Approach to diarrhea in HIV

What is the approach to diarrhea in HIV infected patients? 

  • It is important to consider patient exposures.
  • A history of new medications or an alteration in a current regimen, such as antiretrovirals or antibacterials, is important because many protease inhibitors are associated with diarrhea and antibacterials are associated with Clostridium difficile colitis.
  • In febrile patients, blood cultures should be obtained for common bacteria such as are mandatory.
  • If stool and blood culture studies are negative, the next step is endoscopic evaluation with biopsy.
  • In the presence of colitis symptoms, flexible sigmoidoscopy or colonoscopy is recommended. 

The below table summarizes the studies and laboratory tests used in the evaluation of diarrhea in AIDS.

Studies and Laboratory Tests Used in the Evaluation of Diarrhea in AIDS

StoolCultures (Salmonella, Shigella, Campylobacter spp.)
Toxin ( Clostridium difficile )
Ova and parasites ( Giardia lamblia, Entamoeba histolytica, Cryptosporidium spp.)
Modified Kinyoun acid-fast ( Cryptosporidium spp., Isospora belli )
Concentrated stool (zinc sulfate, Sheather sucrose flotation) (microsporidia)
BloodCultures ( Mycobacterium avium complex, Salmonella, Campylobacter spp.)
Antibodies ( Entamoeba histolytica, CMV)
Gastrointestinal fluidsDuodenal aspirate ( Giardia lamblia, microsporidia)
Electron microscopy ( Cryptosporidium spp., adenovirus)
Biopsy stainsHematoxylin-eosin
Gyms or methenamine silver (fungi)
Methylene blue–azure II–basic fuchsin (microsporidia)
Fite (mycobacteria)
Immunohistochemical stains (CMV), immunologic methodsIn situ hybridization (CMV)
DNA amplification (CMV)
Culture of tissue
Herpes simplex virus

AIDS, Acquired immune deficiency syndrome; CMV, cytomegalovirus.

lists the most common infectious causes of diarrhea in AIDS. 

The below table lists common associations between exposures and infections.

Infectious Causes of Diarrhea in AIDS

Small round virus
Salmonella spp.
Shigella spp.
Campylobacter jejuni
Clostridium difficile
Mycobacterium avium complex
Treponema pallidum
Neisseria gonorrhoeae
Vibrio cholera
Aeromonas spp.
Pseudomonas spp. (?)
Staphylococcus aureus
Giardia lamblia
Entamoeba histolytica
Enterocytozoon bieneusi
Encephalitozoon intestinalis (formerly Septata )
Cyclospora cayetanensis
Cryptosporidium spp.
Isospora belli
Blastocystis hominis (?)
Histoplasma capsulatum
Candida albicans

AIDS, Acquired immune deficiency syndrome; HIV, human immunodeficiency virus.

Sources of Infectious Diarrhea

Infectious AgentAssociation
Clostridium difficileRecent antibiotics, nursing home or hospital exposures
Recent visit to a farm, contact with farm animals, use of a public swimming pool
GiardiaCamping, stream water
Mycobacterium aviumCD4 count less than 50
Cyclospora cayetanensisCommon cause of diarrhea in South America
MicrosporidiosisUncommon in the southern United States
RotavirusCommon cause of diarrhea in Australia

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