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

Making the diagnosis of coeliac disease: is there a role for push enteroscopy?

BACKGROUND

Push enteroscopy is used in the assessment of refractory coeliac disease. However, its value in making the diagnosis of coeliac disease is still not defined.

METHODS

Thirty-one patients (22 females, nine males) were recruited prospectively between September 2001 and October 2002; the age range was 20-80 years (mean age, 52.7 years). All patients had symptoms suggestive of coeliac disease and positive serology but duodenal biopsy was not diagnostic. Twenty-three patients had positive IgA or/and IgG antigliadin antibodies, eight patients had positive endomysial antibodies (EMA). All patients underwent enteroscopy with repeat quadrantic duodenal and additional jejunal biopsies.

RESULTS

All samples were reviewed by a single, blinded, histopathologist. There were no cases of coeliac disease diagnosed on further biopsy in patients who had a positive gliadin antibody in isolation. In the eight EMA-positive cases repeat biopsy demonstrated coeliac disease in five patients. In 3/5 cases the changes were confined to the jejunal biopsies only.

CONCLUSION

EMA-positive patients with initially normal histology should have a further duodenal biopsy. In our series three of the five newly diagnosed coeliac disease patients only had villous atrophy demonstrable in the jejunum. There may be a role for push enteroscopy in making the diagnosis of coeliac disease. However, further prospective studies are needed.

HIV1 and the gut in the era of highly active antiretroviral therapy

The gut and its gut-associated lymphoid tissue serve as a preferential site for HIV1 entry, active viral replication, reservoir, and HIV-mediated CD4 cell apoptosis. The widespread use of highly active antiretroviral therapy (HAART) has resulted in a significant decrease in the incidence of opportunistic enteric pathogens as a consequence of immune recovery. Nonetheless, patients with advanced HIV1 disease who were recently diagnosed or have poor response to HAART can still suffer from opportunistic infections with pathogens such as Cryptosporidium, microsporidia, Isospora belli, Cyclospora cayetanensis, Mycobacterium avium complex, and cytomegalovirus, among others. This review describes the impact of HIV1 infection on gut immune function, the salient features of the most common opportunistic enteric pathogens and HIV-associated enteropathy, and the effects of immune reconstitution after introduction of HAART.

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.

Enteroscopy

It is now more than 25 years since small bowel enteroscopy (SBE) was first described. For several reasons, this technique developed more slowly than other more usual forms of endoscopy. First, small bowel disease is relatively rare in comparison with other gastrointestinal diseases. Also, there was lack of initial design agreement, and three different types of enteroscopes were developed within a short time of each other, two of which (push-type and sonde) are now available commercially. Finally, commercial interests of the manufacturers of endoscopes were mainly focused on the more conventional, large volume markets. In the last few years, specifically designed modern small bowel enteroscopes have become available and, in centers that have access to them, they have superseded attempts at SBE using adult or pediatric colonoscopes. There are now clear indications for SBE, such as: the investigation of obscure causes of bleeding and anemia; malabsorption; clarification of x-ray abnormalities; and, increasingly, the application of therapeutic endoscopy to lesions within the small bowel. Problem areas remain, but with advancing technology and more professional interest in this area, these will be addressed during the next few years.

Gastrointestinal infections in the immunocompromised host

Infectious diseases of the gastrointestinal tract continue to be an important source of morbidity and mortality. Viruses, bacteria, fungi, and protozoa that infect normal hosts also infect the gastrointestinal tract in immunocompromised hosts. Disease caused by these pathogens may be more severe and more difficult to treat in immunocompromised hosts. In addition, pathogens that rarely cause disease in normal hosts cause significant disease in immunosuppressed hosts. Diagnostic decisions need to take into account expected pathogens and response to therapy. Treatment decisions must be based on the findings of diagnostic procedures; expected pathogens; and recent data suggesting that highly active antiretroviral therapy, with its ability to reconstitute immune function, is an essential component of treatment. This review summarizes the most important developments made in the pathogenesis, clinical presentation, diagnosis, and treatment of gastrointestinal infections in immunocompromised hosts in the past year.