Histopathology of gastric and duodenal Strongyloides stercoralis locations in fifteen immunocompromised subjects

Human strongyloidiasis: complexities and pathways forward

Strongyloidiasis is a World Health Organization neglected tropical disease usually caused by Strongyloides stercoralis, a parasitic worm with a complex life cycle. Globally, 300-600 million people are infected through contact with fecally contaminated soil. An autoinfective component of the life cycle can lead to chronic infection that may be asymptomatic or cause long-term symptoms, including malnourishment in children. Low larval output can limit the sensitivity of detection in stool, with serology being effective but less sensitive in immunocompromise. Host immunosuppression can trigger catastrophic, fatal hyperinfection/dissemination, where large numbers of larvae pierce the bowel wall and disseminate throughout the organs. Stable disease is effectively treated by single-dose ivermectin, with disease in immunocompromised patients treated with multiple doses. Strategies for management include raising awareness, clarifying zoonotic potential, the development and use of effective diagnostic tests for epidemiological studies and individual diagnosis, and the implementation of treatment programs with research into therapeutic alternatives and medication safety.

Intestinal helminths—an outlander in a case of protein losing enteropathy

Malabsorption is the major disease burden in tropical countries. Both primary and secondary forms exist and a secondary form overshadows the primary category. Intestinal parasitic infections lead to secondary form of tropical malabsorption in both native and travelers and presentation varies from mild glossitis to severe protein losing enteropathy. The underlying condition is often masked unless an endoscopic biopsy is performed. This is followed by a histopathological examination which unravels the etiology.

Strongyloides stercoralis hyperinfection presenting with shock and intermittent eosinophilia: A case report

RATIONALE

Strongyloidiasis is a parasitic disease caused by Strongyloides stercoralis. The clinical presentation varies according to the stage of infection. Diagnosing strongyloidiasis is a challenge in clinical practice due to the inconsistency of eosinophilia and the low sensitivity of standard microscopic stool examination. Strongyloides infection presenting with shock is rare.

PATIENT CONCERNS

In this case, the condition of a 77-year-old immunocompromised patient with intermittent diarrhea progressed to shock and hypoalbuminemia. Reviewing her medical records, we learned that she had experienced intermittent peripheral eosinophilia during the past 10 months. Although a series of examinations were done, the disease progressed and the diagnosis remained uncertain.

DIAGNOSIS

Using standard microscopic stool examination and gastroduodenscopy with biopsy, a diagnosis of strongyloidiasis was made.

INTERVENTIONS

After the diagnosis of strongyloidiasis was made, 2 courses of ivermectin were administered.

OUTCOMES

The patient recovered uneventfully after treatment and there is no recurrence of eosinophilia in 1 year follow-up.

LESSONS

This report provides a brief review of the current modalities used for diagnosing strongyloidiasis. It emphasizes the low sensitivity of microscopic examination, and highlights the role of gastroduodenoscopy in the diagnosis of strongyloidiasis. This report also assures that patients with strongyloidiasis have a good prognosis when they are treated timely and appropriately.

Strongyloides stercoralis in a dog litter: Evidence suggesting a transmammary transmission

Strongyloides stercoralis is a soil-transmitted helminth with an unusual life cycle, causing canine and human strongyloidiasis, mainly endemic in tropical and subtropical areas. Following percutaneous or oral transmission of infective third-stage larvae in the vertebrate host, the parasite can cause autoinfection, leading to life-long infection. At present, the transmammary transmission was only assessed in experimentally infested dogs. Here, we provide observational evidence of S. stercoralis transmammary transmission in puppies suckling from a truffle dog from Central Italy, from where its presence was neglected.

Mimics of Crohn's Disease

Crohn's disease is a chronic inflammatory disease that can affect any portion of the gastrointestinal tract. Associated symptoms can vary based on the severity of disease, extent of involvement, presence of extraintestinal manifestations, and development of complications. Diagnosis is based on a constellation of findings. Many diseases can mimic Crohn's disease and lead to diagnostic conundrums. These include entities associated with the gastrointestinal luminal tract, vascular disease, autoimmune processes, various infections, malignancies and complications, drug- or treatment-induced conditions, and genetic diseases. Careful consideration of possible causes is necessary to establish the correct diagnosis.

