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cute Lobar Nephronia in a Renal Allograft: A Case Report anditerature Review

.C. Tai, P.J. Yang, P.H. Lee, S.D. Chung, S.C. Chueh, and H.J. Yu

ABSTRACT

We report a diabetic renal transplant recipient who presented with fever and right lowerquadrant abdominal pain. Acute appendicitis was considered initially and she underwentemergent appendectomy. However, persistent symptoms postoperatively made us performan imaging study to identify the problems. Abdominal and pelvic computed tomographydisclosed several focal wedge-shaped lesions of low attenuation in the renal allograft.Acute lobar nephronia was successfully managed with parenteral antibiotics. The patientrecovered without any sequela. A renal allograft in the right iliac fossa complicates thediagnosis among acute renal infection, malignancy, acute rejection, and even acuteappendicitis. Biopsy of the renal allograft is sometimes needed due to clinically ambiguousimaging results. In this report, we not only detail the clinical course of such a rare case, butalso review the previous 3 cases of acute lobar nephronia in renal allografts in the

literature.

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CUTE LOBAR NEPHRONIA (ALN), synonymouswith acute focal bacterial nephritis (AFBN), refers to

n acute localized renal infection without liquefaction.linically, it may present as acute pyelonephritis (APN),ut is distinguished by the presence of a focal mass onltrasonography (US) or computed tomography (CT).1

hile the majority of reported cases involve native kid-eys,2–4 only 3 cases of ALN involving renal allografts haveeen reported in the literature.5–7 Herein we have reported

case of renal allograft ALN which mimicked acuteppendicitis in a renal transplant recipient.

ASE REPORT

58-year-old woman with end-stage renal disease secondary to

iabetic nephropathy received a deceased donor renal transplant in C

2008 by Elsevier Inc. All rights reserved.60 Park Avenue South, New York, NY 10010-1710

ransplantation Proceedings, 40, 1737–1740 (2008)

er right iliac fossa 8 years prior. She presented to the emergencyepartment with a 2-day history of fever and right lower quadrantRLQ) abdominal pain. At the time of presentation, she was tak-ng cyclosporine (Neoral; 75 mg) and mycophenolate mofetilCellCept; 250 mg) twice a day. On physical examination, she waslert but toxic with fever of 38.2°C. RLQ rebound tenderness waslso noted. Significant laboratory data included a white blood cellount of 13,500/�L, serum creatinine 1.3 mg/dL (baseline, 0.8

From the Department of Urology, National Taiwan Universityospital, Taipei, Taiwan (H.C.T., P.J.Y., P.H.L., S.D.C., S.C.C.,.J.Y.); and the Department of Urology, Buhddist Tzu Chieneral Hospital, Taipei Branch, Taipei, Taiwan (H.C.T.).Address reprint requests to Huai-Ching Tai, MD, National

aiwan University Hospital, No. 7, Chung-Shan South Road,

linical Research Bldg, Rm 11-09, Taipei 100, Taiwan.

0041-1345/08/$–see front matterdoi:10.1016/j.transproceed.2007.10.014

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g/dL), C-reactive protein 24.5 mg/dL, and serum glucose 306g/dL. Urinalysis revealed microscopic hematuria (10–20/HPF)

nd mild pyuria (5–10/HPF).The initial diagnosis was acute appendicitis; the patient under-

ent an emergent appendectomy. There was a small amount oferosanguineous fluid in the peritoneal cavity around the appendix.he appendix was grossly normal and pathological examination

howed only very mild acute inflammation.However, her symptoms persisted for several days postopera-

ively. CT scan of the abdomen and pelvis demonstrated focaledge-shaped lesions of low attenuation in the renal allograft

Figs 1, 2). This finding was highly suggestive of ALN of the renalllograft. Furthermore, Klebsiella pneumoniae was isolated from 2eparate blood cultures, whereas the urine culture was negative.reatment with parenteral antibiotics (piperacillin/tazobactam)as initiated; her clinical symptoms ameliorated gradually over the

ollowing 3 weeks. In addition, the graft function returned toaseline levels. Follow-up US of the renal allograft showed reso-

ution of the wedge-shaped lesions (Fig 3). The patient wasischarged home after 22 days of antibiotic treatment in stableondition.

ISCUSSION

LN was first described by Rosenfield et al8 in 1979. Itepresents a localized nonsuppurative acute bacterial infec-ion, which typically involves 1 or more renal lobules. It haseen considered to be a transitional form of acute renal

nfection between uncomplicated APN and frank renalbscess formation.4 The typical clinical presentations ofLN include fever, flank pain, leukocytosis, pyuria, andacteriuria, which are similar to those of renal abscess orPN. US and CT are the choice of imaging modalities to

stablish the diagnosis. Sonographically, ALN generally

ig 1. Axial view of contrast-enhanced abdominal and pelvicT scan demonstrated multiple wedge-shaped areas of low

ttenuation in the renal allograft in the right iliac fossa. F

resents as an enlarged kidney or a poorly defined focalass with a variety of echogenicities.9 CT images of ALN-

nfected areas typically appear as wedge-shaped, poorlyefined lesions of low attenuation. Huang et al2 classifiedLN into 3 subgroups of progressive clinical severity ac-

ording to the CT findings: namely, wedge-shaped lesions,ocal mass-like lesions, and diffuse mass-like lesions.

