Diagnostic yield of duodenal aspirate for G. lamblia and comparison to duodenal mucosal biopsies

Our objective was to examine the diagnostic yield of duodenal aspirates for Giardia in children and compare it to results of duodenal mucosal biopsies. The results of all duodenal aspirates submitted for direct parasite examinations over a 31-month period were reviewed, as were the histological results of duodenal mucosal biopsies from these patients. In all, 161 children (89 boys; age range 0.33-18 years) were included in the study. Giardia was identified in the duodenal aspirate of 5.6% (9/161) patients and on duodenal mucosal biopsies from all nine patients. In conclusion, the 5.6% diagnostic yield of duodenal aspirates for Giardia is higher than reported in a previous study of adult patients from a similar geographical region (0.7%). The detection of Giardia on duodenal mucosal biopsies from all patients with positive duodenal aspirates brings into question the utility and cost of the latter test. Duodenal aspirates for Giardia may be unnecessary if duodenal mucosal biopsies are obtained for histological examination.

[Strongyloidosis. Part VIII. Parasitological diagnosis]

The effectiveness and safety of the methods of detecting Strongyloides stercoralis, by passing larvae from the faeces to water, in duodenal fluid (duodenal intubation, Enterotest), in sputum and other body fluids, have been estimated. The author recommend Baermann technique for detecting S. stercoralis in individual examinations and Dancescu technique in mass field examinations. The detection of S. stercoralis larvae by the two methods ought to be checked by Fülleborn agar Petri dish technique in order to identify parasite to the species level.

The relationship between circulating and intestinal Heligmosomoides polygyrus-specific IgG1 and IgA and resistance to primary infection

Specific serum and intestinal immunoglobulin (Ig)G1 and IgA responses to Heligmosomoides polygyrus were measured in a panel of seven inbred mouse strains which exhibit 'rapid' (<6 weeks (SWRxSJL)F1), 'fast' (<8 weeks, SJL and SWR), 'intermediate' (10-20 weeks, NIH and BALB/c) or 'slow' (>25 weeks, C57BL/10 and CBA) resolution of primary infections. Mice with 'rapid', 'fast' or 'intermediate' response phenotypes produced greater serum and intestinal antibody responses than those with 'slow' phenotypes. The F1 hybrids ((SWRxSJL)F1) of two 'fast' responder strains showed the earliest antibody response with maximum titres evident within 6 weeks of infection. There was a negative correlation between the serum IgG1 responses and worm burdens in individual mice within a number of mouse strains, and also between serum IgG1 and IgA responses and worm burdens in the 'rapid' ((SWRxSJL)F1) responder strain. The presence of IgG1 in the gut was found to be due to local secretion rather than plasma leakage. Using Western immunoblotting, serum IgG1 from 'rapid' and 'fast' responder but not 'slow' responder mice was found to react with low molecular weight antigens (16-18 kDa) in adult worm excretory/secretory products.

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.

Diagnostic yield of duodenal biopsy and aspirate in AIDS-associated diarrhea

OBJECTIVES

To evaluate the diagnostic yield of performing duodenal biopsies and aspirates in AIDS patients with chronic diarrhea.

METHODS

Retrospective review of esophagogastroduodenoscopy (EGD) records from January 1993 to March 1995 to identify those patients who underwent EGD for evaluation of AIDS associated diarrhea and had a duodenal biopsy and/or aspirate. Biopsies were examined for pathogens using routine histology and special stains, viral culture, and electron microscopy. Duodenal aspirates were evaluated for ova and parasites. All patients had previous negative stool studies. Pathology laboratory charges (hospital and professional fees) for each test and charges per positive test were determined.

RESULTS

Of the 57 patients included in this study, 56 had a duodenal biopsy and 42 had a duodenal aspirate. An established pathogen was identified in only 15 (26%) patients. One patient had both Mycobacterium avium complex and microsporidia. Pathogens were identified in seven patients by hematoxylin and eosin stain, in three patients by acid-fast bacillus stain, and in six patients by electron microscopy. No pathogens were identified with Gomori's methenamine silver stain (44 patients), duodenal aspirate for ova and parasites (46 patients), immunoperoxidase stains (4 patients), or viral culture (4 patients). Cryptosporidia were identified in six, microsporidia in five, Mycobacterium avium complex in three, and Giardia lamblia and adenovirus each in one patient.

CONCLUSIONS

In this series, the diagnostic yield of EGD with duodenal biopsy and aspirate in AIDS associated diarrhea was low. Pathogens were identified in 26% of patients; predominantly Cryptosporidium organisms and microsporidia. The routine performance of aspiration of duodenal contents for parasite examination and staining of duodenal tissue with Gomori's methenamine silver stain for fungal identification are not recommended. One should consider obtaining tissue for electron microscopy whenever duodenal biopsies are performed. The utility of EGD in AIDS associated diarrhea may improve as more effective therapies become available.

