Infectious Colitis

Published on 20/07/2015 by admin

Filed under Radiology

Last modified 22/04/2025

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 3332 times

 Mucosal hyperenhancement, marked submucosal edema, ascites

image Multiple air-fluid levels, inflamed pericolonic fat
• Ultrasound findings

image Symmetric wall thickening and submucosal echogenicity
image Increased mural flow on color Doppler
• Fluoroscopic findings

image Used less frequently than before; now supplanted by CT, US, and endoscopy
• Clostridium difficile, Campylobacter, Escherichia coli, CMV

image Accordion sign: Alternating bands of enhancing mucosa and submucosal edema with compressed lumen
• May progress to hemorrhagic necrosis and perforation; toxic megacolon

TOP DIFFERENTIAL DIAGNOSES

• Ulcerative colitis

image Wall thickening is generally less prominent with UC
• Granulomatous colitis (Crohn disease)
• Ischemic colitis

image Usually located in watershed areas, rarely pancolitis
image Rectum is rarely affected by ischemic colitis

CLINICAL ISSUES

• C. difficile colitis occurs mostly in institutionalized patients or those on antibiotic, chemotherapy, or immunosuppressive medication
• Acute infectious diarrhea is most often foodborne or waterborne disease
• Most common bacterial causes of infectious colitis in USA

image C. difficile, Salmonella, Campylobacter, and E. coli
• Symptoms: Watery or bloody diarrhea, fever

image Painful abdominal cramps and tenderness
image Usually acute onset, except TB (chronic)
• Diagnosis: Stool cultures, blood cultures, endoscopic biopsy, serology studies
• Often self-limited or responsive to antimicrobial therapy in previously healthy patients
image
(Left) Graphic illustration demonstrates pancolitis with marked mural thickening and multiple elevated yellow-white plaques, or pseudomembranes, typical for Clostridium difficile colitis

image
(Right) Axial CECT in a 62-year-old man who presented with diarrhea and dehydration demonstrates a classic case of pseudomembranous (C. difficile) colitis. Note the severe bowel wall thickening throughout the entire colon image, and ascites. C. difficile colitis typically presents as a pancolitis, as in this example.
image
(Left) A 71-year-old woman had a history of recent antibiotic use for cellulitis and presented with nausea, vomiting, and diarrhea. Axial CT shows moderate diffuse bowel wall thickening image and hyperemia of the entire colon and rectum.

image
(Right) Coronal CECT in the same patient again illustrates moderate diffuse bowel wall thickening image of the entire colon. C. difficile (pseudomembranous) colitis was confirmed.

TERMINOLOGY

Definitions

• Colonic inflammation due to bacterial, viral, fungal, or parasitic infections
• Pseudomembranous colitis: Descriptive term usually applied to Clostridium difficile colitis

IMAGING

General Features

• Best diagnostic clue

image Usually pancolitis, including rectum
• Location

image Dependent on etiology

– C. difficile: Segmental or pancolitis

image Entire colon usually involved; distal SB uncommonly
– Campylobacteriosis: Pancolitis ± small bowel
– Escherichia  coli (O157:H7): Pancolitis
– Cytomegalovirus (CMV): Distal ileum and right colon or pancolitis
– Yersinia enterocolitis: Predominantly right colon, occasionally left; invariably in terminal ileum

image RLQ clusters of enlarged nodes
– Typhoid fever (salmonellosis): Cecum or right colon, invariably in ileum
– Shigellosis: Predominantly in left colon
– Tuberculosis: Right and proximal transverse colon, involves ileum
– Actinomycosis: Rectosigmoid colon (intrauterine devices), ileocecal region (appendectomy)
– Gonorrhea, chlamydia, herpes, syphilis: Rectosigmoid colon
– Histoplasmosis: Ileocecal region
– Mucormycosis: Right colon
– Anisakiasis: Occasionally in right colon, rarely in transverse colon
– Amebiasis: Right colon ±  terminal ileum
– Schistosomiasis: Left or sigmoid colon