Histologic features of colonic infections

Background

The histopathologic diagnosis of infectious colitis remains relevant despite recent advances in microbiologic techniques.

Objective

This article aims to describe the histologic features of selected infectious diseases of the colon.

Materials and methods

Existing reports on histopathologic and clinical aspects of colonic infectious agents were reviewed.

Results

While histology alone may not be as sensitive as current microbiologic methods, tissue identification of infectious agents still plays an important role in patient care. Infectious colitis can have a variety of clinical manifestations, ranging from strongyloidiasis, which can cause a smoldering, subclinical infection for decades, to syphilis, which can clinically mimic cancer or inflammatory bowel disease. Therefore, the histopathologic identification of infection as the cause of a patient’s colitis has a considerable impact on treatment decisions. Morphologic overlap can occur between infection and other diseases, however. Moreover, some infections can elicit various tissue responses beyond acute colitis. Immunosuppressed patients may not mount an inflammatory response to pathogens such as cytomegalovirus or adenovirus. Sexually transmitted proctocolitis can cause plasma-cell-rich inflammation. Gastrointestinal histoplasmosis is more likely to cause diffuse histiocyte infiltration rather than the expected granuloma formation. In some cases, ancillary tests are useful, but equivocal results can cause diagnostic dilemmas.

Conclusion

Given the range with which colonic infectious disorders can manifest, pathologists should be aware of the typical features of infectious colitis, as well as findings beyond the classic morphologies.

Duodenal strongyloidiasis - Our 15-year histopathological experience at a tertiary gastrointestinal centre

In order to emphasise the importance of histopathology in the clinically unsuspected diagnosis of duodenal strongyloidiasis, we report six cases diagnosed on duodenal biopsies identified from the database over a period of 15 years, and clinical, endoscopic and histopathological findings were analysed retrospectively. Four were elderly males and the remainder young females. Only one patient had an underlying immunocompromised state. Three presented with cholestatic jaundice and simulated hepatobiliary malignancy. In all cases, endoscopy provided non-specific findings. Only one case showed a predominant eosinophilic infiltrate. Eggs, larvae and adult forms of strongyloides were seen in crypts and showed intense basophilic staining on HE stain. It is concluded that since mostly undetected clinically, duodenal biopsy serves as the first step in the diagnosis of strongyloidiasis. Hepatobiliary manifestations, though very infrequent, should raise the suspicion for strongyloidiasis and thus necessitate the need for duodenal biopsy.

Autochthonous Human and Canine Strongyloides stercoralis Infection in Europe: Report of a Human Case in An Italian Teen and Systematic Review of the Literature

Autochthonous human and canine strongyloidiasis is reported in Europe but is unclear whether the transmission of infection still occurs. We report a previously unpublished human case in an Italian teen and perform a systematic review of literature on autochthonous human and canine strongyloidiasis in Europe to investigate the current dynamic of transmission. Overall, 109 papers published after 1987 were included and one previously unpublished Italian case was added. Eighty case reports were retrieved and 42 of them (52.5%) had severe strongyloidiasis. Most cases were diagnosed in Spain, Italy and France. The median age was 58, the most represented age group was 61-70 years, 11 patients were under 30, and 7 of them were diagnosed after 2000. Epidemiological studies on human strongyloidiasis showed prevalence ranging from 0.56% to 28%. Overall, agriculture work, mine work and walking barefoot were the most commonly reported risk factors for infection. Canine strongyloidiasis was reported mainly in Italy (68 cases), but a few cases occurred also in Iceland, Finland, England, Germany, France, Switzerland, Russia, Slovakia, Romania and Greece. Autochthonous strongyloidiasis is still reported in Europe and sporadic transmission still occurs. Health care professionals should be aware of this issue to identify infected subjects and avoid adverse outcomes, especially in immunosuppressed patients. Further investigations are needed to clarify the zoonotic transmission of this nematode.

Strongyloidiasis: A Neglected Tropical Disease

Most of the 30 to 100 million people infected with Strongyloides stercoralis have subclinical (or asymptomatic) infections. These infections are commonly chronic and longstanding. A change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. The use of corticosteroids and HTLV-1 infection are most commonly associated with the hyperinfection syndrome. Strongyloides adult parasites reside in the small intestine and induce immune responses that are like other nematodes. Definitive diagnosis of S stercoralis infection is based on stool examinations for larvae. S stercoralis remains largely neglected.

