Gastrointestinal Disorder Associated with Olmesartan Mimics Autoimmune Enteropathy

Cellular and molecular basis of proximal small intestine disorders

The proximal part of the small intestine, including duodenum and jejunum, is not only dedicated to nutrient digestion and absorption but is also a highly regulated immune site exposed to environmental factors. Host-protective responses against pathogens and tolerance to food antigens are essential functions in the small intestine. The cellular ecology and molecular pathways to maintain those functions are complex. Maladaptation is highlighted by common immune-mediated diseases such as coeliac disease, environmental enteric dysfunction or duodenal Crohn's disease. An expanding spectrum of more than 100 rare monogenic disorders inform on causative molecular mechanisms of nutrient absorption, epithelial homeostasis and barrier function, as well as inflammatory immune responses and immune regulation. Here, after summarizing the architectural and cellular traits that underlie the functions of the proximal intestine, we discuss how the integration of tissue immunopathology and molecular mechanisms can contribute towards our understanding of disease and guide diagnosis. We propose an integrated mechanism-based taxonomy and discuss the latest experimental approaches to gain new mechanistic insight into these disorders with large disease burden worldwide as well as implications for therapeutic interventions.

Advances in Nonresponsive and Refractory Celiac Disease

Nonresponsive celiac disease (CeD) is relatively common. It is generally attributed to persistent gluten exposure and resolves after correction of diet errors. However, other complications of CeD and disorders clinically mimicking CeD need to be excluded. Novel therapies are being evaluated to facilitate mucosal recovery, which might benefit patients with nonresponsive CeD. Refractory CeD (RCeD) is rare and is divided into 2 types. The etiology of type I RCeD is unclear. A switch to gluten-independent autoimmunity is suspected in some patients. In contrast, type II RCeD represents a low-grade intraepithelial lymphoma. Type I RCeD remains a diagnosis of exclusion, requiring ruling out gluten intake and other nonmalignant causes of villous atrophy. Diagnosis of type II RCeD relies on the demonstration of a clonal population of neoplastic intraepithelial lymphocytes with an atypical immunophenotype. Type I RCeD and type II RCeD generally respond to open-capsule budesonide, but the latter has a dismal prognosis due to severe malnutrition and frequent progression to enteropathy-associated T-cell lymphoma; more efficient therapy is needed.

Letter: The enigma of angiotensin receptor blocker-associated enteropathy

This article is linked to Schiepatti et al papers. To view these articles, visit https://doi.org/10.1111/apt.17855 and https://doi.org/10.1111/apt.18017.

Non-celiac Enteropathy and Olmesartan: An Essential Consideration

Emerging evidence has shed light on non-celiac causes of enteropathy in recent years, presenting a diagnostic challenge for clinicians. This study discusses the diagnostic challenges related to non-celiac enteropathy, specifically focusing on olmesartan-induced enteropathy (OIE). A 73-year-old lady presented to the emergency department with a six-month history of watery diarrhea exacerbated by food intake and significant weight loss. The patient at admission was found to be dehydrated with severe hypokalemia and hypocalcemia. The extensive testing that was performed was unremarkable, including celiac disease panel, enteric panel, ova and parasites, Clostridium difficile, fecal calprotectin, and computed tomography of the abdomen and pelvis. A significant electrolyte imbalance was corrected at admission, and subsequent upper endoscopy investigation with duodenal biopsies revealed moderate to severe villi blunting with a significant intraepithelial infiltrate of CD3+ lymphocytes. A colonoscopy that was performed at the same time was unremarkable, with negative biopsies for microscopic colitis. Given the suspicion of OIE, olmesartan was discontinued. One-month follow-up revealed resolution of malabsorption, with electrolyte normalization and duodenal biopsies showing improved duodenitis. This study emphasizes the importance of considering medication history and ruling out other potential causes of enteropathy. Olmesartan is an angiotensin II receptor antagonist that is commonly prescribed for hypertension. However, in rare cases, it may induce enteropathy, which often remains underdiagnosed. This rare side effect may present as chronic diarrhea, weight loss, and signs of malabsorption. Interestingly, OIE presents with overlapping clinical and histopathological features to celiac disease and, therefore, may mislead physicians to an extensive diagnostic investigation. Greater awareness of medication-related diarrheal syndromes such as OIE should be promoted, given that simple discontinuation of the medication can lead to dramatic clinical improvement.

Systematic review: Clinical phenotypes, histopathological features and prognosis of enteropathy due to angiotensin II receptor blockers

BACKGROUND

Although enteropathy due to angiotensin II receptor blockers (ARBs) has been known for over 10 years, clinicians' awareness of this condition is still low.

AIMS

To systematically review the literature about clinical phenotypes, distribution of mucosal changes throughout the gastrointestinal tract and prognosis of enteropathy due to ARBs.

METHODS

According to PRISMA guidelines, we searched PubMed and Embase for relevant articles up to November 6, 2023. We included full-text papers, letters, case reports and case series describing enteropathy due to ARBs. Patients were classified into subgroups based on endoscopic and histological findings of different regions of the gastrointestinal tract. The protocol was registered with Open Science Framework (https://doi.org/10.17605/OSF.IO/TK67C).