Fluoroscopic Findings

• Contrast enema

image Used less frequently than before; now supplanted by CT, US, and endoscopy
image Narrowed lumen, haustral thickening (edema/spasm)
image Colonic wall, ulceration → mucosal irregularity, superficial or deep “collar-button” ulcers
image Discrete punctate, aphthous, or large oval ulcers, may simulate Crohn disease
image Small nodules or inflammatory polyps ± diffuse mucosal granularity (may simulate ulcerative colitis)
image Possible extrinsic mass with inflammatory changes → distortion, short strictures (may simulate carcinoma)
image Thumbprinting, may simulate ischemic colitis
image May show fistulas or sinus tracts
image Typhoid fever: Ileal fold thickening and ulceration
image Shigellosis: Mucosal granularity of rectum
image Tuberculosis

– Oval/circumferential transverse ulcers; loss of demarcation between distorted terminal ileum and ascending colon
– Fleischner sign: Right-angle intersection between ileum and cecum, marked ileocecal valve hypertrophy
– Marked mural thickening > Crohn disease
– “Apple core” colonic stricture, indistinguishable from carcinoma
image Histoplasmosis: Rectal polyps, pericecal masses, may simulate appendicitis
image Mucormycosis: Polypoid mass
image Amebiasis

– Skip lesions, may simulate granulomatous colitis
– Ameboma: Marked granulation in short segments of right colon
– Discrete ulcers appearing as marginal effects or granularity with barium flecks
image Schistosomiasis: Inflammatory polyps, granulation response to eggs deposited in bowel wall

CT Findings

• C. difficile, Campylobacter, E. coli, CMV

image Mucosal hyperenhancement, marked submucosal edema, ascites
image Accordion sign: Alternating bands of enhancing mucosa and submucosal edema, with compressed lumen
image Multiple air-fluid levels, infiltrated pericolonic fat
image Deep ulcers and marked wall thickening

– May progress to hemorrhagic necrosis and perforation
– Toxic megacolon
• TB: Marked low-density enlargement of mesenteric lymph nodes

image Enterocolitis is often due to ingestion of Mycobacterium bovis
image Lungs may not be involved
• Histoplasmosis: Mesenteric adenopathy, hepatosplenomegaly ± calcifications
• Schistosomiasis: Changes in mesenteric or hemorrhoidal vein

image ± calcification of bowel wall or liver
image Bladder wall thickening and calcification
• Salmonellosis: May show small bowel thickening and effacement
• Actinomycosis: Large inflammatory masses
• Mucormycosis: Sinus, lung, and central nervous system changes

Imaging Recommendations

• Best imaging tool

image CECT with multiplanar reformation

Ultrasonographic Findings

• Wall thickening with increased symmetric thickening and submucosal echogenicity
• Increased mural flow on color Doppler

DIFFERENTIAL DIAGNOSIS

Ulcerative Colitis (UC)

• Wall thickening is generally less prominent with UC vs. infectious colitis
• Barium enema

image Pancolitis with decreased haustration and multiple ulcerations
image Mucosal “islands” or inflammatory pseudopolyps
image Diffuse and symmetric thickening of colon wall
image Chronic phase → “lead pipe” colon

Granulomatous Colitis (Crohn Disease)

• Concurrent SB (distal ileum) disease
• Barium enema

image Cobblestoning: Longitudinal and transverse ulcerations produce paving stone appearance
image Transmural skip lesions, sinuses, fistulas

Ischemic Colitis

• Usually located in watershed areas, rarely pancolitis
• Rectum is rarely affected by ischemic colitis
• CT: May show pneumatosis, portomesenteric venous gas, ± thrombus within splanchnic vessels

