Gastrointestinal complications in renal transplant recipients: MITOS study

Physical Exercise After Solid Organ Transplantation: A Cautionary Tale

An increasing body of randomized controlled trials suggests the safety of engaging in moderate to vigorous intensity exercise training following solid organ transplantation. Fueled by emerging sport events designed for transplant recipients and the ever-growing body of research highlighting the diverse health benefits of physical activity, transplant recipients are now increasingly participating in strenuous and occasionally competitive physical endeavors that largely surpass those evaluated in controlled research settings. This viewpoint article adopts a cautionary stance to counterbalance the prevalent one-sided optimistic perspective regarding posttransplant physical activity. While discussing methodological limitations, we explore plausible adverse impacts on the cardiovascular, immunological, and musculoskeletal systems. We also examine the physiological consequences of exercising in the heat, at high altitude, and in areas with high air pollution. Risks associated with employing performance-enhancing strategies and the conceivable psychological implications regarding physical activity as a tribute to the 'gift of life' are discussed. With a deliberate focus on the potential adverse outcomes of strenuous posttransplant physical activity, this viewpoint aims to restore a balanced dialogue on our comprehension of both beneficial and potentially detrimental outcomes of physical activity that ultimately underscores the imperative of well-informed decision-making and tailored exercise regimens in the realm of posttransplant care.

Gastrointestinal symptoms and endoscopy findings after pediatric solid organ transplantation: A case series

BACKGROUND

Gastrointestinal symptoms are common among solid organ transplant (SOT) recipients. Information about colonoscopy findings after pediatric SOT is limited. This retrospective study reports endoscopy findings in a nationwide pediatric transplant recipient cohort.

METHODS

All pediatric recipients (kidney, liver, or heart) transplanted between 2010 and 2020 at our institution (n = 193) who had undergone ileocolonoscopy and upper gastrointestinal endoscopy after SOT were enrolled. Sixteen patients were identified. A meticulous search on clinical data including transplantation, gastrointestinal symptoms, endoscopy findings, and follow-up data was performed.

RESULTS

Endoscopy was performed at a median of 2.6 years (0.4-13.3) after the first transplantation (median age at SOT 1.2 years). Gastrointestinal symptoms leading to endoscopy did not differ between the different transplant groups. The leading endoscopy indications were prolonged diarrhea and anemia. PTLD was found in 8 (50%) patients. Five were histologically early PTLD lesions and three were monomorphic large B-cell PTLDs (two EBV-positive and one EBV-negative), one having previously been diagnosed with autoimmune enteropathy. One patient had EBV enteritis. De novo inflammatory bowel disease was found in one patient, eosinophilic gastroenteritis in another, and in one patient with several episodes of watery diarrhea, the histological finding was mild non-specific colitis. In four patients, the endoscopy finding remained unclear and the symptoms were suspected to be caused by infectious agents or mycophenolate.

CONCLUSIONS

PTDL with various stages is a common finding after pediatric SOT in patients with gastrointestinal symptoms. Endoscopy should be considered in transplant recipients with prolonged diarrhea, anemia, and/or abdominal pain.

Resolution of Cryptosporidiosis in Transplant Recipients: Review of the Literature and Presentation of a Renal Transplant Patient Treated With Nitazoxanide, Azithromycin, and Rifaximin

Background

Cryptosporidium is a major cause of diarrheal disease worldwide, including chronic disease in malnourished children and patients with acquired immune deficiency syndrome. There are increasing reports of cryptosporidiosis in transplant patients, especially from middle-income countries.

Methods

The literature on treatment of cryptosporidiosis in transplant patients was reviewed and included no controlled trials but only small case series. Nitazoxanide, azithromycin, spiramycin, and combination therapies have been used, but none are consistently efficacious.

Results

We present a case of chronic diarrhea from cryptosporidiosis in a renal transplant patient. His illness resolved with decreasing immunosuppression and treatment with the 3-drug combination of nitazoxanide, azithromycin, and rifaximin.

Conclusions

Although current therapies are not reliably effective in the absence of an effective cellular immune response, combination therapies hold promise for improved responses.

Diarrhea in pediatric recipients of solid organ or bone marrow transplants

Diarrhea is common in adults after solid organ transplantation (SOT) and bone marrow transplantation (BMT), but data in children are limited. Therefore, we aimed to determine the incidence and etiology of pediatric early-onset diarrhea in post SOT and BMT.We reviewed children aged 6 months to 18 years who underwent liver transplantation, kidney transplantation or BMT between January 2015 and December 2019 with duration of diarrhea > 72 hours within the first 6 months after transplantation. Clinical data and diarrheal course were collected. Regression analyses were performed to define factors associated with the interested outcomes.Among 252 transplanted patients, 168 patients (66.6%) had 289 documented episodes of diarrhea. A diagnosis of 68.2% of post-transplant diarrhea remained 'indefinite'. Enteric infection in SOT and gastrointestinal acute graft-versus-host disease (GI-aGVHD) in BMT were the commonly identified etiologies. Among 182 episodes among BMT children, skin rash was more pronounced when compared the ones with diarrhea > 7 days vs ≤ 7 days (odds ratio [OR] 13.9; 95% CI 1.8, 107.6). Males were more likely to develop GI-aGVHD as compared to females (OR 8.9). We found that GI-aGVHD was more common in the ones with skin rash and the presence of white blood cells in stool examination (OR 8.4 and 3.1, respectively). Deaths occurred in 7.7%.Two-thirds of post-transplant children experienced at least one episode of early-onset diarrhea, of which the etiology mainly remains undefined. Various clinical factors of prolonged/chronic diarrhea and GI-aGVHD may help clinicians when managing these children.

