Natural history and prognosis of diarrhoea of unknown cause in patients with acquired immunodeficiency syndrome (AIDS)

Opportunistic and non-opportunistic intestinal parasites in HIV/ AIDS patients in relation to their clinical and epidemiological status in a specialized medical service in Goiás, Brazil

Patients infected with the Human Immunodeficiency Virus (HIV) often have opportunistic infections, among which strongyloidiasis and coccidiosis are the most common parasitic infections that aggravate their health status. This study examined the prevalence of intestinal parasites, particularly of Strongyloides stercoralis and intestinal coccidia in patients with the Human Immunodeficiency Virus (HIV)/ Acquired Immunodeficiency Syndrome (AIDS) who were treated at the Specialized Assistance Service (SAE) of Jataí, State of Goiás, Brazil, and analyzed its correlation with clinical, laboratory, and socio-epidemiological parameters. A total of 270 stool samples were analyzed by the Lutz technique, Rugai's method, Agar Plate Culture, Ritchie's method and specific staining, Ziehl-Neelsen modified technique, Kinyoun's method and the rapid safranin method. The prevalence of intestinal parasites was 28.88% including 3.8% of S. stercoralis, Cryptosporidium sp. and Cystoisospora belli. There was a significant positive correlation between intestinal parasites and the clinical status and the use of antiretroviral therapy (ART), smoking, CD4+ lymphocyte counts and sexual orientation. In conclusion, the widespread use of antiretroviral therapy and health assistance contributed to the low prevalence of S. stercoralis and coccidiosis in patients with HIV/ AIDS who were followed up at the SAE.

Comparative study of entero-parasitic infections among HIV sero-positive and sero-negative patients in Lagos, Nigeria

BACKGROUND

Intestinal parasites are endemic in many parts of the world where HIV infection is also widespread. Previous studies had shown that the spectrum of opportunistic and common endemic parasitic infections with HIV vary in different regions and usually reflect the infections prevalent in these regions. This present study was aimed at comparing the prevalence and types of intestinal parasitic infections in HIV sero-positive and sero-negative patients in Lagos.

MATERIALS AND METHODS

Venous blood and stool samples of 1080 patients, recruited from three health care institutions were screened for HIV infection and intestinal parasites using HIV-1, HIV-2 rapid tests, direct wet mount with saline/iodine and formol-ether technique, respectively.

RESULTS

Results showed that 6% (65/1080) of patients were sero-positive for HIV infection. In addition, 23.3% (252/1080) patients were infected with intestinal parasites and 33.8% (22/65) of patients with HIV had intestinal parasites co-infections. The prevalence of Entamoeba histolytica/Entamoeba dispar, Entamoeba coli, Iodamoeba butschilii, Giardia intestinalis, and Hookworm were statistically significantly higher among HIV sero-positive patients as compared to the HIV sero-negative patients. In addition, HIV sero-positive patients had higher odds of mixed intestinal parasites than the HIV sero-negative patients (9.1% versus 3.9%; adjusted OR 2.05, 95% CI, 1.14-3.72, P=0.021).

CONCLUSION

In this study population, HIV sero-positive patients were more likely to have intestinal parasitic infections. The study underscores the public health significance of intestinal parasitic infections in HIV infected individuals.

Review article: the aetiology, investigation and management of diarrhoea in the HIV-positive patient

BACKGROUND

Diarrhoea is a common presentation throughout the course of HIV disease.

AIM

To review the literature relating to aetiology, investigation and management of diarrhoea in the HIV-infected adult.

METHODS

The PubMed database was searched using major subject headings 'AIDS' or 'HIV' and 'diarrhoea' or 'intestinal parasite'. The search was limited to adults and to studies with >10 patients.

