IgA nephropathy and thin basement membrane disease in association with Crohn disease

Glomerulonephritis and inflammatory bowel disease: A tale of gut-kidney axis dysfunction

The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased over the past decades, imposing a growing socioeconomic burden on healthcare systems globally. Most of the morbidity and mortality related to IBD is typically attributed to gut inflammation and its complications; yet the disease is characterized by various extraintestinal manifestations that can be severe. Glomerulonephritis (GN) is of particular interest since a significant proportion of patients evolve into end-stage kidney disease, requiring kidney replacement therapy and associated with high morbidity and mortality. Herein, we review the GN landscape in IBD and define the clinical and pathogenic associations reported to date in the literature. Underlying pathogenic mechanisms suggest either the initiation of antigen-specific immune responses in the inflamed gut that cross react with non-intestinal sites, such as the glomerulus, or that extraintestinal manifestations are gut-independent events that occur due to an interaction between common genetic and environmental risk factors. We present data associating GN with IBD either as a bona fide extraintestinal manifestation or reporting it as an extraneous co-existing entity, involving various histological subtypes, such as focal segmental glomerulosclerosis, proliferative GN, minimal change disease, crescentic GN, but most emphatically IgA nephropathy. Supporting the pathogenic interplay between gut inflammation and intrinsic glomerular processes, enteric targeting the intestinal mucosa with budesonide reduced IgA nephropathy-mediated proteinuria. Elucidating the mechanisms at play would provide insight not only into IBD pathogenesis but also into the gut's role in the development of extraintestinal diseases, such as glomerular diseases.

The pathological and outcome characteristics of renal lesions in Crohn's disease

Background

The inflammatory bowel disease, containing Crohn’s disease and ulcerative colitis, was rare in the population, especially in the complication of kidney disease. A few studies had found proteinuria played a potential indicator of inflammatory bowel disease occurrence and activity. This study aimed to better define the histopathologic spectrum and study the outcome of renal disease in Crohn’s disease.

Methods

A retrospective study of 3557 Crohn's disease from January 1^st, 2016 to July 1^st, 2021 in the Sixth Affiliated Hospital of Sun Yat-sen University identified 20 (0.56% [20/3557]) patients who underwent kidney biopsy. All biopsy specimens were examined by standard procedures containing light microscopy, immunofluorescence, and electron microscopy.

Results

Twenty cases were shown in this review study. Subnephrotic proteinuria (30% [6 of 20]), persistent hematuria and proteinuria (25% [5 of 20]), and isolated hematuria with acanthocytes (25% [5 of 20]) were the main indications for kidney biopsy. The most common diagnosis was IgA nephropathy (70% [14/20]), followed by minimal change disease (10% [2/20]), acute interstitial nephritis (5% [1/20]), granulomatous interstitial nephritis (5% [1/20]), non-IgA mesangial proliferative nephritis (5% [1/20]) and thin basement membrane nephropathy (5% [1/20]). The Lee classification of IgA nephropathy was mostly II or III level. Glomerular mesangial hyperplasia was the most common pathologic manifestation according to the MEST-C Sore. After twelve-month treatment, the majority of patients turned to complete remission of renal disease by measuring proteinuria, while 3 patients still stayed in the relapse stage and 6 patients turned to partial remission by measuring hematuria.

Conclusions

IgA nephropathy is the most common kidney biopsy diagnosis in Crohn's disease. Renal damage in Crohn's disease mainly involves the glomerulus, especially the mesangial matrix. After the treatment, proteinuria might be in remission, but hematuria remains.

IgA nephropathy in a child: Crohn's disease-associated or adalimumab induced?