RESULTS

We included 94 articles reporting 183 cases (101 female, mean age at diagnosis 69 ± 10 years). The clinical picture at diagnosis was characterised by severe diarrhoea (97%) and weight loss (84%, median -13 kg), leading to hospital admission in 167 (95%) patients. Olmesartan (90%) was most frequently implicated. Villous atrophy (VA) was reported in 164/183 (89%) patients. One hundred and nine had only VA, 12 had pan-gastrointestinal involvement, 23 had VA and gastric involvement and 19 had VA and colon involvement (predominantly microscopic colitis). Outcomes were reported for 178/183 (97%) patients, who all recovered clinically on ARBs withdrawal. Histological recovery occurred in all 96 patients with VA at baseline who underwent follow-up duodenal biopsy.

CONCLUSIONS

Enteropathy due to ARBs is characterised by severe malabsorption often requiring hospital admission and can involve the entire gastrointestinal tract. Clinician awareness can lead to prompt diagnosis and excellent prognosis.

Olmesartan-induced enteropathy associated with antiphospholipid syndrome

Olmesartan-induced enteropathy (OIE) is an emergent enteropathy related to this angiotensin II receptor blocker. Main clinical manifestation is chronic diarrhea and duodenal biopsy is characterized by villous atrophy. Therefore, it is necessary to exclude other causes of enteropathy such as celiac disease, autoimmune enteropathy, intestinal lymphoma, parasitic infections, immunodeficiencies, or Crohn disease. Although it is supposed to be triggered by an immune mechanism, it is not clear its relation to other autoimmune disorders. We report for the first time a case of OIE associated with antiphospholipid syndrome.

What do we know today about drug-induced microscopic colitis? A case of lymphocytic colitis on olmesartan

Microscopic colitis is part of the differential diagnosis of chronic watery diarrhea. Colonoscopy discloses a normal looking mucosa, therefore its diagnosis is based on histology of colonic biopsies. Two main phenotypes are distinguished: collagenous colitis and lymphocytic colitis. A third entity, incomplete microscopic colitis or unspecified microscopic colitis has been reported in the literature. It affects preferentially women over 60 years of age and its association with certain drugs is increasingly established. In case of suspected drug-induced microscopic colitis, identification of the responsible drug is a key to management. After discontinuation of the suspected drug, the gold standard of treatment is budesonide both for induction and for maintenance in case of clinical relapse, as is often the case after discontinuation. Therapy with immunomodulators, biologics, or surgery is reserved for refractory forms of microscopic colitis after multidisciplinary consultation. Through the clinical case of colitis on olmesartan, we will review the latest recommendations on drug-induced microscopic colitis.

[Immunopathology of the small intestine]

The gastrointestinal tract is the site of exciting immunological interactions between the epithelium and the mucosa-associated lymphoid tissue, leading to the immune response to food and microbial antigens in the digestive lumen. The objective of this review is to present the main dysimmune pathologies of the digestive tract leading to an enteropathy. As examples, we describe celiac and non-celiac enteropathies to clarify a florid diagnostic framework, by identifying a spectrum of elementary lesions, which must be confronted with the clinico biological context of the patient to orient the diagnosis. The microscopic lesions observed are most often non-specific and may be encountered in several diagnostic settings. Moreover, it is a set of elementary lesions in each clinical context that will orient the diagnostic framework. Celiac disease is the main etiology of enteropathy with villous atrophy, its diagnosis is multidisciplinary and there are many differential diagnoses. We will discuss celiac disease lymphomatous complications as enteropathy associated T-cell lymphoma including refractory sprue type 2. We will then present the non-celiac enteropathies. Among these, enteropathies of unknown etiology may be associated with a primary immune deficiency that may be reflected by florid lymphoid hyperplasia of the gastrointestinal tract and/or be associated with an infectious etiology that should also be constantly sought. Finally, we will discuss of induced enteropathy by new immunomodulatory treatments.

[Lymphocytic "…itis", from esophagus to large bowel]

Intra-epithelial lymphocytosis is an elementary lesion frequently observed in the gastrointestinal tract, which can be found from the esophagus to the colon. Many conditions of a varied nature (dysimmunitary diseases, drugs, infections…) are associated with intra-epithelial lymphocytosis, and the etiological diagnosis most often requires an anatomo-clinical correlation. The pathologist will have to identify histological lesions associated with intra-epithelial lymphocytosis allowing the diagnosis to be oriented in order to propose appropriate treatment. In this review, the main entities associated with digestive intra-epithelial lymphocytosis will be presented, detailing the key elements allowing their diagnosis.

The immunomodulatory effects of antihypertensive therapy: A review

Hypertension remains the leading preventable risk factor for stroke and coronary artery disease, significantly contributing to all-cause global mortality and predisposing patients to renal and heart failure, as well as peripheral vascular disease. Due to the widespread usage of antihypertensive drugs, global mean blood pressure has remained unchanged or even slightly decreased over the past four decades. However, considering the broad spectrum of mechanisms involved in the action of antihypertensive drugs and the prevalence of their target receptors on immune cells, possible immunomodulatory effects which may exert beneficial effects of lowering blood pressure but also potentially alter immune function should be considered. In this review, we attempt to assess the consequences to immune system function of administering the five most commonly prescribed groups of antihypertensive drugs and to explain the mechanisms behind those interactions. Finally, we show potential gaps in our understanding of the effects of antihypertensive drugs on patient health. With regard to the widespread use of these drugs in the adult population worldwide, the discussed results may be of vital importance to evidence-based decision-making in daily clinical practice.

