Pancreatic allograft exocrine urinary tract diversion. Pathophysiology

Exocrine secretions of 16 of 22 pancreas allografts were drained into the urinary tract. Seven of these 16 patients have functioning allografts, six with pancreaticocystostomies and one with duct-to-ureter anastomosis. A notable problem has been a chronic metabolic acidosis, along with weight loss and hypotension, secondary to chronic bicarbonate loss and volume depletion through the urinary pancreatic fistula. This occurred as early as one week posttransplant, and intermittently thereafter up to four years. The syndrome was aggravated by episodes of renal dysfunction (acute tubular necrosis or rejection), and febrile syndromes. An inverse relationship between serum and urine bicarbonate concentrations existed, with a correlation coefficient, r = -0.746, (P less than 0.05). A negative correlation was also noted between serum bicarbonate and serum creatinine, r = 0.726, (P less than 0.05). Hyperchloremic metabolic acidosis with normal anion gap occurred despite periods of marginal pancreas allograft function resulting from ongoing rejection. Treatment consisted of intravenous and/or oral bicarbonate supplementation, and bicarbonate dialysis for uremic patients. In addition, one patient was first seen with severe balanitis and urethritis due to documented activation of trypsinogen and chymotrypsinogen, presumably caused by recurrent episodes of urinary tract infection. Urinary assay revealed a 10(2-3) increase in activated trypsin and chymotrypsin in comparison with other asymptomatic allograft recipients. Conversion to ductal enteric drainage led to resolution of both the balanitis and bicarbonate wasting. Measurement of urinary amylase levels were gross indicators of graft viability since no correlation could be found between these levels, onset of hyperglycemia, and eventual graft rejection confirmed by pathological examination.