PREDOMINANT SYMPTOMS IN IRRITABLE-BOWEL-SYNDROME CORRELATE WITH SPECIFIC AUTONOMIC NERVOUS-SYSTEM ABNORMALITIES

Background/Aims: Irritable bowel syndrome may be influenced by the aut onomic nervous system. Abnormalities in autonomic function, colon tran sit time, and psychological profiles in 21 patients were assessed. Met hods: Using modified Manning criteria for irritable bowel syndrome, pa tients were classified as constipation-predominant or diarrhea-predomi nant. Autonomic function was determined by one vagal cholinergic and t wo sympathetic adrenergic measures. Colon transit was assessed by radi opaque markers, and psychological profiles were determined by three in ventories. Results: Autonomic function tests showed that diarrhea-pred ominant subgroup values for one sympathetic adrenergic measure (postur al adjustment ratio) were significantly different from controls (P < 0 .01). Constipation-predominant subgroup values were significantly lowe r for the vagal cholinergic measure R-R interval (P < 0.05). Colon tra nsit measures differed by subgroup in left, right, rectosigmoid, and t otal colon transit times. Both subgroups differed significantly from c ontrols on psychological measures; the constipation subgroup showed mo re psychological distress. Conclusions: Irritable bowel syndrome speci fic-symptom subgroups had different patterns of autonomic functioning, colonic transit, and psychological measures. The constipation subgrou p is associated with a cholinergic abnormality and the diarrhea-predom inant subgroup with an adrenergic abnormality. These findings suggest specific associations between the autonomic nervous system, predominan t physical symptoms, colon transit time, and psychological factors in patients with irritable bowel syndrome.