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Case Report

mphysematous Pyelonephritis inialysis Patient After Embolizationf Failed Allograft

lberto Ortiz, Vladimir Petkov, Jose Urbano, Julio Contreras, Simona Alexandru,licia Garcia-Pérez, Ana Ramos, Jesus M. Cabrera, Marta Albalate, anduan V. Garcia-Cardoso

mphysematous pyelonephritis is an uncommon acute infection characterized by the presence of gas in the renalarenchyma. Diabetics account for most cases, and the mortality rate is high. We report a case of emphysematousyelonephritis after therapeutic embolization of a nonfunctioning renal graft in a nondiabetic dialysis patient. Givenhe increasing popularity of therapeutic embolization to control graft intolerance syndrome associated with rejectedidneys, physicians should be aware of this potentially severe complication. We discuss the differential diagnosis fromntities requiring different management strategies, such as postembolization syndrome, persistence of graft intolerance,

nd the presence of sterile intrarenal. UROLOGY 70: 372.e17–372.e19, 2007. © 2007 Elsevier Inc.

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mphysematous pyelonephritis is an uncommonacute necrotizing infection characterized by thepresence of gas in the renal parenchyma.1 It usually

evelops in patients with defined risk factors, such asiabetes mellitus. Rapid progression to septic shock canccur, and it carries an overall mortality rate of approx-mately 50%.1 Emphysematous pyelonephritis can infre-uently occur in functioning renal grafts and is excep-ional in nonfunctioning grafts.2 Embolization ofonfunctioning renal grafts is increasingly used as a less-

nvasive alternative to nephrectomy when clinical intol-rance of a chronically rejected graft occurs.3–6 As therocedure becomes more widely used, the occurrence ofomplications will likely increase. One of the main com-lications is infection, which can be difficult to diag-ose.3–5 We report a case of emphysematous pyelonephri-is after therapeutic embolization of a nonfunctioningenal graft and discuss the differential diagnosis.

ASE REPORT40-year-old white man in hemodialysis was admitted

ecause of fever and septic signs 3 weeks after emboliza-ion of a nonfunctioning renal graft. He had end-stageenal disease secondary to reflux nephropathy and neu-ogenic bladder related to myelomeningocele. A kidneyraft had been implanted in 1996, but hemodialysis was

. Ortiz has been supported by the Programa de Intensificación de la Actividadnvestigadora in the Sistema Nacional de Salud of the Instituto de Salud Carlos III andhe Agencia “Pedro Laín Entralgo” of the Comunidad de Madrid.

From the Departments of Nephrology, Radiology, and Urology, Fundación Jiménezíaz, Madrid, SpainAddress for correspondence: Alberto Ortiz, M.D., Unidad de Diálisis, Fundación

ciménez Díaz, Av Reyes Católicos 2, Madrid 28040, Spain. E-mail: aortiz@fjd.es

Submitted: December 29, 2006; accepted (with revisions): April 30, 2007

2007 Elsevier Inc.ll Rights Reserved

esumed in February 2005, because of chronic allograftephropathy. Graft intolerance syndrome appeared afteriscontinuing immunosuppressive therapy. The signs andymptoms of allograft intolerance included low-grade fe-er, erythropoietin resistance, hypoalbuminemia, and in-reased C-reactive protein and ferritin levels. The bloodnd urine cultures were negative. Low-dose steroids con-rolled the symptoms but could not be withdrawn with-ut reappearance of fever. His blood glucose levels wereormal. In July 2005, allograft embolization was per-

ormed in two steps. First, the small distal vessels of theenal parenchyma were occluded with 300 to 500-�molyvinylalcohol particles. Next, the main renal vesselsere occluded with cyanoacrylate mixed with lipiodol.efazolin (1 g intravenously) was administered at theeginning of the procedure. Neither local complicationsor nontarget embolization occurred. Complete occlu-ion of the intrarenal arteries was confirmed by Dopplerltrasonography. Transient hematuria developed aftermbolization, and his fever reappeared within 24 hours ofmbolization. Pain over the graft was noted and the-reactive protein level had increased further, all consis-

ent with postembolization syndrome.Three weeks after embolization, he was readmitted

ecause of persistent fever and the recent development ofemodynamic instability. At admission, the significant

aboratory data included leukocytosis and neutrophilia.he urine and blood cultures remained negative. Empir-

cal antibiotic therapy with vancomycin and gentamicinas started. A renal sonogram showed ill-defined, highlyyperechogenic foci in the graft related to gas formation.ultidetector computer tomography of the abdomen

Fig. 1) showed an enlarged graft that contained paren-

hymal gas, as well as hyperdense material in the hilum

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orresponding to the embolization material. Drainageielded purulent material, with growth of Bacteroides cap-llosus. Graft nephrectomy was performed. The histologictudy showed a massive renal infarction, extensive puru-ent inflammatory material, and polyvinylalcohol parti-les. He recovered fully from the episode with normal-zation of systemic inflammation parameters.

