Megan Brooks

March 02, 2016

Migraine and tension-type headache may share links with irritable bowel syndrome (IBS), a preliminary study hints.

"Our results suggest a high possibility of phenotypic and genotypic associations between IBS and primary headache disorders (particularly migraine) and support the presence of some shared pathophysiology," Derya Uluduz, MD, from Istanbul University in Turkey, told Medscape Medical News.

"Greater attention should be focused on the comorbidities of these conditions and their potential contribution to better understanding and managing the disorder. Physicians should examine the presence of IBS in migraine and tension-type headache patients or vice versa for accurate management of these disorders," Dr Uluduz added.

The study was released February 23 ahead of presentation in April at the American Academy of Neurology (AAN) 68th Annual Meeting in Vancouver, Canada.

"Migraine of the Bowels"

"In designing this study, we were interested in whether IBS and migraine coexist within a same spectrum of central sensitization syndrome and have phenotypic and genotypic associations," Dr Uluduz explained. "We already knew that brain plays significant role in IBS. IBS may be characterized by dysfunctions in processing of information by the central nervous system. IBS patients have increased hypothalamic activity suggesting an association among IBS, stress and hypothalamic axis. In this respect, IBS may be defined as the 'migraine of the bowels.'"

The study included 107 people with migraine, 53 with episodic tension-type headache (ETTH), 107 with IBS, and 53 healthy individuals. "This is the first study to investigate the relationship between IBS and primary headaches, including ETTH, using a comprehensive face-to-face clinical diagnostic evaluation and information on multiple serotonin transporter gene polymorphisms," Dr Uluduz told Medscape Medical News.

The researchers found that IBS, diagnosed according to strict criteria, occurred in 54.2% of patients with migraine and 28.3% of patients with ETTH. In addition, 35.5% of patients with IBS had migraine and 22.4% had ETTH.

In addition, their analysis of the serotonin transporter gene and the serotonin receptor 2A gene showed that the IBS, migraine, and ETTH groups had at least one gene that differed from the genes of the healthy participants.

Notably, "5-HTTLPR (LL-LS-SS) polymorphisms were found to be higher in patients with migraine and IBS but not in ETTH patients compared to controls," Dr Uluduz said. "The frequency of the 10/12 genotype in the 5-HTT-VNTR genotype was significantly more frequent in patients with migraine, ETTH, and IBS compared to control subjects. The frequency of the 12/12 genotype in the 5-HTT-VNTR genotype tended to be more insignificantly frequent in patients with migraine and IBS but not in ETTH."

The researchers say further studies are needed to explore links between headache disorders and IBS, which could help guide management.

"The effects of antidepressants on IBS and chronic pain syndromes, such as migraine and ETTH, by downregulation of peripheral pain-mediating systems have been demonstrated," Dr Uluduz commented. "Along with genotypic similarities, this indirectly indicates similarities in the central alterations of the serotonergic system in these disorders."

The Brain-Gut Axis

Reached for comment, Teshamae S. Monteith, MD, chief of the Headache Division at the University of Miami's Miller School of Medicine, Florida, said the link is not entirely novel.

"Based on clinical and epidemiological observations, it has long been recognized that migraines and IBS are likely linked," Dr Monteith told Medscape Medical News. "The association is a good example of the brain-gut axis and how it relates to disease. There appears to be a genetic link resulting in disturbances within the serotoninergic neurotransmitter system."

Dr Monteith also thinks it's important to assess for the presence of IBS in headache patients and vice versa for accurate management.

"Often, patients reporting both abdominal pain and headache are labeled as somatic. The study provides further evidence to support the biological vulnerability to pain in patients with primary headache and IBS. Based on these results, the role of treatments that target the brain-gut axis should be further explored. The association between these genes, pain persistence and food sensitivities should also be explored," Dr Monteith said.

The study was supported by Mersin University. The authors have disclosed no relevant financial relationships.

To be presented at the 68th American Academy of Neurology (AAN) Annual Meeting, April 15-21, 2016. Abstract 3367.


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