HIV diarrhea

Background

• Chronic diarrhea (over 28 days), can be presenting symptom of AIDS, or in countries without HAART
• Less common after introduction of HAART

Clinical Presentation

• Ascertain whether small bowel vs large bowel diarrhea
  • Small Bowel
    • Diarrhea watery and copius
    • Weight loss
    • Bloating, gas, cramping
    • Vit B12 deficient if terminal illeum involved
  • Large Bowel
    • Frequent small volume, possibly painful stools
    • Hematochezia - Consider opportunistic pathogens, also consider classic hemorrhagic bacteria (e. coli O157, campylobacter, shigella, salmonella, Yersinia)
• Weight loss is concerning for infiltrative disease, opportunistic infx
• Receptive anal sex - consider local HSV infx, Gonorrhea, Chamlydia, Entamoeba

Differential Diagnosis

CD4>400

• Consider routine pathogens causing Diarrhea
• Side effect of nelfinavir and ritonavir
• Cryptosporidium parvum (brief course of illness) - severe watery diarrhea
• C. diff if abx exposed

CD4<200

• M. tuberculosis
• Histoplasma
• Cryptococcus
• Lymphoma
• Kaposi
• Enteroaggregative Escherichia coli (EAEC) (can also affect immunocompetent children)
• HIV can directly infiltrate bowel wall leading to diarrhea

CD4 <100

• Cryptosporidium parvum (chronic course of illness)
• Mycobacterium avium complex (MAC) - infiltration of bowel assoc with malabsorption
• CMV
• Isospora
• Microsporidium

Diagnosis

• Many workups will be non diagnostic
• Start with stool WBCs, cultures, Ova and Parasites x3
• Acid fast smear to assess for Cryptosporidium, Isospora, and Cyclospora
• CD4<100 - Microsporidium more likely, test with Trichrome staining
• Blood cultures with fungal / acid fast if disseminated disease a concern
• Endoscopy
  • Indicated if w/u is negative and severely immunocompromised
  • Small bowel bx to look for MAC, lymphoma, or microsporidiosis
  • Guaic postive stools and weight loss, consider Kaposi Sarcoma of bowel, dx with colonoscopy
• Imaging
  • Generally not helpful, but could be indicated if severe tenderness, peritonitis, concern for biliary pathology, obstructing lesions.

Disposition

• If near normal CD4 and symptoms consistent with small bowel disease (copius, watery), may be managed as outpatient if no other admission indication

References

UpToDate: "Evaluation of the HIV-infected patient with diarrhea"