Figure 1515

Indications for enteric conversion (EC). A set of complications unique to pancreas transplantation arise as a consequence of urinary diversion of graft exocrine secretions. The development of one of these complications is the most frequent cause for re-admission to the hospital after pancreas transplantation with BD. These include the following: persistent gross hematuria, recurrent or chronic urinary tract infections (UTIs), urethritis, urethral stricture or disruption, urinary or pancreatic enzyme leak, graft (reflux) pancreatitis, and excessive bicarbonate loss and acidosis [18]. Surgical conversion to ED is indicated when these complications are incapacitating or refractory to conservative therapy. Except for leaks and pancreatitis, these complications are largely avoided in ED pancreas grafts.

Hematuria in the immediate postoperative period is usually mild and self-limited, occasionally requiring irrigation, cytoscopic fulguration, or both. Hematuria occurring late after transplantation (ie, months to years) may be caused by UTIs, suture granulomas, bladder stones, or ulceration of the duodenal segment. In total, hematuria occurs in 17% of patients. Conversion to ED is indicated when hematuria persists despite appropriate therapy and is required in up to a third of patients who present with late or chronic hematuria.

Pancreatic enzyme or urinary leaks also can occur in the early postoperative period or as late as several years after transplantation. Early leaks usually occur at the bladder-duodenum suture line, whereas late leaks occur most commonly at the lateral duodenal staple line or at the location of a duodenal ulcer. The cause is unclear. Whereas some early leaks may be technically related, late leaks are more likely a result of rejection, cytomegalovirus infection, ischemia, or a combination of all these. Patients usually present with sudden-onset lower abdominal pain, fever, leukocytosis, increased serum amylase and slightly increased creatinine. Diagnosis is confirmed by cystogram (see Fig. 15-17). Fortunately this complication is unusual, occurring in 10% to 15% of patients.

The most common infectious complication after pancreas transplantation is UTI, occurring in 63% of pancreas transplant recipients with BD. These recipients may be more predisposed to UTIs than are kidney transplant recipients because of the additive effect of several factors. These factors include alkalinization of the urine secondary to bicarbonate exocrine secretion, presence of a diabetic neurogenic bladder with incomplete emptying, mucosal injury at the bladder anastomosis, and prolonged catheter drainage. Occasionally, a cause for therapy-resistant or recurrent infections is found on cystoscopy and study of the upper tracts also is indicated. When no source is found, EC is indicated.

If persistent, urethritis may result in urethral stricture, disruption, or both. Although its exact cause is unclear, urethritis is most likely caused by the digestive action of pancreatic enzymes on the urothelium. Urethritis usually is manifested as perineal pain and discomfort during urination and seems to occur almost exclusively in males. Initially, conservative treatment with Foley catheter drainage for several weeks is recommended. When perforation occurs, it usually is in the membranous portion of the urethra and presents with perineal and testicular swelling. To avoid complications of urethral stricture and disruption, early enteric conversion is recommended when urethritis fails to respond to an initial short course of conservative treatment. Fortunately, these complications are unusual, occurring in only 5% of simultaneous pancreas-kidney (SPK) transplantation recipients.

Early postoperative hyperamylasemia, thought to be caused by preservation injury, is not uncommon and, fortunately, usually is asymptomatic and improves rapidly. Persistent or marked elevations of amylase indicate possible technical errors, including ductal ligation or leak. Graft pancreatitis (sometimes referred to as reflux pancreatitis) presents in a manner similar to that of a leak. Graft pancreatitis is further defined by absence of a leak on radi-ologic study; evidence of gland edema on CT scan, without evidence of abscess or fluid collections; and; most important, resolution of symptoms within 48 hours of Foley catheter drainage. Treatment with Foley catheter drainage for several days is usually successful. When an infection is found in the patient's urine at this time, appropriate parenteral antibiotics may be beneficial.

Metabolic acidosis is present postoperatively in about 80% of patients after pancreas transplantation with BD and usually is due to excessive urinary loss of bicarbonate-containing exocrine fluids. Because urinary bicarbonate loss is accompanied by an obligate loss of fluid, low serum levels are associated with dehydration. Oral fluid replacement should be instituted to maintain a serum bicarbonate level of at least 20 to 25 mg/dL, and dehydration is treated appropriately. Fortunately, this problem usually stabilizes over time and infrequently requires conversion from bladder to enteric drainage.

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