Mechanisms of Intestinal Failure in Crohn's Disease A. O. Agwunobi, F.R.C.S., G. L. Carlson, M.D., I. D. Anderson, M.D., M. H. Irving, M.D., N. A.

Scott, M.D.

From the Intestinal Failure Unit, Department of Surgery, Hope Hospital, Salford, Manchester, United Kingdom PURPOSE: The purpose of this study was to determine the mechanisms by which patients with Crohn's disease develop intestinal failure and, in particular, to assess the relative importance of severe primary disease, repeated uncomplicated elective small intestine resection, and resection performed as a consequence of intra-abdominal septic surgical complications. METHODS: This was a retrospective analysis of 41 patients with Crohn's disease referred to a specialized intestinal failure unit between January 1987 and September 1998 for permanent home parenteral nutrition. To compare the surgical activity in patient groups, a resection index was calculated by dividing the number of intestinal resections by the interval in years between the first resection for Crohn's disease and referral for management of intestinal failure. RESULTS: Extensive primary Crohn's disease was responsible for intestinal failm-e in 7 cases (17 percent). The remainder (n = 34, 83 percent) developed intestinal failure after intestinal resection. Nine of the "surgical" Crohn's patients developed intestinal failure after uncomplicated sequential resection, (median small-bowel length 65 (range, 60-120) cm) after a median of 3 (range, 2-8) operations over a median of 17 (range, 3-27) years. By contrast, the other 25 surgical Crohn's patients developed intestinal failure after multiple unplanned laparotomies for intra-abdominal sepsis (median small-bowel length 70 (range, 60-200) cm), with a median of 4 (range, 2-7) laparotomies performed over a median of 0.5 (range, 0.1 to 1.5) years (P < 0.001). The resection index for the 25 Crohn's patients undergoing laparotomies for intra-abdominal sepsis was significantly greater than that of the 9 patients who had planned sequential resections (2.1 (0.27-25) vs. 0.23 (0.1-1.0); P < 0.002, Mann-Whitney Utest). CONCLUSION: Intestinal failure develops in Crohn's disease primarily as a result of complications of surgical treatment. The largest group of patients at risk consists of those who are undergoing multiple tmplanned laparotomies to control intra-abdominal sepsis. [Key words: Short bowel syndrome; Sepsis; Parenteral nutrition]

accounts for at least 40 percent o f all patients requiring h o m e parenteral nutrition (HPN). 2'3 Although a reasonable quality of life can be achieved in a p o p u lation of Crohn's patients o n HPN, 4'5 for the individual Crohn's patient, the d e v e l o p m e n t of IF and the requirement for HPN represents a tragedy that has significant financial implications for the provision of health care. 6 The incidence of IF in patients with Crohn's disease is too small to allow the majority o f centers to determine the relative f r e q u e n c y b y w h i c h surgical strategies lead to IF. 7 H o p e Hospital cares for the biggest institutional p o p u l a t i o n of patients with IF w h o require HPN in Europe. From this population, w e identified 41 patients with Crohn's disease w h o required HPN b e t w e e n 1987 a n d 1998 for IF. O u r aim was to identify the clinical m e c h a n i s m s of IF in each patient, with particular reference to the f r e q u e n c y and indications for surgical resection.

PATIENTS AND METHODS

Agwunobi AO, Carlson GL, Anderson ID, Irving MH, Scott NA. Mechanisms of intestinal failure in Crohn's disease. Dis Colon Rectum 2001;44:1834-1837. ntestinal failure (IF) is defined as a reduction in functioning gut mass b e l o w the minimal a m o u n t necessary for the a d e q u a t e digestion and absorption of nutrients. 1 Crohn's disease is the most c o m m o n cause of IF in adults in the United Kingdom, w h e r e it

I

Address reprint requests to Mr. Carlson: Intestinal Failure Unit, Department of Surgery, Hope Hospital, Salford, Manchester M6 8HD, United Kingdom.

