Crohn’s Disease

Regional Enteritis

 

Pathology

           • Non-caseating granulomas involved with transmural inflammation of the entire GI tract

             • Usual age at onset is 15-30, equal male:female ratio

 

Clinical

             • Recurrent episodes of diarrhea

             • Occult blood loss and anemia

             • Abdominal pain

             • Low grade fever

             • Anorexia, weight loss

             • Perirectal abscess and fistulae

             • Malabsorption

             • Erythema nodosum and pyoderma gangrenosum

 

 

Location

             • The maximum length of the involved segment(s) is determined at the time of initial study; i.e. longitudinal spread is uncommon-except after surgery

             • Esophagus (very rare)

             • Stomach (2-20%)

                        • Usually involves antrum producing granulomatous gastritis

                        • Almost always associated with terminal ileal disease

                        • Rams horn sign=poorly distensible, smooth tubular antrum, widened pylorus and narrowed bulb

                        • Apthous ulcers

                        • Antral-duodenal fistula

             • Duodenum  (rare) (4-10%)

                        • Thickened folds

                        • Almost never occurs without antral involvement

             • Small Bowel (80%) = regional enteritis=terminal ileitis

                        • Thickening and nodularity of folds

                        • Apthous ulcers

                        • Cobblestone mucosa

             • Colon (22-55%) = granulomatous colitis

                        • Frequently right sided with sparing of rectum and sigmoid

                        • Apthous ulcers with target or bull’s-eye appearance

                        • Long, longitudinal fistulous tracts parallel to bowel lumen

                        • Colon may be involved without small bowel, along with small bowel or become involved after surgery for Crohn’s

             • Rectum (35-50%)

                        • Sinus tracts

                        • Deep, collar-button ulcers

X-Ray Manifestations

             • Squaring of the folds-early manifestation from obstructive lymphedema

             • Apthous ulcers-small nodular filling defects (mound of edema) with central ulceration

             • Skip lesions-discontinuous involvement of the bowel with intervening normal areas

             • Proud loops-separation of the loops caused by infiltration of the   mesentery, increase in mesenteric fat and enlarged lymph nodes; simulates a mass

             • Cobblestoning-irregular, blanket-like appearance to bowel wall caused by criss-crossing longitudinal and transverse ulcers separated by areas of edema

             • Pseudopolyps-islands of hyperplastic mucosa between denuded areas of mucosa

             • Filiform post-inflammatory polyps

             • Pseudodiverticula-from bulging area of normal wall opposite side of scarring from disease, usually on anti-mesenteric side

             • String-sign-marked narrowing of terminal ileum (usually) from a combination of edema, spasm and (sometimes, but not always) fibrosis; frequently associated with proximal dilatation                                                                                               

Differential Diagnosis

           • Ulcerative colitis–continuous involvement L colon and rectum;TI normal

             • Diverticulitis–tics; intact mucosa; TI normal

             • Tuberculosis–but TB has more involvement of cecum, less of TI

             • Radiation ileitis–should have other loops involved and appropriate hx

             • Lymphoma–should have tumor masses, less spasm

             • Carcinoid–should have mass; marked fibrosis with angulation of loops

             • Yersinia– may affect TI but clears in 3-4 months

             • Infarction–rare for this location

             • Potassium stricture–lacks full clinical picture

             • Amebiasis–cone-shaped cecum 

Extra-intestinal Manifestations

           • Fatty infiltration of the liver

             • Gallstones (28-34%)

             • Sclerosing cholangitis

             • Bile duct carcinoma

             • Amyloidosis

             • Urolithiasis:oxalate/uric acid stones

             • Migratory arthritis

             • Sacroiliitis and ankylosing spondylitis

             • Erythema nodosum and uveitis 

Complications

             • Fistula (33%)

                • Fistulae occur more often with regional enteritis than with granulomatous colitis

                • Enterocolic fistulae are mostly between ileum and cecum

                • Enterocutaneous fistulae mostly from rectum to skin, but also to vagina and bladder

                • Perineal fistula  [Other common causes of fistula are iatrogenic and diverticulitis]

             • Intramural sinus tracts

             • Abscess formation [common]

             • Rarely, perforation

             • Toxic megacolon (dilated transverse colon with pseudopolyps in toxic person=no BE)

             • Small bowel obstruction

             • Adenocarcinoma (rare) 

Prognosis

           • Recurrence rate up to 40% after resection, commonly at the site of the new terminal ileum and usually within the first two years post-op

             • X-ray demonstration of improvement in regional enteritis is rare

             • Mortality rate of 7% at 5 years and 12% at 10 years after the first resection

 

 

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