Irritable bowel syndrome

Irritable bowel syndrome (IBS) is a disorder characterized by chronic abdominal pain or discomfort and altered bowel habits. IBS is the most frequently diagnosed gastrointestinal (GI) condition, with an estimated US prevalence of 5%-25% [1,2]. The diagnosis of IBS is established by fulfilling the symptom-based Rome III criteria (Table 13.1) [3]. IBS accounts for 36%-50% of all referrals to gastroenterologists but is often seen in primary care settings as well [1,2]. In a study to assess the economic burden and health care usage of various GI disorders, IBS accounted for 3.7 million annual office visits, being second only to the number of visits for gastroesophageal reflux [4]. IBS and disorders with which it is related has been associated with a significant decrease in quality of life [5,6]. Functional GI disorders that include IBS have been shown to negatively impact quality of life more so than “organic” GI disorders, such as inflammatory bowel disease [7]. Along these lines, IBS is the second leading cause of work absenteeism [2]. IBS appears to have a female predominance, with two-thirds of patients being women [1]. While the greater prevalence among women is well established, the reasons for this sex difference remain elusive. IBS in women appears to be linked to other chronic functional pain disorders that are sex-based, such as fibromyalgia, chronic fatigue syndrome, chronic constipation, interstitial cystitis, and migraine headaches with aura and temporomandibular joint disorder.