The Intestinal Failure Unit at H o p e Hospital, Salford, United Kingdom, maintains a prospective database of all n e w referrals for the m a n a g e m e n t of IF. The records of all patients referred with Crohn's disease w h o required p e r m a n e n t HPN at the time of discharge b e t w e e n J a n u a r y 1987 a n d September 1998 w e r e obtained. Patients in w h o m t e m p o r a r y HPN w a s p l a n n e d only until intestinal continuity could be restored w e r e e x c l u d e d from the study. All patients on p e r m a n e n t HPN w e r e regularly seen in the outpatient clinic o n c e every three months, initially for o n e year, a n d every six m o n t h s thereafter to assess their nutritional status and continued n e e d for HPN b y anthropometric, hematologic, and biochemical measurements. 8 A retrospective review of charts from the referring hospitals was c o n d u c t e d for each of the identified Crohn's patients with IF o n p e r m a n e n t HPN. In addition to d e m o g r a p h i c details, the disease history up to

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the development of IF was noted. In particular, we determined the temporal course and indication for intestinal resection for each patient, along with the length and nature of the remaining small intestine at the time of referral to Hope Hospital, using a combination of small-bowel contrast radiology,9 operation notes from referring centers, and use of sterile measuring tape during laparotomy at Hope Hospital where relevant. Statistical Analysis Data are presented as median (range). Comparison between groups for age, intestinal length, and time between first intestinal resection and diagnosis of IF was made with the Mann-Whitney U test. To allow comparison of surgical activity between patient groups, a resection index (RI) was calculated for each patient by dividing the number of intestinal resections by the interval in years between the first resection for Crohn's disease and referral for management of IF. Statistical comparison between surgical groups for RI was made with the Mann-Whitney U test. P < 0.05 was taken as the level of statistical significance. RESULTS Forty-two consecutive patients (27 females; median age, 47 (range, 19-71) years) with IF caused by Crohn's disease were referred to the Intestinal Failure Unit of Hope Hospital between January 1987 and September 1998. Two of these patients developed IF after surgical treatment of Crohn's disease at Hope hospital. The remainder were referred after developing IF associated with Crohn's disease at the referring hospital. All patients required home parenteral support, with the majority of patients (n = 34, 83 percent) requiring intravenous nutritional support. Seven patients (17 percent) required only home intravenous fluids and electrolytes therapy. One patient was excluded because of inadequate records. Seven patients (17.1 percent; 3 females) with a median age of 28 (range, 19-47) years required HPN for the management of primary extensive Crohn's disease (i.e., they had not undergone surgical treatment). The indications for HPN in these patients included malnutrition (n = 3) and failure to grow or reach sexual maturity (n =- 4) despite aggressive medical therapy, including enteral feeding (n = 7), steroid use (n = 7), and azathioprine therapy (n = 3). The

1835

median age at diagnosis of Crohn's disease was 12 (range, 7-18) years in the patients with primary extensive Crohn's disease. In the remaining 34 patients (82.9 percent), IF requiring permanent HPN developed as a direct consequence of loss of gut mass caused by surgery for Crohn's disease (Table 1). Only nine (26.5 percen0 of the "surgical" Crohn's patients developed IF as a consequence of repeated sequential uncomplicated elective resection. By contrast, the majority (n = 25, 73.5 percent) of surgical Crohn's patients developed IF after surgical resection complicated by postoperative intra-abdominal sepsis. In 18 of the 25 patients, repeated laparotomies were performed to deal with intra-abdominal sepsis complicating elective surgical excision of Crohn's disease, with development of IF during the course of a single hospital admission. This sepsis was secondary to postoperative complication and was not directly related to Crohn's disease. In seven cases, this was the patient's first admission for surgical treatment. The median age at diagnosis of Crohn's disease in both groups of surgical Crohn's patients was similar (27 (range, 18-32) years for repeated sequential uncomplicated resection group and 25 (range, 15-39) years for the group undergoing frequent laparotomies for postoperative intra-abdominal sepsis). In the nine surgical Crohn's patients who underwent uncomplicated sequential resection, IF (median small-bowel length 65 (range, 60-120) cm) developed after a median of 3 (range, 2-8) operations over a median of 17 (range, 3-27) years. By contrast, the 25 Crohn's patients who underwent unplanned multiple laparotomies for sepsis developed IF (median smallbowel length 70 (range, 60-200) cm) after a median of 4 (range, 2-7) resections performed over a median of 0.5 (range, 0.1 to 1.5) years (P < 0.001). The RI for the 25 Crohn's patients undergoing frequent laparotomies for sepsis was significantly greater than the RI of the 9 patients who had planned sequential resections (2.1 (0.27-25) vs. 0.23 (0.1 - 1.0), P < 0.002, Mann-Whitney Utest; Fig. 1). DISCUSSION Crohn's disease is responsible for the majority of cases of adult IF in the United Kingdom.2'3 The mechanisms by which patients with Crohn's disease develop IF have not been studied previously. In this retrospective study of a consecutive cohort of Crohn's patients referred for IF management, surgical loss of gut mass accounted for the large majority of cases.

