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Acute rejection occurs in approximately 40% of recipients who receive prednisone, cyclosporine, ± azathioprine. The incidence of acute rejection is lowered with the addition of either an anti–IL -2 receptor antibody (see I H 7) or replacing azathioprine with mycophenolate mofetil. Only 20% of perfect-match living related recipients will experience acute rejection.

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Treatment is pulse corticosteroids or antilymphocyte sera. Approximately 80% of episodes of acute rejection are reversible. If the episode is irreversible, the graft fails and the patient returns to dialysis.

Chronic rejection is reflected in the half -life (Table 24 -4). A prior episode of acute rejection is the strongest predictor of increased risk of chronic rejection. Chronic rejection results in graft failure and return to dialysis.

Surgical complications are not uncommon, and they can usually be treated if they are recognized at an early stage.

Vascular complications include renal artery stenosis or thrombosis and renal vein thrombosis and occur in 3%–5% of recipients. Patients may present with sudden anuria or hypertension.

Lymphatic complications occur in less than 5% of recipients and appear as a perinephric lymph collection (lymphocele). The diagnosis is made by decreased urine output or an elevated creatinine level, which prompts a diagnostic ultrasound. The lymphocele is drained by percutaneous aspiration or, optimally, by (laparoscopic) drainage into the peritoneal cavity.

Urologic complications occur in less than 10% of renal transplant patients and include urine leakage at the ureter -bladder anastomosis and ureter obstruction or infarction caused by compromise of the ureteral blood supply, which may occur during donor nephrectomy. Arteries leading to the lower pole of the kidney usually vascularize the upper ureter and must be preserved. The diagnosis of urologic complications can be confirmed by means of radioisotope scanning, ultrasound examination, or cystography.

VI Pancreas Transplantation

Pancreas transplantation provides an entire cadaver donor pancreas as an endogenous source of insulin to replace exogenous insulin for patients with type I insulin -dependent diabetes mellitus. With long-term euglycemia, improvement or stabilization of diabetic complications of the eyes, kidneys, and diabetic neuropathy can be demonstrated. Transplantation of the islets of Langerhans without the exocrine pancreatic tissue (islet transplants) is now performed under experimental protocols with excellent short-term results. As of yet, the longevity of islet transplants has not equalled that of whole pancreas transplants.

A

Candidates are usually 25–55 years of age, as it takes 10–20 years of diabetes to develop diabetic complications, particularly nephropathy.

Candidates can be considered in three groups.

Diabetic patients with end -stage renal disease are candidates for a simultaneous pancreas -kidney (SPK) transplant.

Diabetic patients with renal failure may opt for a kidney transplant first (particularly if they have a good living donor) and later undergo pancreas after kidney (PAK) transplantation.

Recipients without nephropathy but with other severe complications (e.g., retinopathy, severe neuropathy, hypoglycemic unawareness) are candidates for pancreas transplantation alone (PTA).

The high prevalence of coexistent coronary artery disease mandates cardiac evaluation , including stress testing.

Contraindications to pancreas transplantation include age higher than 60 years, severe peripheral vascular or coronary artery disease, obesity, and type II diabetes.

B

Donors are younger than 60 years. Contraindications to donation include current or prior pancreatitis, pancreatic damage from trauma, diabetes (any type), and alcoholism.

Operatively, the blood supply of the liver and pancreas of the donor must be identified and shared when both organs will be used.

Pancreas donors also donate the iliac artery bifurcation for arterial reconstruction.

The spleen is removed with the pancreas and is separated after revascularization.

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C Types of operations

SPK transplantation. Rejection is the most common cause of pancreas graft loss. Unfortunately, it is difficult to diagnose and often is irreversible. An important advantage to SPK transplantation is that the kidney serves as a marker for rejection of the pancreas.

Advantages. Other advantages to SPK transplantation include the following:

Only one surgery is needed.

High doses of induction immunosuppression drugs are needed only once.

Disadvantages to SPK transplantation are the extended procedure for some patients and, until recently, the inability to use potential living kidney donors. A newer procedure, the simultaneous cadaver pancreas and living donor kidney transplantation (the SPLK), is currently used in select centers. This procedure avoids the necessity of two separate operations.

PAK transplantation

Advantage. The advantage to the PAK approach is that this group is selected by their good response to a kidney transplant. It is hoped that these patients have a relatively low risk of rejection.

Disadvantages include two separate procedures: a repeat course of induction immunosuppression drugs, and the kidney not serving as a marker for rejection because the pancreas is from a different donor.

D Operative strategy

Anatomy. Embryologically, the pancreas is derived at the foregut -midgut junction and therefore receives blood supply from the celiac axis and the superior mesenteric artery. The splenic artery from the celiac axis supplies the tail, whereas the inferior pancreaticoduodenal arteries from the superior mesenteric artery supply the head.

Recipients receive the whole pancreas along with a segment of duodenum.

The exocrine secretions pass via the ampulla of Vater into the duodenum, which is anastomosed either to the bladder or to the small bowel.

In children, causes include congenital atresias, volvulus, necrotizing enterocolitis, and gastroschisis.

