Emergency (****); * (*): *-* This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 171 Emergency (2016); 4 (4): 171-183 REVIEW ARTICLE Gastrointestinal Headache; a Narrative Review Majid T Noghani1, Hossein Rezaeizadeh2, Sayed Mohammad Baqer Fazljoo3, Mansoor Keshavarz2,4* 1. Department of Iranian Traditional Medicine, Faculty of Medicine, Shahed University, Tehran, Iran. 2. School of Traditional Medicine, Tehran University of Medical Sciences, Tehran, Iran. 3. School of Traditional Medicine, Tabriz University of Medical Sciences, Tabriz, Iran. 4. Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. *Corresponding author: Mansoor Keshavarz; Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Email: mkeshavarz@tums.ac.ir; Tel/Fax: +9821-66419484. Received: July 2015; Accepted: September 2015 Abstract There are studies reporting primary headaches to be associated with gastrointestinal disorders, and some report resolution of headache following the treatment of the associated gastrointestinal disorder. Headache disorders are classified by The International Headache Society as primary or secondary; however, among the secondary head- aches, those attributed to gastrointestinal disorders are not appreciated. Therefore, we aimed to review the litera- ture to provide evidence for headaches, which originate from the gastrointestinal system. Gastrointestinal disor- ders that are reported to be associated with primary headaches include dyspepsia, gastro esophageal reflux disease (GERD), constipation, functional abdominal pain, inflammatory bowel syndrome (IBS), inflammatory bowel disor- ders (IBD), celiac disease, and helicobacter pylori (H. Pylori) infection. Some studies have demonstrated remission or improvement of headache following the treatment of the accompanying gastrointestinal disorders. Hypotheses explaining this association are considered to be central sensitization and parasympathetic referred pain, serotonin pathways, autonomic nervous system dysfunction, systemic vasculopathy, and food allergy. Traditional Persian physicians, namely Ebn-e-Sina (Avicenna) and Râzi (Rhazes) believed in a type of headache originating from disor- ders of the stomach and named it as an individual entity, the "Participatory Headache of Gastric Origin". We suggest providing a unique diagnostic entity for headaches coexisting with any gastrointestinal abnormality that are im- proved or cured along with the treatment of the gastrointestinal disorder. Keywords: Headache; migraine disorders; gastrointestinal diseases; medicine, traditional; headache disorders, primary; headache disorders, secondary Cite this article as: Noghani MT, Rezaeizadeh H, Fazljoo SMB, Keshavarz M. Gastrointestinal headache; a narrative review. Emer- gency. 2016;4(4):171-183 Introduction: eadache is one of the common reasons for daily visits to emergency departments (ED). Sadly, in some cases despite all the diagnostic and treat- ment measures, the cause of the headache cannot be de- termined and only symptoms are treated. In these cases, the patient experiences decreased quality of life and re- lapse, and therefore frequently revisits ED and neuro- logic clinics. The international headache society (IHS) re- leased the second edition of the international classifica- tion of headache disorders (the ICHD-II) in 2004, and the ICHD-III (beta version) recently, with which various headache disorders are diagnosed by physicians throughout the globe. Primary headaches, which are not considered to be attributed to another disorder are partly found to be cured or relieved by management of gastrointestinal (GI) abnormalities in the affected pa- tients (1, 2). In the initial evaluations, some probable causes of headaches, such as GI disorders, are over- looked. Providing evidence for primary headaches asso- ciated with GI disorders, may help classify this type of headache as a unique diagnostic entity. Ancient Persian physicians believed in a type of headache arising from disorders of the stomach and as an individual entity, de- scribed it in their writings as participatory headache of gastric origin or simply, “Gastric Headache” (3). We therefore, performed a review of the available literature to show the extent of the studies demonstrating the prevalence of headache and GI disorders’ coexistence, as well as studies proposing GI abnormalities as etiologies for headaches in which, treatments targeting the GI dys- function relieved the headache. H mailto:mkeshavarz@tums.ac.ir This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Noghani et al 172 Methods: Review of the available literature from 1980 to July 2014, through a PubMed search was provided. Searching the MeSH terms “Gastrointestinal Diseases” or “Migraine Disorders” or “Headache Disorders” by the PubMed search builder altogether revealed roughly 900 articles. Abstracts from pertinent articles were obtained. There were no language restrictions. If the study pointed to the association of any headache disorder with GI dysfunc- tions the paper was completely studied. In addition, bibilography and citations to the selected studies were evaluated and relevant articles not found previously were also included in order to augment the search re- sults. In addition, a MEDLINE search was conducted us- ing the keywords “Iranian Traditional Medicine”, “Per- sian Medicine”, and “Islamic Medicine” and relevant pa- pers were extracted. Finally, principle texts of Tradi- tional Persian Medicine and the highly credited manu- scripts on the subject of headache were studied. Results: - Dyspepsia Dyspepsia, defined as postprandial fullness, early sa- tiety, or epigastric pain