Diarrhea in the pediatric solid organ transplantation recipient: A multidisciplinary approach to diagnosis and management

Diarrhea in the pediatric solid organ transplantation (SOT) recipient is a frequent complaint that is associated with significant morbidity and impaired quality of life. There are limited published data regarding the specific epidemiology, diagnostic evaluation, and treatment of diarrhea after SOT in children. Pediatric SOT recipients have an increased risk of developing diarrhea because of a generalized immunosuppressed state, epidemiologic exposures, and polypharmacy. There is a need to standardize the diagnostic evaluation of diarrhea in children after SOT to facilitate an accurate diagnosis and timely treatment. Herein, we review the available published data and propose a systematic, stepwise approach to the evaluation of diarrhea in this high-risk population, focusing on timely diagnosis of both infectious and non-infectious causes, in order to provide focused management. Prospective studies are needed to better assess the true prevalence, risk factors for, etiologies, and complications of diarrhea in pediatric SOT patients that will guide optimal management. Development of effective vaccines and antiviral therapies for enteric viruses may also contribute to improved outcomes.

Etiological profile of diarrhea in solid organ transplant recipients at a tertiary care center in Southern India

BACKGROUND

Diarrhea is one of the common gastrointestinal (GI) adverse events after solid organ transplantation. Diarrhea may be caused by infectious or non-infectious etiology. The infectious etiology of diarrhea varies according to the location and duration of diarrhea. Non-infectious etiologies include drugs, inflammatory bowel disease, neoplasia. The objective of this study was to evaluate the etiological profile of diarrhea in solid organ transplant recipients presenting to a tertiary care center in Southern India.

METHODS

This was a retrospective analysis of prospectively collected data of all solid organ transplantation recipients referred to the Department of Medical Gastroenterology for evaluation of diarrhea from April 2012 till May 2014. All patients had stool evaluated by wet mount examination, modified acid fast (AFB) stain, trichrome stain, culture, and Clostridium difficile toxin assay. EDTA plasma was collected for quantitative Cytomegalovirus (CMV) detection by real-time PCR. If the diarrhea was acute (<2 wk), and no etiological agent was identified, empirical antibiotic therapy was instituted and followed up. If persistent or chronic diarrhea (>2-4 wk), endoscopic evaluation (upper GI endoscopy and/or colonoscopy with biopsies), depending on the clinical type of diarrhea was done. If no specific etiological diagnosis was established after endoscopic evaluation, breath test for SIBO and celiac serology were done. If no specific etiology was identified after the above investigations, dose of immunosuppressive drugs was reduced. If diarrhea responded to dose reduction, it was considered to be drug related.

RESULTS

Fifty-eight episodes of diarrhea occurred in 55 solid organ transplant recipients during the study period. Renal transplant recipients constituted the majority (70%). Most (79%) of patients included in the study had their transplant > 6 mo ago. Infective diarrhea was the etiology in 46%, drug-related diarrhea in 29.3%. No specific etiology was identified in 22.4% of patients. Parasites accounted for 69% of all infective diarrhea. Stool evaluation was the main investigation in establishing diagnosis in acute diarrhea. Endoscopic evaluation was required in two thirds of patients to establish diagnosis in chronic diarrhea.

CONCLUSION

GI infections and drug-related diarrhea were the common causes of diarrhea in solid organ transplant recipients. Parasites were the most common infectious etiology of diarrhea. Step-wise evaluation was able to identify the etiology in ~ 77% of patients. Overall, 98% of diarrheal episodes resolved.

Etiological Spectrum of Infective Diarrhea in Renal Transplant Patient by Stool PCR: An Indian Perspective

Introduction:

Diarrhea is a common cause of morbidity and mortality among renal transplant patients. The etiological spectrum of pathogens varies with regional diversity, socioeconomic conditions, sanitation, and eating habits. We aimed to delineate the etiological profile of gastrointestinal pathogens in renal transplant patients using the stool Polymerase chain reaction.

Methods:

In this single-center, retrospective analysis of patients from January 2016 to January 2018, all renal transplant patients who were admitted with severe diarrhea and underwent the stool Polymerase chain reaction (PCR) were included. In the control group, we included patients from the general population who were admitted with similar complaints in the general medicine ward and underwent stool PCR over the same duration.

Results:

One hundred ten admissions occurred over 2 years in the transplant group. 86% of samples were positive for infection. More than one organism was seen in 68% of the patient. Norovirus was the most common organism isolated. Giardia lamblia with Norovirus was the most common coinfection among the transplant population. In the control group, 87% of samples tested positive, with 53% of patients having more than one organism. Enteroaggregative E. coli was the common organism, Enteroaggregative E. coli with Enteropathogenic E. coli and Enterotoxigenic E. coli were the most common organism in combination. Both the groups had similar incidence of infection with multiple organisms.