PATHOLOGY

General Features

• Etiology

image Most common bacterial causes of infectious colitis in USA

– C. difficile, Salmonella, Campylobacter, and  E. coli
– Others:  Mycobacterium tuberculosis, Actinomyces, Chlamydia trachomatis,  Neisseria gonorrhoeae

image Chlamydia is causative agent for lymphogranuloma venereum
image Most common viral agents of gastroenteritis: Norovirus and rotavirus
image Most common protozoal: Cryptosporidium, Giardia, Cyclospora

– In developing countries: Anisakis, Amoeba, Schistosoma, Strongyloides, Trichuris
image Fungal organisms: Histoplasma, Mucor
image Risk factors

– C. difficil e: Prior antibiotic use (especially clindamycin)

image Institutionalized patients (hospitals, nursing homes, prisons)
image Chemotherapy with colonic mucosal injury
– CMV: Immunosuppression (e.g., transplant recipients)
– Salmonella, Shigella: Outbreaks, warm weather
– E. coli (0157:H7): Fecal contamination of meat (hamburger) or vegetables
– Mycobacterium tuberculosis, CMV:  Immunosuppression, including AIDS
– Actinomyces: Intrauterine devices, appendectomy
– Histoplasma, Mucor: Chronic debilitation or immunosuppression
– Strongyloides: Severe debilitation
image Pathogenesis

– Ingestion of pathogenic organisms (often fecal-oral route)
– Chlamydia, Neisseria gonorrhoeae, herpesvirus: Direct inoculation of rectum (anal intercourse)

Gross Pathologic & Surgical Features

• Varies based on etiology

Microscopic Features

• Varies based on etiology

CLINICAL ISSUES

Presentation

• Most common signs/symptoms

image C. difficile colitis occurs mostly in institutionalized patients or those on antibiotics, chemotherapy, or immunosuppressants medication
image Acute infectious diarrhea is most often a foodborne or waterborne disease

– Symptoms: Fever, headache, nausea, vomiting, weight loss, anemia, malaise, rash
– Watery or bloody diarrhea, painful abdominal cramps and tenderness
– Arthritis, pneumonitis, seizures, peripheral neuropathy, microangiopathy
• Laboratory data

image Bacterial organisms: Increased neutrophilic count
image Viral organisms: Increased lymphocytes (decreased in AIDS)
image Fungal, parasitic organisms: Eosinophilia
• Diagnosis: Stool cultures, blood cultures, endoscopic biopsy, serology studies

Demographics

• Age

image All ages, but incidence increases with age
image Up to 1% of hospitalized patients develop C. difficile colitis
• Gender

image M = F
• Epidemiology

image Prevalence is grossly underestimated

– Most patients do not seek medical attention
– Testing for specific cause is frequently not done

Natural History & Prognosis

• Complications

image Hemorrhage, perforation, obstruction, toxic megacolon, bacteremia, sepsis, death
image Yersinia enterocolitis: Hepatic abscess
image Amebiasis: Liver and lung abscesses
image Schistosomiasis: Hepatosplenomegaly → portal hypertension
• Prognosis

image Usually very good with treatment

– Often self-limited in previously healthy patients
image Campylobacteriosis: 25% recurrence if untreated
image E. coli (O157:H7) colitis: Higher morbidity and mortality

– Hemolytic-uremic syndrome
image CMV colitis: Hemorrhage and ischemia can be fatal

– Often occurs in immunocompromised patients, adding to morbidity and mortality
image Mucormycosis, strongyloidiasis: May be fatal

Treatment

• Bacterial organisms: Mostly self-limiting, last 1-2 weeks, up to 1 month

image C. difficile: Metronidazole; fecal transplantation to restore normal flora to colon
image Salmonellosis: Parenteral cephalosporins if severe
image Shigellosis: Ampicillin in severe cases
image Yersinia enterocolitis: Lasts several months; no treatment available
image E. coli (O157:H7) colitis: Supportive treatment, isolation procedures
image TB: Antituberculosis drugs, no steroids
• Viral organisms: Mostly self-limiting

image CMV: Treat underlying AIDS
• Parasitic organisms: Anthelmintic drugs

image Anisakiasis: Mostly self-limiting, last 7-10 days
• Fungal organisms: Antifungal drugs