or burning by the Rome Commit- tee, is reported to be present in a significant number of patients suffering from migraine (Table 1). Kurth et al. studied a population of migraineurs and compared them with a group of controls using a bowel disease question- naire and reported pain centered in the upper abdomen to be significantly more frequent among patients with migraine (4). In another case-control study conducted by Meucci et al. among dyspeptic patients, it was noted that this group of patients suffer significantly from migraine compared to the control group. It was suggested that dyspeptic patients of the dismotility-like or with nausea / vomiting referred for endoscopy be worked up for a di- agnosis of migraine. Given the completely normal endo- scopic appearance seen in 90% of the migraineurs it was concluded that dyspeptic symptoms may be a conse- quence of the migraine (5). Mavromichalis et al. how- ever, demonstrated underlying inflammatory lesion in 29 of the 31 migraineurs undergoing endoscopy, sup- porting a causal link between GI inflammation and mi- graine. Treatment targeting the GI tract resulted in relief of migraine (6). Since the former two studies were not interventional, one could not conclude whether treatment of dyspepsia would have attenuated migraine headaches. However, Sung Hwang et al. demonstrated the resolution of head- ache in a group of children with epigastric pain or ten- derness diagnosed with primary headache after initiat- ing regular anti-acid medication (7). Spierings reported a 50 year old dyspeptic male complaining of headache since early adulthood. Patient`s dyspeptic symptoms were treated by Cisapride 20 mg daily before dinner and subsequently the headache was almost completely re- solved (2). Interventional studies are needed to provide more evidence to support the concept that in at least some migraineurs, their dyspeptic symptoms are the cause of their headaches. - Gastroesophageal Reflux Disease Gastroesophageal reflux disease (GERD), described as abnormal reflux of gastric contents into the esophagus resulting in symptoms or mucosal damage, may manifest with typical and atypical symptoms (8). However, among the extra-esophageal symptoms, headache is not pro- nounced as other atypical symptoms are. There is a growing body of literature demonstrating the associa- tion of headache with reflux symptoms (Table 1). Aamodt et al. performed the Head-HUNT study involving more than 43,000 individuals and reported reflux symp- toms to be the most common symptom in this population with a rough prevalence of 30%. Headache was noted to have a higher prevalence among individuals with much reflux symptoms compared to those without such com- plaints. In this study, patients suffering from headache were classified into migrainous and non-migrainous (9). In another study, Katic et al. aimed to determine the prevalence of GERD and heartburn in a group of more than 1800 migraine patients. Almost half of the mi- graineurs were reported to have GERD, heartburn, or re- lated symptoms and this group suffered from more se- vere migraines and greater frequency of attacks (10). A population based study, enrolling close to 2000 indi- viduals, reported significant correlation between head- ache and symptoms associated with GERD. It was noted that some patients’ headaches intensified with increased heartburn, and therefore, headaches were assumed to be a complication of GERD. The types of headaches, how- ever, were not classified in this study (11). Spierings reported two patients with headaches associ- ated with reflux, in whom proton pump inhibitors re- solved their headaches (1). Further interventional stud- ies targeting acid reflux suppression in patients affected by both disorders may be of benefit for understanding the causal relationship. - Constipation Constipation is well known as a factor precipitating en- cephalopathy in patients with advanced liver disease. The mechanism involves retention of waste materials in the gut and reabsorption of toxic elements namely am- monia through blood circulation, reaching the brain and causing central nervous system (CNS) dysfunction (12). However, when hepatic function is not compromised, the ammonia is cleared out of the circulation and there- fore, constipation is not considered to cause any signifi- cant disturbance. On the other hand, there is evidence that constipation may be associated with headache, rais- ing the question about the impact of constipation on CNS even in the absence of advanced liver disease. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 173 Emergency (2016); 4 (4): 171-183 T a b le 1 : G a st ro in te st in a l d is o rd e rs r e p o rt e d t o b e a ss o ci a te d w it h h e a d a ch e i n cl u d in g m ig ra in e S tu d y Y e a r C o u n tr y S a m p le s iz e A g e g r o u p G e n d e r (f e m a le ) F in d in g s D y s p e p s ia M a v ro m ic h a li s e t a l. ( 1 3 ) 1 9 9 7 G re e ce 3 1 C h il d re n 5 8 .1 % T h e re i s ca u sa l li n k b e tw e e n r e cu rr e n t a b d o m in a l p a in a n d m ig ra in e . S p ie ri n g s* ( 1 ) 2 0 0 2 U S A 2 A d u lt 1 0 0 % T h e d y sp e p si a t ri g g e re d h e a d a ch e s. M e u cc i e t a l. ( 5 ) 2 0 0 5 It a ly 6 9 8 A d u lt 3 9 .2 % M ig ra in e i s a ss o ci a te d w it h d y sm o ti li ty -l ik e d y sp e p si a . P u cc i e t a l. ( 1 4 ) 2 0 0 5 It a ly 1 4 A d u lt 8 5 .7 % T h e re i s ca u sa l li n k b e tw e e n r e cu rr e n t a b d o m in a l p a in a n d m ig ra in e . A u ro ra e t a l. ( 1 5 ) 2 0 0 6 S w e d e n 2 0 A d u lt 7 5 % M ig ra in e s p a ti e n ts s u ff e r fr o m g a st ri