Conclusion:

The etiological profile of gastrointestinal pathogens differs significantly between the transplant and general population. Coinfections are common in both populations. Norovirus is the most common pathogen in the transplant population, presenting as isolated as well as in coinfections.

Patient-Reported Gastrointestinal Symptoms and the Association With Quality of Life Following Kidney Transplantation

Background

There has been limited study of the prevalence of gastrointestinal symptoms and their impact on the quality of life (QOL) in kidney transplant recipients. The aim of this study was to examine the prevalence and predictors of gastrointestinal symptoms and the association with QOL in kidney transplant recipients.

Methods

All chronic kidney transplant recipients at the Princess Alexandra Hospital were provided with 3 questionnaires, the Gastrointestinal Quality of Life Index (GIQLI), the Gastrointestinal Symptoms Rating Scale (GSRS), and Structured Assessment of Gastrointestinal Symptoms (SAGIS) scale, to ascertain QOL impairment and to screen gastrointestinal symptom severity. Linear regression was used to determine the predictors of gastrointestinal QOL and gastrointestinal symptom severity.

Results

Of the 343 participants, the median age was 47 (interquartile range [IQR] 36–55) years, 58% were men, 79% were white, 39% had chronic glomerulonephritis, 83% had received their first graft, and median time since transplant was 6.3 (IQR 1.8–13.1) years. Using GSRS, 88% of participants reported at least 1 gastrointestinal symptom, most commonly indigestion (57%) and diarrhea (54%). Using GIQLI, 42% and 38% of participants reported mild and moderate QOL impairment, respectively. Gastrointestinal symptoms were predicted by female sex (coefficient −0.11, 95% CI −0.21 to −0.02) and mycophenolate (coefficient 0.0001, 95% CI 0.0001 to 0.0002), and were associated with poorer QOL (coefficient −0.38, 95% CI −0.45 to −0.30). Similar findings were observed using SAGIS for gastrointestinal symptoms.

Conclusions

Gastrointestinal symptoms are frequent in kidney transplant recipients, particularly in women and those receiving mycophenolate, and are strongly associated with poorer QOL.

Feasibility and Comparison Study of Fecal Sample Collection Methods in Healthy Volunteers and Solid Organ Transplant Recipients Using 16S rRNA and Metagenomics Approaches

The human microbiome encompasses a variety of microorganisms that change dynamically and are in close contact with the body. The microbiome influences health and homeostasis, as well as the immune system, and any significant change in this equilibrium (dysbiosis) triggers both acute and chronic health conditions. Microbiome research has surged, in part, due to advanced sequencing technologies enabling rapid, accurate, and cost-effective identification of the microbiome. A major prerequisite for stool sample collection to study the gut microbiome in longitudinal prospective studies requires standardized protocols that can be easily replicated. However, there are still significant bottlenecks to stool specimen collection that contribute to low patient retention rates in microbiome studies. These barriers are further exacerbated in solid organ transplant recipients where diarrhea is estimated to occur in up to half the patient population. We sought to test two relatively easy sample collection methods (fecal swab and wipes) and compare them to the more cumbersome "gold" standard collection method (scoop) using two different sequencing technologies (16S ribosomal RNA sequencing and shotgun metagenomics). Our comparison of the collection methods shows that both the swabs and the wipes are comparable to the scoop method in terms of bacterial abundance and diversity. The swabs, however, were closer in representation to the scoop and were easier to collect and process compared to the wipes. Potential contamination of the swab and the wipe samples by abundant skin commensals was low in our analysis. Comparison of the two sequencing technologies showed that they were complementary, and that 16S sequencing provided enough coverage to detect and differentiate between bacterial species identified in the collected samples. Our pilot study demonstrates that alternative collection methods for stool sampling are a viable option in clinical applications, such as organ transplant studies. The use of these methods may result in better patient retention recruitment rates in serial microbiome studies.

Newer approaches in diagnosis of diarrhea in immunocompromised patients

PURPOSE OF REVIEW

This review will focus on the epidemiology and cause of diarrheal illness in solid organ transplant and stem-cell transplant population recipients with a specific focus on the role of advanced multiplex technology in the diagnosis of diarrhea within this patient population.

RECENT FINDINGS

A wide range of infectious and noninfectious causes of diarrhea have been described in immunocompromised patients. The most common infections noted are Clostridioides difficile, norovirus, and cytomegalovirus, whereas immunosuppressive drugs and mucositis are the most common noninfectious causes of diarrhea. Historically, diagnostic evaluation has been limited to an array of single pathogen assays. Newer multiplex assays have become available that allow rapid, sensitive detection of a wide range of pathogens in a single assay. These assays have improved the number of patients with a diagnosed pathogen but may identify colonizing pathogens that are not pathogenic. Studies are needed to inform the discrimination and optimal use of these newer assays.

SUMMARY

Diarrhea is a common complication in immunocompromised patients and is associated with greater morbidity and rare mortality. New diagnostics facilitate detection of recognized pathogens and may allow for improved outcomes through the use of pathogen-targeted therapy.

