Granulomatous Interstitial Nephritis as the Presenting Manifestation of Crohn’s Disease: A Case Report and Review of Literature

Abstract

Introduction: Extraintestinal manifestations are reported in 6-47% of patients with IBD and may be diagnosed before, concurrently. or after the diagnosis of IBD. We hereby report an unusual presentation of granulomatous interstitial nephritis preceding the GI manifestations of Crohn’s disease. Case Report: A 17-year-old male with history of obesity and attention deficit hyperactivity disorder on dextroamphetamine presented with new onset of acute kidney injury with creatinine (Cr) level of 4.5 mg/dL. After an extensive negative blood work, renal biopsy was performed, which revealed marked chronic granulomatous tubulointerstitial nephritis. Further work-up for granulomatous disease (chest CT) was negative. Prednisone was initiated for presumed autoimmune process and the serum Cr improved to 2-3 mg/dL. Six months later, the patient developed chronic watery, non-bloody diarrhea. Colonoscopy with terminal ileal biopsy showed active enteritis with granulomatous inflammation consistent with Crohn’s disease. Azathioprine and prednisone were initiated with modest response. Infliximab was then started and his diarrhea resolved. His renal function was restored back to baseline. Unfortunately, he was lost to follow-up and did not receive infliximab. His serum Cr worsened to 9.2 mg/dL. Infliximab was promptly reinstituted and his Cr again improved to his baseline. However, his renal function gradually deteriorated and he eventually needed renal transplant after 5 years from the initial diagnosis. Discussion: To our knowledge, this is the first case of Crohn’s with renal involvement preceding GI symptom. Table 1 summarizes a total of 9 previously reported patients with granulomatous tubulointerstitial nephritis related to Crohn’s disease. All the cases progressed to chronic kidney disease; 2 with end stage renal disease. Eight cases initially presented with GI manifestations; 1 with both diarrhea and renal failure. In conclusion, granulomatous interstitial nephritis associated with Crohn’s disease usually portends a poor prognosis. It is important for clinicians to promptly recognize it as a possible extraintestinal manifestation of Crohn’s disease, as this condition often demands early aggressive treatment with immunomodulators.Table 1