'Conversion' from ulcerative colitis to Crohn's disease associated with corticosteroid treatment

A Case Report and Literature Review of Rectosigmoid Crohn's Disease: A Diagnostic Pitfall Ultimately Leading to Spontaneous Colonic Perforation

Inflammatory bowel disease (IBD) is a chronic condition that affects the gastrointestinal tract, with ulcerative colitis (UC) and Crohn's disease (CD) as the two major entities. While these conditions share some similarities in clinical presentation, they have distinct histopathological features. UC is a mucosal disease affecting the left colon and rectum, while CD can affect any part of the gastrointestinal tract and all layers of the bowel wall. Accurate diagnosis of UC and CD is important for effective management and prevention of complications. However, distinguishing between the two conditions based on limited biopsy specimens or atypical clinical presentations can be challenging. We present a case of a patient diagnosed with UC based on a single endoscopic biopsy from the sigmoid colon, who later presented with colonic perforation and was found to have CD on the colectomy specimen. This case emphasizes the importance of clinical guidelines when dealing with any patient of suspected IBD, considering alternative diagnoses in patients with atypical presentations and the need for careful clinical, endoscopic, and histological evaluation to make an accurate diagnosis. Delayed or missed diagnosis of CD can lead to significant morbidity and mortality.

Ulcerative colitis and Crohn's disease: is Mycobacterium avium subspecies paratuberculosis the common villain?

Mycobacterium avium, subspecies paratuberculosis (MAP) causes a chronic disease of the intestines in dairy cows and a wide range of other animals, including nonhuman primates, called Johne's ("Yo-knee's") disease. MAP has been consistently identified by a variety of techniques in humans with Crohn's disease. The research investigating the presence of MAP in patients with Crohn's disease has often identified MAP in the "negative" ulcerative colitis controls as well, suggesting that ulcerative colitis is also caused by MAP. Like other infectious diseases, dose, route of infection, age, sex and genes influence whether an individual infected with MAP develops ulcerative colitis or Crohn's disease. The apparently opposite role of smoking, increasing the risk of Crohn's disease while decreasing the risk of ulcerative colitis, is explained by a more careful review of the literature that reveals smoking causes an increase in both diseases but switches the phenotype from ulcerative colitis to Crohn's disease. MAP as the sole etiologic agent of both ulcerative colitis and Crohn's disease explains their common epidemiology, geographic distribution and familial and sporadic clusters, providing a unified hypothesis for the prevention and cure of the no longer "idiopathic" inflammatory bowel diseases.

Pathologic features of early inflammatory bowel disease

Often the pathologic changes of IBD are subtle and may not be present in a proportion of biopsy specimens. In cases of early disease, the changes may be missed, and additional specimens should be taken after a period of time. Modifying factors, such as prebiopsy treatment and coexisting disease, should be considered. A forum to review cases and allow for communication between gastroenterologists and pathologists is especially useful for clinicopathologic correlation and assignment of a working diagnosis to each case. Careful attention to the pathologic features of early UC and CD would be most useful when evaluating new therapies for IBD.

The natural history of ulcerative proctitis: a multicenter, retrospective study. Gruppo di Studio per le Malattie Infiammatorie Intestinali (GSMII)

OBJECTIVE

The aim of this study was to evaluate the clinical features and the long term evolution of patients with a well defined initial diagnosis of ulcerative proctitis.

METHODS

Patients with an original diagnosis of ulcerative proctitis who had been seen at any of 13 institutions from 1989 to 1994 were identified. Data on disease onset and subsequent evolution were recorded. In addition, 575 patients with more extensive disease, treated in the same centers, were used as controls.

RESULTS

A total of 341 patients satisfied the inclusion criteria. The percentage of smokers in these patients was slightly lower than in controls; no differences were found in the other clinical/demographic variables evaluated. A total of 273 patients entered long term follow-up (mean, 52 months). Proximal extension of the disease occurred in 74 of them (27.1%). The cumulative rate of proximal extension and of extension beyond the splenic flexure was 20% and 4% at 5 yr and 54% and 10% at 10 yr, respectively. The risk of proximal extension was higher in nonsmokers, in patients with >3 relapses/yr, and in patients needing systemic steroid or immunosuppressive treatment. Refractory disease was confirmed as an independent prognostic factor at multivariate analysis.

CONCLUSIONS

Proximal extension of ulcerative proctitis is frequent and may occur even late after the original diagnosis. However, the risk of extension beyond the splenic flexure appears to be quite low. Smoking seems to be a protective factor against proximal extension, whereas refractoriness is a risk factor for proximal extension of the disease.

Multivariate identification of metabolic features in inflammatory bowel disease

Weight loss and malnutrition are commonly reported in inflammatory bowel disease (IBD), but differences between Crohn's disease (CD) and ulcerative colitis (UC) patients have rarely been pointed out. In this regard, a sample of 102 consecutive patients with a diagnosis of either CD (n = 63, 33 males) or UC (n = 39, 25 males) based on previously reported clinical, morphologic, and histopathologic criteria were studied. Twenty-six anthropometric and metabolic variables were measured upon admission. Body composition was assessed by both anthropometry and bioimpedance measurements, and energy expenditure and substrate oxidation were assessed by indirect calorimetry. The data were subjected to principal-component analysis and to factor rotation to derive a set of a few basic independent descriptors of the metabolic features of each subject. Six descriptors were found to be responsible for greater than 86% of the total sample variability and to associate very well with mutually disjoint subsets of the original variables. The six summarizing factors are listed in order of decreasing percentage of explained variation (size 41.8%, fatness 17.9%, fuel 12.2%, shape 5.4%, energy 5.2%, and steroid 3.9%). CD and UC patients differed significantly with respect to fatness (CD lower, P = .004) and carbohydrate (CHO) fuel preference (CD lower, P = .030). Hence, CD patients showed a reduced fat mass (FM) compared with UC patients, and from a metabolic point of view, too, CD and UC are not superimposable. In fact, the lower CHO oxidation (CHOox) rate and consequent preferential lipid utilization found in CD patients may be taken into account as a contributing cause of lipid tissue wasting and in planning therapeutic enteral regimens.

The differential diagnosis of Crohn's disease and ulcerative colitis

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.