Diagnosis and management of diarrhea in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of diarrhea in the pre- and post-transplant period. Diarrhea in an organ transplant recipient may result in significant morbidity including dehydration, increased toxicity of medications, and rejection. Transplant recipients are affected by a wide range of etiologies of diarrhea with the most common causes being Clostridioides (formerly Clostridium) difficile infection, cytomegalovirus, and norovirus. Other bacterial, viral, and parasitic causes can result in diarrhea but are far less common. Further, noninfectious causes including medication toxicity, inflammatory bowel disease, post-transplant lymphoproliferative disease, and malignancy can also result in diarrhea in the transplant population. Management of diarrhea in this population is directed at the cause of the diarrhea, instituting therapy where appropriate and maintaining proper hydration. Identification of the cause to the diarrhea needs to be timely and focused.

Prevalence of rotavirus and human bocavirus in immunosuppressed individuals after renal transplantation in the Northern Region of Brazil

Immunosuppressive therapy causes severe impairment of host defense and diarrhea is a frequent complication in renal transplant recipients. This study aimed to describe the occurrence of Rotavirus A (RVA) and Human Bocavirus (HBoV) in fecal samples of immunosuppressed patients submitted to renal transplantation during posttransplant follow-up. A longitudinal study was carried out involving a 25-patient cohort, selected for kidney transplantation. A total of 126 fecal samples were collected between May 2014 and May 2016. Molecular techniques were used to detect and characterize circulating RVA and HBoV genotypes and statistical analysis were applied to verify the association between epidemiological and clinical characteristics. The prevalence of RVA and HBoV was 24% (6/25) and 40% (10/25), respectively. Among RVA and HBoV positive cases, the majority was female; did not conduct water treatment nor had adequate sewage facilities. The most detected genotypes were RVA G3 (62.5%) and HBoV-3 (95%). Phylogenetic analysis of HBoV strains indicated that studied samples were similar to those found in Asian and American countries. The present study point out the circulation of these viral agents among immunosuppressed individuals and these findings will enable the construction of new knowledge and care perspectives on the cause of diarrhea in this population.

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.

Decline in prevalence and risk of helicobacter pylori in kidney transplant recipients: A systematic review and meta-analysis

OBJECTIVE

The study's aims were (1) to investigate the prevalence and (2) to assess the risk of Helicobacter pylori (H. pylori) infection in kidney transplant recipients.

METHODS

A comprehensive literature search was performed from inception until September 2016. Studies that reported prevalence, relative risks, odd ratios, or hazard ratios of H. pylori among kidney transplant recipients were included. Pooled risk ratios and 95% CI were calculated using a random-effect model.

RESULTS

Eleven observational studies with 2545 kidney transplant recipients were enrolled. Between year 1990 and 2000, the estimated prevalence of H. pylori among people with kidney transplant was 50% (95% CI: 31% to 68%), with a prevalence of 46% (95% CI: 23% to 70%) in high-income countries and 55% (95% CI: 22% to 86%) in middle-income countries, respectively. From year 2000 to 2016, the estimated prevalence of H. pylori among people with kidney transplant was 35% (95% CI: 26% to 45%), with a prevalence of 28% (95% CI: 19% to 37%) in high-income countries and 45% (95% CI: 38% to 51%) in middle-income countries. Data regarding prevalence of H. pylori infection in low-income countries were limited. The pooled RR of H. pylori in kidney transplant recipients was 0.57 (95% CI: 0.33 to 1.00) when compared to people with non-transplant.

CONCLUSIONS

There has been a decline in prevalence of H. pylori in kidney transplant recipients with the overall estimated prevalence of H. pylori in kidney transplant recipients of 35%, particularly in both high-income and middle-income countries. Also, our meta-analysis demonstrates a potential decreased risk of H. pylori infection in kidney transplant recipients compared with non-transplant populations.

Adverse symptoms of immunosuppressants: A survey of Canadian transplant clinicians

Adverse symptoms of immunosuppressants (ASI) impact quality of life (QOL) in solid organ transplant recipients; however, standardized approaches for active ASI surveillance and intervention are lacking. While management is highly clinician dependent, clinician views remain largely unexplored. We surveyed Canadian Society of Transplantation members on their perceptions of ASI including frequency, perceived QOL impact, causal attribution, management strategies, and success. Sixty-one clinicians participated in the survey of 12 ASI (tremor, diarrhea, nausea, constipation, dyspepsia, insomnia, edema, dyspnea, arthralgia, acne, mouth sores, paresthesias), for a 22% response rate. Forty-nine completed the survey (80% completion rate). Diarrhea, dyspepsia, and insomnia were most frequent, requiring management in ≥ 2% of patients by 96%, 90%, and 82% of respondents, respectively. Diarrhea, insomnia, and dyspnea were deemed to have an important QOL impact by 92%, 82%, and 69%. Immunosuppressants were universally implicated as causative of tremor, diarrhea, acne, and mouth sores. Over 80% reported success in managing mouth sores, dyspepsia, and constipation. Management strategies included adjustment of immunosuppressant or other medications, drug therapy, and nonpharmacologic approaches and varied according to perceived causal attribution. More study is needed to compare clinician and patient views. These results will be used to establish priorities for further investigation of ASI.

Intestinal infection at onset of mycophenolic acid-associated chronic diarrhea in kidney transplant recipients

BACKGROUND

Chronic diarrhea after kidney transplantation is often attributed to mycophenolic acid (MPA) toxicity. We hypothesize that intestinal infections contribute to the pathogenesis of chronic MPA-associated diarrhea.