In pediatric patients with Inflammatory Bowel Disease renal parenchymal disease is infrequent. There are only two reports about the association between IgA Nephropathy and Pediatric Crohn Disease. IgA Nephropathy is a rather uncommon complication of Tumor Necrosis Factor-alpha (TNF-α) inhibition. We describe a case of IgA Nephropathy which has arisen in a 11-year-old child 2 years after Crohn disease diagnosis, during therapy with anti-TNF-α. An ileal e jejunal Crohn disease was diagnosed at 9 years old, initially treated with prednisone, followed by biological therapy with anti-TNF-α (Adalimumab) due to severe disease activity, with gradual improvement of clinical conditions until clinical remission is achieved. Two years after the diagnosis, the child suddenly presented macroscopic hematuria. Subsequent laboratory examinations showed acute renal failure. So kidney biopsy was performed and IgA Nephropathy diagnosis was made. Adalimumab was discontinued and the child has been treated with steroids for sixth months associated with angiotensin-converting enzyme inhibitor resulted in clinical improvement over the following year and remission was maintained. To our knowledge the association of IgA Nephropathy and pediatric IBD during therapy with anti-TNF-α has never been reported. Careful monitoring of renal function, proteinuria, and autoantibodies is advised in patients treated with anti-TNF-α agents.

IgA nephropathy in association with inflammatory bowel diseases: results from a national study and systematic literature review

BACKGROUND

Little is known about clinical characteristics and kidney outcome in patients with biopsy-proven immunoglobulin A nephropathy (IgAN) in a context of inflammatory bowel disease (IBD).

METHODS

We conducted a retrospective multicenter study with centralized histological review, to analyze the presentation, therapeutic management and outcome of 24 patients suffering from IBD associated IgAN relative to a cohort of 134 patients with primary IgAN without IBD.

RESULTS

Crohn's disease and ulcerative colitis accounted for 75% and 25% of IBD-associated IgAN cases, respectively. IBD was diagnosed before IgAN in 23 cases (a mean of 9 years previously) and was considered active at IgAN onset in 23.6% of patients. Hypertension was present in 41.7% of patients. Urinary protein-to-creatinine ratio exceeded 100 mg/mmol in 70.8% of patients (mean: 254 mg/mmol). Estimated glomerular filtration rate (eGFR) exceeded 60 ml/min/1.73m2 in 13/24 patients and only one patient required dialysis. In the Oxford MEST-C classification of renal biopsies, 57% were M1, 48% E1, 76% S1, 57% T1+T2 and 38% C1+C2. Steroids were administered in 50% of cases. After a mean follow-up of 7.2 years, four patients (16.7%) had a poor kidney outcome: end-stage renal disease (n = 3) or a > 50% decrease in eGFR from initial values (n = 1). A similar evolution was observed in patients with primitive IgAN.

CONCLUSIONS

This first case series suggests that IBD-associated IgAN have frequent inflammatory lesions at onset and variable long-term outcome.

Renal involvement in children and adolescents with inflammatory bowel disease

Purpose

The incidence of inflammatory bowel disease (IBD) is rapidly increasing, and several reports have described the renal complications of IBD. We sought to evaluate the clinical manifestations of renal complications in children with IBD in order to enable early detection and prompt treatment of the complications.

Methods

We retrospectively reviewed the medical records of 456 children and adolescents aged <20 years who had been diagnosed with IBD since 2000. We analyzed patient age, sex, medication use, IBD disease activity, and clinical manifestations of renal symptoms.

Results

Our study comprising 456 children with IBD included 299 boys (65.6%) and 157 girls (34.4%). The study included 346 children with Crohn disease and 110 children with ulcerative colitis. The incidence of kidney-related symptoms was 14.7%, which was significantly higher than that in normal children. We observed 26 children (38.8%) with isolated hematuria, 30 children (44.8%) with isolated proteinuria, and 11 children (16.4%) with hematuria and concomitant proteinuria. A renal biopsy was performed in 7 children. Histopathological examination revealed immunoglobulin A nephropathy in 5 children (71.4%). All children presented with mild disease and well-controlled disease activity of IBD.

Conclusion

Children with IBD are more likely to show kidney-related symptoms than healthy children and adolescents are. Therefore, regular screening of urine and evaluation of renal function in such children are necessary for early detection of renal complications.