Refractory Coeliac disease-a case series from Pakistan

Coeliac disease or gluten intolerance is a frequent cause of chronic diarrhoea leading to malabsorptive symptoms. Refractory coeliac disease is a rare entity, which is not only harder to diagnose but managing it can be challenging. We hereby present three such cases.

Olmesartan-associated Enteropathy with Acute Kidney Injury

Olmesartan, a recently introduced angiotensin II receptor blocker for hypertension, has been reported to cause drug-induced small bowel enteropathy. The diagnosis of olmesartan-associated enteropathy (OAE) needs clinical suspicion and the exclusion of coeliac disease, as it mimics coeliac sprue. Once diagnosed, it can be completely cured with the discontinuation of olmesartan. However, due to the extremely low incidence of OAE in Korea, clinical suspicion and diagnosis may be a challenge. The authors report the first case of OAE presenting with chronic diarrhea and acute kidney injury in Korea.

Diarrhea and angiotensin II receptor blockers: Is there any difference between the different drugs?

Diarrhea is an adverse drug reaction (ADR) widely reported with olmesartan, an angiotensin II receptor blocker (ARB). Isolated case reports described this ADR with other ARBs. The present study was performed to investigate if, among the different ARBs, some drugs are more at risk of diarrhea than others. Using VigiBase®, the WHO pharmacovigilance database, we performed a disproportionality analysis (case/noncase study). Cases were reports with the MedDRA PT term « diarrhea » and noncases all other reports registered during the same period in Vigibase® from April 6, 1995 to December 31, 2020. After comparison of ARBs and angiotensin converting enzyme inhibitors (ACEIs), the main analysis was a comparison of the diarrhea reporting risk between each ARB and the seven other ARBs. Results are reported as reporting odds ratio (ROR) adjusted on age, gender, exposure to antihypertensive, and antidiabetic drugs with their 95% confidence interval. Among the 22,429,334 deduplicated reports registered in VigiBase® during the study period, 73,507 involved ARBs, including 2119 diarrhea. The reporting risk of diarrhea was higher with ARBs than with ACEIs (ROR = 2.06 (1.55-2.17)). Diarrhea with ARBs mainly occurred in females with a mean age of 65 years. After exclusion of olmesartan (to minimize a notoriety bias), two ARBs were significantly associated with diarrhea: eprosartan (ROR = 1.93 (1.32-2.72) and telmisartan (ROR = 1.41 (1.23-1.62) but not the six others. The present study found first that diarrhea is more frequently reported with ARBs than with ACEIs and second that the risk of diarrhea differs according to the different ARBs. Diarrhea with ARBs is not a class effect.

An unusual cause of diarrhoea: case report and literature review of olmesartan-associated enteropathy

Olmesartan is an angiotensin II receptor blocker, approved in 2002 by the Food and Drug Administration for the treatment of hypertension. During chronic therapy with olmesartan, sprue-like enteropathy can occur, being mainly characterised by non-bloody diarrhoea, weight loss and variable degrees of duodenal mucosal damage, which resolved after withdrawal of olmesartan. We hereby report the case of a 77-year-old, poli-treated male patient with a 3-month history of diarrhoea, vomiting and weight loss, associated with severe intestinal villous atrophy and lymphocytic infiltration of gastric and colonic mucosa. After extensive investigations aimed at excluding other possible causes of chronic diarrhoea, a diagnosis of olmesartan-associated enteropathy was made, which was later confirmed by clinical improvement after the discontinuation of the drug. Repeated endoscopy 8 months later showed complete healing of duodenal mucosa with normal villous architecture. Villous atrophy and lymphocytic infiltration of duodenal mucosa are the most described pathologic finding, but several cases of gastric and colonic involvement have also been reported. We, therefore, reviewed the available literature, focussing on the extent of mucosal damage throughout the whole intestine and on its possible causative factors.

Review article: drug-induced small bowel injury

BACKGROUND

Drug-induced gastrointestinal injury has been increasingly reported, but its exact incidence is not known. The small and large intestines represent the most affected sites of injury, accounting for 20%-40% of all gastrointestinal side effects.

AIM

To provide an updated literature review detailing medications linked to the development of small bowel injury.

METHODS

We conducted a literature search on PubMed from its inception to May 1, 2021. We included English-language original studies, meta-analyses, systematic reviews, review articles and case reports.

RESULTS

Drug-induced enteropathy can range from asymptomatic histological changes resulting in a subtle, self-limited disease to a chronic inflammatory condition mimicking inflammatory bowel disease, or bowel perforation. Endoscopy can demonstrate erythema, mucosal friability, oedema, erosions, ulcers or strictures in severe cases. Histology may include mucosal erosions and ulcerations, focal active enteritis, villous atrophy, epithelial apoptosis or necrotising enteritis. A well-established association has been found with the use of nonsteroidal anti-inflammatory drugs, immunosuppressants, chemotherapeutic agents, antibiotics, immunotherapies, etanercept and olmesartan. Possible associations have been reported with other biologic agents, medications used for glycemic control, antihypertensives, cholinesterase inhibitors, potassium and iron supplements, with conflicting data regarding contraceptives/hormonal therapy and isotretinoin.

CONCLUSION

Physicians should be aware of the manifestations of drug-induced enteropathy as early recognition can lead to prompt discontinuation of the offending therapy and, therefore, a reduced risk of future complications.