METHODS

In this retrospective study, all patients (n = 726) receiving a kidney transplant between 2000 and 2010 at the University Hospital Zurich were followed until July 2014 for occurrence of chronic diarrhea (≥4 weeks). Infectious triggers at diarrhea onset were assessed by reviewing medical history, stool microbiology, and histology of colon biopsies.

RESULTS

In 46 patients (6.3% of the cohort), a total of 51 episodes of chronic diarrhea during MPA treatment were documented. The diarrhea episodes were often severe, as confirmed by significant weight loss. The cumulative incidence of chronic diarrhea was uniformly distributed throughout the post-transplant period, with 2.0%, 5.1%, and 9.6% at 1, 5, and 10 years, respectively. Evidence was found for intestinal infection at diarrhea onset in 38 episodes (74.5%). Occurrence of diarrhea onset showed a seasonal distribution with peaks in April and October/November. Specific antimicrobial treatment alone was associated with a 19% resolution rate only, whereas combination with dose reduction of MPA or switch from mycophenolate mofetil to enteric-coated mycophenolate sodium resulted in a 22.7% and 76.5% resolution rate, respectively. Change to an MPA-free regimen was associated with a 100% resolution rate.

CONCLUSION

These results provide first evidence for a contribution of intestinal infections in chronic post-transplant diarrhea associated with MPA treatment.

Routine prophylaxis with proton pump inhibitors and post-transplant complications in kidney transplant recipients undergoing early corticosteroid withdrawal

Surgical stress, corticosteroids, and mycophenolate may contribute to gastrointestinal ulcers/bleeding after kidney transplantation. Prophylactic acid suppression with H2RAs or PPIs is often utilized after transplantation, although unclear if truly indicated after early corticosteroid withdrawal (CSWD). PPIs have been associated with increased risks of Clostridium difficile infection (CDI), pneumonia, and acute rejection. This retrospective cohort study investigated benefits and risks of prolonged PPI use following kidney transplantation and included 286 kidney recipients undergoing CSWD within five d of transplant who were maintained on tacrolimus and mycophenolate mofetil/sodium. Patients on PPI before transplant, H2RA before/after transplant, and/or those with pre-transplant GI complications were excluded. A total of 171 patients received PPI>30 d, mean duration 287 ± 120 d (PPI group); 115 patients were not maintained on acid suppression (No-PPI group). GI ulceration and bleeding events were rare in PPI group (1.2% and 2.3%, respectively) and not observed in No-PPI group (p = NS). The incidence of infectious or hematological complications was not significantly different between groups. The PPI group experienced more biopsy-proven acute rejection (9.4% vs. 2.6%, p = 0.03). No direct benefit was observed with PPI in reducing the incidence of GI ulcers and bleeding events in kidney transplant recipients undergoing early CSWD. Further studies are needed to investigate the association of PPI and acute rejection.

Diarrhea in solid organ transplant recipients

PURPOSE OF REVIEW

Diarrhea is a common complaint in the solid organ transplant recipient. Unlike the immune-competent patient, diarrhea in an organ transplant recipient may result in dehydration, increased toxicity of medications, and rejection. There is a wide range of causes for diarrhea in transplant recipients, but the most common causes are Clostridium difficile infection, cytomegalovirus, and norovirus. This review will focus on new epidemiology data as to the cause of diarrhea in the transplant population.

RECENT FINDINGS

Recent data have identified C. difficile, cytomegalovirus, and norovirus as important causes of diarrhea in this population, and management should be focused on these causes. Newer diagnostic platforms (such as PCR) are being evaluated, which may help in identification of the cause of diarrhea.

SUMMARY

New epidemiologic data and new testing techniques offer an opportunity for research into better testing strategies for transplant patients with diarrhea. These newer testing strategies may offer better insight into the cause of diarrhea and more appropriate treatment for this illness.

Cryptosporidium infection after renal transplantation in an endemic area

BACKGROUND

Cryptosporidium is one of the common causes of infective diarrhea in post-transplant patients in endemic areas. However, data are limited on Cryptosporidium infection in recipients of solid organ transplantation. The aim of this study was to determine the incidence, disease manifestation, management, and outcome of Cryptosporidium infection in living-donor renal transplant recipients (RTR).

METHODS

We performed a detailed retrospective review of the data on all RTR who had diarrheal illness requiring evaluation and hospitalization, and Cryptosporidium infection.

RESULTS

During the study period, 119/1235 (8.98%) RTR developed diarrhea, and Cryptosporidium was found in 34/119 (28.5%). Nine of 680 (1.3%) patients were on a cyclosporine (CSA)-based regimen, and 25/643 (3.8%) patients were on a tacrolimus (Tac)-based regimen. The relative risk of developing Cryptosporidium infection was lower on the CSA-based regimen, compared with the Tac-based regimen (odds ratio [OR]: 0.35, 95% confidence interval [CI]: 0.17-0.72, P = 0.003). Twelve of the 34 patients had acute graft dysfunction, mainly caused by combined Tac toxicity and dehydration. Mean serum creatinine and trough Tac level were 2.04 ± 0.65 mg/dL and 8.24 ± 1.19 ng/dL, respectively. Nitazoxanide alone was used in 13 patients, and nitazoxanide in combination with fluoroquinolone in 21 patients, with duration of treatment ranging from 16 to 60 days. Tac was changed to CSA in 8/11 patients. The clearance of cysts and response to nitazoxanide alone were significantly lower, compared with combination therapy (61.53% vs. 95.23%, P = 0.01, 38.46 vs. 85.71%, P = 0.004, respectively). The OR for cyst clearance and response was also significantly lower with nitazoxanide alone, in comparison with combination therapy (OR: 0.65, 95% CI: 0.34-0.92, P = 0.01, OR: 0.45, 95% CI: 0.21-0.81, respectively). Four (16%) of 24 patients with response had relapse.

