Opportunistic Intestinal Infections



Opportunistic Intestinal Infections


Michael P. Federle, MD, FACR

R. Brooke Jeffrey, MD





Key Facts


Terminology



  • Gastrointestinal infection of immunocompromised host by virus (CMV), protozoa (Cryptosporidium), or Mycobacterium (MAI)


Imaging



  • Best imaging tool



    • Small bowel follow through, CECT


  • Protocol advice



    • CECT: 150 mL IV contrast at 2.5 mL/sec with 5 mm collimation


Top Differential Diagnoses



  • Giardiasis


  • Tuberculosis


  • Gastrointestinal lymphoma


  • Whipple disease


Clinical Issues



  • Most common signs/symptoms



    • Abdominal pain, nausea, vomiting, diarrhea, fever, GI bleeding


  • CMV and cryptosporidiosis respond to nitazoxanide in early stage


  • MAI in AIDS patients often difficult to treat


  • CMV: Antiviral therapy with acyclovir or ganciclovir


  • MAI: Antituberculous chemotherapy


  • Cryptosporidiosis: Chemotherapy with nitazoxanide


Diagnostic Checklist



  • Image interpretation pearls



    • CMV: Deep ulcerations and focal enteritis or colitis


    • MAI: Enteritis and low-attenuation nodes


    • Cryptosporidiosis: Thickened bowel wall and edematous folds






(Left) Axial CECT in a 31-year-old woman with cystic fibrosis status post bilateral lung transplant, now with diarrhea, shows diffuse thickened, dilated, edematous folds of small bowel with prominent mucosal enhancement image involving much of the small bowel. (Right) Coronal CECT in the same patient reveals that the colon is spared image. Endoscopy and biopsy confirmed Cytomegalovirus. CT appearance is nonspecific; the patient’s clinical scenario drives the diagnosis.






(Left) Axial CECT in a 39-year-old woman with a history of HIV, now presenting with diarrhea, illustrates a common appearance of Cryptosporidium enteritis. Note the diffuse distention of the small bowel with low-attenuation fluid image. (Right) Axial CECT in the same patient further reveals lymph nodes in the root of the mesentery image. This infection typically affects patients with HIV, and is less common in the other immunocompromised hosts.



TERMINOLOGY


Synonyms



  • Cytomegalovirus (CMV), Mycobacterium avium-intracellulare (MAI), atypical mycobacterial infection, cryptosporidiosis, Cryptosporidium parvum


Definitions



  • Gastrointestinal (GI) infection of immunocompromised host by virus (CMV), protozoa (Cryptosporidium), or Mycobacterium (MAI)


IMAGING


General Features



  • Best diagnostic clue



    • CMV: Thickened folds with deep ulcerations of small bowel (SB) or colon on barium studies


    • MAI: Thickened SB folds, mesenteric, or periportal adenopathy with low-attenuation nodes


    • Cryptosporidiosis: Secretory enteritis with thickened small bowel folds and increased fluid in bowel


  • Location



    • CMV: Small bowel, colon, stomach


    • MAI: Small bowel, nodes


    • Cryptosporidiosis: Small bowel


Fluoroscopic Findings



  • CMV: Barium enema



    • Diffuse colitis



      • Early stage resembles ulcerative colitis


    • Aphthous ulcers


    • Terminal ileum characteristically involved, with thickened folds &/or ulceration


    • Later stages show deep ulceration


  • CMV: Small bowel follow through (SBFT)



    • Thickened edematous folds


    • Discrete ulcerations


    • Deep ulcers in sinus tracts


  • MAI: Small bowel follow through



    • Diffuse enteritis with thickened folds


    • Micronodular mucosal pattern


  • Cryptosporidiosis: Small bowel follow-through



    • Secretory enteritis


    • Thickened folds


    • Increased fluid in bowel

Tags:
Jun 13, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Opportunistic Intestinal Infections

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