Pathologic Features of Infectious Gastritis

This manuscript presents a review of infectious causes of gastritis aimed at the practicing anatomic pathologist. We shall highlight unique histologic findings and clinical attributes that will assist those analyzing endoscopically obtained mucosal biopsies of the stomach or resection specimens.

Acid-Suppressive Therapy and Risk of Infections: Pros and Cons

This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.

Mucosal Biopsy After Bone Marrow Transplantation

Gastrointestinal mucosal biopsies in the hematopoietic stem cell transplantation setting are challenging because histologic features of graft-versus-host disease (GVHD), which is treated by increasing immunosuppression, overlap with those of other conditions, such as infection, which can get worse with GVHD treatment. More than one condition can occur at the same time. It is important to understand the histologic features of GVHD, drug toxicity, infection, and clinical factors surrounding patients, including timing of biopsy in relation to transplantation, medication history, and laboratory data. Rendering a correct diagnosis and generating a pathology report with standard language that can direct clinical management ensure proper management.

Colorectal Cancer Associated with Strongyloides stercoralis Colitis

Strongyloides stercoralis colitis is a severe but easily curable disease with a high mortality rate if left untreated. Strongyloidiasis can persist up to several decades and may lead to a chronic colitis similar to that seen in inflammatory bowel disease (IBD), and the two are often confused. Chronic colitis from IBD is associated with an increased risk of colorectal cancer, so it is plausible that chronic colitis from strongyloidiasis may carry a similar risk. Our case report associates chronic Strongyloides colitis and colorectal cancer.

Human infection with Strongyloides stercoralis and other related Strongyloides species

The majority of the 30-100 million people infected with Strongyloides stercoralis, a soil transmitted intestinal nematode, have subclinical (or asymptomatic) infections. These infections are commonly chronic and longstanding because of the autoinfective process associated with its unique life cycle. A change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. Corticosteroid use and HTLV-1 infection are most commonly associated with the hyperinfection syndrome. Strongyloides adult parasites reside in the small intestine and induce immune responses both local and systemic that remain poorly characterized. Definitive diagnosis of S. stercoralis infection is based on stool examinations for larvae, but newer diagnostics - including new immunoassays and molecular tests - will assume primacy in the next few years. Although good treatment options exist for infection and control of this infection might be possible, S. stercoralis remains largely neglected.

Strongyloidiasis with emphasis on human infections and its different clinical forms

Strongyloidiasis (caused by Strongyloides stercoralis, and to a lesser extent by Strongyloides fuelleborni) is one of the most neglected tropical diseases with endemic areas and affecting more than 100 million people worldwide. Chronic infections in endemic areas can be maintained for decades through the autoinfective cycle with the L3 filariform larvae. In these endemic areas, misdiagnosis, inadequate treatment and the facilitation of the hyperinfection syndrome by immunosuppression are frequent and contribute to a high mortality rate. Despite the serious health impact of strongyloidiasis, it is a neglected disease and very little is known about this parasite and the disease when compared to other helminth infections. Control of the disease is difficult because of the many gaps in our knowledge of strongyloidiasis. We examine the recent literature on different aspects of strongyloidiasis with emphasis in those aspects that need further research.

The laboratory diagnosis and follow up of strongyloidiasis: a systematic review

BACKGROUND

Strongyloidiasis is frequently under diagnosed since many infections remain asymptomatic and conventional diagnostic tests based on parasitological examination are not sufficiently sensitive. Serology is useful but is still only available in reference laboratories. The need for improved diagnostic tests in terms of sensitivity and specificity is clear, particularly in immunocompromised patients or candidates to immunosuppressive treatments. This review aims to evaluate both conventional and novel techniques for the diagnosis of strongyloidiasis as well as available cure markers for this parasitic infection.

METHODOLOGY/PRINCIPAL FINDINGS

The search strategy was based on the data-base sources MEDLINE, Cochrane Library Register for systematic review, EmBase, Global Health and LILACS and was limited in the search string to articles published from 1960 to August 2012 and to English, Spanish, French, Portuguese and German languages. Case reports, case series and animal studies were excluded. 2003 potentially relevant citations were selected for retrieval, of which 1649 were selected for review of the abstract. 143 were eligible for final inclusion.

