Etiology and evaluation of diarrhea in AIDS: A global perspective at the millennium

Table 1 Enteric pathogens in AIDS

Viruses

Cytomegalovirus

Astrovirus

Picornavirus

Coronavirus

Rotavirus

Herpesvirus

Adenovirus

Small round virus

HIV

Bacteria and mycobacteria

Salmonella

Shigella

Campylobacter

Clostridium difficile

Treponema pallidum

Spirochaetes

Neisseria gonorrheae

Vibrio cholerae

Pseudomonas 问号

Staphylococcus aureus

Mycobacterium avium-complex

Mycobacterium tuberculosis

Parasites

Giardia lamblia

Entamoeba histolytica

Microsporidia

-Enterocytozoon bieneusi

-Encephalocytozoon intestinalis

Cyclospora

Cryptosporidium

Isospora belli

Blastocystis hominis问号

Fungi

Histoplasma

Candida albicans

Table 2 Laboratory tests used to investigate diarrhea in HIV -infected patients

Stool studies

Stool cultures (Salmonella, Shigella, Campylobacter)

Toxin (Clostridium difficile)

Stool for ova and parasites (Giardia lamblia, Entamoeba histolytica)

(using saline, iodine, trichrome and acid-fast stains)

Stool stains:

a. Modified Kinyoun acid-fast (Cryptosporidium and Isospora belli)

b. Concentrated stool (Zinc sulfate, Shether sucrose flotation)

Fecal fat

Giardia antigen

Blood studies

CD4 cell count

White blood cell and differential

Creatinine, electrolytes

Liver function tests

Total albumin

Blood cultures (Mycobacterium avium-complex)

Tissue and fluids

Duodenal aspirate (Giardia lamblia, microsporidia)

Biopsy: duodenum, jejunum, ileum, colon, rectum

Biopsy stains:

a. Hematoxylin-eosin

b. Giemsa or methenamine silver (fungi)

c. Methylene blue-azure II-basic fuchsin (microsporidia)

d. Fite (mycobacteria)

Immunohistochemical stains (Cytomegalovirus)

In-situ hybridization (CMV)

DNA amplification (CMV)

Electron microscopy for cryptosopridia, adenovirus

Touch preparation

Culture of colonic mucosal biopsy

a. Cytomegalovirus

b. Herpes simplex virus

c. Bacteria

Table 3 Drugs used in the therapy of diarrhea in AIDS

Condition	Treatment	Dosage	Duration
Cytomegalovirus	Ganciclovir	5 mg/kg, 2/d	2-4 wk
	Foscarnet	90 mg/kg, 2/d	2-4 wk
Herpes simplex	Acyclovir	400-800 mg, 14 d (5/d)
	Foscarnet	60-90 mg/kg, 2/d	14 d
	Valacyclovir	500 mg, 3/d	14 d
	Famciclovir	500 mg, 2/d	7-10 d
Cryptosporidia	No definite therapy	known
	Paromomycin	25-35 mg/kg, 3/d	14-28 d
	Spiramycin	1g, 3/d	14-28 d
	Azithromycin	900 mg, 1/d	14-28 d
	Letrazuril	50-100 mg, 1/d	14-28 d
	Bovine colostrum	50 g, 1/d	14-28 d
Microsporidia
Septata intestinalis	Albendazole	400 mg, 2/d	14-28 d
Enterocystozoon	No definite therapy
	known
	Albendazole	400 mg, 2/d	14-28 d
	Metronidazole	500 mg, 3/d	14-28 d
Isospora belli	TMP-SMX DS	1 tab, 4/d	10-14 d
Cyclospora	TMP-SMX DS	1 tab, 4/d	10-14 d
Giardia lamblia	Metronidazole	500 mg, 3/d	10-14 d
Entamoeba histolytica	Metronidazole	750 mg, 3/d	10-14 d
	Iodoquinol	650 mg, 3/d	10-14 d
MAC	Clarithromycin	500 mg, 2/d	4 wk
EMB, Cipro, RFP
Clostridium difficile	Metronidazole	500 mg, 3/d	10-14 d
	Vancomycin	250 mg, 4/d	10-14 d
Salmonella	Ciprofloxacin	500 mg, 2/d	10-14 d
	TMP-SMX DS	1 tab, 4/d	10-14 d
Shigella	Ciprofloxacin	500 mg, 2/d	10-14 d
	Ampicillin	500 mg, 4/d	10-14 d
Campylobacter	Ciprofloxacin	500 mg, 2/d	10-14 d
	Erythromycin	500 mg, 4/d	7-14 d

RFP = Rifampicin, EMB = Etrhambutol, TMP-SMX = trimethoprim sulphamethoxazole, DS = double strength.

Table 4 Yield of colonoscopy with biopsy in HIV infected patients with chronic diarrhea

Ref Proximal	No. pts.	Diagnosis	Most common dx (No.pts)	Distal
Connolly*	81	34 (42)	CMV (12)	32	+
Wilcox	48	13 (27)	CMV (11)	12	1
Kearney	79	22 (100)°	CMV (15)	17	1
Bini	317	116 (37)	CMV (75)	60 (55)	33 (30)

Diagnosis expressed as number of patients (%). Numbers under distal and proximal represent number of patients. ^*patiens with Cryptosporidium on stool testing were excluded, some patients had more than one diagnosis; ⁺CMV and KS in one patient each; °biopsy of terminal ileum at time of colonoscopy; pts: patients; dx: disease. Three patients had diagnosis with biopsy at terminal ileum

Table 5 Yield of upper Endoscopy in HIV-infected patients with chronic diarrhea

References	No. pts.	Diagnosis n (%)	Most common dxs
Connolly	33	2 (36)	Crypto 2
			CMV 4
Wilcox	48	9 (19)	Micro 7, crypto 1
			CMV 1
Bown	56	15 (26)	Crypto 6, micro 5
Kearney	79	9 (11)	Micro 5
Bini	442	123 (28)	Micro 54 (12%)

Crypto: cryptosporidum; Micro: microsporidium; Dxs:diseases

Table 6 Yield of extensive work up of HIV-infected patients with negative stool studies

Ref	No. pts.	Diagnosis n (%)	Most common diagnosis
Wilcox	48	21 (44)	CMV 9
			Micro 7
Kearney	79	22 (28)	CMV 15
			Micro 5
Connolly	33	12 (36)	Crypto 5
			CMV 4

Crypto: cryptosporidium; Micro: microsporidium.