Bailliere's clinical gastroenterology最新文献

Patients with Crohn's disease are haunted by the likelihood of recurrence following resection of their disease. In an effort to better counsel patients about their relative risk, many centres have evaluated a myriad of factors thought to be harbingers of recurrence. Insightful review of the numerous studies requires consideration of the definition of recurrence, length and manner of follow-up, and statistical tools used for analysis of the data. Factors that may possibly influence recurrence include: age of disease onset; gender; tobacco use; anatomical pattern of disease; clinical pattern of disease; extra-intestinal manifestations; duration of pre-operative symptoms; previous resections; operative indication; blood transfusion; extent of resection; faecal diversion; pathological features of resected bowel; and chemotherapy following resection. Unfortunately, the role that these factors play in disease recurrence remains poorly understood.

Laparoscopic surgery for patients with Crohn's disease is feasible and safe. It may be conducted in appropriately selected patients including those with localized abscess, phlegmon, simple intra-abdominal fistulas, and perianastomotic recurrent disease. However, as the technique is just evolving and has yet to be shown to be of advantage over conventional open surgery, it should not be considered as a standard care. Randomized prospective clinical studies are needed to determine that laparoscopic surgery for Crohn's disease is at least equivalent or better than conventional open surgery.

About 90% of patients with Crohn's disease require surgery at some time in their lives but the clinical recurrence rate after surgery is about 50% within 5 years, with 50% requiring further surgery within 10 years. Endoscopic evidence of relapse can be found in 75% within 12 weeks of resection. There is therefore a major problem to be solved. The solution is less clear. Retrospective studies suggest that smoking is a major factor determining a poor prognosis after surgery and it is most important that patients are encouraged to stop. There is strong evidence linking diet with Crohn's disease but the mechanism and nature of this link remains unclear. A low total fat intake, possibly supplemented with eudragitcoated n-3 fatty acid (fish oil) looks reasonable on current evidence but not proven.

Mesalazine and metronidazole are the drugs for which most supportive evidence is available. The individual trials of mesalazine have generally proved inconclusive and meta-analyses have been needed to demonstrate a significant beneficial effect (approximately halving the relapse rate at 1 year). More recent large controlled studies performed after the meta-analyses however have again proved negative and the benefit is probably more modest than the meta-analyses suggested. Metronidazole, 20 mg/day for the first 3 months after surgery, has been shown to reduce relapse by just over one-third with a beneficial effect that was surprisingly sustained throughout a 3 year follow-up period. Peripheral neuropathy is a problem and further studies are needed at lower dosage. Azathioprine, 1.5-2 mg/kg/day is effective as maintenance therapy but there is insufficient evidence to recommend its routine post-operative use, moreover it takes up to 3 months to have an effect. Although budesonide has been shown to delay the time to relapse in nonoperated patients it, like other corticosteroids, has been shown to be no better than placebo when maintenance is assessed according to the proportion of patients who remain relapsefree after 1 year.

Patients undergoing operation for Crohn's disease should therefore be strongly advised to stop smoking. A 3 month course of oral metronidazole plus continued maintenance with oral mesalazine can be justified on current evidence but further studies are needed.

Most cases of inflammatory bowel disease (IBD) can be correctly labelled as Crohn's disease (CD) or ulcerative colitis (UC) with careful initial gross and microscopic examination of biopsy and resection specimens together with close clinical and radiological correlation. Until we understand more of the aetiology and immunology of IBD we should admit that there are limitations imposed by current diagnostic criteria, consider the use of reporting proforma to improve diagnostic accuracy, and accept that in a small number of patients clinicopathological features will overlap, and CD may masquerade as UC.