CONCLUSION

Patients with Tac and mycophenolate mofetil combination therapy had a significantly high risk of Cryptosporidium infection. Cryptosporidial infection may require prolonged nitazoxanide therapy, either alone or in combination, with or without reduction in immunosuppression.

Diagnostic yields in solid organ transplant recipients admitted with diarrhea

BACKGROUND

Although diarrhea is a frequent complaint among solid organ transplant recipients, the contribution of infectious etiologies remains incompletely defined. We sought to define the etiologies of diarrhea and the yields of testing at our institution.

METHODS

We performed a retrospective analysis over an 18-month period of hospitalized solid organ transplant recipients. We stratified diarrhea by community onset vs hospital onset of diarrhea.

RESULTS

We identified 422 admissions (representing 314 unique patients) with community-onset diarrhea, and 112 admissions (representing 102 unique patients) with hospital-onset diarrhea. The majority of community- and hospital-onset diarrheal episodes had no identified etiology (60.9% and 75.9%, respectively; P = .03), yet were also self-limited (91% and 91%, respectively; P = .894). Thereafter, the most frequently encountered infectious etiologies were Clostridium difficile infection (13.3% and 11.8%, respectively), norovirus enteritis (8.2% and 3%), cytomegalovirus disease or colitis (6.3% and 2.7%), and bacterial enterocolitis (0.9% and 0%) (P = .03). In aggregate, these entities represented 93.7% and 90.5% of the identified infectious etiologies, respectively. Protozoan causes were rarely seen. Coinfection, or the simultaneous detection of ≥2 pathogens, occurred in 8 (1.9%) and 2 (1.8%) community- and hospital-onset diarrheal admissions, respectively (P = .99).

CONCLUSIONS

In solid organ transplant recipients who presented at our institution with diarrhea, approximately one-third had infectious etiologies identified, consisting predominantly of C. difficile, norovirus, cytomegalovirus, and bacterial enterocolitis. Other infectious etiologies were rare.

Outcomes of Clostridium difficile infection in recipients of solid abdominal organ transplants

Knowledge of outcomes of Clostridium difficile infection (CDI) in solid organ transplant (SOT) recipients is limited. To evaluate this population, we undertook a retrospective cohort study of all recipients of kidney and liver transplants diagnosed with CDI at a single center over 14 yr. Data pertaining to all episodes of CDI were collected. Multivariate analysis using logistic regression was performed to determine independent predictors of clinical cure. Overall, 170 patients developed 215 episodes of CDI. Among these patients, 162 episodes (75%) were cured, and in 103 episodes (48%), patients were cured within 14 d. In a multivariate analysis, lack of clinical cure at 14 d was predicted by recurrent episode (0.21, 95% CI 0.06-0.72, p = 0.0128), treatment with vancomycin (OR 0.27, 95% CI 0.1-0.74, p = 0.011), vasopressor support (OR 0.23, 95% CI 0.07-0.76, p = 0.0161), and CDI before the year 2004 (OR 0.44, 95% CI 0.2-0.98, p = 0.0446). The latter three factors are likely markers for severity of illness. In this cohort, 13 patients (8%) died during hospitalization, and 49 patients (29%) died within one yr. No deaths were attributed to CDI. Recurrent episode was a major predictor of treatment failure, suggesting that research into development of therapeutic options for recurrent disease is needed.

Diarrhea in solid-organ transplant recipients: a review of the evidence

OBJECTIVE

To provide a comprehensive review of the literature as it relates to diarrhea in solid organ transplant (SOT) recipients. In this article, we review the epidemiology, pathogenesis, clinical manifestations, diagnosis and management of diarrhea in SOT recipients and discuss recent advances and challenges.

METHODS

Two investigators conducted independent literature searches using PubMed, Web of Science, and Scopus until January 1st, 2013. All databases were searched using a combination of the terms diarrhea, solid organ transplant, SOT, transplant associated diarrhea, and transplant recipients. Articles that discussed diarrhea in SOT recipients were reviewed and relevant cross-references also read and evaluated for inclusion. Selection bias could be a possible limitation of the approach used in selecting or finding articles for this article.

FINDINGS

Post-transplant diarrhea is a common and distressing occurrence in patients, which can have significant deleterious effects on the clinical course and well-being of the organ recipient. A majority of cases are due to infectious and drug-related etiologies. However, various other etiologies including inflammatory bowel disease must be considered in the differential diagnosis. A step-wise, informed approach to post-transplant diarrhea will help the clinician achieve the best diagnostic yield. The use of diagnostic endoscopy should be preceded by exclusion of an infectious or drug-related cause of diarrhea. Empiric management with antidiarrheal agents, probiotics, and lactose-free diets may have a role in managing patients for whom no cause can be determined even after an extensive investigation.