CONCLUSIONS

Sensitivity of microscopic-based techniques is not good enough, particularly in chronic infections. Furthermore, techniques such as Baermann or agar plate culture are cumbersome and time-consuming and several specimens should be collected on different days to improve the detection rate. Serology is a useful tool but it might overestimate the prevalence of disease due to cross-reactivity with other nematode infections and its difficulty distinguishing recent from past (and cured) infections. To evaluate treatment efficacy is still a major concern because direct parasitological methods might overestimate it and the serology has not yet been well evaluated; even if there is a decline in antibody titres after treatment, it is slow and it needs to be done at 6 to 12 months after treatment which can cause a substantial loss to follow-up in a clinical trial.

Human and animal dirofilariasis: the emergence of a zoonotic mosaic

Dirofilariasis represents a zoonotic mosaic, which includes two main filarial species (Dirofilaria immitis and D. repens) that have adapted to canine, feline, and human hosts with distinct biological and clinical implications. At the same time, both D. immitis and D. repens are themselves hosts to symbiotic bacteria of the genus Wolbachia, the study of which has resulted in a profound shift in the understanding of filarial biology, the mechanisms of the pathologies that they produce in their hosts, and issues related to dirofilariasis treatment. Moreover, because dirofilariasis is a vector-borne transmitted disease, their distribution and infection rates have undergone significant modifications influenced by global climate change. Despite advances in our knowledge of D. immitis and D. repens and the pathologies that they inflict on different hosts, there are still many unknown aspects of dirofilariasis. This review is focused on human and animal dirofilariasis, including the basic morphology, biology, protein composition, and metabolism of Dirofilaria species; the climate and human behavioral factors that influence distribution dynamics; the disease pathology; the host-parasite relationship; the mechanisms involved in parasite survival; the immune response and pathogenesis; and the clinical management of human and animal infections.

Clinical, endoscopic and histopathological profiles of parasitic duodenitis cases diagnosed by upper digestive endoscopy

CONTEXT

Intestinal parasites induce detectable histopathological changes, which have been studied in groups with known diagnosis of parasitic disease. There is no available study with a larger base without previous diagnosis.

OBJECTIVE

To describe clinical and histopathological findings of parasitosis diagnosed by endoscopic biopsy in patients submitted to upper digestive endoscopy.

METHODS

Recorded biopsies archive at "Complexo Hospitalar Professor Edgar Santos" , a general teaching Hospital in the state of Bahia, Northeast Brazil, from January 1995 to January 2009, were reviewed. One thousand ten duodenal biopsy reports were found. Reports positive for parasites had their specimens reviewed and photographed. All blocks of biopsy selected as case were retrieved and reviewed by an experienced pathologist. Clinical, laboratorial and endoscopic data were collected.

RESULTS

Eleven biopsies showed parasites, including cases of Cryptosporidium sp. and Strongyloides stercoralis. Vomiting (91%), abdominal pain (78%), diarrhea (78%) and weight loss (78%) were usual symptoms. Seventy-five percent had duodenal mucosa changes on endoscopy, while 25% have no changes. Anemia and low serum albumin were important laboratorial data. HIV infection association was observed. Villus atrophy and reactive epithelium were usual in Strongyloides cases.

CONCLUSIONS

No endoscopic or histopathologic finding was pathognomonic. One percent of duodenal endoscopic biopsies showed parasites.

Histopathologic diagnosis of eosinophilic conditions in the gastrointestinal tract

Eosinophils, a constitutive component of the columnar-lined gastrointestinal tract, play an essential role in allergic responses and parasitic infections. The tissue density of these cells also increases in a variety of conditions of uncertain etiology. With the exception of the esophageal squamous epithelium, in which no eosinophils are normally present, the population of normal eosinophils in the remainder of the luminal gut is poorly defined. Therefore, histopathologists must rely on their subjective judgment to determine when a diagnosis of eosinophilic gastritis, enteritis, or colitis should be rendered. Eosinophilic esophagitis is currently the best defined and most studied eosinophilic condition of the digestive tract; therefore, the confidence in accurate diagnosis is increasing. In contrast, the characteristic clinicopathologic features of eosinophilic conditions affecting other parts of the digestive tract remain somewhat elusive. This review was designed to present pathologists with simple and practical information for the biopsy-based histopathologic diagnosis of eosinophilic esophagitis, gastritis, enteritis, and colitis. It was prepared by critically reviewing more than 200 articles on the topic, along with incorporating evidence accumulated through our own collective experience. We anticipate that by increasing pathologists' confidence in reporting these abnormal but often nameless eosinophilic infiltrates, we can help better define and characterize their significance.