OMMENTour groups have published series of 25 or more patientsreated with arterial embolization of the kidney for graftntolerance syndrome3–6 (Table 1). Embolization wasomplicated by a purulent infection of the graft in 0% to0% of the patients.3–6 At least 1 case of emphysematousyelonephritis was noted.3 The lack of clinical data inhe other reports4,5 does not exclude additional cases ofmphysematous pyelonephritis.

Emphysematous pyelonephritis in renal allografts hasemained an infrequent condition. Only 17 cases haveeen reported,2 including the present one.3,7,8 Most cases

igure 1. (A) Axial and (B) coronal multidetector computeromography images showing enlarged renal graft whosearenchyma has been replaced by a fluid and gas collectionelimitated by renal capsule (short arrows). Note, presencef embolization material (lipiodol) in renal hilum (longrrows).

ccurred in functioning grafts.2,3,7,8 The transplant pa- m

72.e18

ients usually had classic risk factors for emphysematousyelonephritis, such as diabetes. However, we would likeo emphasize the occurrence of the disease in 3 dialysisatients with nonfunctioning grafts (Table 2). The caus-tive microorganisms can differ from patients with func-ioning grafts, in whom the disease was caused by Enter-bacteriaceae.2,7,8 A coagulase-negative staphylococcus,uggesting blood-born infection, was isolated in a hemo-ialysis patient,9 and our case was caused by an anaerobe.he occurrence of at least 2 cases among a relatively lowumber of reported graft embolization patients (the foureries summarized in Table 1 equal 136 patients, plus 12atients who underwent embolization at our institution).his suggests that emphysematous pyelonephritis mighte especially frequent after graft embolization, althoughdditional studies are needed to confirm this hypothesis.ven in patients who are not diabetic (the leading causef end-stage renal disease in many countries), other riskactors for emphysematous pyelonephritis are commonlyound in patients undergoing graft embolization. Thesenclude ischemia, immunosuppression, and, in someases, urinary tract abnormalities.

Certain diagnostic aspects of emphysematous pyelone-hritis after graft embolization merit discussion. The di-gnosis of infection in this context can be problematic.n the largest series, a preoperative diagnosis of persistentraft intolerance was made in 2 of 5 patients subsequentlyhown to have purulent graft infections.4 The signs andymptoms of infection should be differentiated from feveraused by inflammation secondary to tissue necrosis (ie,he so-called postembolization syndrome) and from per-istent graft intolerance.3–6 In the particular case of em-hysematous pyelonephritis, the diagnosis is further com-licated by the transient presence of gas in asepticmbolized tissues10–13 and by radiologic artifacts causedy the embolization materials.The most frequent complication of percutaneous graft

mbolization is postembolization syndrome (Table 1). Itonsists of fever and local pain. The latency period ishort (24 to 48 hours), and the duration is variable, butt usually subsides within 1 week. However, fever canemain high for as long as 60 days.3 In addition, 8% to5% of patients have persistent graft intolerance syn-rome (Table 1), which can also be characterized byever and local pain.

The prolongation of fever beyond 10 to 14 days or theppearance of toxic manifestations should lead to addi-ional studies. The radiologic demonstration of gas in theenal parenchyma is required for the diagnosis of emphy-ematous pyelonephritis.1 Ultrasonography identifies gass ill-defined bright echogenic foci with shadowing in theidney. However, certain embolization materials, such asolyvinylalcohol particles, interfere with ultrasonographynd can mimic the presence of intrarenal gas. Comput-rized tomography allows for confirmation of the pres-nce of renal gas. The materials used to embolize the

ain renal artery, such as metal coils or lipiodol, have

UROLOGY 70 (2), 2007

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etal density and can induce artifactual images on com-uted tomography or magnetic resonance imaging. Thelinical context is important for the diagnosis of emphy-ematous pyelonephritis because gas can form in asepticmbolized tissues.10 The presence of gas is a frequentnding in the first few days after embolization.11 Theourse of aseptic parenchymal gas is benign, and in re-eated control imaging studies, the amount of gas willecrease, although it has been detected up to 3 weeksater.10,12,13

