tailieunhanh - Emergencies and Complications in Gastroenterology - part 6

Sinh lý bệnh đường ruột của thất bại Mặc dù sự mất mát ruột thất bại ruột có thể cực kỳ cao, đôi khi vượt quá 5 litres/24 h và giống như một tiêu chảy tiết, vấn đề cơ bản là thất bại của sự hấp thụ. | Fig. 1 . Intestinal fluid balance. Acute Intestinal Failure Chronic intestinal failure may occur in a variety of settings including severe motility disorders systemic sclerosis intestinal pseudo-obstruction radiation injury and occasionally malignancy but the most common cause of admission to an intestinal failure unit is small bowel Crohn s disease. These conditions may require long-term intravenous nutrition IVN but this can usually be planned and thus cannot be considered a medical emergency 28 29 . However intestinal failure may develop acutely presenting initially with major problems in fluid and electrolyte balance with substantial losses of other cations. This situation most commonly arises following massive intestinal resection for mesenteric infarction volvulus Crohn s disease or desmoid tumours 30 . Two major groups of patients with intestinal failure have emerged those with a high jejunostomy in which the colon ileum and part of the jejunum have been resected and patients with a jejuno-colic anastomosis in which all or a substantial part of the colon remains in situ 28 29 31 . The risk of developing intestinal failure or the short bowel syndrome is determined not by length of bowel that is removed but by how much remains. The length of normal small intestine varies widely between individuals when measured at laparotomy ranging from 320 to 846 cm with a mean of about 500 cm. The length of the remaining intestine is a good predictor of future needs with respect to fluid electrolyte and nutritional support 32 . Pathophysiology of Intestinal Failure Although the intestinal loss in intestinal failure can be extremely high sometimes in excess of 5 litres 24 h and resembling a secretory diarrhoea the fundamental problem is failure of absorption. Failure to absorb fluid and electrolytes particularly sodium and magnesium results in the most clinically important deficits during the initial phase of the illness. There are however qualitative and quantitative .