Last reviewed: March 2026
Contents
MDM Templates
HIV Diarrhea — Stable / Low Risk
Patient with HIV (on HAART, CD4 ***, viral load ***) presents with diarrhea. They are afebrile, non-toxic appearing, tolerating PO fluids, and without signs of significant dehydration. No bloody stool, no severe abdominal pain, no peritoneal signs.
History and exam lower suspicion for serious bacterial or opportunistic infection causing this presentation. Patient’s preserved immune function on HAART and clinical stability make opportunistic etiology less likely. Presentation is not consistent with bowel obstruction, bowel ischemia, DKA, or pancreatitis.
Plan: Stool studies sent (culture, ova and parasites, C. difficile toxin). Symptomatic management with PO hydration.
Disposition: Discharge with return precautions for persistent fever, bloody stool, inability to tolerate PO, or worsening abdominal pain. PCP and ID follow-up within 48 hours for stool study results.
HIV Diarrhea — Concern for Opportunistic Infection
Patient with HIV (CD4 ***, viral load ***, HAART compliance ***) presents with diarrhea, fever, and evidence of systemic illness. Given immunocompromised state and low CD4 count, opportunistic infectious etiologies must be actively excluded.
Presentation warrants comprehensive workup given risk for CMV colitis, Cryptosporidium, Microsporidium, MAC, and other opportunistic pathogens. History and exam raise concern beyond a simple viral gastroenteritis.
Plan: CBC, BMP, LFTs, lipase, blood cultures, stool studies (culture, ova and parasites x3, C. difficile toxin, AFB, modified acid-fast stain for Cryptosporidium/Microsporidium).
Disposition: Admit if febrile, dehydrated requiring IV fluids, hemodynamically unstable, or concern for CMV colitis (may need colonoscopy). ID consultation for treatment guidance.
Clinical Education
Diarrhea Differential by CD4
Well-controlled HIV (CD4 >200, suppressed viral load) — the differential is essentially the same as any immunocompetent patient: viral gastroenteritis, bacterial enteritis, C. difficile, medication side effect, IBS.[1]
Advanced HIV (CD4 <200) — the differential broadens significantly:
| Pathogen | Key Features | CD4 Threshold |
| Cryptosporidium | Profuse watery diarrhea, can be chronic and debilitating | <200 |
| CMV colitis | Bloody diarrhea, fever, abdominal pain. Dx by colonoscopy with biopsy | <50 |
| MAC (Mycobacterium avium complex) | Chronic diarrhea, weight loss, fever, anemia. Disseminated disease | <50 |
| Microsporidium | Chronic watery diarrhea, wasting | <100 |
| Isospora (Cystoisospora) | Watery diarrhea, responds to TMP-SMX | <200 |
Stool Studies in HIV
Standard stool studies may miss opportunistic pathogens. For patients with CD4 <200, send: routine stool culture, C. difficile toxin, ova and parasites x3 (sensitivity improves with multiple samples), modified acid-fast stain (for Cryptosporidium and Isospora), and trichrome stain (for Microsporidium). CMV colitis is diagnosed by colonoscopy with biopsy, not stool studies.[2]
Practical pearl: If CD4 >200 and on suppressive HAART, standard stool studies are usually sufficient. Don’t reflexively send the full opportunistic panel on a well-controlled HIV patient with acute diarrhea — the yield is very low.
ART-Related Diarrhea
ART medications are a common cause of diarrhea in HIV patients. Protease inhibitors (especially nelfinavir, lopinavir/ritonavir) are the most frequent offenders. Tenofovir can cause GI upset. The newer integrase inhibitors (dolutegravir, bictegravir) have less GI toxicity but are not immune from causing it.[3]
Don’t stop ART in the ED for diarrhea. Medication-related diarrhea is a chronic management issue for the patient’s HIV provider. In the ED, the job is to rule out dangerous etiologies and refer back to their outpatient team for medication adjustment if needed.
References
- Feasey NA et al. Gastrointestinal and Hepatic Disease in HIV Infection. Medicine. 2013;41(8):450-455. PubMed
- Wilcox CM et al. Evaluation of the HIV-Infected Patient with Diarrhea. Am J Gastroenterol. 1996;91(11):2236-2240. PubMed
- MacArthur RD, DuPont HL. Etiology and Pharmacologic Management of Noninfectious Diarrhea in HIV-Infected Individuals. Clin Infect Dis. 2012;55(6):860-867. PubMed
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