Clinical diagnosis : When is it not inflammatory bowel disease ?

Three situations mimic ulcerative colitis. First, in homosexual men, acute self-limited colitis due to campylobacter, salmonella or shigella is seen. Neisseria gonorrhea, herpes simplex, Chlamydia trachomatis and Entamoeba histolytica or a combination of these may also be present. The second setting is that of acquired immune deficiency syndrome (AIDS), where opponunistic infections, cytomegalovirus, cryptosporidium, Salmonella typhimurium and Escherichia coli O 15 7: H 7 may cause diagnostic difficulty. The third situation is when patients have recently returned from or are in an endemic area for infectious diarrhea. This particularly affects the elderly, where salmonella, E coli 0157:H7, shigellosis and, increasingly, pseudomembranous colitis secondary to cycotoxin from Clostridium difficile, occur. The differential diagnoses for Crohn's disease include such disparate conditions as solitary rectal ulcer in females, and ischemic change in the elderly, which usually involves the splenic flexure area of the colon, but may also involve the recrosigmoid area. When a mass is present in the right lower quadrant, the differential diagnosis also includes local abscess formation from a perforated appendix or foreign body, tuberculosis and carcinoma. In the immunocompromised patient, Mycobacterium avium-intracellulare infection and Kaposi's sarcoma may mimic inflammatory bowel disease. Yersinia enterocolitica is becoming increasingly recognized as a cause of acute enteritis, predominantly in the ileum, often with coexistent mesenteric adenitis. Drugs may also cause diagnostic confusion. The one most recognized is antibiotic-associated pseudomembranous colitis. However, cleansing soapsuds, Fleet (Frosst) and bisacodyl enemas, methyldopa and Myochrysine (Rhone-Poulenc) may also cause colitis. Nonsteroidal anti-inflammatory agents may produce ilea! ulceration and a clinical and radiological picture resembling Crohn's disease. Potassium chloride also causes discrete ileal ulcers. Five case reports arc presented to illustrate these diagnostic difficulties. Can J Gastroenterol 1990;4(7):341-346 (pourresume, voir page 342)

