title: A case of rapidly progressive IgA nephropathy in a patient with exacerbation of Crohn's disease.
abstract: BACKGROUND
  IgA nephropathy has been reported as a renal involvement in Crohn's disease. Crescentic IgA nephropathy, which accounts for fewer than 5% of cases of IgA nephropathy, has a poorer prognosis than other forms of crescentic glomerulonephritis. We recently experienced a case of rapidly progressive IgA nephropathy concurrent with exacerbation of Crohn's disease.
  
  
  METHODS
  An 18-year-old male diagnosed with Crohn's disease underwent a hemicolectomy 2 years prior previously. He had maintained a state of Crohn's disease remission with 5-aminosalicylic acid treatment. Four months prior to referral to the nephrology clinic, he experienced non-bloody diarrhea. He simultaneously developed proteinuria and microscopic hematuria with deterioration of renal function. Based on renal biopsy findings, the patient was diagnosed with crescentic IgA nephropathy. Immunostaining for interleukin-17 in renal tissue and previous exacerbated colonic ulcers was positive. Steroid pulse therapy was administered, followed by high-dose glucocorticoid and oral cyclophosphamide therapy. The patient's renal function recovered and his gastrointestinal symptoms were alleviated.
  
  
  CONCLUSIONS
  We report a case of crescentic IgA nephropathy presenting with exacerbation of Crohn's disease, and present a review of the literature focusing on the pathophysiologic relationship between these two conditions.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Kyungpook National University School of Medicine and Clinical Research Center for End Stage Renal Disease in Korea, 130 Dongduk-ro, Jung-gu, Daegu, South Korea.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Choi
authors.forename: Chung Hoon
authors.initials: CH
authors.lastname: Yu
authors.forename: Hee-Yeon
authors.initials: HY
authors.lastname: Jung
authors.forename: Min Kyu
authors.initials: MK
authors.lastname: Jung
authors.forename: Yong-Jin
authors.initials: YJ
authors.lastname: Kim
authors.forename: Jang-Hee
authors.initials: JH
authors.lastname: Cho
authors.forename: Chan-Duck
authors.initials: CD
authors.lastname: Kim
authors.forename: Yong-Lim
authors.initials: YL
authors.lastname: Kim
authors.forename: Sun-Hee
authors.initials: SH
authors.lastname: Park
mesh_terms: D000293:Adolescent; D003424:Crohn Disease / Q000150:complications* / Q000175:diagnosis* / Q000188:drug therapy; D005922:Glomerulonephritis, IGA / Q000175:diagnosis* / Q000188:drug therapy / Q000209:etiology*; D006801:Humans; D008297:Male; D013256:Steroids / Q000627:therapeutic use; D016896:Treatment Outcome
chemical_list: D013256:Steroids