Lymphocytic gastritis and its relationships with other gastrointestinal disorders

BACKGROUND

Lymphocytic gastritis (LyG) is a histopathologic finding of unknown clinical relevance.

AIMS

To explore the clinical epidemiology of LyG and its associations with Helicobacter pylori (Hp) infection, coeliac disease (CD) and microscopic colitis (MC) METHODS: In a cross-sectional study, the demographic, clinical, and histopathologic data of patients with and without LyG were compared. Between 2008 and 2020, 1.5 million patients with endoscopic biopsies of the gastroduodenal mucosa were extracted from a database. LyG diagnoses were reviewed to collect detailed information regarding its topographic distribution within the stomach. In a large subgroup of 400 000 patients, tissue samples from the colon were also available.

RESULTS

Of 1 481 336 patients, 341 had LyG with Hp and 2697 had Hp-negative LyG (with an overall prevalence of 0.21%). In patients with Hp-negative LyG, 450 (17%) had corpus-predominant LyG, 1068 antrum-predominant LyG (40%), and 1179 pangastric LyG (44%). LyG was more common in males and in subjects aged 50-70 years. There was no significant ethnic variation. Anaemia, diarrhoea, and weight loss were more common in patients with than without LyG. In 35% and 19% of patients, LyG was associated with CD and MC, respectively. All 72 patients with Hp-positive LyG and 280 of 310 patients with Hp-negative LyG with follow-up biopsies became free of LyG within a year.

CONCLUSIONS

Most cases of LyG may represent a self-limited expression, frequently associated with other GI conditions, such as Hp infection, CD, and MC. In most patients, LyG is likely to resolve within a year after its initial diagnosis.

Clinical and gastro-duodenal histopathological features of enteropathy due to angiotensin II receptor blockers

BACKGROUND

Clinical elements differentiating enteropathy due to angiotensin II-receptor-blockers (ARBs-E) from coeliac disease (CD) are poorly defined. The histopathological features on duodenal and gastric biopsies in these patients still need to be investigated.

AIMS

To describe the clinical phenotype of ARBs-E in comparison to CD, and the histological findings of gastric and duodenal biopsies in ARBs-E.

METHODS

Clinical data of patients with ARBs-E and CD diagnosed between 2013 and 2020 were retrospectively reviewed. Baseline presenting symptoms and demographics were compared (Fisher's exact test and t-test). Gastric and duodenal histology in ARBs-E were revised by two independent pathologists.

RESULTS

14 ARBs-E and 112 CD patients were enroled. Weight loss (p < 0.01), acute onset of diarrhoea (p < 0.01), hospitalization (p < 0.01), and older age at diagnosis (p < 0.01) were more common in ARBs-E. Duodenal histology in ARBs-E showed intraepithelial lymphocytosis in 71%, increased mucosal eosinophilic count in 57%, with preserved neuroendocrine, Paneth and goblet cells in all patients. Gastric histologic lesions at baseline, including lymphocytic gastritis, eosinophilic gastritis, chronic active gastritis, and metaplastic atrophic gastritis patterns were observed in 73% of patients, without Helicobacter pylori infection.

CONCLUSIONS

ARBs-E showed a severe clinical phenotype, often requiring hospital admission. Gastric involvement at diagnosis is very common, and this could further support this diagnosis.

Adult-Onset Autoimmune Enteropathy in an European Tertiary Referral Center

INTRODUCTION

Adult-onset autoimmune enteropathy (AIE) is a rare cause of severe chronic diarrhea because of small intestinal villous atrophy. We report on patients with adult-onset AIE in an European referral center.

METHODS

Retrospective study including patients diagnosed with AIE in the Amsterdam UMC, location VUmc, between January 2003 and December 2019. Clinical, serological, and histological features and response to treatment were reported. The specificity of antienterocyte antibodies (AEA) was evaluated by examining the prevalence of AEA in (i) controls (n = 30) and in patients with (ii) AIE (n = 13), (iii) celiac disease (CD, n = 52), (iv) refractory celiac disease type 2 (n = 18), and (v) enteropathy-associated T-cell lymphoma (EATL, n = 10).

RESULTS

Thirteen AIE patients were included, 8 women (62%), median age of 52 years (range 23-73), and 6 (46%) with an autoimmune disease. AEA were observed in 11 cases (85%), but were also found in CD (7.7%), refractory celiac disease type 2 (16.7%), and EATL (20%). Ten patients (77%) were human leukocyte antigen DQ2.5 heterozygous. Total parenteral nutrition was required in 8 cases (62%). Steroids induced clinical remission in 8 cases (62%). Step-up therapy with rituximab, cyclosporine, infliximab, and cladribine in steroid-refractory patients was only moderately effective. Four patients died (31%), but 4 (31%) others are in long-term drug-free remission after receiving immunosuppressive treatment, including 1 patient who underwent autologous stem cell transplantation.

DISCUSSION

Adult-onset AIE is a rare but severe enteropathy that occurs in patients susceptible for autoimmune disease. Four patients (31%) died secondary to therapy-refractory malabsorption, while immunosuppressive therapy leads to a long-lasting drug-free remission in one-third of patients.