ONCLUSIONSe have presented the second case of an infrequent,

lthough severe, complication of therapeutic emboliza-ion of a nonfunctioning kidney graft. The diagnosis ofmphysematous pyelonephritis in this setting presentslinical and imaging obstacles and requires a high indexf suspicion. The symptoms should be differentiated fromersistent graft intolerance and postembolization syn-rome. Radiologically, it should be differentiated fromseptic tissue gas and from artifacts generated by thembolization materials. Additional studies are needed to

Table 1. Therapeutic embolization of failed renal allograft

InvestigatorPatients

(n)SuccessRate (%)

Postem

Delgado etal.,4 2005

48 65

Gonzalez-Satueet al.,5 2000

33 85

Cofan et al.,6

200230 80 4

Atar et al.,3

200225 92 92

*Purulent material/abscess confirmed at nephrectomy; no furthe†Proportion was 25% in patients receiving steroids as prophylaxis‡Routine antibiotic prophylaxis instituted after occurrence of emp§One case of emphysematous pyelonephritis.

Table 2. Emphysematous pyelonephritis in nonfunction-ing renal allografts from dialysis patients

InvestigatorAge

(yr)/Sex

Interval afterEmbolization

(wk) Risk Factor

Goral et al.,9

199755/F NA Diabetes

Atar et al.,3

200249/M 2 Diabetes

Presentstudy

40/M 3 Neurogenicbladder

NA � not applicable.

etter characterize the incidence of this complication,

ROLOGY 70 (2), 2007

hich appears to be greater than previously suspected,nd the spectrum of causative bacteria.

eferences1. Huang JJ, and Tseng CC. Emphysematous pyelonephritis: clinico-

radiological classification, management, prognosis, and pathogen-esis. Arch Intern Med 160: 797–805, 2000.

2. Fujita S, Watanabe J, Reed AI, et al: Case of emphysematouspyelonephritis in a renal allograft. Clin Transplant 19: 559–562,2005.

3. Atar E, Belenky A, Neuman-Levin M, et al: Nonfunctioning renalallograft embolization as an alternative to graft nephrectomy: re-port on seven years’ experience. Cardiovasc Intervent Radiol 26:37–39, 2003.

4. Delgado P, Diaz F, Gonzalez A, et al: Intolerance syndrome in failedrenal allografts: incidence and efficacy of percutaneous emboliza-tion. Am J Kidney Dis 46: 339–344, 2005.

5. Gonzalez-Satue C, Riera L, Franco E, et al: Percutaneous emboli-zation of the failed renal allograft in patients with graft intolerancesyndrome. BJU Int 86: 610–612, 2000.

6. Cofan F, Real MI, Vilardell J, et al: Percutaneous renal arteryembolisation of non-functioning renal allografts with clinical in-tolerance. Transpl Int 15: 149–155, 2002.

7. Iqubal M, John GT, Gopalakrishnan G, et al: Abdominal gas is notalways bowel associated: lessons from an allograft recipient. Neph-rol Dial Transplant 19: 503–504, 2004.

8. Al-Makadma AS, and Al-Akash SI: An unusual case of pyelone-phritis in a pediatric renal transplant recipient. Pediatr Transplant9: 258–260, 2005.

9. Goral S, and Stone W: Emphysematous pyelonephritis in a non-functioning renal allograft of a patient undergoing hemodialysis.Am J Med Sci 314: 354–356, 1997.

0. Rankin RN: Gas formation after renal tumor embolization withoutabscess: a benign occurrence. Radiology 130: 317–320, 1979.

1. Weckermann D, Schlotmann R, Tietze W, et al: Gas formationafter renal artery embolisation: genesis and clinical relevance. UrolInt 49: 211–214, 1992.

2. Eggener SE, Hua V, Schaeffer AJ, et al: A noninfectious source ofrenal gas: embolization. J Urol 170: 913, 2003.

3. Mazer MJ, Baltaxe HA, and Wolf GL: Therapeutic embolization ofthe renal artery with Gianturco coils: limitations and technical

h graft intolerance syndrome

zation SyndromeDurationdays])

RoutineProphylactic

Antibiotic Use

InfectiousComplications

(%)

0/2–8 No 10*

1/2–5 No 9*

4.2 � 2.4 Yes,ceftriaxone

0

4 and �60 Yes‡,multiple

antibiotics

8§

ils provided.postembolization syndrome vs. 71% in those without steroids.matous pyelonephritis in third patient in series.

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pitfalls. Radiology 138: 37–46, 1981.

372.e19