RESULTS

Diarrhoea affects 40-80% of HIV-infected adults untreated with antiretroviral therapy (ART). First-line investigation is by stool microbiology. Reported yield varies with geography and methodology. Molecular and immunological methods and special stains have improved diagnostic yield. Endoscopy is diagnostic in 30-70% of cases of pathogen-negative diarrhoea and evidence supports flexible sigmoidoscopy as a first line screening procedure (80-95% sensitive for CMV colitis), followed by colonoscopy and terminal ileoscopy. Radiology is useful to assess severity, distribution, complications and to diagnose HIV-related malignancies. Side effects and compliance with ART are important considerations in assessment. There is a good evidence base for many specific therapies, but optimal treatment of cryptosporidiosis is unclear and only limited data support symptomatic treatments.

CONCLUSIONS

The immunological response to HIV infection and Antiretroviral therapy remains incompletely understood. Antiretroviral therapy regimens need to be optimised to suppress HIV while minimising side effects. Effective agents for management of cryptosporidiosis are lacking. There is an urgent need for enhanced regional diagnostic facilities in countries with a high prevalence of HIV. The ongoing roll-out of Antiretroviral therapy in low-resource settings will continue to change the aetiology and management of this problem, necessitating ongoing surveillance and study.

Advances in sexually transmitted infections of the gastrointestinal tract

The gastrointestinal mucosa is a target of many sexually transmitted infections, and major advances have increased our understanding of the consequences of such infections within the gastrointestinal system. HIV-1 is associated with a marked loss of mucosal CD4(+) T cells that express CC-chemokine receptor 5. This process seems to be more rapid and more severe in mucosa-associated lymphoid tissue than in the peripheral blood. Mechanistic insights into the underlying cause of acute and chronic gastrointestinal damage with HIV infection-microbial translocation, defects in intestinal epithelial barrier function and activation of a systemic immune response-have also been achieved. Increased understanding of the pathogenesis of mucosal HIV-1 infection may identify therapeutic targets to restore immunological function and the integrity of the intestinal mucosal epithelial barrier. The increasing prevalence of lymphogranuloma venereum in Europe, mostly in HIV-positive men who have sex with men, suggests a change in the epidemiology of what was previously considered to be a 'tropical' disease. The increasing incidence of acute HCV infection transmitted via sexual contact has also been fueled by high-risk sexual behaviors among men who have sex with men, many of whom are also HIV-positive. The first part of this Review discusses the pathogenesis and gastrointestinal complications of HIV infection, and the second part summarizes advances in our understanding of other sexually transmitted infections of the gastrointestinal system.

Mycobacterium ulcerans infection as a cause of chronic diarrhea in an AIDS patient: A case report

Chronic diarrhea is one of the most frequent gastro-intestinal manifestations in acquired immunodeficiency syndrome (AIDS). Protozoa and nontuberculous mycobacteria (NTM) are opportunistic pathogens that can easily infect these patients. Among the NTM, Mycobacterium avium complex (MAC) is the most frequently observed pathogen in HIV-infected patients. However, NTMs other than MAC have not been reported as a gastrointestinal pathogen as yet. We present a case of chronic diarrhea in an AIDS patient in whom Mycobacterium ulcerans and cryptosporidium co-infection is evidenced from colonic tissue.

Viral and fungal infectious colitides

Viral and fungal colitides are rare in the immunocompetent host but are most clinically significant in populations with compromised immune function. They may be associated with high mortality, particularly when treatment is delayed. It is important to be aware of these diseases when treating patients with colitis to allow early diagnosis and treatment, which will improve outcome.

Infectious diarrhea in human immunodeficiency virus

Chronic HIV-associated diarrhea is currently a field in flux. Improved noninvasive diagnostic tests, improved pathogen-specific regimens, and better empiric therapies may change some of the assumptions used to select algorithms for diagnostic evaluation and management. Any shift in the cause of diarrhea from pathogen-associated to idiopathic or a reduction in the overall incidence of diarrhea would have considerable impact. It is unclear how significant the problem of pathogen relapse in previous responders will become. Existing studies reviewed in this article show that the high diagnostic yield of endoscopy when stool tests are negative, coupled with significantly better outcomes when pathogens are identified, support the current practice of routine endoscopic evaluation. There currently are scant data on the economic impact of HIV-associated diarrhea as it relates to pathogen-specific and empiric therapy in the era of protease inhibitors. Such data would be integral to future evaluation of the impact of diagnostic and therapeutic strategies.