Renal Manifestations of Inflammatory Bowel Disease

Renal and urinary involvement has been reported to occur in 4% to 23% of inflammatory bowel disease (IBD) patients. Parenchymal renal disease is rare and most commonly affects glomerular and tubulointerstitial compartments. The most common findings on renal biopsy of IBD patients are IgA nephropathy and tubulointerstitial nephritis. Overall morbidity of IBD-related renal manifestations is significant, and there is often only a short window of injury reversibility. This, along with subtle clinical presentation, requires a high index of suspicion and routine monitoring of renal function. There are no established guidelines for the optimal screening and monitoring of renal function in IBD patients.

Iatrogenic Kaposi's Sarcoma in an HIV-Negative Young Male With Crohn's Disease and IgA Nephropathy: A Case Report and Brief Review of the Literature

BACKGROUND

Kaposi's sarcoma (KS) is a vascular tumor arising in association with human herpesvirus-8 (HHV-8) infection, and different variants show different clinical presentations. Isolated intestinal KS in the background of Crohn's disease (CD) is exceedingly rare with only 3 cases reported in the English literature (from 1966 to 2016).

CASE PRESENTATION

Herein, we report a case of intestinal KS in a 21-year-old HIV-negative Ethiopian male with a long-standing history of steroid therapy for his underlying IgA nephropathy. Recent gastrointestinal biopsies confirmed an additional diagnosis of CD. Despite the addition of Infliximab to his therapy, his CD remained refractory, and a laparoscopic-assisted ileocolectomy was performed to alleviate a partial small bowel obstruction. Examination of his terminal ileum demonstrated a polypoid mass with adjacent incidental ileal submucosal nodules. These nodules were composed of plump spindle cells with scattered mitoses and vascular channels with extravasated red blood cells. Intratumoral hyaline globules were also noted. Immunohistochemistry revealed HHV-8 positivity, confirming the histologic impression of KS.

CONCLUSIONS

Here we report the fourth case of KS in CD in an HIV-negative patient and only the third case of isolated intestinal KS in the setting of CD. A review of the literature suggests that attenuation of immunosuppressive therapy may be adequate management of iatrogenic KS in the absence of a systemic HHV-8 infection.

Renal Involvement in Inflammatory Bowel Diseases

The prevalence of extraintestinal manifestations in inflammatory bowel diseases varies from 6% to 46%. The aetiology of extraintestinal manifestations remains unclear. There are theories based on an immunological response influenced by genetic factors. Extraintestinal manifestations can involve almost every organ system. They may originate from the same pathophysiological mechanism of intestinal disease, or as secondary complications of inflammatory bowel diseases, or autoimmune diseases susceptibility. The most frequently involved organs are the joints, skin, eyes, liver and biliary tract. Renal involvement has been considered as an extraintestinal manifestation and has been described in both Crohn's disease and ulcerative colitis. The most frequent renal involvements in patients with inflammatory bowel disease are nephrolithiasis, tubulointerstitial nephritis, glomerulonephritis and amyloidosis. The aim of this review is to evaluate and report the most important data in the literature on renal involvement in patients with inflammatory bowel disease. Bibliographical searches were performed of the MEDLINE electronic database from January 1998 to January 2015 with the following key words (all fields): (inflammatory bowel disease OR Crohn's disease OR ulcerative colitis) AND (kidney OR renal OR nephrotoxicity OR renal function OR kidney disease OR renal disease OR glomerulonephritis OR interstitial nephritis OR amyloidosis OR kidney failure OR renal failure) AND (5-aminosalicylic acid OR aminosalicylate OR mesalazine OR TNF-α inhibitors OR cyclosporine OR azathioprine OR drugs OR pediatric).

The histopathologic spectrum of kidney biopsies in patients with inflammatory bowel disease

BACKGROUND AND OBJECTIVES

Kidney disease as a complication of inflammatory bowel disease (IBD), including Crohn disease (CD) and ulcerative colitis (UC), has been the subject of case reports. However, no cases series examining IBD and kidney disease has been published to date. This study aimed to evaluate a large series of kidney biopsy specimens from patients with IBD to better define the spectrum and relative frequencies of IBD-associated kidney pathology.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

A retrospective review of native kidney biopsy specimens obtained from March 2001 to June 2012 identified 83 patients with IBD. Standard processing of all biopsy specimens included light microscopy, immunofluorescence, and electron microscopy.