Giardiasis. Taming this pervasive parasitic infection

Parasitic infection due to Giardia lamblia can produce severe, disabling gastrointestinal symptoms. Outbreaks have been linked to contaminated municipal water supplies and situations involving person-to-person contact. Immunocompromised patients are especially at risk. Because microscopic examination of stool detects the parasite in only about half of infected patients, use of enzyme-linked immunosorbent assay to detect Giardia-specific antigen is becoming increasingly popular. In most patients, therapy with quinacrine (Atabrine) hydrochloride, metronidazole (Flagyl, Protostat), or a combination of the two is effective.

Quantitation of salivary, urinary and faecal sIgA in children living in different conditions of antigenic exposure

A sandwich-type ELISA was developed to quantify salivary, urinary and faecal secretory IgA (sIgA). The assay is based on binding of sIgA to microplates coated with anti-SC antibodies and reaction with peroxidase-labelled anti-IgA. The sensitivity of the technique was approximately 5 micrograms/L. Children, 1-6 years old (n = 142), were divided into two groups. Group 1 (n = 80) was composed of children living in a place with presumably low antigenic exposure conditions. Group 2 (n = 62) was composed of well-nourished (2A, n = 53) and malnourished children (2B, n = 9) living in a São Paulo slum with presumably high antigenic exposure. The subgroup 2A had salivary levels higher than group 1 and the ranges were similar to those found in the literature for older children and adults. The same subgroup presented a high incidence of undetectable faecal sIgA; their levels of urinary sIgA did not differ from group 1. The subgroup 2B did not have levels of salivary, urinary and faecal sIgA different from subgroup 2A. Our results suggest that environmental factors influence the ontogenesis of sIgA system.

Human giardiasis: correlation of specific secretory IgA levels in duodenal fluid to the severity of disease and infestation by Giardia lamblia

Giardia lamblia specific secretory immunoglobulin A (sIgA) levels in the duodenal fluid of adult giardiasis cases are reported for the first time. The sIgA levels in the study group were found to be significantly higher (p less than 0.01) than in the 20 age- and sex-matched controls comprising cases classified as non-ulcerative dyspepsia who did nor reveal any G. lamblia in their stools and the duodenal fluid. An inverse relationship between the clinical severity of giardiasis and the level of sIgA in the duodenal fluid was noted. Cases with a higher trophozoite load in duodenal aspirate tended to be associated with envanescent G. lamblia-specific antibodies.

Giardia lamblia in patients undergoing upper G.I. endoscopy

To determine the frequency of giardiasis in patients undergoing upper G.I. endoscopy for dyspepsia and other upper G.I. disorders, duodenal aspirates were collected in 200 patients and simultaneous duodenal biopsies in 163 patients. Nine percent aspirates and 1.8% duodenal biopsies showed Giardia lamblia trophozoites. Giardia as a cause of dyspepsia should be considered in patients with negative endoscopy and in those who remain symptomatic inspite of adequate treatment for known upper G.I. disorders.

Diagnosis of Strongyloides and hookworm infections: comparison of faecal and duodenal fluid microscopy

Faecal microscopical diagnosis of Strongyloides and hookworm infections is insensitive. We have therefore compared duodenal fluid and faecal microscopy for detection of these parasites in a group of 292 patients being investigated for gastrointestinal symptoms who were examined by both techniques. Thirty-three of these patients (8%) were infected with Strongyloides stercoralis and 88 (30%) had hookworm infections. Microscopical examination of up to 3 faecal specimens detected only 33% and 65% of patients with Strongyloides and hookworm infections, respectively. Microscopical examination of a single specimen of duodenal fluid was more sensitive for detection of strongyloidiasis, identifying 76% of patients; the parasite was found exclusively in duodenal fluid (and not in faeces) in 67% of patients. For hookworm, the diagnostic sensitivity was similar with both techniques but duodenal fluid microscopy detected some patients (35%) who had not been identified by faecal microscopy. This study confirms previous work indicating the insensitivity of faecal microscopy in these infections and emphasizes the need to consider routine examination of duodenal fluid to exclude chronic strongyloidiasis. This may have particular relevance for south-east Asian war veterans and immunocompromised patients.

