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
| Stool | Cultures (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) |
| Blood | Cultures ( Mycobacterium avium complex, Salmonella, Campylobacter spp.) Antibodies ( Entamoeba histolytica, CMV) |
| Gastrointestinal fluids | Duodenal aspirate ( Giardia lamblia, microsporidia) Electron microscopy ( Cryptosporidium spp., adenovirus) |
| Biopsy stains | Hematoxylin-eosin Gyms or methenamine silver (fungi) Methylene blue–azure II–basic fuchsin (microsporidia) Fite (mycobacteria) |
| Immunohistochemical stains (CMV), immunologic methods | In situ hybridization (CMV) DNA amplification (CMV) Culture of tissue CMV Herpes simplex virus Mycobacteria |
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
| Viruses | Bacteria | Parasites | Fungi |
|---|---|---|---|
| Cytomegalovirus Astrovirus Picornavirus Coronavirus Rotavirus Herpesvirus Adenovirus Small round virus HIV | Salmonella spp. Shigella spp. Campylobacter jejuni Clostridium difficile Mycobacterium avium complex Treponema pallidum Spirochetes Neisseria gonorrhoeae Vibrio cholera Aeromonas spp. Pseudomonas spp. (?) Staphylococcus aureus | Giardia lamblia Entamoeba histolytica Microsporidia 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 Agent | Association |
|---|---|
| Clostridium difficile | Recent antibiotics, nursing home or hospital exposures |
| Cryptosporidiosis Microsporidiosis | Recent visit to a farm, contact with farm animals, use of a public swimming pool |
| Giardia | Camping, stream water |
| Mycobacterium avium | CD4 count less than 50 |
| Cyclospora cayetanensis | Common cause of diarrhea in South America |
| Microsporidiosis | Uncommon in the southern United States |
| Rotavirus | Common cause of diarrhea in Australia |
