Non-calculous obstructive uropathy, i.e. hydronephrosis and hydroureter result from ileal Crohn s disease often with psoas abscess. Urinalysis is usually normal. A CAT scan will delineate the lesion and surgery should be directed at the primary disease and not ureterolysis. Amyloidosis of the kidney occurs in Crohn s and almost never in ulcerative colitis. Amyloidosis also causes nephrotic syndrome, and should be suspected in the presence of carpal tunnel syndrome or worsening and disproportionately severe malabsorption.
Diagnosis requires histologic proof either by rectal or gingival biopsy.
A trial of colchicine may be worthwhile. Occasionally, resection of the affected bowel has been associated with regression of amyloid deposits. Enterovesical fistulae represent a communication usually between the bladder, although colovesical fistulae may present in a similar manner with pneumaturia and urinary tract infection. Interestingly, air bubbles in the urine often go unreported unless specifically queried by the physician. Such fistulae are usually well tolerated without the expected crises of ascending pyelonephritis or progressive renal insufficiency.