HIV-related diarrhea is multifactorial and fat malabsorption is commonly present, independent of HAART

OBJECTIVE

Highly active antiretroviral therapy (HAART) has significantly decreased the incidence of infectious diarrhea affecting HIV-infected patients. Still, diarrhea remains a common symptom in HIV. We sought to determine the incidence of fat malabsorption as a cause of diarrhea in HIV patients receiving non-HAART (nucleoside analog only) and HAART (protease inhibitor-containing) antiretroviral regimens.

METHODS

From June, 1995, to April, 1999, 88 HlV-infected patients underwent evaluation for diarrhea, which included endoscopy. We examined the incidence of fat malabsorption with a 24-h stool collection for fecal fat in a cohort of these patients (N = 33). Patients were divided into two groups, those receiving protease inhibitor-containing HAART and those receiving less intensive, nucleoside analog-only, non-HAART regimens.

RESULTS

Thirty of 33 patients (90.9%) had fat malabsorption. Twenty of 21 patients not receiving HAART (95.2%) had fat malabsorption with a mean of 34 +/- 38 g of stool fat and a mean stool weight of 797 +/- 454 g. Ten of 12 patients receiving HAART (83.3%) had fat malabsorption with a mean of 46 +/- 86 g of stool fat and a mean stool weight of 800 +/- 647 g. Stool weight correlated with the degree of fat malabsorption (R = 0.77).

CONCLUSION

Fat malabsorption represents a commonly undiagnosed entity in HIV-infected patients with diarrhea, whether or not they are receiving HAART therapy. Fecal fat determination should be considered a routine part of the diagnostic workup of HIV-infected patients experiencing diarrhea.

Emerging concepts in gastrointestinal aspects of HIV-1 pathogenesis and management

GASTROENTROLOGY 2001;120:607-621

Enteric viruses in HIV-related diarrhoea

HIV-related diarrhoea is an important cause of morbidity and mortality in HIV infection. Cytomegalovirus is a well-established cause of diarrhoea, but the role of other enteric viruses is less clear and will be discussed here. The clinical manifestations, disease mechanisms, diagnostic techniques and current treatments for the management of these infections are reviewed.

Endoscopy in acquired immunodeficiency syndrome patients with diarrhea and negative stool studies

BACKGROUND

Diarrhea is a frequent gastrointestinal symptom in patients with acquired immuno-deficiency syndrome (AIDS) and is a major source of morbidity and mortality. A stepwise diagnostic approach is often recommended to search for treatable causes. However, whether the stepwise diagnostic approach is adequate for planning treatment and whether specific treatment for infectious etiologies will affect the survival of patients with AIDS remain unknown.

METHODS

From March 1996 to September 1997, endoscopy was performed in AIDS patients with diarrhea, the etiology of which was not identified by noninvasive methods. Specific treatment was given according to the identified etiologies and symptomatic treatment was given for those without definite diagnosis. The clinical symptoms, signs, and duration of follow-up were recorded and survival patterns were analyzed.

RESULTS

Etiologic diagnoses were made in 26 of 40 patients (65%) who underwent endoscopic studies. Amebic colitis and cytomegalovirus colitis were the 2 leading causes of prolonged diarrhea in patients with AIDS. Thirty-five patients (87.5%) recovered after treatment. The difference in survival time after diarrhea between patients whose symptoms resolved after treatment and those who continued to have diarrhea was statistically significant (p < 0.001).

CONCLUSIONS

Endoscopic studies were helpful for the diagnosis of prolonged diarrhea in AIDS patients who had negative stool studies and did not respond to 2 weeks of empiric treatment. Specific treatment according to the results of endoscopy may improve survival in these patients.