CONCLUSIONS

Physicians should be familiar with the common etiologies that result in post-transplant diarrhea. A directed approach to diagnosis and treatment will not only help to resolve the diarrhea but also prevent potentially life-threatening consequences including loss of the graft as well. Prospective studies are required to determine the etiology of post-transplant diarrhea in different clinical and geographic settings.

Microbiological diagnosis of severe diarrhea in kidney transplant recipients by use of multiplex PCR assays

Diarrhea is a frequent complication after kidney transplantation, ascribed to adverse effects of the immunosuppressive therapy in case of negative microbiological examination of the stools. The aim of this study was to improve the microbiological diagnosis by implementing molecular tests. Fifty-four severe diarrhea events that occurred in 49 adult kidney transplant recipients from September 2010 to November 2011 were investigated. One or several enteric pathogens were detected in 13 (23%) stool samples using classical microbiological methods versus 39 (72%) for the seven commercially available multiplex PCR assays used retrospectively (P = 0.006). Interestingly, molecular diagnosis identified 15 multiple infections compared to none using classical techniques. The primary pathogens detected were enteropathogenic Escherichia coli (EPEC) (n = 15; 38%), Campylobacter spp. (n = 15; 38%), and Norovirus (n = 14; 36%). Specificities for Campylobacter and Norovirus infection diagnosis were 75 and 100%, respectively, by comparison to reference methods. Based on molecular findings, a cyclosporine-mycophenolate mofetil combination was identified as a risk factor for developing Norovirus-induced diarrhea. Norovirus infections were also responsible for higher weight loss than all the other causes of diarrhea. In samples from asymptomatic immunocompromised and immunocompetent patients, EPEC but not Norovirus and Campylobacter infections were detected at a frequency similar to that observed in symptomatic kidney transplant recipients. In conclusion, molecular tools significantly improved the detection of single and multiple enteric infections by comparison to classical techniques and could quickly become the key element in the management of severe acute diarrhea in transplant recipients.

Evaluation of potential interactions between mycophenolic acid derivatives and proton pump inhibitors

OBJECTIVE

To evaluate the incidence of gastrointestinal (GI) complications in solid organ transplant (SOT) recipients, impact of the complications on transplant outcomes, and the potential interactions between mycophenolic acid (MPA) derivatives and proton pump inhibitors (PPIs).

DATA SOURCES

An unrestricted literature search (1980-January 2012) was performed with MEDLINE and EMBASE using the following key words: drug-drug interaction, enteric-coated mycophenolic acid, GI complications, mycophenolate mofetil, solid organ transplant, and proton pump inhibitor, including individual agents within the class. Abstracts from scientific meetings were also evaluated. Additionally, reference citations from identified publications were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Relevant English-language, original research articles and review articles were evaluated if they focused on any of the topics identified in the search or included substantial content addressing GI complications in SOT recipients or drug interactions.

DATA SYNTHESIS

GI complications are frequent among SOT recipients, with some studies showing prevalence rates as high as 70%. Transplant outcomes among renal transplant recipients are significantly impacted by GI complications, especially in patients requiring immunosuppressant dosage reductions or premature discontinuation. To this end, PPI use among patients receiving transplants is common. Recent data demonstrate that PPIs significantly reduce the overall exposure to MPA after oral administration of mycophenolate mofetil. Similar studies show this interaction does not exist between PPIs and enteric-coated mycophenolic acid (EC-MPA). Unfortunately, most of the available data evaluating this interaction are pharmacokinetic analyses that do not investigate the clinical impact of this interaction.

CONCLUSIONS

A significant interaction exists between PPIs and mycophenolate mofetil secondary to reduced dissolution of mycophenolate mofetil in higher pH environments. EC-MPA is not absorbed in the stomach; therefore, low intragastric acidity does not impact EC-MPA and bioavailability is maintained with this formulation during PPI coadministration. The clinical impact of this interaction is unknown, yet one can theorize that reduced exposure to MPA in SOT recipients can increase the risk of allograft rejection and/or failure.

Early ileocolonoscopy with biopsy for the evaluation of persistent post-transplantation diarrhea

AIM: To investigate the significance of ileocolonoscopy with histology in the evaluation of post-transplantation persistent diarrhea (PD).

METHODS: We retrospectively reviewed all records of renal transplant patients with PD, over a 3-year period. All patients were referred for ileocolonoscopy with biopsy, following a negative initial diagnostic work up. Clinical and epidemiological data were compared between cases with infectious or drug-induced diarrhea.

RESULTS: We identified 30 episodes of PD in 23 renal transplant patients (1-3 cases per patient). There were 16 male patients and the mean age at the time of PD was 51.4 years. The average time from transplantation to a PD episode was 62.3 ± 53.2 mo (range 1-199 mo). Ileocolonoscopy detected mucosal abnormalities in 19 cases, whereas the intestinal mucosa appeared normal in 11 cases. Histological examination achieved a specific diagnosis in 19/30 cases (63.3%). In nine out of 11 cases (82%) with normal endoscopic appearance of the mucosa, histological examination of blinded biopsies provided a specific diagnosis. The etiology of PD was infectious in 11 cases (36.6%), drug-related in 10 (33.3%), of other causes in three (10%), and of unknown origin in six cases (20%). Infectious diarrhea occurred in significantly longer intervals from transplantation compared to drug-related PD (85.5 ± 47.6 mo vs 40.5 ± 44.8 mo, P < 0.05). Accordingly, PD due to drug-toxicity was rarely seen after the first year post-transplantation. Clinical improvement followed therapeutic intervention in 90% of cases. Modification of immunosuppressive regimen was avoided in 57% of patients.

