Obstructive colitis Definition & Clinical Features

Obstructive colitis Definition & Clinical Features • Occurrence of a segment of colonic inflammation and ulceration proximal to a complete or partial obstruction • >in elderly people, particularly those with a history of HTN, DM or other chronic illness, who may also have a background of generalised atherosclerosis and cardiac insufficiency • In less typical cases, a diagnosis of ischemia may be suggested by the age of the patient, associated cardiovascular disease, and x-ray appearances such as thumb printing

Obstructive colitis Definition & Clinical Features • In many patients, a diagnosis of ischemia may have to await the outcome of the disease • Resolution of the symptoms within several weeks is suggestive of a reversible ischemic episode • The development of strictures within 1 to 3 months of the onset of symptoms also suggests ischemia • The incidence of this condition is between 0.3% and 7% among patients with obstruction • The patients are typically female and elderly with a mean age of 73 years

Obstructive colitis/ Etiology • inflammatory stricture due to diverticular disease or CD, volvulus or food impaction, or cancer • Obstructing tumour, common cause • Diverticular disease, 30% of cases • Crohn’s disease • Radiation colitis • Chronic ischaemiccolitis • Volvulus • Torsion • Hernias

Obstructive colitis/ Etiology • Strictures • Atresias • Food impaction • Colonic pseudo-obstruction • Due to Hirschsprung’s disease or in Ogilvie’s syndrome , a complication of pregnancy, orthopaedic and other surgery, and major states of debilitation, in which the colon becomes grossly dilated, especially the caecum and/or ascending colon, often leading to perforation • Any disturbance of motility can be responsible

Obstructive colitis/ Pathogenesis • Ischaemia, especially of the mucosa • Vascular compromise by the obstructing lesion • Mechanical causes • With stretching of the mucosa as a result of dilatation leading to relative mucosal ischaemia with haemorrhage and edema • Altered intestinal flora

Obstructive colitis/ Macroscopy • The affected segment may measure up to 250 mm in length and typically is separated from the site of obstruction by a length of normal, or only slightly dilated, colon of ≥35cm • This normal segment may even involve virtually the whole length of the colon because the caecum is a relatively common place for the pathology to occur irrespective of how distal the obstruction is

Obstructive colitis/ Macroscopy • It is usually separated from the site of obstruction by a segment of normal mucosa, sometimes in excess of 10 cm, the cecum being a relatively common place for this to occur irrespective of how distal the obstruction is • The tumor may also lie within the ischemic area • Rarely obstructive pathology, with similar macroscopic and microscopic pathology, is seen in the small intestine

Obstructive colitis Macroscopy • Segmental inflammatory and ulcerating condition • Endoscopically, the involved colon usually appears mildly to massively dilated and exhibits moderate intramural thickening with a granular luminal surface accentuated by deeper longitudinal transverse ulcers. Perforation and peritonitis may develop

Obstructive colitis in a right hemicolectomy specimen: there is an area of inflammation, ulceration and perforation in the lateral wall of the caecum. The cause in this case was acute colonic pseudo-obstruction (Ogilvie’s syndrome) in a post-puerperal woman.

Obstructive enteritis and colitis. Obstructive carcinoma in UC with marked dilatation and hemorrhage of the mucosa proximal to the carcinoma. Note that the 1 or 2 cm immediately proximal to the tumor appears relatively spared, possibly because it is not dilated.

Postcarcinomatous ischemic colitis, the primary tumor being in the cecum, with extensive venous infiltration. The distal mucosa is focally ulcerated and fibrosed

Carcinoma with ischemia. The ischemic areas lie within and immediately adjacent to the carcinoma and are identified by the presence of a greenish tan pseudomembrane

The ascending and transverse colon of the transverse colon cancer in a patient. The mucosal surface of the transverse colon shows a relatively well-defined linear longitudinal ulcer which extends to the distal resection margin.

The descending colon of the descending colon cancer. The ill-defined linear longitudinal shallow ulceration and ill-defined ulcerative lesion extend to the proximal resection margin. The metallic stent of the obstructive lesion which was inserted preoperatively is noted in the left figure. The ruler is 15 cm long.

The descending colon of the descending colon cancer. The ill-defined linear longitudinal shallow ulceration and ill-defined ulcerative lesion extend to the proximal resection margin.

Obstructive colitis/ Microscopy • The histology is essentially the same as that for the earlier stages of ischemic colitis, but in addition, inflammation is more prominent • The histologic changes such as a mixed inflammatory infiltrate, crypt abscesses, and mucosal ulceration and fibrosis are not diagnostic, and the diagnosis is often “colitis unclassified”

Obstructive colitis / Microscopy • Early phases • A primary inflammatory pathology of the mucosa • DD: combination of a distal stricture with a proximal ‘skip lesion’ and inflammatory pathology in the mucosa may represent Crohn’s disease • Later • Ischaemic-type ulceration • Sometimes with fissures and fibrosis • May progress to transmural necrosis and perforation

Obstructive colitis/ Microscopy • The changes vary depending on whether the obstruction developed over a long time or acutely • Slowly developing lesions result in chronic superficial ulceration with evidence of both acute and chronic injury • The diseased bowel is separated from the obstruction by a variable length (2.5 to 35 cm) of normal mucosa • The severity of the injury varies from single ulcers to confluent areas of mucosal loss with multiple pseudopolyps

Obstructive colitis/ Microscopy • Fissuring ulcers may be present • The changes may mimic IBD or ischemic colitis • Ulcers and pseudopolyps may be present, and the overall architecture may appear cobblestoned • The changes are patchy in nature • Distinguishing the lesion from ulcerative colitis • Rapidly developing cases resemble necrotizing enterocolitis • Loss of individual muscle fibers in the muscularis propria results in “vanishing muscle” • This disorder often develops in the right colon

Obstructive colitis / Microscopy • The lesions range in severity from discrete ulcers to extensive areas of fulminant colitis with necrosis, diffuse ulceration, and fibrosis • Because the biopsy features of obstructive colitis are nonspecific, it may be impossible to distinguish this entity from other disorders, particularly ischemia, due to other causes • The mucosa distal to the obstructing lesion usually appears normal

Mucosal fibrosis of this type is invariably ischemic

Trichrome stain showing focal mucosal and submucosal fibrosis (green).

Obstructive colitis / Differential diagnosis • IBD • The condition may closely mimic CIBD • Diffuse nature of the involvement and predominant mucosal pathology perhaps suggesting UC • The segmental nature of the disease, with a length of normal mucosa beyond it is reminiscent of CD • Stercoralulcers • In the large bowel one can also see ‘stercoral’ ulcers secondary to faecalimpaction • >in bedridden individuals in whom a degree of pseudo-obstruction may be present • There may a distinct overlap between the ‘obstructive colitis’ of pseudo-obstruction and stercoral pathology

Obstructive colitis Differential diagnosis • It is interesting that when it occurs with CD, the ulcerations proximal to the strictures disappear after stricturoplasty

Obstructive colitis Others

Obstructive colitis

Obstructive colitis Definition & Clinical Features