Diarrhoea with the angiotensin receptor neprilysin inhibitor sacubitril + valsartan: A pharmacovigilance study

Diarrhoea is an adverse drug reaction of the angiotensin receptor neprilysin inhibitor (ARNI) sacubitril + valsartan. It was also described with olmesartan and more recently with other angiotensin receptor blockers. The study was performed to compare diarrhoea reports in pharmacovigilance databases with sacubitril + valsartan and valsartan. The study used reports of diarrhoea with the ARNI sacubitril + valsartan registered: first in the French PharmacoVigilance Database (FPVD) and second in Vigibase®, the WHO Global Individual Case Safety Report database. After description of the main characteristics, disproportionality analyses were performed. Results are reported as reporting odds ratios (ROR) with 95% confidence interval. We found 29 reports of diarrhoea with sacubitril + valsartan in the FPVD and 686 in Vigibase®. With sacubitril + valsartan, diarrhoea occurred more frequently in males around 70 years with a median delay of 3 days. With valsartan, diarrhoea occurred more frequently in females around 68 years with a median delay of 0.5 days. In the FPVD, a significant association was found with sacubitril + valsartan in comparison with valsartan alone before (ROR = 8.78 [5.19-14.85]) and after (ROR = 11.19 [5.89-21.25]) exclusion of concomitant drugs known to be associated with diarrhoea. A significant association was also found in Vigibase® after adjustment on age, sex, reporter and its location (ROR = 1.31 [1.14-1.50]). Diarrhoea reported with sacubitril + valsartan has marked differences in gender, delay of occurrence and frequency of reporting in comparison with diarrhoea with valsartan. From a pharmacodynamic point of view, these results suggest a specific role of sacubitril in diarrhoea.

Adult autoimmune enteropathy in autoimmune hepatitis patient. Case report and literature review

Autoimmune enteropathy (AIE) is a rare disease characterized by prolonged diarrhea, vomiting and weight loss; although it is mainly a rare pediatric disease, over the years a number of adults have also been found to be affected. In this study, we present a case report of a 73-year-old woman with a history of autoimmune hepatitis, antinuclear (ANA) and positive anti-enterocyte antibodies (AEA), who has suffered two months of intractable diarrhea, nausea, anorexia and severe weight loss. The histological examination of the endoscopic duodenal mucosa biopsies revealed severe shortening and flattening of the villi, resulting in mucosal atrophy. The immunohistochemical study revealed a polymorphic lymphoid population, exhibiting a B cell (CD20+) phenotype in follicles and a T cell phenotype (CD3+) in the diffuse component within the lamina propria. Our patient had a complete recovery after two weeks of taking prednisone and following a gluten-rich diet. To our knowledge this is the first case of autoimmune enteropathy in adults with ANA and AEA 7 years after a diagnosis of autoimmune hepatitis. To date, the patient is still in clinical remission on a low dose of orally administered predinisone without any additional immunosuppression.

Olmesartan-associated duodenal villous atrophy, an emerging clinical issue

Duodenal villous atrophy with olmesartan was described in 2012, 10 years following registration of olmesartan. Clinical features are severe watery diarrhoea, usually occurring in association with weight loss. Onset is delayed, with a mean duration of prior exposure to olmesartan of 3 years. Diagnosis may be delayed. Symptoms resolve over weeks following cessation of olmesartan. Epidemiological studies suggest increased risk with olmesartan, rather than a class effect of all angiotensin receptor blockers. Post-marketing surveillance for drug safety remains important.

Acute Flare of Adult-Onset Autoimmune Enteropathy Associated With Cyclophosphamide

This is a case of adult-onset autoimmune enteropathy (AIE) in a 46-year-old man with multiple autoimmune conditions who presented with worsening disease process after receiving cyclophosphamide. We describe the investigations and management of this patient over a 6-year timeline. The diagnosis and management of AIE is challenging given the heterogeneity in clinicopathologic findings and a small number of adult case reports. We describe the current diagnostic criteria, review the literature on treatment options and outcomes, and discuss the evidence for cyclophosphamide in the treatment of AIE. Adult-onset AIE should be considered in the differential diagnosis of refractory diarrhea and weight loss.

Immune-mediated enteropathies: From bench to bedside

Immune-mediated enteropathies are caused by excessive reactions of the intestinal immune system towards non-pathogenic molecules. Enteropathy leads to malabsorption-related symptoms and include (severe) chronic diarrhea, weight loss and vitamin deficiencies. Parenteral feeding and immunosuppressive therapy are needed in severe cases. Celiac disease has long been recognized as the most common immune-mediated enteropathy in adults, but the spectrum of immune-mediated enteropathies has been expanding. Histological and clinical features are sometimes shared among these enteropathies, and therefore it may be challenging to differentiate between them. Here, we provide an overview of immune-mediated enteropathies focused on clinical presentation, establishing diagnosis, immunopathogenesis, and treatment options.

The role of histopathology in the diagnosis and management of coeliac disease and other malabsorptive conditions

Most absorption of nutrients takes place in the proximal small intestine, and the most common disorders leading to malabsorption are associated with a morphological abnormality in the duodenal mucosa that is appreciable in histological sections of biopsy specimens. Coeliac disease is the most well-known example, causing intraepithelial lymphocytosis, inflammation and villous atrophy in the duodenum. Remarkably similar inflammatory changes can be induced by other processes, including medications, e.g. angiotensin II receptor blockers and immune checkpoint inhibitors, immune dysregulation disorders, e.g. common variable immunodeficiency and autoimmune enteropathy, infections, collagenous sprue, and tropical sprue. However, there are often subtle histological differences from coeliac disease in the type of inflammatory infiltrate, the presence of crypt apoptosis, and the extent and type of inflammation beyond the duodenum. The clinical setting and serological investigation usually allow diagnostic separation, but some cases remain challenging. Histopathology is also important in assessing the response to treatment, such as the change in villous architecture caused by a gluten-free diet, or the response to cessation of a potentially causative medication. This review examines the practical role that histopathology of duodenal biopsy specimens plays in the assessment and management of inflammatory malabsorptive processes of the proximal small intestine, with a particular emphasis on coeliac disease.