c st a si s b o th d u ri n g a n d o u ts id e a n a cu te m ig ra in e a tt a ck . K u rt h e t a l. ( 4 ) 2 0 0 6 G e rm a n y 5 8 7 A d u lt 4 6 .5 % U p p e r a b d o m in a l sy m p to m s a re s ig n if ic a n tl y m o re f re q u e n t in p a ti e n ts w it h m ig ra in e c o m p a re d w it h h e a lt h y c o n tr o ls H w a n g e t a l. *( 7 ) 2 0 0 8 K o re a 5 8 C h il d re n 7 0 % T h e s tu d y s u p p o rt s a n y s p e ci fi c co rr e la ti o n b e tw e e n h e a d a ch e a n d e p ig a st ri c p a in o r te n d e rn e ss M o d ir i e t a l. ( 1 6 ) 2 0 1 2 U S A 8 4 A d u lt 8 2 .1 % H e a d a ch e s, e sp e ci a ll y m ig ra in e s, a re p re se n t in t w o -t h ir d s o f p a ti e n ts w it h g a st ro p a re si s. R e fl u x s y m p to m s S p ie ri n g s* ( 1 ) 2 0 0 2 U S A 2 A d u lt 1 0 0 % T h e r e fl u x t ri g g e re d h e a d a ch e s a n d r e sp o n d e d t o s p e ci fi c re - fl u x t re a tm e n t. A a m o d t e t a l. ( 9 ) 2 0 0 8 N o rw a y 4 3 ,7 8 2 A d u lt / C h il d re n 6 3 .3 % T h e f in d in g m a y s u g g e st t h a t h e a d a ch e s u ff e re rs g e n e ra ll y a re p re d is p o se d t o r e fl u x . S a b e ri -F ir o o z i e t a l. (1 1 ) 2 0 0 7 Ir a n 1 ,9 5 6 A d u lt 6 4 .8 % g a st ro e so p h a g e a l re fl u x d is e a se i s a ss o ci a te d w it h h e a d a ch e . K a ti c e t a l. ( 1 0 ) 2 0 0 9 U S A 1 ,8 3 2 A d u lt 7 3 % 2 2 .0 % O F m ig ra in e u rs r e p o rt e d h a v in g d ia g n o se d G E R D a n d 1 5 .8 % r e p o rt e d r e fl u x s y m p to m s. C o n s ti p a ti o n A a m o d t e t a l. ( 9 ) 2 0 0 8 N o rw a y 4 3 ,7 8 2 A d u lt / C h il d re n 6 3 .3 % T h e f in d in g s h o w e d p re v a le n ce o f th e m ig ra in e w a s h ig h e r in co n st ip a te p a ti e n ts . In a lo o e t a l. ( 1 7 ) 2 0 1 4 Ir a n 3 2 6 C h il d re n 4 8 .2 % T h e s tu d y s h o w e d a s tr o n g c o rr e la ti o n b e tw e e n h e a d a ch e a n d ch ro n ic f u n ct io n a l co n st ip a ti o n P a rk e t a l. ( 1 8 ) 2 0 1 5 K o re a 1 6 8 C h il d re n 5 2 .1 % R e so lu ti o n o f co n st ip a ti o n i m p ro v e s h e a d a c h e i n m a n y p a - ti e n ts d ia g n o se d w it h p ri m a ry h e a d a ch e *, S tu d ie s in w h ic h h e a d a ch e w a s re p o rt e d t o i m p ro v e o r re so lv e f o ll o w in g m a n a g e m e n t o f th e G I d is o rd e r. http://www.springerlink.com/content/?Author=I.+Mavromichalis This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Noghani et al 174 T a b le 1 : C o n ti n u e … S tu d y Y e a r C o u n tr y S a m p le s iz e A g e g r o u p G e n d e r (f e m a le ) F in d in g s A b d o m in a l p a in A n tt il a e t a l. (1 9 ) 2 0 0 1 F in la n d 5 1 3 C h il d re n 4 9 .9 % C h il d re n w it h m ig ra in e a n d n o n m ig ra in o u s h e a d a ch e s re p o rt h ig h e r fr e q u e n ci e s o f a b d o m in a l p a in . G ro h o lt e t a l. (2 0 ) 2 0 0 3 N o rd ic co u n tr ie s 6 ,2 3 0 C h il d re n 4 6 .7 % T h e re w a s a n a ss o ci a ti o n b e tw e e n t h e a b d o m in a l p a in a n d i n ci d e n c e o f h e a d a ch e . B o cc ia e t a l. (2 1 ) 2 0 0 6 It a ly 6 0 C h il d re n 5 8 % M o st c h il d re n w it h m ig ra in e r e p o rt F G ID s, a ss o ci a te d w it h a d e la y e d g a st ri c e m p ty in g W a lk e r e t a l. (2 2 ) 2 0 1 0 U S A 2 0 0 Y o u n g a d u lt 6 2 % C h il d re n w it h a b d o m in a l p a in t h a t p e rs is ts i n to a d u lt h o o d m a y b e a t in cr e a se d r is k f o r h e a d a ch e . D e n g le r- C ri sh e t a l. ( 2 3 ) 2 0 1 1 U S A 2 4 9 C h il d re n 6 7 .9 % C h il d re n w it h f u n ct io n a l a b d o m in a l p a in m a y i d e n ti fy a g ro u p t h a t is a t ri sk f o r h e a d a ch e l a te r in l if e . C h e li m sk y e t a l. ( 2 4 ) 2 0 1 2 U S A 3 8 C h il d re n 6 3 .2 % 4 0 % o f fu n ct io n a l g a st ro in te st in a l d is o rd e rs p a ti e n ts h a d m ig ra in e . In fl a m m a to r y b o w e l s y n d r o m e V a n d v ik e t a l. (2 5 ) 2 0 0 4 N o rw a y 2 0 8 A d u lt 6 7 % 4 4 .7 % o f p a ti e n ts w it h i rr it a b le b o w e l sy n d ro m e s u ff e r fr o m h e a d - a ch e o r m ig ra in e . H e rs h fi e ld e t a l. ( 2 6 ) 2 0 0 5 C a n a d a 2 0 0 A d u lt 6 4 .5 % 4 7 % o f p a ti e n ts w it h i rr it a b le b o w e l sy n d ro m e H a v e h e a d a ch e . A g ra w a l e t a l. (2 7 ) 2 0 0 9 U K 2 1 1 O ld a d u lt 6 5 .2 % 5 0 % o f p a ti e n ts w it h i rr it a b le b o w e l sy n d ro m e s u ff e r fr o m h e a d a ch e . P a rk e t a l. ( 2 8 ) 2 0 1 3 K o re a 1 0 9 A d u lt 8 7 .2 4 0 .4 % o f m ig ra in e p a ti e n ts h a v e i rr it a b le b o w e l sy n d ro m e . In fl a m m a to r y b o w e l d is o r d e r s H e rs h fi e ld e t a l. ( 2 6 ) 2 0 0 5 C a n a d a 2 0 0 A d u lt 6 6 .5 % 1 9 % o f p a ti e n ts w it h i rr it a b le b o w e l sy n d ro m e s u ff e r fr o m h e a d a ch e . O li v ie ra e t a l. (2 9 ) 2 0 0 8 B ra z il 8 2 A d u lt 5 1 .2 % N e u ro lo g ic a l d is o rd e rs , su ch a s h e a d a ch e , a re c o m m o n i n i n fl a m m a - to ry b o w e l d is e a se p a ti e n ts F o rd e t a l. (3 0 ) 2 0 0 9 U S A 1 0 0 A d u lt 7 7 % T h e p re v a le n ce o f m ig ra in e i n t h e i n fl a m m a to ry b o w e l d is e a se s a m - p le w a s 3 0 % . M ig ra in e w a s m o re p re v a le n t in t h e C D s u b je ct s (3 6 % ) th a n U C s u b je ct s (1 4 .8 % ) D im it ro v a e t a l. ( 3 1 ) 2 0 1 3 U S A 5 0 2 A d u lt 6 7 .3 % M ig ra in e w a s m o re p re v a le n t in c e li a c d is e a se a n d i n fl a m m a to ry b o w e l d is e a se s u b je ct s th a n i n c o n tr o ls . *, S tu d ie s in w h ic h h e a d a ch e w a s re p o rt e d t o i m p ro v e o r re so lv e f o ll o w in g m a n a g e m e n t o f th e G I d is o rd e r. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 175 Emergency (2016); 4 (4): 171-183 T a b le 1 : C o n ti n u e … S tu d y Y e a r C o u n tr y S a m p le s iz e A g e g r o u p G e n d e r (f e m a le ) F in d in g s C e li a c d is e a s e S e rr a tr ic e e t a l. *( 3 2 ) 1 9 9 8 F ra n ce 1 A d u lt 1 0 0 % T re a tm e n t o f co e li a c d is e a se c o in ci d e d w it h t o ta l d is a p p e a ra n ce o f se v e re m ig ra in e a tt a ck s. S p in a e t a l. * (3 3 ) 2 0 0 0 It a ly 1 C h il d re n 1 0 0 % T re a tm e n t w it h t h re e m o n th s o f g lu te n f re e d ie t, i t w a s o b ta in e d t h e co m p le te r e so lu ti o n o f th e h e a d a ch e . R o ch e -H e rr e ro e t a l. ( 3 4 ) 2 0 0 0 S p a in 8 6 C h il d re n N R A n i n cr e a se d p re v a le n ce o f b o th m ig ra in e a n d t e n si o n h e a d a ch e s w a s o b se rv e d i n t h e c o e li a c p a ti e n ts . G a b ri e ll i e t a l. * (3 5 ) 2 0 0 3 It a ly 2 3 6 A d u lt 7 0 % D u ri n g t h e 6 m o n th s o f g lu te n f re e d ie t, o n e o f th e f o u r p a ti e n ts h a d n o m ig ra in e a tt a ck s, a n d t h e r e m a in in g t h re e p a ti e n ts e x p e ri e n ce d a n im p ro v e m e n t in f re q u e n cy . A le h a n e t a l. (3 6 ) 2 0 0 8 T u rk e y 2 0 0 C h il d re n 5 6 .2 % T h e re w a s a n a ss o ci a ti o n b e tw e e n m ig ra in e a n d c e li a c d is e a se . L io n e tt i e t a l. * (3 7 ) 2 0 0 9 It a ly 5 5 4 C h il d re n 6 7 .5 % T h e r e se a rc h e rs r e p o rt e d a h ig h f re q u e n cy o f h e a d a ch e s in p a ti e n ts w it h c e li a c d is e a se s. F ra n ca v il la e t a l. ( 3 8 ) 2 0 1 4 It a ly 1 5 C h il d re n 3 3 .3 % 2 0 % o f p a ti e n ts w it h c e li a c d is e a se s u ff e r fr o m h e a d a ch e . H e li c o b a c te r p y lo r i in fe c ti o n G a sb a rr in i e t a l. * (3 9 ) 1 9 9 7 It a ly 2 2 5 A d u lt N R H . p y lo ri i s co m m o n i n s u b je ct s w it h m ig ra in e . B a ct e ri u m e ra d ic a ti o n ca u se s a s ig n if ic a n t d e cr e a se i n a tt a ck s o f m ig ra in e . G a sb a rr in i e t a l. * (4 0 ) 1 9 9 8 It a ly 1 4 8 A d u lt 6 6 .4 % H . p y lo ri i n fe ct io n i s co m m o n i n p ri m a ry h e a d a ch e ; b a ct e ri u m e ra d i- ca ti o n a p p e a rs t o b e r e la te d t o a s ig n if ic a n t re d u ct io n i n c li n ic a l a t- ta ck s o f th e d is e a se T u n ca e t a l. * (4 1 ) 2 0 0 4 T u rk e y 1 2 0 C h il d re n 6 1 .7 % H e li co b a ct e r p y lo ri p o si ti v e n e ss i s m o re r e le v a n t in t h e m ig ra n o u s p a ti e n ts c o m p a re d w it h c o n tr o ls . Y ia n n o p o u lo u e t a l. ( 4 2 ) 2 0 0 7 G re e ce 3 9 A d u lt 7 5 .5 % H . p y lo ri i n fe ct io n i s a p ro b a b le i n d e p e n d e n t e n v ir o n m e n ta l ri sk f a c- to r fo r m ig ra in e w it h o u t a u ra . H o n g e t a l. * (4 3 ) 2 0 0 7 C h in a 5 0 A d u lt 4 2 % In te n si ty , d u ra ti o n , a n d f re q u e n cy o f a tt a ck s o f m ig ra in e w e re r e - d u ce d a ft e r H . p y lo ri e ra d ic a ti o n . H o ss e in z a d e h e t a l. ( 4 4 ) 2 0 1 1 Ir a n 1 4 0 A d u lt s 7 6 .5 % A ct iv e H . p y lo ri i n fe ct io n i s st ro n g ly r e la te d t o t h e o u tb re a k a n d s e - v e ri ty o f m ig ra in e h e a d a ch e s. F a ra ji e t a l. * (4 5 ) 2 0 1 2 Ir a n 6 4 A d u lt 7 3 .4 % H . p y lo ri e ra d ic a ti o n m a y h a v e a b e n e fi ci a l ro le o n m a n a g e m e n t o f m ig ra in e h e a d a ch e . A n sa ri e t a l. * (4 6 ) 2 0 1 5 Ir a n 1 3 3 A d u lt N R H . p y lo ri e ra d ic a ti o n c o u ld b e a c u re o r to r e d u ce t h e s e v e ri ty a n d co u rs e o f m ig ra in e h e a d a ch e s. *, S tu d ie s in w h ic h h e a d a ch e w a s re p o rt e d t o i m p ro v e o r re so lv e f o ll o w in g m a n a g e m e n t o f th e G I d is o rd e r. N R : N o t re p o rt e d . This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Noghani et al 176 Spierings reported a 47 year old female patient with chronic constipation complaining of headaches since ad- olescence. Dietary change targeting the treatment of constipation reduced the frequency of the headaches (2). The Head-HUNT study further demonstrated this associ- ation and reported a higher prevalence of headache among individuals with much constipation compared with those without such a complaint (9). This suggests constipation to be considered in the con- text of and as a triggering factor for headaches including migraine. - Abdominal pain & inflammatory bowel syndrome Headaches with migrainous features are reported in 40% of children with functional gastrointestinal disor- ders (FGID) (24). GI symptoms occurring during mi- graine attacks such as nausea or vomiting are well ap- preciated, but there is a growing body of evidence, which points to the occurrence of GI symptoms especially ab- dominal pain, outside the bouts of headaches (Table 1). A population-based follow-up study investigated the comorbidity of other pains in 513 school-aged children with primary headache and found recurrent abdominal pain to be present in 50% of the patients (19). A large cross sectional study involving 6230 subjects evaluated the prevalence of recurrent complaints in various sites among 7-17 year-old population. The most common pain combination was reported to be headache and ab- dominal pain (20). Boccia et al. determined the prevalence of FGIDs in mi- grainous children and found it to be present in 70% of the patients, among