RESULTS

There were 45 cases of CD and 38 cases of UC represented. The most common indication for kidney biopsy was acute or chronic kidney failure (63% [52 of 83]) and nephrotic-range proteinuria (16% [13 of 83]). IgA nephropathy was the most common diagnosis (24% [20 of 83]), followed by interstitial nephritis (19% [16 of 83]), arterionephrosclerosis (12% [10 of 83]), acute tubular injury (8% [7 of 83]), proliferative GN (7% [6 of 83]), and minimal-change disease (5% [4 of 83]). When compared, the frequency of IgA nephropathy in IBD was significantly higher than in all other native renal biopsy specimens from the same time period (24% [20 of 83] versus 8% [2734 of 33,630]; P<0.001). Of the 16 cases of interstitial nephritis, 9 (56%) had current or recent past exposure to aminosalicylates, including all cases of granulomatous interstitial nephritis.

CONCLUSIONS

IBD is associated with a spectrum of kidney diseases most commonly affecting the glomerular and tubulointerstitial compartments. IgA nephropathy is the most frequent kidney biopsy diagnosis in IBD and has a significantly higher diagnostic prevalence compared with all non-IBD kidney biopsy specimens. This may reflect a common pathogenic mechanism. Although many cases of tubulointerstitial nephritis are related to aminosalicylate exposure, the possibility of a direct relationship with IBD cannot be ruled out.

In vitro-generated immune complexes containing galactose-deficient IgA1 stimulate proliferation of mesangial cells

IgA nephropathy (IgAN) patients have elevated serum levels of immune complexes consisting of IgA1 with galactose-deficient hinge-region O-glycans (Gd-IgA1) and anti-glycan IgG. These immune complexes deposit in the kidney and activate mesangial cells. To confirm that the activity of these immune complexes depends on the interaction of Gd-IgA1 with anti-glycan IgG, we generated in vitro analogous immune complexes using Gd-IgA1 myeloma protein and anti-glycan IgG from cord blood of healthy women. The Gd-IgA1 and anti-glycan IgG from cord-blood serum formed IgA1-IgG immune complexes that resembled those in sera of patients with IgAN. Furthermore, the ability to activate cellular proliferation was dependent on a heat-sensitive serum factor. In summary, we developed a new protocol for in-vitro formation of IgA1-IgG immune complexes, thus providing a new tool for studies of the pathogenesis of IgAN.

IgA nephropathy associated with thin basement membrane with or without inflammatory disease: getting a different prognosis?

BACKGROUND

Thin basement membrane nephropathy (TBMN) patients with additional inflammatory diseases and IgA nephropathy (IgAN) have not been reported before. It was unclear that if the prognosis of these patients is better or worse than patients with IgAN and TBMN, or IgAN patients with normal glomerular basement membrane (GBM).

METHODS

We first reported five TBMN patients with additional inflammatory diseases and IgAN: three were with rheumatoid arthritis, and two had Crohn's disease. Clinical and laboratory features were analyzed between this group (group 3), IgAN patients with normal GBM (group 1), and patients with TBMN and IgAN (group 2).

RESULTS

Significant differences were observed in serum levels of IgG, IgA, and IgM between groups 1 and 3, p < 0.001, and between groups 2 and 3, p < 0.001. Glomerular filtration rate (GFR) in group 3 was significantly lower than that of groups 1 and 2, p < 0.01, respectively.

CONCLUSION

The prognosis of these patients is worse than patients with IgAN and TBMN or IgAN patients with normal GBM. Serum immunoglobulin levels and GFR in these patients were different from patients with IgAN and TBMN, or IgAN patients with normal GBM.