Olmesartan-induced Enteropathy: A Rare Side Effect of a Common Medication

Ischemic heart disease and stroke are the leading causes of mortality worldwide according to the World Health Organization. Hypertension is a major factor in the development of these diseases. Olmesartan is an angiotensin II receptor blocker (ARB) indicated in the treatment of hypertension. There are several case reports describing sprue-like enteropathy caused by olmesartan. We report on a 72-year-old patient referred to our hospital for work-up of chronic diarrhoea, vomiting and weight-loss, and villous atrophy on intestinal biopsy. The patient’s symptoms abated upon cessation of olmesartan. This case illustrates the need for a thorough medication history and regular review during work-up. We hope it will add to the current understanding of this rare phenomenon. 

Significant Weight Loss in a Patient Taking Olmesartan: An Unusual Case Report

Objective:

Olmesartan-induced enteropathy consists a syndrome that mimics celiac disease both clinically and histologically. Cases of this entity have sporadically been reported since 2012 and are usually characterized by severe diarrhea and malabsorption, followed by significant weight loss.

Case Report:

Herein, we report an uncommon case of this syndrome, where weight loss preceded several months the onset of gastrointestinal symptoms.

Discussion and Conclusion:

Physicians should be aware of unexplained weight loss in patients taking olmesartan, as prompt discontinuation of the drug may prevent the deleterious consequences of malabsorption.

Recent advances in celiac disease and refractory celiac disease

Celiac disease (CeD), defined as gluten-induced enteropathy, is a frequent and largely underdiagnosed disease. Diagnosis relies on the detection of highly specific serum IgA anti-transglutaminase auto-antibodies and on the demonstration of duodenal villous atrophy. Treatment necessitates a strict gluten-free diet, which resolves symptoms and enables histological recovery. However, regular follow-up is necessary to assess mucosal healing, which emerges as an important prognostic factor. Recent work on CeD pathogenesis has highlighted how the cross-talk between gluten-specific CD4 + T cells and interleukin-15 can activate cytotoxic intraepithelial lymphocytes and trigger epithelial lesions. Moreover, acquisition by a subset of intraepithelial lymphocytes of somatic gain-of-function mutations in the JAK-STAT pathway was shown to be a decisive step in the progression toward lymphomas complicating CeD, thus opening new therapeutic perspectives for these rare but life-threatening complications.

Overview in the clinical management of patients with seronegative villous atrophy

Differential diagnosis and management of enteropathies found in the context of seronegative villous atrophy (VA) are still a clinical challenge. Although seronegative coeliac disease may be the most frequent cause of serology-negative VA, other conditions must be taken into account in the differential diagnosis of seronegative VA. The rarity of these enteropathies with frequent overlapping of histological features may result in misclassification of such patients as affected by a seronegative or a refractory form of coeliac disease with consequent inappropriate treatments and long-term morbidity. The aim of this review is to summarize the current knowledge and to provide an evidence base and practical algorithmic approach for the investigation and management of seronegative VA.

Biopsy Diagnosis of Celiac Disease: The Pathologist's Perspective in Light of Recent Advances

Celiac disease is a common immune-mediated disorder that occurs in individuals with permissive genetics (HLA-DQ2/DQ8 genotype) following exposure to certain wheat proteins. The histopathologic manifestations of small intestinal mucosal injury (villus atrophy, crypt hyperplasia, and intraepithelial lymphocytosis) are well recognized. However, these findings are not specific for celiac disease, because they are observed in other small intestinal disorders. These mimics include common and rare entities, the list of which continues to grow. This article discusses the histopathology and differential diagnosis of celiac disease and provides the pathologist's perspective on biopsy adequacy, evaluation, and reporting in light of current knowledge.

Refractory Celiac Disease

Refractory celiac disease (RCD) refers to persistence of malnutrition and intestinal villous atrophy for more than 1 to 2 years despite strict gluten-free diet in patients with celiac disease. Diagnosis remains difficult and impacts treatment and follow-up. RCD has been subdivided into 2 subgroups according to the normal (RCDI) or abnormal phenotype of intraepithelial lymphocytes (IELs) (RCDII). RCDII is considered as a low-grade intraepithelial lymphoma and has a poor prognosis due to gastrointestinal and extraintestinal dissemination of the abnormal IELs, and high risk of overt lymphoma.

