Ursachen und Therapie des Megakolons beim Erwachsenen

The term »megacolon« is descriptive without etiologic implication. Apart from mechanic, metabolic, endocrinologic, pharmacologic or neurologic causes, colonic dilatation can be provoked also by intestinal innervation disorders. Aganglionosis (Hirschsprung's disease) is considered to be the most acknowledged form. Furthermore, also non-aganglionic malformations of the enteric nervous system (e.g. hypoganglionosis, intestinal neuronal dysplasia) may underly formation of a megacolon. Causes for an aquired megacolon are infectious (Chagas disease) as well as autoimmunologic (enteric ganglionitis). Intestinal pseudoobstruction and idiopathic megabowel are considered to represent special forms of megacolon. Differenciated diagnosis is mandatory to select patients to be offered a rational surgical approach. In patients with chronic constipation due to intestinal innervation disorder surgical resection is the only appropriate therapy. Extent of resection is primarily dependent on the length of the morphologically altered bowel wall and the intestinal segments affected by the disturbed transit. In our policy, subtotal colectomy is only indicated in patients with functional disorders of the entire gastrointestinal tract, whereas left colectomy including resection of the proximal rectum is sufficient in colonic inertia. Proctectomy with coloanal anastomosis seems to be the preferred option in both Hirschsprung's disease and idiopathic megarectum.