Airway responsiveness to inhaled methacholine in patients with irritable bowel syndrome

Interpretation of the “positive” methacholine challenge

“…Multiple studies have identified gastrointestinal disorders such as irritable bowel syndrome (IBS), Crohn's disease, ulcerative colitis, and gastroesophageal reflux (GERD) as risk factors for BHR [White et al, 1991;Louis et al, 1995Louis et al, , 1999Bartholo et al, 2005]. In the case of IBS, White et al [1991] suggested these individuals may have common alterations in smooth muscle function outside the gastrointestinal tract.…”

Visceral Perception in Functional Gastro-Intestinal Disorders: Disease Marker or Epiphenomenon?

“…affecting vis ceral organs other than the gastro-intcstinal tract. Using inhaled methacholine to induce bronchoconstriction, it has been demon strated that in IBS patients a significantly low er concentration of methacholine induced a fall of 20% in FEV\ (1-second expired volume during forced vital capacity) when compared to patients with organic disease or normal controls (197.6 mg/ml in normals and 12.8mg/ml in IBS, p < 0.001) [51]. Also, greater increases in blood pressure in response to a 'cold pressor test' have been demon strated [52], and urodynamic [53] and oe sophageal motility abnormalities [54] have been described in IBS patients.…”

Defecation-related Asthma

“…However, it is a reasonable possibility that a strong urge to defecate and bronchospasms share a common pathophysiological mechanism due to autonomic imbalance. In fact, previous studies have demonstrated increases in airway hyperresponsiveness and a high prevalence of asthma among patients with irritable bowel syndrome (3,4). We assume that, in the present case, activation of the parasympathetic nerves during intestinal peristalsis associated with the Valsalva maneuver stimulated the autonomic nervous system to secrete acetylcholine, leading to bronchospasms as a response to the contraction of the bronchial smooth muscles.…”