T HE FIRST QUESTION TO BE ASKED when faced with a potential inflammatory bowel disease (lBD) paLienr is: Does the patient suffe r from IBO ?If so, is the disease ulcerative colitisorCrohn'sdisease? How active is the disease?Is it fulminant, severe , moderate, mild or inactive/What is the anatomical situation of the disease in the bowel?Is there a site-specific malfunction present?What is the general nutritional status of the patient?Are there intestinal complications?Are there extraintestinal complications?Is malignancy present or nm?Does the du ration of Lhe disease require a surveillance program for the development of malignancy?
In general, the main differential diagnosis in patients with ulcerative colitis is that of acute self-limiting colitis.The groups in which this most resembles ulcerative colitis are: homosexual men, human immunodeficiency virus (HIV) infection and the elderly (5).
In homosexual men, acute selflimiting colitis may be caused by single or multiple organisms.The most common organisms being campylobacter, Figure 1) Top The sigmoidoscopic appearance of a single mucosa/ ulcer.Bottom Characteristic vesicles of herpes simplex infection salmonella, shigella, Neisseria gonorrhea, herpes simplex, chlamydia or Entamoeba histolytica.The sigmoidoscoptc findings in a 30-year-old homosexual male, who presented with extreme rectal pain, tenesmus and rectal bleeding are shown in Figure I .He had a perianal rash.In this instance, the considerations were gonococcal proctitis, foreign body injury, chlamydia or Treponema pallidum infection.However, the vesicles with surrounding red halo are classical for herpes simplex infection, and herpes simplex was isolated from biopsies taken from the characteristic rectal ulcer.
With HIV infection, conditions that give rise to difficulty include: cytomegalovirus colitis, colitis as- sociaced with cryptosporidium, Salmonella bifermentans, and the syndrome associated with Escherichia coli 0157:H7 (6).ln chis last situation, the stools are characteristically liquid, perfuse, but nonbioody for the first 24 h, changing then co bloody.In ulcerative colitis, blood is present in each and every bowel movement from the first moment of onset of the illness.More recently, Kaposi's sarcoma, when situated in the rectum or left colon, may present with rectal bleeding and diarrhea, as indeed, will colitis associated with Mycobacterium avium-intracellulare.
As an example of this, a 45-year-old male presented with a one week history of abdominal pain and diarrhea without fever.Four days later, he had a massive rectal bleed.Abdominal x-rays showed a dilated right colon.Subtotal colectomy was performed for fulminant colitis with impending toxic megacolon.His lover had died eight months earlier from acquired immune deficiency syndrome (AIDS).Sigmoidoscopy confirmed rectal involvement with diffuse change, with erythema, edema and no ulceration.The resected colon showed transmural disease, with linear longitudinal ulcers in the descending colon, the rectum being relatively spared.The patient eventually presented with Pneumocystis carinii In the elderly, especially when they have visited areas where endemic infections are prevalent, differential diagnoses include: acute self-limiting colitis particularly with organisms such as salmonella, shigella and E coli 0157:H7.
There is a special situation usually seen in association with broad-spectrum antibiotic ingestion, that of pseudomembranous colitis due to cytotoxin from Clostridium difficile.The characteristic endoscopic appearances are described ebewhere (7), as is the characteristic histological change (8).
Crohn's disease is a chronic IBO characterized by transmural inflammation, with a characteristic constellation of symptoms, depending on the site involved (9)(10)(11)(12).There are characteristic radiological, endoscopic and surgical findings, often with characteristic granuloma formation on biopsy.The characteristic sites involved are: the distal ileum, the ileum plus colon, the colon, the rectum, perianal areas; less commonly the upper gastrointestinal tract and rarely skin are involved.There may be fistulas present from an infected site to an adjacent loop of howel, an adjacent organ, such as the bladder or skin.Characteristically, when Crohn's disease presents with ilea! involvement there may be an associated inflammatory mass in the right lower quadrant.The differential diagnosis of this includes: appendiccal abscess, foreign body abscess, carcinoma, lymphoma, tuberculosis or, more rarely, sarcoidosis and yersiniosis.
An illustration in this setting is the case of a 3 5-year-old man who presented with right lower quadrant pain, bloating, diarrhea and poor appetite.He was not anemic.He had Diagnosis of IBD right lower quadrant tenderness and a white count of 16,000/mm 3 .Radiological findings demonstrated what appeared to be mucosa!irregularities in the terminal ileum consistent with Crohn's disease (Figure 2).He was given prednisone and sulphasalazine, but was unresponsive after three months because of continuing symptoms, mainly pain.A laparotomy was performed.In this particular case, an abscess was found in relation to a perforated diverticulum in the sigmoid colon, and in the centre of this abscess was a fish bone.There was no evidence of Crohn's disease affecting che bowel, with the characteristic surgical findings of'creeping fat'.
A further example was a 57-year-old female who presented m February 1988 with malaise, vomiting, abdominal cramps and diarrhea.Bowel movements were three to fou r per day and disturbed her sleep.These attacks lasted 24 h and occurred every one co two weeks.By June 1988, her weight had diminished by about 3. 5 kg; upper and lower gastrointestinal tract contrast studies showed skip lesions in the ileum and colon (Figure 3 ).
The diagnosis nfCrohn's disease wa~ made, and symptoms improved on sulphasalazine.
However, persistent nausea resulted in a further weight loss of 3.5 kg.Prednisone was added and abolished her symptoms and she regained 2.7 kg in weight.In October 1988, the patient was well with excellent energy, and had gained a further 3 kg.Bowel movement was one formed motion per day.The prednisonc dose was tapered and discontinued.
In December 1986, left lower quadrant pain occurred with constipation and the patient stayed off work.A I 2x8 cm tender mass was palpable just below and co the left of the umbilicus.The white count was 12,000/mm\ hemoglobin 130 g/L; mean corpuscular volume 103/fl.; and platelets 20xl0 9 /L.This illness sett.ledquickly and the patient was discharged on prednisone and metronidazole.
In February 1987, she was admitted to hospital with further attacks of abdominal pain with associated distension and vomiting, and no bowel Hemoglobin was 155 g/L; white count l l,OOO/mm 3 ; mean corpuscular volume 10 l /fl ; sedimentation rate of 31 mm/L; serum B 12 was 50 pg/ml ( normal 150 to 600); serum albumin was 34 g/L (normal 35 to 50).She was treated with intravenous fluids and nasogastric suction an<l symptoms regressed.Her white count fell to normal; however, bowel movement did not return an<l laparotomy was performed.The diag-nosis prior co laparotomy was Crohn's disease with ileocolitis, with probable abscess formation.It was thought that obstruction had supervened from Crohn's disease, with a small possibility of carcinomatous change or a foreign body-induced obstruction.Ac laparotomy, a lesion was found in the colon, with a secondary lesion in the ileum.These areas were resected, and histology revealed an adenocarcinoma infiltrating the bowel wall and spreading through the lymphatics (Figure 3 ).
Other situations mimicking Crohn's Figure 4) Top Sigmoidoscopic appearance of mucosa!ulceration on both the antenor and posterior rectal wall approximately l O cm from the anal margin.Bottom Masson's trrchrome stain of the ulcers shown above.There is exces, sive fibrosis shown in green, the diagnosnc fibromuscular proliferation m the musculam mucosa.Note the pseudovillus configuracronai the cop and the displaced mucosa/ glands at the bottom of this photomicrograph disease include: the spastic colon variety of the irritable bowel syndrome; ischemic colitis; diverticulitis (13); solitary rectal ulcer syndrome; carcinoma or lymphoma effecting the colon; amebiasis; and the increasing drug-induced forms of colitis or ileitis.A 22-year-old female presented with intermittent rectal bleeding and urgen, cy with a sense of incomplete evacuation.She had been taking oral contraceptives for several months.Fig, No granulomas were present.The ulcer is thought to be Jue to ischcmi.1.The sense of incomplete evacuation a nd the Jemonstra n on of mucosal prolapse on defecography arc often helpful diagnosuc pointers.
Ischemic colitis often causl.!s diagnostic confusion in the elderly (5).There may be an underlying condition associated with an ischemic colitis pre,wtation .A 6 1-ycar-old female presented with a on e <lay history of malaise, nausea, anorexia and abdominal cramps and diarrhea.The stool was liqu1J, brown, small in volume and, after 24 h, became bloody with each bowel movement.There was no fever, chilb or rash.A<lmissinn laboratory findmgs are sh own in Table 2. Sigmoidoscopy revealed a <liffusely reddened, swollen, no nfriable mucosa, and biopsy was n o nspecific.Acute selflimiting colitis was considered, specifically E coli 0157:H7 infection, because white cells were frequent in the swol smear and because of the delayed hematochezia.E coli 0157:H7 and shigella, salmonella, yersinia, campylobacter, aeromonas an<l C difficile cytotoxin were not found in the stoo l.An indium scan sh owed inc reased uptake in the descending colon.
The clues for diagnosis were present on a peripheral bloo<l smear at admission, suggestive o f underlying hemolysis.The subsequent course showed profound thrombocytopenia with early hemolysis.Persistent thrombocyto-  munication).Acute colitis has also recently been described secondary tll methyl<lopa administration ( 14).Proctitis has also been descnbe<l 111 association with contraceptive pill use, and recently there has been much interest concerning nonsteroidal anti -inflammatory drug-induced small bowel lesions (15).These bions may mimic C rohn's disease of the ileum, an<l may mimic the ulceration seen with potassium chloride.In addition, there are spec ific lesions Jescribe<l with n o nsteroida l anti-inflammatory drugs, ie, multiple diaphragmatic strictures.
When IBO 1s present, in the great majority of situations the specific diagnosis can be made readily by the constellation of symptoms and signs, and sigmoidoscopy with biopsy, or by the additional use of colonoscopy, indium scan s or careful contrast studies of the CAN J GASTROENTEROL V OL 4 No 7 NOVEMBER l 990