Autoimmune Enteropathy: An Updated Review with Special Focus on Stem Cell Transplant Therapy

Autoimmune enteropathy (AIE) is a complex disease affecting both children and adults. Although associated with significant morbidity and mortality, the pathophysiology of the disease and its treatment have not been well characterized. This study aims to review the medical literature available on this rare but clinically significant ailment, to help establish a better understanding of its pathophysiology and enumerate the available diagnostic and treatment modalities. A literature search was conducted on PubMed using key terms related to autoimmune enteropathy and intractable diarrhea, with no restrictions on the date of publication or language. We found a total of 98 reports of AIE published in the form of case reports and case series. The evidence reviewed suggests that AIE is a multifaceted disorder that requires a high index of suspicion in the appropriate clinical setting to be able to make an early diagnosis. Current evidence supports the use of supportive care to correct nutritional and metabolic deficiencies, and immunosuppressives and immunomodulators as directed therapies. Hematopoietic stem cell transplant is an aggressive, but successful curative modality for patients with AIE as part of immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. Cumulative clinical experience with management of AIE has allowed improved outcomes in transplanted and non-transplanted AIE patients even though morbidity and mortality with are still high in patients with this condition. More research is needed to further define the role of new therapies for AIE, and a central registry with participation of multiple institutions might help share and standardize care of patients with this rare but serious condition.

Case of olmesartan-associated enteropathy and transient positive antitissue transglutaminase serology

Olmesartan-associated enteropathy (OAE) is increasingly being recognised as a major differential diagnosis in patients with villous atrophy and negative coeliac disease (CD) serology. OAE and positive coeliac markers have rarely been reported. We report a case of diarrhoea and small bowel villous blunting associated with a transient elevation of antitissue transglutaminase antibody (ATTG). On discontinuation of olmesartan, symptoms improved, repeat biopsies were normal and levels of ATTG also returned normal. We discuss a possible explanation for the transient elevation in ATTG and the significance of considering OAE/CD overlap.

Olmesartan-associated severe gastritis and enteropathy

Olmesartan is an angiotensin II receptor antagonist, used in the treatment of hypertension. We report a case of olmesartan-associated severe gastritis with enteropathy in a 74-year-old woman who presented with mainly upper gastrointestinal symptoms. There was significant endoscopic improvement in the mucosal inflammation on stopping the drug. Subsequent gastroscopy showed mucosal healing and normal gastric and duodenal mucosa. To our knowledge, this is the first case report of olmesartan-associated gastritis and enteropathy predominantly involving and affecting the whole of stomach with limited small bowel involvement.

Psoriasis during angiotensin receptor blocker exposure: an underestimated adverse drug reaction

BACKGROUND

Angiotensin receptor blockers (ARBs) can induce or exacerbate psoriasis. Psoriasis is unlisted in the Summary of Product Characteristics (SmPC) of ARBs. We aimed to investigate the association between psoriasis and ARB exposure.

METHODS

We reviewed spontaneous reports recorded in the French national Pharmacovigilance Database (FPVD). The association between psoriasis and ARB exposure was assessed using the case/non-case method. We also analyzed literature reports.

RESULTS

We identified 89 reports of psoriasis during ARB exposure in the FPVD. Time to onset was most often less than 1 year. Outcome was favorable in 67% of reports after ARB discontinuation. Almost all ARBs were concerned. The reporting odds ratio (ROR) for psoriasis with this therapeutic class was 4.86 (95%CI 3.92-6.03). In the literature, we found 14 published reports of psoriasis with ARB exposure. Time to onset ranged from 6 weeks to 9 months. Outcome was also favorable after ARB discontinuation in the literature.

CONCLUSIONS

This underestimated adverse drug reaction is a class effect, time to onset is most often less than 1 year and outcome seems favorable after ARB discontinuation. The case/non-case approach highlights a potential safety signal. The SmPC of ARBs should be updated, increased awareness among healthcare professionals is warranted.

Acute Gastrointestinal Bleeding in Olmesartan-Associated Collagenous Gastroduodenitis: A Potential Endoscopic Complication

Collagenous gastroenteritis is a rare disease that is known to be associated with the drug olmesartan, an angiotensin II receptor antagonist used to treat hypertension. It is characterized histologically by increased subepithelial collagen deposition with associated inflammation and epithelial injury. Endoscopically, the mucosa appears inflamed and friable and may be nodular or atrophic. We report a case of acute gastric bleeding on direct mucosal contact during endoscopy in a patient with olmesartan-associated collagenous gastroduodenitis to raise awareness of this potential endoscopic complication.

Severe intestinal malabsorption associated with ACE inhibitor or angiotensin receptor blocker treatment. An observational cohort study in Germany and Italy

Purpose

The angiotensin II receptor blocker (ARB) olmesartan has been recently associated with sprue‐like enteropathy (SLE), a gastrointestinal condition characterized by intestinal malabsorption (IM) and severe diarrhea. Whether the increased risk of SLE is substance‐specific or a class effect involving all ARBs is uncertain. The aim of this study is to assess the risk of enteropathy associated with ARBs and angiotensin converting enzyme inhibitors (ACE‐i) by using data from large administrative and claim databases.

Methods

We obtained data from Italian local health‐care units and a large German claim database and included patients treated with olmesartan, other ARBs, and ACE‐i. In the absence of a specific diagnosis code for SLE, International Classification of Diseases codes for IM were used. Analysis implemented a Poisson regression with robust error variance procedure, which allowed accounting for different clusters (local health‐care units and countries) and correctly estimating the standard error for the relative risk of rare event occurrence.

Results

Patients were divided into 3 groups: olmesartan (25.591, 5.5%), other ARBs (104.901, 22.5%), and ACE‐i patients (334.951, 72.0%). Baseline characteristics were similar overall. The incidence of unspecified IM in ACE‐i patients was not different compared with that of olmesartan, whereas a higher rate ratio was observed when comparing ARB patients with the olmesartan group (RR: 2.50, 95% CI 1.21 to 5.19, P .01). When International Classification of Diseases codes for coeliac disease were included, no differences were observed.