Eosinophilic gastritis: histopathological characterization and quantification of the normal gastric eosinophil content

There is limited information about normal eosinophil counts in the gastric mucosa. The purpose of this study was to evaluate the histopathology of 60 patients whose biopsies showed increased eosinophils in the gastric mucosa. We also investigated the eosinophil content in gastric biopsies from normal controls (matched for age, sex, and zip code), from patients with Helicobacter pylori gastritis, and patients with Crohn's disease. Eosinophils were counted in five random high-power fields (HPFs) and reported in eosinophils/mm(2). Involvement of the muscularis mucosae or submucosa, sheets of eosinophils, and infiltration of the gastric epithelium were also evaluated. The median eosinophil count in the study patients was 539 eosinophils/mm(2); mean±SD=653±418 eosinophils/mm(2); range 127-2108. Sheets of eosinophils were seen in 38 patients, 27 showed involvement of the muscularis mucosae or submucosa. There were 7 patients without epithelial infiltration by eosinophils, whereas 34 were tallied as rare and 19 were scored as abundant. No study patient had no evidence of H. pylori. The mean eosinophil count for the 135 normal controls was 15.5±16.8 SD eosinophils/mm(2) (range 0-110); in the 93 controls with H. pylori gastritis the mean eosinophil count was 25±32.6 SD eosinophils/mm(2) (range 0-219); and for the 53 controls with Crohn's disease it was 31.4±44.4 SD eosinophils/mm(2) (range 0-203). There were no significant differences between the counts in biopsies from the antrum and corpus, and no significant variations by age, geographic location, or season. This study confirms that, in the United States population, the normal gastric eosinophilic counts are usually <38 eosinophils/mm(2). We recommend 'histological eosinophilic gastritis' for the diagnosis of gastric biopsies that show an average density ≥127 eosinophils/mm(2) (or ≥30 eosinophils per HPF) in at least five HPFs in the absence of known associated causes of eosinophilia.

Strongyloides stercoralis infection in the immunocompromised host

Strongyloides stercoralis is an intestinal nematode acquired in the tropics or subtropics. Most often, it causes chronic, asymptomatic infection, but a change in immune status can increase parasite numbers, leading to hyperinfection syndrome, dissemination, and death if unrecognized. Corticosteroid use is most commonly associated with hyperinfection syndrome. Diagnosis of Strongyloides infection is based on serology and serial stool examinations for larvae. The treatment of choice for chronic, asymptomatic infection is oral ivermectin. Alternative pharmacologic agents include albendazole and thiabendazole. For hyperinfection syndrome, ivermectin remains the drug of choice, though therapy duration must be individualized with the end point being complete parasite eradication. Recurrent strongyloidiasis should prompt an evaluation for human T-cell lymphotropic virus type 1 coinfection. No test of cure is currently available, although immunoglobulin G antibody levels have been shown to decline within 6 months of successful treatment.

Respiratory infections in immunocompromised patients

PURPOSE OF REVIEW

Immunosuppressive states and therapies are becoming common in clinical practice. Recent advances and trends in bacterial, fungal, viral and parasitic pulmonary infections in immunosuppressed patients are described.

RECENT FINDINGS

Pulmonary infections can jeopardize the prognosis of immunosuppressed patients. The number of patients infected with multidrug-resistant bacteria or opportunistic pathogens like rapid-growing environmental mycobacteria, Strongyloides stercoralis or Rhodococcus equi is increasing with the increased numbers of immunosuppressed patients due to HIV/AIDS and the potent immunosuppressive therapies used in solid-organ and haematopoietic transplantations, cancer and systemic illnesses. The slow development of more effective antibiotics underlines the necessity of preventive measures, development of rapid detection tests for pathogens and appropriate treatment regimens to avoid development of further resistance.

SUMMARY

Adequate prophylaxis, clinical suspicion, microbiological and molecular investigations, drug susceptibility-based antibiotic treatment and new drug development are strategies required to face up to the challenge of pulmonary infections in immunodepressed patients.