which functional abdominal pain (FAP) comprised 35% of all. This population also suf- fered from prolonged total gastric emptying time. Treat- ment with Flunarizine significantly reduced the head- aches and GI symptoms (21). FAP in childhood is be- lieved to persist into adulthood in nearly a third of the cases. One study reported that among those with unre- solved FAP, headaches are reported to be more preva- lent compared to adults in whom childhood FAP did not continue (22). In addition, children with FAP have been shown to suffer more from headache and other non-GI somatic symptoms compared to healthy controls. More than one-third of these children go on to develop FGIDs at follow up as adolescents and adults (23). One of the most common FGIDs is IBS, which manifests with abdominal pain or discomfort and changes in bowel habits. The comorbidities of this disorder have been widely studied and it is now evident that patients with IBS suffer from a wide range of non-GI symptoms. One of the most appreciated comorbid non-GI symptoms is headache. It has been reported that 30-50% of patients with IBS, complain of headache (Table 1) (25-28, 47, 48). On the other hand, up to 30% of migrainous patients are reported to suffer from IBS. These findings may be ex- plained in two ways. Either migraine or other primary headaches are not episodic diseases, but in fact they are disorders with underlying abnormality involving other systems that manifest with episodic attacks, or the head- aches are manifestations or sequels of disorders in other body systems namely the GI tract. - Inflammatory bowel disorders Migraine headaches have a higher prevalence in patients with IBD compared to that of the general population (30). Dimitrova studied 111 patients with IBD 23% of which reported chronic headaches and this figure was significantly higher than controls (OR = 2.66; 95% con- fidence interval [CI]: 1.08-6.54) (31). In Brazil, a pro- spective study demonstrated headache to be the most common neurological complaint among 82 patients with IBD, 25% of which met the migraine criteria (29). Gener- alized inflammatory response rather than isolated bowel inflammation may play the key role in the pathogenesis of the extra-intestinal manifestations of IBD (49). - Celiac disease Also known as non-tropical sprue and gluten-sensitive enteropathy, celiac disease (CD) is now recognized as a multisystem autoimmune disorder characterized by in- flammation of the small intestine caused by dietary glu- ten and related proteins in genetically susceptible indi- viduals (50). After the publication of case reports introducing mi- graine as the first manifestation of CD and complete res- olution of symptoms following gluten free diet (32, 33), many studies aimed at investigating the association of primary headaches with CD in children and adults (Table 1) (34-38). Recruiting 188 adult patients with CD and 25 with gluten sensitivity using an ID-Migraine tool, Dimitrova reported chronic headaches to be present in 30% of celiac patients (OR = 3.79; 95% CI: 1.78-8.10) and 56% of patients with non-celiac gluten sensitivity, but only in 14% of controls (P < 0.0001) (31). Two studies involving pediatric CD pa- tients were also conducted and similar results to adult studies were reported. In a case control study, contrary to the study performed previously (51), Alehan et al. in- vestigated the presence of tissue transglutaminase IgA antibodies in a group of pediatric migraineurs and found it to be positive in 5.5% of the patients compared to 0.6% of the control group and the difference was statistically significant (36). In an interesting study, Lionetti et al. ret- rospectively evaluated the prevalence of primary head- ache (based on the IHS criteria) in 354 children diag- nosed with CD. In addition, they prospectively studied the prevalence of CD in a group of pediatric patients with primary headache. In the retrospective phase, they re- ported headache to be present in 25% of the patients be- fore the diagnosis of CD, compared with eight percent of the control group (P < 0.001). In the prospective part, CD was diagnosed by the means of serology and biopsy in 5% of the patients compared with 0.6% of the general This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 177 Emergency (2016); 4 (4): 171-183 population (P < 0.005). Headaches were relieved (and in some completely resolved) after the institution of GFD in patients affected by both conditions (37). Contradicting results have been recently reported in a study, which demonstrates the prevalence of CD in migraine children to be the same as in healthy controls. However, they also showed that GFD improved headaches in the group of children found to have CD (52). Large multicentric stud- ies may resolve these discrepancies. - Helicobacter Pylori Infection H. Pylori infection is associated with various extradiges- tive diseases such as ischemic heart disease, primary Raynaud phenomenon, primary headache, alopecia ar- eata, and hepatic encephalopathy (53). Gasbarrini et al. reported the association of H. Pylori in- fection with primary headache and the improvement of symptoms with eradication of the bacteria (39, 40). Con- tradictory results were reported afterwards (54, 55), however, more recent studies mainly using histological analysis of gastric mucosa biopsy for H. Pylori detection have favored its pathogenic role in migraine (41-44). A double blind randomized clinical trial in 2012, reported the beneficial effects of H. Pylori eradication in manage- ment of migraine patients (45). Overall, regarding stud- ies supporting a role for H. Pylori