Tubulointerstitial nephritis as an extraintestinal manifestation of Crohn's disease.
BACKGROUND
A 12-year-old boy presented to hospital with a 6-month history of crampy pre-defecation abdominal pain, non-bloody diarrhea, anorexia and weight loss. Investigations revealed hypochromic microcytic anemia, a low serum iron level, a low serum ferritin level and an elevated serum creatinine level. Histopathological examination of tissue specimens obtained at esophagogastroduodenoscopy and colonoscopy revealed features of Crohn's disease, and a renal biopsy demonstrated tubulointerstitial nephritis. A second case of tubulointerstitial nephritis in a patient with Crohn's disease, is also presented.


METHODS
Physical examination, laboratory tests including full blood count, electrolytes, renal function, serum albumin, urinalysis and 24 h urinary protein, esophagogastroduodenoscopy, colonoscopy, abdominal ultrasonography, dimercaptosuccinic acid scan, renal diethylene triamine pentaacetic acid clearance study and renal biopsy.


METHODS
Tubulointerstitial nephritis secondary to Crohn's disease.


RESULTS
Prednisone therapy (60 mg/day) for 1 month followed by a tapering schedule over 3 months.
Waters
Aoife M
AM
Hospital for Sick Children, Toronto, ON, Canada. aoife.waters@sickkids.ca
Zachos
Mary
M
Herzenberg
Andrew M
AM
Harvey
Elizabeth
E
Rosenblum
Norman D
ND
D002648:Child; D003424:Crohn Disease / Q000150:complications*; D006801:Humans; D008297:Male; D009395:Nephritis, Interstitial / Q000209:etiology*