1836

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It has previously been assumed that repeated disease recrudescence followed by repeated resection over several years accounts for the majority of cases of surgically induced Crohn's IF. 1° This assumption has led to the development of strategies to preserve intestinal length, such as strictureplasty. :1':2 Because the present study could not identify the denominator population of Crohn's patients from which the 34 surgical patients originated, it cannot judge the success or failure of these strategies in avoiding IF. However, the relatively low incidence (26 percent) of IF associated with uncomplicated sequential resection in the present study corresponds with reports that uncomplicated Crohn's resection has a low risk of IF (0.5 to 2.2 percent of cases). :3':4 Among the 34 patients with surgically induced IF, 74 percent developed this problem after a rapid series of repeated laparotomies to deal with postoperative intra-abdominal sepsis, during which large lengths of gut were resected to control sepsis. This sepsis was associated with fistulating disease or anastomotic breakdown. The age at diagnosis of Crohn's disease in both groups of surgical Crohn's patients was similar, but those with primary IF caused by Crohn's were significantly younger (P < 0.001, Mann-Whitney U tesO, However, the significantly higher RI in the Crohn's patients who developed IF after repeated laparotomies to deal with postoperative complications compared with those patients who developed IF after uncomplicated sequential resection illustrates the difference in clinical course between the two groups. Thus, both strategies that preserve intestinal length and surgical strategies that avoid postoperative intraabdominal sepsis are needed to :'educe the risk of IF

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INTESTINAL FAILURE IN CROHN'S DISEASE

in the surgery of Crohn's disease. Such sepsis-avoidance strategies might include judicious exteriorization in the p r e s e n c e o f fistulating disease p r o d u c i n g systemic sepsis with h y p o a l b u m i n e m i a .

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home parenteral nutrition service. Baillieres Clin Gastroenterol 1988;2:905-14. Egger NG, Carlson GL, Shaffer JL. Nutritional status and assessment of patients on home parenteral nutrition: anthropometry, bioelectrical impedance, or clinical judgement? Nutrition 1999;15:1-6. Nightingale JM, Bartram CI, Lennard-JonesJE. Length of residual small bowel after partial resection: correlation between radiographic and surgical measurements. Gastrointest Radiol 1991;16:305-6. Forbes A. Surgery for inflammatory bowel disease. In: Clinicians guide to inflammatory bowel disease. London: Chapman and Hall, 1997:137-60. Tjandra JJ, Fazio VW. Strictureplasty without concomitant resection for small bowel obstruction in Crohn's disease. BrJ Surg 1994;81:561-3. Dehn TC, Kettlewell MG, Mortensen NJ, Lee EC, Jewell DP. Ten year experience of strictureplasty for obstructive Crohn's disease. Br J Surg 1989;76:339-41. DeDombal FT, Burton I, GoligherJC. The early and late results of surgical treatment for Crohn's disease. Br J Surg 1971;58:805-16. Post S, Herfarth C, B6hm E, el al. The impact of disease pattern, surgical management, and individual surgeons on the risk for relaparotomy for recurrent Crohn's disease. Ann Surg 1996;223:253-60.