Diagnosis of IBD
gastrointestinal tract.In a small percentage of pattcnts, pmhahly less than 5<Xi, it may not he possible to make a spcc1tic diagnosis mmally, a condltlon calll.!d 'indetcrmmate colitis'.The diagnosis usually becomes apparent with time.The usual difficulty is with patients diagnosed as having ulccrarive colitis that actually have Crohn's Jbease affectmg the colon, rather than the reverse situation.A careful drug history, attenrion to detail of recent travel where exposure to endemic mtections may have occurred, an<l the apprnpnatc hacteriolog1cal investigatlons will Jetect patients who have acute selt-ltmlflng colitis.If the an-llLipatt'd tht.!rapeutK rcspon~e is not st!cn when rhe patient 1s consi<lcrcJ to have Crohn's <liscasc, laparotomy may he necessary to make a spec1f1c, often unusual, diagnns1s.This is part1rnlarly true for the more obsLure <l1ffcrent1al Jiagnoses related to foreign boJy, carc moma or lymphoma.

Figure 2 )
Figure 2) Barium enema showing excellent filling of the distal ileum.There are mucosa/ nregularities in keeping with ulceration (arrows)

Figure 3 )
Figure 3) Top left Barium enema showing irregularity and narrowing of the ileum and colon in two skip lesions, compat1ble with the diagnosis of Crohn 's disease.Bottom Resected specimen showing the skip lesions.Top right Adenocarcrnoma infiltrating the full thickness of the colonic wall with lymphacic spread