Clinical Case Summary

Introduction: Inflammatory Bowel Disease (IBD), which includes Crohn's Disease (CD) and Ulcerative Colitis (UC), is often linked with immune-mediated diseases such as spondylitis, psoriasis, and uveitis. However, its association with Primary Membranous Nephropathy (PMN) is not well-documented, with only eight cases reported since 1985. Of these, five are associated with UC and three with CD. Interestingly, antibodies against the phospholipase A2 receptor (PLA2R), found in 70% of PMN cases, are also prevalent in most IBD cases linked to PMN.
Case report: A 41-year-old male with anti-PLA2R positive PMN, treated with prednisone and tacrolimus, was admitted in January 2022 for abdominal pain and constitutional syndrome. Gastro-colonoscopy, abdominal CT, fecal calprotectin (FC), celiac serology, and stool parasite/culture tests no significant findings.
One year later, he was readmitted with severe abdominal pain and bloody diarrheal stools (6-7times/day). Blood tests showed a CRP of 17.26mg/dL and FC of 8000mg/Kg. Abdominal CT: infectious/inflammatory process in the descending and transverse colon (Figure 1). Colonoscopy: involvement from 50cm from the anal margin to the ileocecal valve, with friable mucosa, deep linear ulcers affecting 100% of the circumference (Figures 2, 3). Biopsies showed distorted colonic mucosa with granulomas (compatible with CD). The patient started vedolizumab and increased tacrolimus doses due to potential corticosteroid failure. He has shown clinical improvement, with normalized FC and CRP levels, and remains on vedolizumab and tacrolimus therapy.
Discussion: Renal complications in IBD are rare but can include amyloidosis, tubulointerstitial nephropathy related to Mesalazine treatment, and glomerulonephritis, often linked with IgA nephropathy. For patients with positive anti-PLA2R PMN or other forms of glomerulonephritis who also show gastrointestinal symptoms, it´s essential to perform complementary tests to effectively exclude underlying IBD.

References

Figure 1: Abdominal CT scan: Thickening of the descending and transverse colon
Figures 2 and 3: Colonoscopy: Friable mucosa with linear, punched-out, and deep ulcers affecting 100% of the circumference.