Impact of protease inhibitors on the outcome of human immunodeficiency virus-infected patients with chronic diarrhea

OBJECTIVE

The effect of protease inhibitors on the outcome of chronic HIV-related diarrhea is unknown. The aim of this study was to compare the response to treatment of chronic HIV-related diarrhea, recurrence of diarrhea, and survival in a large cohort of individuals taking protease inhibitors to the outcome in similar patients not receiving protease inhibitors.

METHODS

We reviewed the medical records of all patients referred between October 1993 and October 1996 at Bellevue Hospital for endoscopic evaluation of chronic HIV-related diarrhea after negative stool examination. Only patients presenting after December 1995 received protease inhibitor therapy. Follow-up data were obtained from chart review and direct telephone contact. The success of antidiarrheal therapy was compared between protease inhibitor and nonprotease inhibitor groups for patients receiving pathogen-specific therapy and for those with no pathogens found on endoscopy.

RESULTS

Two hundred eighty-two of 307 patients evaluated for chronic diarrhea were followed for a mean of 69.9+/-34.1 weeks. Patients receiving protease inhibitors had a significantly higher rate of successful response to antidiarrheal therapy (62.0% vs 33.5%, p < 0.001). Protease inhibitors were associated with a significant decrease in stool frequency (4.8+/-4.5 vs 3.4+/-4.6 bowel movements per day, p = 0.01), an increase in weight (2.4+/-5.9 vs -1.6+/-6.2 kg, p < 0.001), a decrease in recurrence of diarrhea (34.8% vs 15.3%, p = 0.02), and a longer mean survival (148 vs 118 weeks, p = 0.002).

CONCLUSIONS

Protease inhibitors significantly improve the outcome of antidiarrheal therapy and survival in patients with chronic HIV-associated diarrhea.

A double blind, randomized, placebo-controlled phase II study to assess the safety and efficacy of orally administered SP-303 for the symptomatic treatment of diarrhea in patients with AIDS

OBJECTIVE

The aim of this study was to investigate the safety and effectiveness of orally administered SP-303 in patients with AIDS and diarrhea.

METHODS

This is a multicenter, phase II, randomized, double blind, placebo-controlled study. HIV-positive subjects with a history of a CD4 count <200 or an AIDS-defining illness were admitted to an inpatient study unit and screened for diarrhea defined as at least three abnormal (i.e., soft or watery) stools and >200 g of abnormal stool weight over a 24-h period. Subjects discontinued all antidiarrheal agents >24 h before enrollment. Stool samples were studied for routine pathogens. Subjects received 500 mg p.o. of SP-303 or placebo every 6 h for 96 h (4 days). Stool frequency and weights were recorded. Subjects were monitored for symptoms and side effects and were seen 1 wk later in follow-up.

RESULTS

A total of 26 subjects received SP-303, and 25 received placebo. There were no significant demographic differences between treatment arms. A total of 41 subjects (80%) were receiving antiretroviral therapy and 39 subjects (77%) were receiving at least one protease inhibitor. Stool studies revealed no pathogens in 48 of 51 patients (94%). There were no serious adverse events or laboratory abnormalities. The SP-303 treatment group demonstrated a mean reduction from baseline stool weight of 451 g/24 h versus 150 g/24 h with placebo on day 4 of treatment (p = 0.14), and a mean reduction in abnormal stool frequency of three abnormal stools in 24 h versus two in 24 h in the placebo group (p = 0.30). Daily measures analysis over 4 days of treatment demonstrated that SP-303 subjects had a significant reduction in stool weight (p = 0.008) and abnormal stool frequency (p = 0.04) when compared to placebo-treated subjects.

CONCLUSIONS

SP-303 is safe and well tolerated. These results suggest that SP-303 may be effective in reducing stool weight and frequency in patients with AIDS and diarrhea.

Enteric viral infections as a cause of diarrhoea in the acquired immunodeficiency syndrome

BACKGROUND AND AIMS

The role of non-cytomegalovirus (CMV) enteric viral infection in causing diarrhoea in patients with human immunodeficiency virus (HIV) is poorly understood. We aimed to investigate the prevalence of these infections in acute and chronic diarrhoea.