Infliximab treatment for Crohn's disease in a patient with IgA nephropathy

We describe herein a case of IgA nephropathy in a 34-year-old woman with Crohn's disease (CD) treated with infliximab. CD first appeared at the age of 15 years. An elemental diet was started for remission maintenance. Ten years later, the patient suffered from a recto-vaginal fistula and subtotal colectomy with stoma formation was performed. At the age of 33 years, the patient was investigated for painless macroscopic hematuria and proteinuria. Renal biopsy revealed IgA nephropathy. Mizoribine was started but proteinuria persisted. Due to diarrhea she was admitted to our hospital, and scheduled maintenance therapy with infliximab was initiated. After the first infliximab infusion, the patient presented significant clinical improvement in both diarrhea and proteinuria with concomitant decrease of C-reactive protein to normal levels and proteinuria ~1 g/day. This represents the first report of infliximab treatment in a patient with IgA nephropathy associated with CD and clarifies the importance of tumor necrosis factor-alpha (TNFα) in immunity to renal disease. Further studies are needed to draw firm conclusions for the safety of infliximab in patients with IgA nephropathy.

IgA glycosylation and IgA immune complexes in the pathogenesis of IgA nephropathy

Circulating immune complexes containing aberrantly glycosylated IgA1 play a pivotal role in the pathogenesis of IgA nephropathy (IgAN). A portion of IgA1 secreted by IgA1-producing cells in patients with IgAN is galactose-deficient and consequently recognized by anti-glycan IgG or IgA1 antibodies. Some of the resultant immune complexes in the circulation escape normal clearance mechanisms, deposit in the renal mesangium, and induce glomerular injury. Recent studies of the origin of these aberrant molecules, their glycosylation profiles, and mechanisms of biosynthesis have provided new insight into the autoimmune nature of the pathogenesis of this common renal disease. An imbalance in the activities of the pertinent glycosyltransferases in the IgA1-producing cells favors production of molecules with galactose-deficient O-linked glycans at specific sites in the hinge region of the alpha heavy chains. By using sophisticated analytic methods, it may be possible to define biomarkers for diagnostic purposes and identify new therapeutic targets for a future disease-specific therapy.

Fulminant ulcerative colitis associated with steroid-resistant minimal change disease and psoriasis: A case report

A 43-year-old Chinese patient with a history of psoriasis developed fulminant ulcerative colitis after immunosuppressive therapy for steroid-resistant minimal change disease was stopped. Minimal change disease in association with inflammatory bowel disease is a rare condition. We here report a case showing an association between ulcerative colitis, minimal change disease, and psoriasis. The possible pathological link between 3 diseases is discussed.

[Secondary IgA-nephropathy in gastroenterological diseases]

IgA-nephropathy is the most common primary chronic glomerulonephritis worldwide. Beside the primary IgA-nephropathy (IgA-nephropathy with an unknown origin), there are more and more cases, which are associated with diseases of other organs. Although the causality is often not obvious, these forms are called secondary IgA-nephropathy. In this study, the authors cover only the secondary forms of IgA-nephropathy with relation to gastroenterology in a broader sense that includes the liver. They would like to draw the attention to the necessity of analyzing also the associate occurrence of gastrointestinal diseases (principally liver diseases, coeliac disease, Crohn's disease, ulcerative colitis) in patients with IgA-nephropathy, as well. They think that it would be expedient to organize a nationwide clinical analysis that would search the frequency of occurrence of IgA-nephropathy in the above mentioned gastrointestinal diseases.

Immunoglobulin A nephropathy complicating ulcerative colitis

Ulcerative colitis is rarely associated with immunoglobulin A nephropathy (IgAN). The development of IgA nephropathy complicates further the clinical course of patients with ulcerative colitis. A 72-year old man with a 30-year history of ulcerative colitis requiring colectomy and modest renal insufficiency secondary to complications of nephrolithiasis and renal artery stenosis developed glomerular hematuria, proteinuria and progressive renal failure. Percutaneous kidney biopsy revealed IgAN with extensive glomerular and interstitial sclerotic changes. After resection of a chronically infected ileo-rectal pouch, renal function improved, while hematuria and proteinuria gradually disappeared without specific treatment of the IgAN. The manifestations of IgAN complicating ulcerative colitis can be improved with effective treatment of the bowel disease even when there are extensive sclerotic changes in the kidneys.