Intestinal mucus protects Giardia lamblia from killing by human milk

We have previously shown that nonimmune human milk kills Giardia lamblia trophozoites in vitro. Killing requires a bile salt and the activity of the milk bile salt-stimulated lipase. We now show that human small-intestinal mucus protects trophozoites from killing by milk. Parasite survival increased with mucus concentration, but protection was overcome during longer incubation times or with greater milk concentrations. Trophozoites preincubated with mucus and then washed were not protected. Protective activity was associated with non-mucin CsCl density gradient fractions. Moreover, it was heat-stable, non-dialyzable, and non-lipid. Whereas whole mucus inhibited milk lipolytic activity, protective mucus fractions did not inhibit the enzyme. Furthermore, mucus partially protected G. lamblia trophozoites against the toxicity of oleic acid, a fatty acid which is released from milk triglycerides by lipase. These studies show that mucus protects G. lamblia both by inhibiting lipase activity and by decreasing the toxicity of products of lipolysis. The ability of mucus to protect G. lamblia from toxic lipolytic products may help to promote intestinal colonization by this parasite.

Migrational responses of Hymenolepis diminuta to surgical alteration of gastro-intestinal secretions

The effects of the direction of gut flow, of injections of glucose and saline into different regions of the small intestine and of surgical re-routing or ligature of gastric, biliary and pancreatic secretions into the small intestine have been correlated with changes in the migratory response of the rat tapeworm Hymenolepis diminuta. Reversing the normal anterior to distal flow of luminal contents in the small intestine did not affect worm migration following feeding. Injections of a glucose-saline solution into the duodenum did not initiate a migratory response; similar injections into the mid- and posterior regions of the small intestine resulted in migrational responses similar to those following intragastric glucose feeding. Re-routing gastric secretions to the distal duodenum inhibited anterior migration of the worms beyond the new point of entry of gastric juices. Results following re-routing and ligation of the biliary and pancreatic secretions suggest that there is a potent cue to anteriad migration in the pancreatic secretions. Biliary secretions also appear to contain an additional migratory cue to worm migration. In order of importance the factors stimulating/inhibiting worm migration are pancreatic greater than gastric greater than biliary greater than glucose. The results support the hypothesis that the factors affecting worm distribution in the small intestine are interactive and synergistic, involve other luminal factors, such as 5-hydroxytryptamine and the physico-chemical gradients, and are of a regional nature such that the migratory response of a particular worm is directly related to its position in the small intestine when the cues to relocation are received.

[Giardiasis]

Giardia Lamblia is considered as the most important cause of parasitic diarrhoea in children and adults. The epidemiology of the infection is determined by environmental and regional factors. The sensitivity of man for this infection depends on factors related to man himself and his environment. Structural changes of the gut such as cellular infiltration and villous atrophy, and functional derangements like malabsorption can explain part of the symptoms. The application of different procedures for the parasitological diagnosis with a variable degree of sensitivity is the cause of difference in recorded prevalence data. This infectious disease can be treated with a number of drugs; single dose treatment is to be preferred especially in childhood. Results of treatment i.a. with a single dose ornidazole are reported.

Scintigraphic evaluation of the liver in Fasciola hepatica with radiocolloid and 67Ga-citrate

A group of 23 patients with Fasciola hepatica have been studied in the province of Biscay. The diagnosis was reached after finding parasite eggs in the faeces or duodenal juice. The liver lesion was confirmed by means of macro and microscopic studies. Radiocolloid demonstrated the presence of cold areas in 18 patients; in 13 of them the uptake with 67Ga was positive. These isotopic findings identified Fasciola hepatica as one of the causes of 'cold areas' in traditional liver scans and positive 67Ga uptake.

The diagnosis of giardiasis

Giardiasis is the most prevalent intestinal parasitic disease in the United States. Most cases can be diagnosed by a single stool examination. However, in periodic cyst excretors, cysts may not be detected unless repeated stool examinations are performed. In clinically highly suspected cases, duodenal fluid should be studies after three negative stool examinations. Scanning electron microscopy is probably superior to light microscopy in screening duodenal fluid if the parasite is scanty or degenerated. A small intestinal biopsy is a last resort for the diagnosis; a mucosal impression smear should be routinely performed on such specimens. The latter is the most sensitive and reliable technique in making the diagnosis.

Single dose treatment with Tiberal of Giardia lamblia infection in children

A new metronidazole derivative, Tiberal (Ro-07-0207, Roche Laboratories), was evaluated in 22 children with Giardia lamblia infection. Seven patients received an oral dose of 1 g twice daily for one day; the remaining 15 patients received a single dose of 50 mg/kg. Parasitological cure was noted in all 22 patients. Significant side effects were observed only in those children who received the drug at the higher dosage regime. The present study also confirms the findings of other authors that a mucosal imprint method is more reliable than examination of stools, duodenal juice or jejunal biopsy material for the detection of G. lamblia infection.