Ending Headaches." from: Purdy, R. Allan, MD, FRCPC; Rapoport, Alan, MD; Sheftell, Fred, MD; Tepper, Stewart, MD. "Advanced Therapy of Headache," Second Edition. B.C. Decker. 2004.
Bigal, Marcelo E., Sheftell, Fred D., Rapoport, Alan M., Tepper, Stewart J. & Lipton, Richard B. (2002) Chronic Daily Headache: Identification of Factors Associated With Induction and Transformation. Headache: The Journal of Head and Face Pain 42 (7), 575-581. doi: 10.1046/j.1526-4610.2002.02143.x
Spierings, Egilius L.H. (2001) "Daily Migraine With Visual Aura Associated With an Occipital Arteriovenous Malformation." Headache: The Journal of Head and Face Pain 41 (2), 193-197. doi: 10.1046/j.1526-4610.2001.111006193.x
Interview with John Claude Krusz, MD, PhD. November 13, 2006.