in migraine it may be judicious to identify H. Pylori infection in migraineurs by noninvasive means especially if suffering comorbid GI symptoms. Pathophysiology The pathophysiology of headache disorders especially migraine and various GI abnormalities are widely stud- ied individually. However, the scientific literature about mechanisms underlying the comorbidity of the two con- ditions is scant. Few hypotheses exist aiming to explain the association of headache and GI disorders. - Central sensitization and parasympathetic re- ferred pain: Longstanding visceral afferent stimuli on convergent viscera-somatic neurons result in expansion of the re- ceptive fields in size and number, decreased response thresholds, and amplification of response magnitude. This process leads to hyper-responsiveness of neurons within the CNS to nociceptive and non-nociceptive stim- uli, which is defined as central sensitization (56). Dyspeptic migraineurs are shown to have postprandial hypersensitivity to gastric distention. It is postulated that this hypersensitivity in dyspeptic patients, results from abnormal processing of gastric stimuli at the level of the CNS. This in turn activates the common pain net- work for both somatic and visceral pain, therefore caus- ing headache (14). The “parasympathetic referred pain” theory is hypothe- sized for explaining the comorbidity of various GI disor- ders with headache including migraine. Continuous stimulus ascending from visceral afferents leads to the central sensitization of trigeminocervical nuclear com- plex expressing a parasympathetic referred pain in the head (57). Reflux of gastric contents into esophagus in GERD may be one example of chronic visceral stimulus leading to sensitization and referred headache. This the- ory may also be applicable for patients with IBS, who have various somatic complaints in addition to their GI symptoms. Migraineurs and patients with IBS may have a very sensitive central and enteric nervous system, which have turned hypervigilant through time and may show exaggerated responses to unpleasant stimuli (58). - Serotonin: The neurotransmitter serotonin is present in the CNS and in the nervous system within the GI tract. Seroto- ninergic drugs are shown to have regulatory effects on gastric motility, and have been proven beneficial in mi- graine treatment and prophylaxis. Serotonin hypothesis may therefore be another explanation for the comorbid- ity of headache and GI abnormalities such as dyspepsia and IBS (14, 59). Serotoninergic pathways may repre- sent the target for the treatment of patients suffering from both conditions. - Autonomic nervous system (ANS) dysfunction: ANS dysfunction is shown to be present in both head- ache and GI complaints. The role of ANS is implicated in postprandial gastric accommodation, thus ANS dysregu- lation may result in delayed gastric emptying and dis- motility-like dyspepsia. In addition, migraineurs are demonstrated to suffer from chronic ANS dysfunctions (4, 9, 60) and are noted to have gastric stasis even out- side acute attacks (15, 16). This phenomena, however, may be more prominent in migraineurs with dyspeptic symptoms in the interictal period, but interictally symp- tom free patients, may have normal gastric morphology and accommodation (61-63). The ANS also has a role in the pathopysiology of GERD in which the lower esopha- geal sphincter is hypotensive or has increased transient relaxations (10). - Calcitonin gene-related peptide (CGRP): CGRP is demonstrated to increase during migraine at- tacks (64-66). This neuropeptide is a potent vasodilator of intracranial vessels (67) and mediates pain transmis- sion in the CNS (68). Infusion of this neuropeptide can induce migraine attack in migraineurs (69). The seroto- nin receptor agonist sumatriptan, which is administered to manage the acute bouts of migraine, is suggested to act partly by blocking the release of CGRP (70). In addition, this neurotransmitter helps to regulate gas- tric relaxations in response to ingestion of food or liquid. CGRP has been shown to have a role in disorders of the gastric reservoir functions leading to functional dyspep- sia with anorexia and early satiety (4, 10). CGRP there- fore, may have a role in the association of migraine and GI disorders. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Noghani et al 178 - Vasculopathy: Vascular tone dysfunction and abnormal regional cere- bral blood flow is demonstrated in migraineurs affected by CD or H. Pylori (35, 37, 42, 71, 72). Since CD arises from an autoimmune response against tissue transglu- taminase it is postulated that the same interaction may take place against this enzyme within the brain vascular endothelium leading to various neurologic symptoms observed in patients with CD (36, 73, 74). This theory, however, may be more applicable for adults than pediat- ric patients (33). In H. Pylori infection, the immune system interacts with the bacterium and vasoactive agents are released. It is hypothesized that this phenomenon may in turn lead to a systemic vasculopathy and alterations of vascular per- meability in various sites including the intracranial ar- teries. This phenomenon along with the production of oxidants and nitric oxide results in regional cerebral blood flow changes; hence inducing migraine headaches (39, 42, 44). The role of oxidative stress however, has re- cently been questioned (75). - Food Allergy: The role of food allergy in the activation of the immune system and subsequent inflammation has been the sub- ject of study for decades (76). Allergy to certain food an- tigens and the development of IgE and IgG