[Megacolon and sigmoid volvulus: incidence and physiopathology]

The etiology of Megacolon is multiple. One of these causes and the most frequent is Chagas disease. Its complication: sigmoid volvulus was de main diagnosis in the admitted patients at the Bolivian and Japanese Gastroenterological Institute of Cochabamba Bolivia. It usually affects people of a low economic income. In this Gastroenterological Hospital a transversal and prospective study has been done, in order to know the real incidence and the physiopathology of this disease. In a six year period, from 2000 to 2006, 8.954 patients were admitted to the Hospital: of these, 814 (9.09%), where diagnosticated as lower intestinal obstruction. In 608 (74.7%) the final diagnosis was sigmoid torsion. Radiological diagnosis was made in 84% of the patients and endoscopic decompression was successful in 88.7%. As reported in the medical literature, the main cause of megacolon in this part of the world is Chagas disease. In our investigation 22% (98 patients), were serology positive to Chagas disease, and another 21.44% (95 patients) were serology negative. They were coca leaf chewers. One of coca leaf compounds is cocaine which blocks the adrenaline and noradrenaline degradation by mean of monoamine oxidase inactivation. These two hormones stay a long term of time in the target organ: the large bowel. By this mean chronic and persistent vessel constriction develops intestinal wall atrophy and lower resistance to the intraintestinal pressure.