The clinical features of Crohn's disease manifest during adolescence are varied as in adults. The potential complication of growth impairment and concomitant delay in pubertal development is unique to this population. Cytokines released from the inflamed bowel and chronic nutritional insufficiency are the major factors in the pathophysiology of growth inhibition. Hence reduction of intestinal inflammation and consistent provision of adequate nutrition are of paramount importance in management. Drug treatment mirrors that of adults; few specifically paediatric clinical trials have been conducted. Enteral nutrition is an important therapeutic alternative for young patients. There is evidence that it constitutes both a primary therapy of inflammation and a means of providing the calories needed for growth. In the setting of extensive disease, dependency on corticosteroids should be minimized through judicious administration of immunosuppressive drugs. For an adolescent with localized stenotic disease optimal management includes a timely referral for intestinal resection as a means of providing an asymptomatic interval during which growth and pubertal development can normalize.

Although much is still to be learned about the pathogenesis of cholelithiasis, recent investigations have greatly advanced our knowledge regarding the mechanisms of cholesterol supersaturation and nucleation. Laparoscopic cholecystectomy has lessened the usual peri-operative morbidity of cholecystectomy, but is associated with a higher bile duct injury rate. Acute cholecystitis, the commonest complication of cholelithiasis, is a chemical inflammation usually requiring cystic duct obstruction and supersaturated bile. The treatment of this condition in the laparoscopic era is controversial. Early operation may lessen hospital stay but an increased risk of biliary injury has been reported.

Gallstones are commonly found within the main bile duct (MBD) of patients undergoing cholecystectomy. Retained MBD stones are a common cause of obstructive symptoms and complications. Endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy (ES) is the recommended modality for both the detection of such stones and their extraction. Recent trials of ERCP in conjunction with laparoscopic cholecystectomy suggest that it should be reserved for use post-operatively. Gallstones within the MBD are the most common single cause of acute pancreatitis. Initial treatment is supportive, although new agents designed to suppress the systemic inflammatory response are under development and have proved beneficial in clinical trials. Severe cases should be treated with systemic antibiotics and early removal of the obstructing stones by ERCP and ES. Prophylactic cholecystectomy is recommended to prevent further attacks of gallstone pancreatitis.

The vast majority of post-operative bile duct strictures occur following cholecystectomy, these injuries having been seen at an increased frequency since the introduction of laparoscopic cholecystectomy. Bile duct injuries usually present early in the post-operative period, obstructive jaundice or evidence of a bile leak being the most common mode of presentation. In patients presenting with a post-operative bile duct stricture months to years after surgery, cholangitis is the most common symptom. The ‘gold standard’ for the diagnosis of bile duct strictures is cholangiography. Percutaneous transhepatic cholangiography is generally more valuable than endoscopic retrograde cholangiography in that it defines the anatomy of the proximal biliary tree that is to be used in surgical reconstruction. The most commonly employed surgical procedure with the best overall results for the treatment of bile duct stricture is a Roux-en-Y hepaticojejunostomy. The results of the surgical repair of bile duct strictures are excellent, long-term success rates being in excess of 80% in most series. Recent data have suggested that, at intermediate follow-up of approximately 3 years, an excellent outcome can be obtained following repair of bile duct injuries after laparoscopic cholecystectomy. Percutaneous and endoscopic techniques for the dilatation of bile duct strictures can be useful adjuncts to the management of bile duct strictures if the anatomical situation and clinical scenario favour this approach. In selected patients, the results of both endoscopic and percutaneous dilatation are comparable to those of surgical reconstruction.

Biliary infections are common conditions that can be life threatening. In the past, many of these conditions mandated emergency surgery, but advances in endoscopic and radiological techniques have allowed some of these to be managed in a minimally invasive fashion. Acute cholangitis is caused by infection in an obstructed biliary tree. Endoscopic drainage, together with broad-spectrum antibiotics, has replaced emergency common duct exploration and T-tube drainage as standard treatment. Oriental cholangitis, sclerosing cholangitis and AIDS-related cholangitis are some of the variants of cholangitis. Pyogenic liver abscesses complicating cholangitis can be managed by radiological percutaneous drainage. Close collaboration between surgeons, endoscopists and radiologists is the key to success in managing biliary infections.