DIAGNOSTIC CHECKLIST

Consider

• Diagnosis by clinical presentation, imaging, lab tests

Image Interpretation Pearls

•  

image
(Left) CT of a young man presenting with acute abdominal pain and diarrhea shows marked mural thickening and submucosal edema image affecting both the ascending colon and distal ileum. A small amount of ascites image is also seen.
image
(Right) Another CT section in the same case shows more of the inflammation of the distal small bowel image. The etiology was C. difficile infection, an unusual cause of small bowel inflammation.
image
(Left) A 61-year-old man was hospitalized for an orthopedic procedure and developed acute pain, diarrhea, and tachycardia. Axial CT shows a large amount of ascites image. The splenic flexure shows mucosal hyperenhancement and submucosal edema image.

image
(Right) CT in the same case shows a loss of mucosal enhancement and transverse folds in some portions of the colon image. These colonic segments seem to have a thin wall, while others are thick walled image.
image
(Left) CT in the same case shows a fluid-distended rectosigmoid colon image with loss of normal transverse folds.

image
(Right) Coronal image in the same case shows gross dilation of the colon with some segments of wall thickening and others of thinning. Toxic megacolon due to C. difficile colitis was suggested on CT and confirmed on urgent total colectomy.

image
(Left) A previously healthy young woman developed diarrhea and tenesmus. CT shows evidence of pancolitis with marked submucosal edema image causing an “accordion” appearance of the colonic wall.
image
(Right) CT in the same case shows involvement of the rectosigmoid colon image but not the small bowel. Campylobacter colitis was the final diagnosis.
image
(Left) A young man with AIDS developed diarrhea and hematochezia. A supine radiograph shows massive thickening of the colonic folds with a “thumbprinted” appearance image.

image
(Right) CT in the same case shows anasarca, ascites, and dilation of the small bowel lumen. The wall of the entire colon image is massively thickened. On endoscopy (not shown) the colonic mucosa was ischemic and biopsy showed cytomegalovirus (CMV) infiltrating the colonic wall and inducing hemorrhagic necrosis.
image
(Left) A young man developed RLQ pain, fever, and diarrhea. CT shows mural thickening of the ascending colon image and RLQ lymphadenopathy image.

image
(Right) Another CT section in the same case shows wall thickening of the terminal ileum image and additional enlarged nodes image. This is a typical example of Yersinia enterocolitis with mesenteric adenitis. Most forms of infectious colitis spare the distal small bowel.

image
(Left) A teenage girl developed acute bloody diarrhea due to E. coli colitis from contaminated hamburger. Coronal CT shows pancolitis with marked submucosal edema, and fluid distention of the entire colon image.
image
(Right) Another coronal CT section in this case shows more of the mucosal hyperenhancement and submucosal edema image throughout the colon. The small bowel was spared.
image
(Left) CT of a 50-year-old woman with confirmed Salmonella colitis shows marked colonic fold thickening image primarily affecting the ascending colon. Note that the presence of dense contrast material within the colon impairs evaluation for mucosal inflammation.

image
(Right) CT in the same case shows marked submucosal edema in the cecum image. The left side of the colon seems uninvolved. Preferential involvement of the right colon is characteristic of Salmonella (typhus), which is endemic in some populations.
image
(Left) An elderly woman developed acute diarrhea and tenesmus. CT shows pancolitis, with thickening of the wall image and adjacent mesenteric hyperemia image. The rectum and small bowel were spared. Campylobacter colitis was confirmed.

image
(Right) Endoscopic image of the ascending colon in the same patient shows marked fold thickening due to Campylobacter colitis.
image
Longitudinal grayscale sonography shows infectious ileocolitis due to Campylobacter. A scan of the terminal ileum demonstrates mural thickening with echogenic submucosa due to edema image.