The majority of reported series of ALN have involved theative kidneys.2–4 ALN in a transplanted kidney has onlyeen reported in 3 cases.5–7 Thomalla et al5 described therst case of ALN developing within a renal allograft at 6eeks after placement of a ureteral stent. The reportedathogens in this case included Escherichia coli,5 Staphylo-occus aureus,6 and Klebsiella pneumoniae. All renal trans-

ig 2. Reconstructed image of contrast-enhanced abdominalnd pelvic CT scan demonstrated multiple wedge-shaped areasf low attenuation in the renal allograft in the right iliac fossa.

ig 3. US of the renal allograft revealed resolution of the ALN.

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ACUTE LOBAR NEPHRONIA IN A RENAL ALLOGRAFT 1739

lant recipients with allograft ALN have been successfullyanaged with parenteral antibiotics. One patient required

emporary hemodialysis during the course of acute renalailure.6 No graft loss was noted. The clinical characteristicsf patients with renal allograft ALN are summarized inable 1.ALN in a renal allograft is more complicated than that in

he native kidneys since renal transplant patients receivemmunosuppression and are at risk for posttransplantationomplications, including acute rejection, infection, and ma-ignancies.10,11 Differential diagnosis is sometimes difficultue to similar clinical manifestations. In this situation, renaliopsy of the affected areas may be needed to clarify theiagnosis. In the previously published reports, 1 case expe-ienced infection-associated allograft dysfunction; allograftiopsy was performed to exclude the possibility of an acuteejection episode.6 In another case, the biopsy confirmed aiagnosis of ALN due to a solid mass in the upper pole ofhe renal allograft.7

We did not perform an allograft biopsy in this patient foreveral reasons. First, her clinical picture favored an inflam-atory or infectious process rather than an acute rejection

pisode or malignancy. Second, the wedge-shaped, low-ttenuated lesions on CT images were typical findings ofLN. Finally, the patient responded to antibiotic treatment

linically and the lesions were diminished on follow-up US.Our case was first misdiagnosed as acute appendicitis and

he underwent appendectomy. A renal allograft in the rightliac fossa complicates the diagnosis of RLQ pain, whichan be a symptom of an acute rejection episode, appendi-itis, or renal infection. Polar infarct of a renal allograft andTG overdose in renal transplant recipients have also been

eported to be mistaken as acute appendicitis in the litera-ure.12,13

Savar et al14 reviewed nearly 8000 patients who receivedolid organ transplants at UCLA between 1989 and 2002;nly 17 patients underwent appendectomy for presumedcute appendicitis, among whom only 3 were renal trans-lant recipients (0.0375%). They concluded that appendi-itis is relatively rare following solid organ transplanta-ion.14

In conclusion, RLQ pain in a patient with a renalllograft in the right iliac fossa presents a diagnostic chal-enge. An image study of the allograft should be obtained asn integral part of the diagnostic procedures. ALN shoulde considered in all patients with a renal mass detected byS or CT. Allograft biopsy may also assist to confirm the

iagnosis. Treatment with parenteral antibiotics alone isdequate and the prognosis is good.

EFERENCES

1. Nosher JL, Tamminen JL, Amorosa JK, et al: Acute focalacterial nephritis. Am J Kidney Dis 11:36, 19882. Huang JJ, Sung JM, Chen KW, et al: Acute bacterial nephri-

tis: a clinicoradiologic correction based on computed tomography.Am J Med 93:289, 1992P

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1740 TAI, YANG, LEE ET AL

3. Klar A, Hurvitz H, Berkun Y, et al: Focal bacterial nephritislobar nephronia) in children. J Pediatr 128:850, 1996

4. Cheng CH, Tsau YK, Lin TY: Effective duration of antimi-robial therapy for the treatment of acute lobar nephronia. Pedi-trics 117:e84, 2006

5. Thomalla JV, Gleason P, Leapman SB, et al: Acute lobarephronia of renal transplant allograft. Urology 41:283, 19936. Yang CW, Kim YS, Yang KH, et al: Acute focal bacterial

ephritis presented as acute renal failure and hepatic dysfunctionn a renal transplant recipient. Am J Nephrol 14:72, 1994

7. Joss N, Baxter G, Young B, et al: Lobar nephronia in aransplanted kidney. Clin Nephrol 64:311, 2005

8. Rosenfield AT, Glickman MG, Taylor KJ, et al: Acute focal

acterial nephritis (acute lobar nephronia). Radiology 132:553, 1979 s

9. Boam WD, Miser WF: Acute focal bacterial nephritis. Amam Physician 52:919, 199510. Penn I: Primary kidney tumors before and after renal

ransplantation. Transplantation 59:480, 199511. Chuang P, Parikh CR, Langone A: Urinary tract infections

fter renal transplantation: a retrospective review at two USransplant centers. Clin Transpl 19:230, 2005

12. Matas AJ, Mauer SM, Sutherland DE, et al: Polar infarct ofkidney transplant simulating appendicitis. Am J Surg 131:383,

97613. Titiz MI, Turkmen F, Yegenaga I, et al: Abdominal pain thatimics acute appendicitis caused by an ATG overdose in a kidney

ransplant recipient. Transpl Int 7:385, 199414. Savar A, Hiatt JR, Busuttil RW: Acute appendicitis after

olid organ transplantation. Clin Transpl 20:78, 2006