METHODS

Stool specimens from 377 HIV-infected patients presenting with diarrhoea were studied prospectively for evidence of non-CMV enteric viral infection. Patients with diarrhoea underwent investigation for gastrointestinal pathogens, including electron microscopic examination of stool for enteric viruses. We collected data on patients in whom enteric virus was identified and examined the association of enteric virus infection with diarrhoeal symptomatology.

RESULTS

Eighty-nine (10.3%) stool specimens from 60 (15.9%) HIV+ individuals were positive for coronavirus (n = 13, 22%), rotavirus (n = 11, 18%), adenovirus (n = 30, 50%) and small round structured viruses (n = 5, 8%) or dual infection (n = 2, 3%). Thirty-four of 52 (65%) patients available for analysis had acute diarrhoea, and 18/52 (35%) had chronic diarrhoea. Twenty-three of 52 (44%) patients had a concurrent gut pathogen. After exclusion of concurrent pathogens enteric viral infections were found to be significantly associated with acute as opposed to chronic diarrhoea (P = 0.004). The presence of adenovirus colitis was significantly more likely to be associated with chronic diarrhoea (15/21 cases) than adenovirus isolated from stool alone (9/23 cases) (P = 0.03). There was a trend towards an association between adenovirus colitis and colonic cytomegalovirus infection (P = 0.06).

CONCLUSION

Enteric viral infection is strongly associated with acute diarrhoea in patients with HIV. Light microscopic examination of large bowel biopsies can identify adenovirus colitis which is significantly associated with chronic diarrhoea, and in addition may facilitate gastrointestinal co-infection with CMV.

A prospective study of endoscopy in HIV-associated diarrhea

OBJECTIVE

Diarrhea commonly occurs in persons with human immunodeficiency virus (HIV) infection. The optimal use of endoscopic procedures remains poorly studied for patients with HIV-related diarrhea. The purpose of this study is to compare the diagnostic yield of a complete endoscopic work-up including an esophagogastroduodenoscopy and colonoscopy to a more limited approach of biopsies obtainable by flexible sigmoidoscopy.

METHODS

A prospective study of 79 patients with HIV-related diarrhea. Upper endoscopy and colonoscopy were performed with tissue biopsies labelled according to location within the colon or small intestine.

RESULTS

A new infection was diagnosed in 22 of 79 patients (28%). Biopsy of the left colon yielded an enteric pathogen in 17 of 22 patients (sensitivity: 77%) and in 15 of 15 patients with cytomegalovirus colitis (sensitivity: 100%). Combined left and right colonic biopsies had a sensitivity of 82%. Combined colonic and terminal ileum biopsies missed no pathogens. Duodenal biopsies yielded no additional pathogens beyond those identified by colonoscopy and terminal ileal biopsy. Patients with a new pathogen diagnosed had significantly lower CD4 lymphocyte counts as compared to patients without a new pathogen (p = 0.001).

CONCLUSIONS

For patients with CD4 counts < 100/mm3 and unexplained AIDS-related diarrhea, flexible sigmoidoscopy with biopsy is a sufficiently thorough endoscopic evaluation.

Gastrointestinal manifestations of HIV infection

As patients with human immunodeficiency virus (HIV) infection become more immunocompromised, gastrointestinal symptoms become more common. Most symptoms result from opportunistic infections and can be diagnosed and treated by gastroenterologists, although medical microbiology and histopathology input is essential.

Small intestine pathogens in AIDS: conventional and opportunistic

The small intestine, coming in direct contact with ingested potential pathogens, depends on active mucosal immunity to withstand invasion and damage. In patients with AIDS and severe impairment of immunoregulatory lymphocytes, proliferation of protozoal, viral, bacterial, and fungal pathogens produces diarrhea and malabsorption. When noninvasive tests of stool and blood fail to identify responsible organisms, endoscopy can reveal mucosal lesions which are suggestive if not diagnostic. Cryptosporidium, cf2E. intestinalis, cf1CMV, MAC, and other infections can be identified by intestinal biopsy quicker and often at lower overall cost than they can be by culture.