Conclusions

We could not confirm previous findings of a higher risk of malabsorption in olmesartan‐only patients, and drug‐induced enteropathy should be considered the result of exposure to the class of ARBs rather than a specific drug‐related effect.

Autoimmune enteropathies

Autoimmune enteropathy (AIE) is a rare condition characterized by intractable diarrhea and immune-mediated injury of the intestinal mucosa. As the clinical and histopathologic manifestations of this disease are highly variable, its diagnosis is challenging for both clinicians and pathologists. In fact, the term autoimmune enteropathies is likely more appropriate since the clinicopathologic manifestations are observed in association with a heterogeneous group of disorders. The pathophysiology of AIE has not been fully elucidated. It appears to result from dysregulation of intestinal immunity and particularly in children, often presents in association with immunodeficiency. The overarching histopathologic changes seen in AIE include mucosal inflammation and epithelial injury, although this can manifest in the form of different patterns. Recognition of the clinical settings and of the various histologic patterns can aid the pathologist in establishing the correct diagnosis.

Olmesartan-associated enteropathy

Olmesartan, an angiotensin-receptor blocker frequently prescribed for hypertension, has been commercially available since 2002. In 2012, olmesartan-associated enteropathy was described, and the Food and Drug Administration now requires a black-box warning for olmesartan regarding severe diarrhea. The disorder can be life-threatening and often requires hospitalization. We present three cases that represent different aspects of this disorder, as well as some unusual features.

Effects of Antihypertensive Agents on Intestinal Contractility in the Spontaneously Hypertensive Rat: Angiotensin Receptor System Downregulation by Losartan

Hypertension is an inflammatory condition controlled by the renin angiotensin system and is linked to kidney disease, diabetes mellitus, and recently to dysfunction of the gut. The aim of this study was to determine what effect antihypertensive drug treatments may have on intestinal function of the spontaneously hypertensive rat (SHR). In the first experiment, SHRs were treated with enalapril, hydralazine, or with no treatment as a control. In the second experiment, SHRs were treated with losartan or with no treatment as a control. All drug treatments led to significant lowering of blood pressure after 16 weeks. At termination, intact tissue sections of the ileum and colon were induced to contract ex vivo by KCl; electrical stimulation; and agonists carbachol, angiotensin II, and prostaglandin E₂ (PGE₂). There were no differences in ileal or colonic contractility due to hydralazine or enalapril compared with no-treatment SHR control. However, for the ileum, the losartan group responded significantly more to KCl and carbachol while responding less to angiotensin II, with no difference for PGE₂ compared with the no-treatment SHR control. In contrast, the colon responded similarly to KCl, electrical stimulation, and PGE₂ but responded significantly less to angiotensin II. These results demonstrate that the ileum responds differently (with KCl and carbachol as agonists) to the colon after losartan treatment, whereas there is a reduced contractile response in both the ileum and colon following losartan treatment. Although there are few well documented major contraindications for angiotensin receptor blockers, the modulation of gut contractility by losartan may have wider implications for bowel health.

Seronegative Intestinal Villous Atrophy: A Diagnostic Challenge

Celiac disease is the most important cause of intestinal villous atrophy. Seronegative intestinal villous atrophy, including those that are nonresponsive to a gluten-free diet, is a diagnostic challenge. In these cases, before establishing the diagnosis of seronegative celiac disease, alternative etiologies of atrophic enteropathy should be considered. Recently, a new clinical entity responsible for seronegative villous atrophy was described—olmesartan-induced sprue-like enteropathy. Herein, we report two uncommon cases of atrophic enteropathy in patients with arterial hypertension under olmesartan, who presented with severe chronic diarrhea and significant involuntary weight loss. Further investigation revealed intestinal villous atrophy and intraepithelial lymphocytosis. Celiac disease and other causes of villous atrophy were ruled out. Drug-induced enteropathy was suspected and clinical improvement and histologic recovery were verified after olmesartan withdrawal. These cases highlight the importance for clinicians to maintain a high index of suspicion for olmesartan as a precipitant of sprue-like enteropathy.

Olmesartan-induced enteropathy associated with cutaneous lesions

Olmesartan is an angiotensin II receptor antagonist which may cause severe sprue‐like enteropathy with duodenal villous atrophy. Skin lesions may be associated as reported for the first time in our case. Clinicians should be informed of this side effect and its reversibility after suspension of the drug.

Olmesartan-Induced Enteropathy: An Unusual Cause of Villous Atrophy

We report a case of a 63-year-old-man presenting with chronic diarrhea and weight loss while on olmesartan treatment for hypertension. Investigation showed multiple nutritional deficiencies associated with diffuse intestinal villous atrophy. Serologies for celiac disease were negative and other causes of villous atrophy were excluded. Olmesartan as a precipitant agent was suspected and withdrawn. Clinical improvement occurred in days with no need for other therapeutic measures. Follow-up at three months showed clinical remission and almost complete recovery of intestinal atrophy. Olmesartan is an angiotensin receptor blocker commonly prescribed for the management of hypertension. Spruelike enteropathy associated with this drug is a recently described entity with few cases reported. It presents with chronic diarrhea and intestinal villous atrophy and should be included in its differential diagnosis. This case intends to alert clinicians for the possibility of this event in a patient on treatment with this drug.