Urogenital complications of Crohn's disease

Urogenital complications in Crohn's disease is a very narrow, specific area for consideration. The most frequent conditions that fall under this rubric include fistulous disease involving the genitourinary tract, nephrolithiasis, intrinsic renal diseases associated with Crohn's disease, and considerations in those who have had surgical procedures that alter normal pelvic anatomy. Fistulas involving the ureters, urinary bladder, and vagina are discussed. Nephrolithiasis is commonly in the form of calcium oxalate and uric acid, and is a well-known complication of Crohn's disease secondary to multiple mechanisms. Intrinsic renal disease is relatively rare and includes interstitial nephritis, amyloidosis, IgA nephropathy, and obstructive uropathy. Women who have undergone ileopouch anal anastomosis procedures are at risk for sexual dysfunction, dyspareunia, and decreased fecundity.

Microproteinuria in patients with inflammatory bowel disease: Is it associated with the disease activity or the treatment with 5-aminosalicylic acid?

AIM: To investigate whether microproteinuria in patients with inflammatory bowel disease (IBD) is associated with the disease activity or the treatment with 5-aminosalicylic acid (5-ASA).

METHODS: We prospectively studied microproteinuria in 86 consecutive patients with IBD, 61 with ulcerative colitis (UC) and 25 with Crohn’s disease (CD), before as well as 2 and 6 months after their inclusion in the study. Forty-six patients received 5-ASA for a period of 28.8 months (range 1-168 mo). Microalbuminuria (mALB) and urine levels of the renal tubular proteins β₂-microglobulin (β₂mGLB) and β-N-acetyl-D-glucosamidase (β-NAG) as well as the creatinine clearance were determined in a 12-h overnight urine collection. Tumor necrosis factor-α (TNF-α) serum levels were also measured.

RESULTS: A total of 277 measurements (194 in UC patients and 83 in CD patients) were performed. The prevalence of abnormal microproteinuria in UC and CD patients was 12.9% and 6.0% for mALB, 22.7% and 27.7% for β₂mGLB, and 11.3% and 8.4% for β-NAG, respectively. mALB was not associated with IBD activity. β₂mGLB and β-NAG urine levels were correlated to UC activity (UCAI: P<0.01; UCEI: P<0.005). mALB in UC patients and β-NAG urine levels in CD patients were related to TNF-α serum levels. An association was noticed between microproteinuria and smoking habit. Treatment with 5-ASA was not correlated to the severity of microproteinuria or to the changes of creatinine clearance.

CONCLUSION: Microproteinuria is mainly associated with UC and its activity but not affected by 5-ASA.

IgA nephropathy in association with Crohn's disease

BACKGROUND

Urological complications of inflammatory bowel disease are seen in up to 25% of patients, but renal parenchymal disease is rarely reported.

CASE REPORT

The authors describe a case of a 29-year-old man with clinical and radiological features of ileocaecal Crohn's disease. He had previously been investigated for painless macroscopic haematuria and a renal biopsy had revealed IgA nephropathy. Despite medical treatment, regular exacerbations of Crohn's disease were associated with deterioration in renal function and the development of haematuria. The patient eventually underwent surgical resection of the terminal ileum and caecum. His renal disease has remained quiescent for the last 5 years following resection.

IgA antiglomerular basement membrane nephritis associated with Crohn's disease: a case report and review of glomerulonephritis in inflammatory bowel disease