Evaluation of diarrhea in HIV-infected patients

Diarrhea is a major problem for patients infected with HIV: initial studies indicated that 50% of HIV-seropositive patients developed diarrhea, but this may be an underestimate. Diarrhea has an appreciable adverse affect on the quality of life of these patients; also, they use more health care facilities and health care dollars than HIV-positive patients without diarrhea. Individuals who have homosexuality or bisexuality as their HIV risk factor are more likely to have diarrhea and to have an enteric pathogen identified as the cause of diarrhea than are patients who have heterosexuality or intravenous drug use as their risk factor.

Evaluation of diarrhea in HIV-infected patients

Diarrhea is a major problem for patients infected with HIV: initial studies indicated that 50% of HIV-seropositive patients developed diarrhea, but this may be an underestimate. Diarrhea has an appreciable adverse affect on the quality of life of these patients; also, they use more health care facilities and health care dollars than HIV-positive patients without diarrhea. Individuals who have homosexuality or bisexuality as their HIV risk factor are more likely to have diarrhea and to have an enteric pathogen identified as the cause of diarrhea than are patients who have heterosexuality or intravenous drug use as their risk factor.

Comparison of duodenal with jejunal biopsy and aspirate in chronic human immunodeficiency virus-related diarrhea

OBJECTIVES

In human immunodeficiency virus (HIV)-infected patients with chronic unexplained diarrhea, upper endoscopy with small bowel biopsy and aspirate is often performed to identify treatable pathogens. The purpose of this study was to compare the diagnostic yield of duodenal with jejunal biopsy and aspirate.

METHODS

All HIV-infected patients with chronic unexplained diarrhea who were evaluated by upper endoscopy at Bellevue Hospital Center between January 1992 and January 1997 were identified. Data were collected by reviewing patient charts, endoscopy reports, and pathology records.

RESULTS

During the 5-yr study period, 442 patients underwent upper endoscopy with sampling of the duodenum (N=173) or jejunum (N=269). A pathogen was identified in 123 patients (27.8%). Microsporidia was the most common organism detected (12.2%). The diagnostic yield of jejunal biopsy and aspirate was significantly higher than that obtained from the duodenum (32.3% vs 20.8%, p=0.009). Small bowel aspirates detected a pathogen in only 1.8% of patients evaluated, and there was no difference in the yield of duodenal and jejunal aspirates (1.3% vs 2.1%, p=0.7). Patients with a CD4 count of < 100 cells/mm3 were significantly more likely to have a pathogen identified than those with higher CD4 counts (38.8% vs 7.1%,p < 0.0001).

CONCLUSIONS

Upper endoscopy with small bowel biopsy and aspirate identifies a pathogen in 27.8% of individuals with HIV-related chronic unexplained diarrhea. In this patient population, jejunal biopsies acquired by enteroscopy are superior to those obtained from the duodenum. Small bowel aspirates are of little value in the workup of chronic HIV-related diarrhea.

Small intestine pathogens in AIDS: conventional and opportunistic

The small intestine, coming in direct contact with ingested potential pathogens, depends on active mucosal immunity to withstand invasion and damage. In patients with AIDS and severe impairment of immunoregulatory lymphocytes, proliferation of protozoal, viral, bacterial, and fungal pathogens produces diarrhea and malabsorption. When noninvasive tests of stool and blood fail to identify responsible organisms, endoscopy can reveal mucosal lesions which are suggestive if not diagnostic. Cryptosporidium, cf2E. intestinalis, cf1CMV, MAC, and other infections can be identified by intestinal biopsy quicker and often at lower overall cost than they can be by culture.

