[Motility of the large intestine: from irritable colon to obstipation].
The investigation of colonic motility is a difficult task. Little is known on the myoelectrical activity of the human colon or on physiologic manometric findings. Scintigraphic studies have been performed to investigate the movement of colonic contents and have revealed that the ascending colon mainly acts as a storage area. Because physiologic data are rare, the interpretation of findings in patients with distinct bowel symptoms may be very difficult to interpret. Only a part of the patients who present with chronic obstipation have colonic inertia which is characterized by a slow transit through the entire colon. Other patients may have anismus, i.e. a disturbance of the highly complex activity of defecation. Elderly patients may have diminished rectal sensitivity to dilation and thus do not feel the urge the defecate. Patients with irritable bowel syndrome have been extensively investigated for underlying motility disorders. In spite of ample data the exact pathogenesis remains unknown. Furthermore, it has become clear that patients with the irritable bowel syndrome not only have irritable guts but also an irritable personality. Treatment of chronic constipation is difficult. Bulking agents and osmotically active laxatives often fail to give a satisfactory result. Patients with irritable bowel syndrome may benefit from both bulking agents, but tranquilizers may be helpful as well.