A case of glomerulonephritis in a 35-year-old man with Crohn's disease is described here. The patient presented with severe diarrhea, nephrotic range proteinuria, hematuria, microangiopathic hemolytic anemia, thrombocytopenia, hypocomplementemia, acute renal failure requiring hemodialysis, cryoglobulinemia, and extensive thrombotic gangrene of the distal upper and lower limbs. The patient did not respond to plasmapheresis and steroid therapy and died of upper gastrointestinal bleeding. Renal tissue obtained at autopsy showed IgA-mediated antiglomerular basement membrane crescentic glomerulonephritis. Linear staining of the glomerular basement membrane by non-IgG antibodies is quite unusual with only 11 cases previously reported in the worldwide literature, 8 caused by IgA. Glomerulonephritis is a rarely reported extraintestinal manifestation of inflammatory bowel disease, and there are only 24 previously described cases that are reviewed and summarized in this report. Glomerulonephritis occurred in the setting of active bowel inflammation in all cases, circulating immune complexes were found in nearly half the cases, and serum complements usually were normal. Renal insufficiency and nephrotic range proteinuria were typically present at the time of diagnosis of glomerulonephritis and most often improved in parallel with treatment of the gastrointestinal disorder. The histologic findings were varied and included membranoproliferative glomerulonephritis, mesangioproliferative glomerulonephritis, membranous nephropathy, IgA nephropathy, and IgM nephropathy. Thus, the authors present the first case of glomerulonephritis caused by antiglomerular basement membrane disease in association with inflammatory bowel disease.

Primary chronic interstitial nephritis in Crohn's disease

BACKGROUND & AIMS

In Crohn's disease, cases of interstitial nephritis with renal failure have been reported in connection with the use of mesalamine.

METHODS

We observed 4 patients with severe interstitial nephritis proven by examination of kidney biopsy specimens. Renal failure was discovered before or simultaneously with the diagnosis of Crohn's disease, and patients were not treated with mesalamine. Impairment of renal function progressed to end-stage renal failure in 3 of the 4 patients.

RESULTS

Our results show that the kidney can be an extraintestinal target of Crohn's disease.

CONCLUSIONS

Several unanswered questions remain concerning the frequency of interstitial nephritis in patients with Crohn's disease, as well as the exact role of mesalamine in the development of chronic interstitial nephritis.

The comorbid occurrence of other diagnoses in patients with ulcerative colitis and Crohn's disease

OBJECTIVES

The comorbidity between inflammatory bowel disease (IBD) and other diagnoses may help to shed light on the etiology and pathophysiology of IBD. The US Vital Statistics offer the opportunity to study causes of death broken down by comorbid disease associations. The aim of this study was to analyze the presence of comorbid conditions in persons who died from ulcerative colitis or Crohn's disease.

METHODS

The numbers of deaths from ulcerative colitis and Crohn's disease were retrieved from the computerized 1991-1996 data files of the National Center for Health Statistics. Comorbid associations between other diagnosis and ulcerative colitis or Crohn's disease were expressed as age-, gender-, and race-standardized proportional mortality ratios.

RESULTS

Ulcerative colitis and Crohn's disease showed, in general, similar patterns of comorbidity. Both diseases were associated with similar sets of GI complications, such as intestinal obstruction and stasis, mucosal inflammation and infection, vascular complications, and complications related to fistula and abscess formation. Extraintestinal complications of both IBD involved disorders of the hepatobiliary system, urinary system, and various coagulopathies. Ulcerative colitis alone was found to be associated with Hirschsprung's disease and schizophrenia, whereas Crohn's disease alone was found to be related with osteoporosis and amyloidosis.

CONCLUSIONS

No completely unexplained or hitherto undescribed association was revealed. The numerous intestinal and extraintestinal complications associated with IBD serve as a reminder of the systemic nature and the resultant clinical severity of both ulcerative colitis and Crohn's disease.

Review article: interstitial nephritis associated with the use of mesalazine in inflammatory bowel disease

5-Aminosalicylic acid (5-ASA) has replaced sulphasalazine as first line therapy for mild to moderately active inflammatory bowel disease and is widely used. A number of reports have linked oral 5-ASA therapy to chronic tubulo-interstitial nephritis and this relationship is now well established. Despite increasing recognition of the potential for this serious adverse event, guidelines for monitoring renal function in patients prescribed 5-ASA preparations are not widely employed. Whilst the incidence of this adverse event in the population of patients with inflammatory bowel disease treated with mesalazine is low, the morbidity in an affected individual is high with some cases progressing to end-stage renal disease. Routine monitoring of renal function is simple and inexpensive and could prevent this outcome. Based on the available data, serum creatinine should be estimated prior to commencing treatment, monthly for the first 3 months, 3-monthly for the next 9 months, 6-monthly thereafter and annually after 5 years of treatment.