antibodies may lead to an inflammation response which can play a role in the pathophysiology of migraine and IBS (77, 78). It is demonstrated that migraineurs are positive for IgG food allergens more frequently than control subjects and their symptoms may improve with an elimination diet (79). In recent years, studies have focused on the IgG- based elimination diet for migraineurs and also IBS pa- tients and successful results have been reported in the attenuation of symptoms (80-82). This supports the the- ory that inflammation may play a key role in the patho- physiology of migraine and may help to explain the comorbidity of primary headaches and GI complaints. The “Persian Medicine” “Traditional medicine is the sum of all the knowledge and practices used in diagnosis, prevention, and elimination of physical, mental, or social imbalance; relying exclusively on practical experience and observation handed down from generation to generation whether verbally or in writ- ing” (83). Traditional medicine (TM) is growing more and more popular worldwide (84). The affordability and accessi- bility of this system along with concerns regarding side effects of chemical drugs and management of chronic de- bilitating diseases such as cancer, diabetes, and heart disease has led many patients to become more inter- ested in TM (85). The TM practiced in Iran, called the “Persian Medicine” (PM), which is known as Greeko-Arabic (Unani) medi- cine elsewhere (86) has a history of more than 8000 years (87). The underlying physiological concept in PM is that of the “Humoral Theory” which is in coordination with the teachings of the ancient Greek scholars namely Hippocrates (460-370 BC) and Galen (129-199 AD). The Humoral Theory states that there are four types of basic particles from which all elements are made. They act on each other and finally make up the humors, which in turn constitute the body organs. Thus, according to this the- ory, health results from the balance of humors within the body and their imbalance leads to disease. Humors are four in number named "Dam" (Sanguis or Blood), the quality of which is warm and moist, "Balgham" (Phlegm) which is cold and moist, "Safra" (Choler or Yellow Bile) which is warm and dry, and "Soada" (Melancholer or Black Bile) which is cold and dry (88, 89). Medieval medical science was gathered by ancient phy- sicians, the most influential of which were Râzi (Rhazes, 860-940 AD) and Ebn-e-Sina (Avicenna, 980-1037 AD) and they added to that their own observations and expe- rience (90). Ebn-e-Sina wrote more than 100 books in his short life span, 16 of which were on medicine (91). His master- piece the “Al-Qanoon fi al-Teb” (The Canon of Medicine) became the principle medical textbook and was taught and studied in universities of Europe and Asia from the twelfth century until the end of the seventeenth century (92). Partly, statements in this book still have relevance today in different issues of health and disease (93-97). Ebn-e-Sina has described headache disorders and thor- oughly discussed the etiology, pathophysiology, symp- toms, and various treatments on this issue, in the third volume of the Qanoon. In this book, headache disorders, referred to as "Soada", are classified into 28 types with each having unique di- agnostic criteria and treatment protocols. Some types are classified as headaches originating from different or- gans which have neurovascular communications with the CNS. One of the most important of these organs was believed to be the stomach, and gastric abnormalities were considered one of the most common etiologies for headache disorders in general (88). Râzi also describes in his book the Al-Hawi (Continents), a kind of headache originating from the stomach due to the production of bitter humors in the gastric fundus. Symptoms aggravate during fasting especially after wak- ing up in the morning (90). Headaches originating from the stomach are classified into seven subtypes. These seven kinds of headache are described here in brief and their key symptoms, aggra- vating and relieving factors of each kind, are summa- rized in Table 2. The first type is headache due to abnormal quality of the This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com 179 Emergency (2016); 4 (4): 171-183 humors within the stomach. Excess warmth, cold, dry- ness, or moisture of the humors within the stomach may induce headaches. Once the normal qualities are reestab- lished headache is relieved. Imbalance of humors within the stomach comprises the second to fourth type. Excess Safra, Balgham, or Soada in the gastric cavity may lead to mucosal injury and gastric dysfunction. Patients with headache due to excess Soada may also present with manifestations of accumulation of Soada within the CNS and therefore, suffer from mood disorders. Another type is headache due to the produc- tion of excess gas as a result of ingestion of gas producing foods such as leguminous seeds. In the first stages, pa- tients may experience epigastric pain just before the ini- tiation of headaches, and once the abdominal pain and bloating is resolved, the headache improves. The sixth type is headache due to the production of excess vapor in the stomach resulting from ingestion of certain kinds of vegetables capable of producing vapors after gastric digestion. The vapors were considered to ascend to the Table 2: The seven types of headache arising from abnormalities within the stomach Etiology Key symptoms Aggravating factors Relieving factors Treatmenta Abnormal quality of humors headache occuring af- ter heavy meals Overeating Eating less; prokinet- ics Restoration