In adults , causes include Crohn's disease, volvulus, trauma, and vascular accidents, such as superior mesenteric artery occlusion.

C Operative strategy

Venous outflow can be to the portal or systemic veins. Options for gastrointestinal continuity include no bowel anastomoses and two stomas, two bowel anastomoses and no stomas, or one bowel anastomosis and one stoma. The last option is preferred because it provides proximal bowel continuity plus a distal stoma for easy biopsy access.

D

Postoperative immunosuppression is usually with tacrolimus plus other drugs.

E

Complications include sepsis, stomal complications (including retraction and ischemia), and graft failure resulting from vascular thrombosis or hemorrhage. Lymphatic drainage problems are usually short term but may affect longchain fatty acid absorption.

Because the small bowel is rich in lymphoid tissue, graft-versus-host disease has been a problem more prevalent in small bowel transplantation than in other organ transplants. This cascade of events is caused by the proliferation of donor-derived immunocompetent cells manifested as skin rash, diarrhea, altered liver functions, and anemia and can appear in the intestine as sloughing, shortening, and blunting of the villi.

Graft function is monitored by looking at various absorption studies (including ethylenediaminetetraacetic acid [EDTA] and maltose) and direct biopsy techniques.

The histologic appearance of the gut during rejection includes blunting of microvilli, mononuclear infiltration of the intestinal wall, and epithelial cell attenuation.

F

Graft survival rates have been reported to be approximately 70% at 1 year for small bowel only and approximately 60% for liver and small bowel. Experience is still limited, and surgical and immunologic challenges lie ahead.

Chapter 25

Urologic Surgery

Hunter Wessells

Bruce L. Dalkin

I Urinary Tract Infections

A Definitions

Bacteriuria is the presence of bacteria in the bladder. It can occur with or without pyuria and can be symptomatic or asymptomatic.

Pyelonephritis is a clinical syndrome with fever, chills, and flank pain accompanied by bacteriuria and pyuria.

Cystitis is an inflammatory condition of the bladder. It can be bacterial or nonbacterial (e.g., radiation, interstitial, fungal causes).

Reinfection signifies recurrent infection with different bacteria from outside the urinary tract.

Relapse indicates recurrent infection caused by the same bacterial strain from a focus within the urinary tract.

Prophylactic antimicrobial therapy refers to prevention of reinfection of the urinary tract by administration of antimicrobial therapy.

Suppressive antimicrobial therapy is used to suppress an existing urinary tract infection (UTI) that cannot be eradicated.

B Etiology

Ascending infection. Most UTIs are thought to result from ascending colonization from the introitus in women or from the periurethral area in men. Fecal flora are the most common pathogens, including Escherichia coli , other gram -negative rods, and entercocci. Other pathogens include staphycoccal species.

Incidence. UTIs are more common in women than in men, possibly because women have a shorter urethra. There may also be a protective effect of the prostatic urethra in men. Newer concepts of bacterial adherence factors in the bladder are being investigated.

C Clinical presentation

Cystitis symptoms include:

Urinary frequency

Urgency

Dysuria

Cloudy or foul -smelling urine

Hematuria

Pyelonephritis symptoms include all of the symptoms of cystitis plus fever, chills, and flank pain.

DDiagnosis

Urinalysis

Pyuria. The presence of white blood cells in the urine indicates inflammation.

Bacteriuria. The detection of bacteria in the urine may require a Gram stain.

Nitrate reduction. Nitrate in the urine is reduced to nitrite in the presence of bacteria.

Leukocyte esterase. White blood cells contain esterases that can be detected in the urine.

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Urine culture is performed on a split agar disposable plate and determines the presence of bacteria in the

urine. The common quantization for infection is ≥10 - 5 bacteria. However, lower numbers present in symptomatic patients may signify infection.

E Treatment

Choice of antimicrobial agent

Uncomplicated cystitis. Good results have been obtained with ampicillin, amoxicillin, first -generation cephalosporins, fluoroquinolones, nitrofurantoin, and trimethoprim-sulfamethoxazole. Regional differences in antibiotic resistance exist and should dictate choice of antimicrobial agent.

Complicated UTI. Fluoroquinolones or parenteral regimens are recommended for initial empirical therapy of a UTI associated with significant anatomic or structural abnormality of the urinary tract or with acute pyelonephritis or prostatitis.

Duration of therapy

Uncomplicated cystitis therapy lasts for 1–3 days.

Complicated UTI therapy lasts for 7–14 days.

Acute prostatitis therapy is given over 14–28 days.

Pyelonephritis therapy lasts for 14–21 days.

F Serious complications of a UTI

Renal papillary necrosis. Sloughing of the renal papillae is frequently seen in diabetic patients. This sloughing can cause ureteral obstruction and hydronephrosis.

Pyonephrosis is infected hydronephrosis associated with infectious destruction of renal parenchyma. Usually, the patient is very ill and has a fever and chills.

Cause. Obstruction (e.g., ureteral calculus) with infection

Treatment

Ureteral catheter drainage