image
Longitudinal power Doppler ultrasound of a cecum in the same patient reveals marked hyperemia image.
image
Supine radiograph shows massive thickening of the colonic haustra with a thumbprint appearance image.
image
Axial CECT in the same patient shows anasarca, ascites, and dilation of the small bowel lumen. The entire colonic wall image is massively thickened. The biopsy showed cytomegalovirus infiltrating the colonic wall and inducing hemorrhagic necrosis.
image
Axial CECT shows mural thickening of the ascending transverse colon image.
image
Axial CECT in the same patient shows mural thickening of the terminal ileum image. Yersinia tends to involve the right colon preferentially, and almost always involves the terminal ileum, unlike most causes of acute infectious colitis.
image
Axial CECT of CMV colitis in an AIDS patient mimics pseudomembranous colitis. Note the marked haustral edema image of the transverse colon.
image
Axial CECT at a more caudal level in the same patient reveals marked submucosal edema of the cecum image.
image
Axial CECT shows pancolitis with colonic wall thickening and mesenteric hyperemia in this 78-year-old woman with Campylobacter colitis.
image
Axial CECT shows mural thickening of the ascending and transverse colon plus dilated mesenteric vessels in this patient with Campylobacter colitis.
image
Single-contrast BE shows a rectal stricture with mucosal irregularity due to “lymphogranuloma venereum” in this patient with Chlamydia trachomatis.
image
Single-contrast BE shows an “apple core” lesion of the ascending colon due to Mycobacterium tuberculosis.
image
Axial CECT shows pancolitis due to CMV in a patient with AIDS.
image
Axial CECT shows proctocolitis with mural thickening and mesenteric hyperemia in a 32-year-old woman due to CMV colitis.
image
Axial CECT shows Campylobacter pancolitis in a previously healthy 26-year-old woman. Note the “thumbprinting” of the colonic wall image.
image
Axial CECT of a 26-year-old woman with Campylobacter colitis shows marked mural thickening of sigmoid colon.

SELECTED REFERENCES

1. Aboutaleb, N, et al. Emerging infectious colitis. Curr Opin Gastroenterol. 2014; 30(1):106–115.

2. Burke, KE, et al. Clostridium difficile infection: a worldwide disease. Gut Liver. 2014; 8(1):1–6.

3. Raman, SP, et al. MDCT and CT angiography evaluation of rectal bleeding: the role of volume visualization. AJR Am J Roentgenol. 2013; 201(3):589–597.

 

Ninan, S, et al. The young patient with acute bloody diarrhoea. Acute Med. 2014; 13(2):90–96.

Antonopoulos, P, et al. An emergency diagnostic dilemma: a case of Yersinia enterocolitica colitis mimicking acute appendicitis in a beta-thalassemia major patient: the role of CT and literature review. Emerg Radiol. 2008; 15(2):123–126.

Thoeni, RF, et al. CT imaging of colitis. Radiology. 2006; 240(3):623–638.

Thielman, NM, et al. Clinical practice. Acute infectious diarrhea. N Engl J Med. 2004; 350(1):38–47.

Horton, KM, et al. CT evaluation of the colon: inflammatory disease. Radiographics. 2000; 20(2):399–418.

Philpotts, LE, et al. Colitis: use of CT findings in differential diagnosis. Radiology. 1994; 190(2):445–449.

Schmitt, SL, et al. Bacterial, fungal, parasitic, and viral colitis. Surg Clin North Am. 1993; 73(5):1055–1062.

Wall, SD, et al. Gastrointestinal tract in the immunocompromised host: opportunistic infections and other complications. Radiology. 1992; 185(2):327–335.

Related posts:

Epithelioid Hemangioendothelioma Postoperative Pancreas Acute Pancreatitis and Complications Emphysematous Cholecystitis Cricopharyngeal Achalasia Boerhaave Syndrome