of the normal quality Excess Safra (Choler or Yellow Bile) Nausea; anorexia; bit- ter taste in the mouth; excess thirst; subic- teric sclera; epigastric burning Starving; Safra producing foodsb Avoiding hunger; vom- iting the excess Safrac Clearing the stom- ach from exces- sive humor Excess Balgham (Phlegm) Increased salivation; regurgitation; bloat- ing; anorexia; de- creased thirst Overeating; Balgham pro- ducing foodsd Starving; vomiting the excess Balgham; Sleep; prokinetics Clearing the stom- ach from exces- sive humor Excess Soada (Melancholer or Black Bile) Food craving; epigas- tric burning; regurgi- tation Anxiety; depres- sion; Soada pro- ducing foodse Relaxation; vomiting the excess Soada Clearing the stom- ach from exces- sive humor Excess luminal gas Frontal headaches; ab- dominal pain; bloating Gas producing foods Avoiding gas produc- ing foods Elimination of the excess gas Excess vapors Pounding headaches; vertigo; tinnitus Vapor producing foods (onion, garlic, pepper, and spicy vege- tables) Avoiding vapor pro- ducing foods; consuming coriander after meals Elimination of the excess vapor; blocking the as- cent of vapors to the brain Weakness of the gastric fundus and the cardia Headache occurs dur- ing hunger especially when waking up in the morning; irritabil- ity Starving; walk- ing under the sun while hun- gry; malodorous smells Avoiding hunger and having breakfast in time; avoiding CNS stimulants; avoiding malodorous smells Strengthening the fundus and the cardia a, Treatment methods presented were carried out by appropriate foods and natural drugs. b, Spicy and salty foods, foods fried in oil, eggs, nuts, grapes, coconut, honey. c, Certain drugs were used to induce vomiting. patients experienced rapid relief of headache afterwards. d, Fish, milk, yogurt, cheese, cucumber, tomato, lettuce, watermelon, strawberry, sour cherry, kiwi, drinking water with meals. e, Beef, pork, fish, sausages, ham, eggplant, lentil, potato, mushroom, sour tasting fruits, barley, black tea, coffee. This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0). Copyright © 2016 Shahid Beheshti University of Medical Sciences. All rights reserved. Downloaded from: www.jemerg.com Noghani et al 180 brain and induce headaches. Patients may also experi- ence anorexia, nausea, and indigestion following the in- gestion of such vegetables (Table 2). The seventh type is headache due to weakness of the gastric fundus. The fun- dus and the cardia have inadequate strength, gastric vis- ceral sensory thresholds are decreased, and patients have gastric hypersensitivity. Patients are also easily ir- ritated in response to unpleasant stimuli (Table 2). Each of these seven subtypes of headache are clearly de- fined and thoroughly described by ancient scholars in medieval medical resources and treatment regarding each kind is provided (88, 98). The pathophysiology un- derlying these types of headache is explained in the con- text of the Aristotle philosophy and the humoral theory. Nevertheless, they may correspond to the neurovascular mechanisms postulated today for explaining the patho- physiology of headache disorders associated with GI ab- normalities such as central sensitization, vasculopathy, and alterations in the regional cerebral perfusion. Patients presenting with primary headache associated with gastric dysfunction (especially dyspepsia), if thor- oughly questioned, may be recognized to fit in with one of the seven types of headache disorders above. If this is the case, then they may undergo remission with the in- stitution of the appropriate treatment. This is exactly what is taking place today in PM offices in Iran. Summary Comorbidity of headache and GI abnormalities has be- come a subject of interest to researchers in recent years. There is evidence supporting the association of various GI disorders with primary headaches classified by the IHS. In addition to functional GI diseases, IBD and CD along with H.Pylori infection are also reported to be pre- sent in a substantial number of patients with headache. Furthermore, there is a growing body of literature demonstrating improvement or resolution of headache following management of the accompanying GI disorder. This raises the idea of existence of a possible unique di- agnostic entity in the classification of headache disor- ders, the “Headache of Gastrointestinal Origin”. This was once believed by ancient scholars namely Râzi and Ebn- e-Sina. They practiced treatment of this kind of headache in their patients and expressed their experiences in their writings. This entity may provide explanation for head- aches which resolve following treatments targeting the associated GI disorder. Efforts should be made to clarify this type of headache, however arriving at a strict crite- ria may be challenging. Patients fulfilling criteria for any type of primary head- aches through the ICHD, should be thoroughly ques- tioned about GI symptoms. If any GI abnormality, either functional or organic, is detected, especially outside the bouts of headaches, treatment targeting the GI abnor- mality is instituted. Once the GI abnormality is managed, symptoms of the primary headache are reevaluated. If headaches are improved or completely resolved, the headache would be the one of gastrointestinal origin and the patient may be given the diagnosis of “Headache at- tributed to GI disorders”. Acknowledgments: The authors would like to thank Dr. R Choopani for his helpful suggestions. Conflict of interest: The Authors declare that they have no conflict of inter- est. Funding support: None. 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