CONCLUSION: Early ileocolonoscopy with biopsies from both affected and normal mucosa is an important adjunctive tool for the etiological diagnosis of PD in renal transplant patients.

Mycophenolate mofetil-related gastrointestinal mucosal injury in multivisceral transplantation

Mycophenolate mofetil (MMF) has become an important and commonly used drug for maintenance immunosuppression therapy in recipients of all types of organ transplants. The drug is an antimetabolite that blocks the de novo pathway of purine synthesis. Although it selectively inhibits B- and T-lymphocyte proliferation, enterocytes are partially susceptible to MMF. One of the main limitations of this drug is gastrointestinal toxicity, with diarrhea the most frequently reported adverse effect. Most studies of MMF-associated gastrointestinal toxicity have been performed in patients with solid-organ transplants, although no data on changes related to MMF toxicity in bowel allografts have been published in the English literature. We evaluated mucosal intestinal biopsy tissue from patients with multivisceral transplants receiving MMF therapy. Our objective was to find morphologic changes that might be attributed to MMF toxicity, as well as changes that could differentiate MMF toxicity from acute rejection. Examination of the surface epithelium, lamina propria, and crypts in this small group of patients showed no specific changes that could be associated with MMF toxicity. Changes such as graft-vs-host disease or inflammatory bowel disease described in previous studies of solid-organ transplantation were not observed. Larger studies and the use of special stains and new markers might be necessary to characterize possible patterns of MMF toxicity and their differences from acute rejection.

Gastrointestinal Symptoms in Kidney Transplant Recipients: What about Silent Sufferers?

Context

Transplantation improves health-related quality of life in patients with end-stage renal disease. However, primarily because of adverse effects of medication, among other gastrointestinal symptoms, health-related quality of life is not completely restored to normal. Although many patients have various gastrointestinal symptoms only a small proportion may be reported spontaneously.

Objective

To evaluate the prevalence of gastrointestinal symptoms in kidney transplant recipients, also the difference between spontaneously reported symptoms and symptoms elicited by specific questioning was assessed. The burden of these symptoms in daily life also was analyzed.

Design

A single-center, sequential, mixed method study to assess the difference between spontaneous patient reports of gastrointestinal symptoms and active screening by a questionnaire in kidney transplant patients.

Patients

In February 2008, patients received a questionnaire on gastrointestinal symptoms; notes in medical records were consulted for patients scoring less than 100. In June 2008, those patients received a second, extended questionnaire aimed to assess the burden of gastrointestinal symptoms in daily life.

Results

Ninety-two of 513 patients eventually proved to have gastrointestinal symptoms. Completed questionnaires were compared with notes in the patients' files of the past year. A total of 51 of these 92 patients appeared to have not mentioned their gastrointestinal symptoms during the outpatient clinic visits. Of these 51 patients, 37 reported a significant impact of gastrointestinal symptoms on daily life.

Conclusions

The silent sufferer exists. Specific questioning helps to improve communication concerning bothersome gastrointestinal symptoms. To assess the burden of these symptoms, a validated questionnaire should be developed.

Mycophenolate mofetil-related gastrointestinal mucosal injury: variable injury patterns, including graft-versus-host disease-like changes

Mycophenolate mofetil (MMF) is a commonly used immunosuppressive drug used in the management of transplant recipients. Although gastrointestinal (GI) toxicity is a known complication of MMF, the literature characterizing the pathologic features of MMF in the GI tract is sparse. This study characterizes the pathologic features of MMF toxicity in both the upper and lower GI tract, correlating it with clinical and endoscopic findings. Seventy-five GI biopsies (9 esophageal, 15 gastric, 16 duodenal, 5 ileal, 30 colonic) from 46 transplant recipients from 2002 to 2006 were obtained and assessed for multiple histologic features. Clinical features were recorded for all cases and endoscopic findings. Only MMF patients showed ulcerative esophagitis (5/7 cases) and reactive gastropathy (4/10 cases). Only MMF patients showed graft-versus-host disease (GVHD)-like features in duodenal (4/12 cases) and ileal (1/5 cases) biopsies. GVHD-like changes were seen more frequently among patients on MMF compared with those not on MMF [9 (56%) vs. 2 (14%); P=0.017]. Crypt architectural disarray [12 (75%) vs. 2 (14%); P=0.001], lamina propria edema [9 (56%) vs. 2 (14%); P=0.017], increased lamina propria inflammation [13 (81%) vs. 3 (21%); P=0.001], dilated damaged crypts [7 (44%) vs. 1 (7%); P=0.024], and increased crypt epithelial apoptosis [9 (56%) vs. 2 (14%); P=0.017] were more common with MMF patients compared with non-MMF patients. In conclusion, pathologists should be aware of the potential manifestations of MMF toxicity throughout the GI tract, including ulcerative esophagitis, reactive gastropathy, and GVHD-like features in intestinal biopsies.