Cytomegalovirus colitis in acquired immunodeficiency syndrome: a clinical and endoscopic study

BACKGROUND

Cytomegalovirus colitis is an important complication of the acquired immunodeficiency syndrome (AIDS), although the clinical and colonoscopic manifestations of this disease have not been systematically characterized.

METHODS

Patients with AIDS and cytomegalovirus colitis were prospectively identified at two medical centers. The diagnosis of cytomegalovirus disease was based on established endoscopic and histologic criteria. At the time of sigmoidoscopic and/or colonoscopic examination, clinical features were recorded; the location, size, and appearance of all endoscopic abnormalities were documented; and multiple biopsies of any lesions were performed.

RESULTS

Fifty-six patients were studied. The majority of the patients were homosexual men with severe immunodeficiency (median CD4 lymphocyte count 15/mm3, range 1 to 294/mm3). Chronic diarrhea and abdominal pain were the most frequent clinical manifestations, seen in 45 (80%) and 28 (50%) patients, respectively. Five patients (9%) presented with lower gastrointestinal hemorrhage, three of whom had no antecedent history of diarrhea. The colonoscopic abnormalities could be categorized into three main groups: colitis associated with ulcer (39%), ulceration alone (38%), or colitis alone (20%). Subepithelial hemorrhage was a prominent endoscopic manifestation of disease. Of the 31 patients undergoing colonoscopy to the cecum, in four (13%) endoscopic evidence of disease was limited to the colon proximal to the splenic flexure.

CONCLUSIONS

Cytomegalovirus colitis in AIDS appears to have variable but stereotypical clinical and colonoscopic manifestations. Distal colitis associated with ulceration is the most common colonoscopic pattern.

Gastrointestinal pathology in HIV-infected patients

Specific pathologic processes, particularly oral, esophageal, and intestinal infections, are common in the alimentary tract of AIDS patients. Many of these diseases are adequately assessed only by biopsy with histologic examination. Most are rare or unreported in immunocompetent hosts and are easily missed by those not familiar with them. This article describes the gross or endoscopic and histologic appearances and the diagnostic criteria for enteric pathologic processes seen in HIV-infected individuals.

Diarrheal diseases associated with HIV infection

Diarrhea is a major complication of HIV infection and adversely impacts health care costs, quality of life, and even survival of patients. There is a wide variety of potential causes of diarrhea in HIV-infected patients, and the number of pathogens found continues to increase with time. In addition, there is some controversy concerning the role of some organisms in the pathogenesis of diarrhea and the appropriate diagnostic evaluation of affected patients. This article reviews our current understanding of these pathogens and some of the diagnostic and therapeutic approaches for diarrhea associated with HIV infection.

Agents of diarrhea

Diarrhea is a common problem for AIDS patients, and is chronic and debilitating. A thorough evaluation will reveal a pathogen in the majority of patients, and the organisms most frequently identified in AIDS patients with chronic diarrhea are Cryptosporidium, microsporidia, and Mycobacterium avium complex. Bacterial pathogens are more common in AIDS patients than in the general population and may present in different ways from infections in immunocompetent hosts. Other pathogens, including Cryptosporidium and microsporidia, are difficult to diagnose and have no effective therapy. Moreover, enteric viruses and HIV itself may contribute to the diarrhea. In addition to microbes, other factors such as medication, immune dysregulation, automatic dysfunction, and nutritional supplementation play a substantial role in diarrhea of AIDS patients.

Gastrointestinal manifestations

Gastrointestinal disease is a common problem in the setting of HIV-1 infection. As patients live longer and other opportunistic pathogens are suppressed, these problems are becoming even more important in the quality of life.

Gastrointestinal manifestations of HIV infection

The harrowing picture of emaciated terminally ill AIDS patients is a reminder of our lack of understanding of immunological mechanisms that normally control opportunistic infections. Many gastrointestinal pathogens in patients with AIDS are resistant to treatment and lead inexorably to weight loss and death. Although knowledge of the pathogenesis and clinical significance of weight loss has improved considerably, this has not yet led to a sustained effort to improve nutritional status during early stages of disease.