대한응급의학회지제 27 권제 4 호 Volume 27, Number 4, August, 2016 원 저 Medical 일측성신우신염과양측성신우신염의임상양상과예후에대한비교 김현우 유승목 안 @ 신 손창환 서동우 이윤선 이재호 오범진 임경수 김원영 울산대학교의과대학서울아산병원응급의학과 Comparison of Clinical Feature and Prognosis between Unilateral and Bilateral Acute Pyelonephritis Hyun Woo Kim, M.D., Seung Mok Ryoo, M.D., Shin Ahn, M.D., Ph.D., Chang Hwan Sohn, M.D., Dong Woo Seo, M.D., Ph.D., Yoon Seon Lee, M.D., Ph.D., Jae Ho Lee, M.D., Ph.D., Bum Jin Oh, M.D., Ph.D., Kyung Soo Lim, M.D., Ph.D., Won Young Kim, M.D., Ph.D.* Department of Emergency Medicine, Asan Medical Center, Ulsan University College of Medicine, Seoul, Korea Purpose: Acute pyelonephritis (APN) usually presents as a mild disease. However, it has been shown to cause substantial morbidity and mortality on occasion. Therefore, it is important to distinguish between the complicated and uncomplicated APN. The purpose of this study was to determine the clinical significance of bilateral APN compared with unilateral APN in the emergency department (ED). Methods: We analyzed the data of 303 consecutive patients with APN who underwent a abdominal computed tomography (CT) examination in the ED from January 2012 to December 2014. We compared the clinical presentation, progress, and outcomes between the unilateral and bilateral APNs that were identified on the CT scan. Results: Of these 303 patients, 110 patients (36.3%) were confirmed as bilateral APN by the CT. The proportion of male was higher in the bilateral APN group (20.0% vs. 10.9%, p=0.029). Moreover, patients in the bilateral group visited the ED post symptom onset (6.5±7.8 vs. 3.6±3.1, p<0.001). However, symptom, sign, laboratory test, and CT findings were not statistically different between the two groups. In addition, severity, resistant pathogen, and outcomes such as occurrence of septic shock, hospital days, and mortality were also not different. Conclusion: This study suggests that bilateral APN, as determined by a CT, does not have clinical significance compared with unilateral APN. Key Words: Emergency service, Hospital, Pyelonephritis, Tomography, X-Ray computed 서론급성신우신염은흔한세균성감염중의하나로배뇨통, 긴급뇨, 빈뇨, 측부통, 발열, 오한, 오심및구토등의증상과함께늑척추각압통을보이는신실질과신집뇨계의감 염으로, 국내에서연간 10,000명당 35.7명이발생하며, 10,000명당 9.96명이입원을한다 1-5). 일반적으로급성신우신염은경한임상양상을보이나때때로급성신손상과패혈증등으로진행하여생명을위협하는양상을보이기도한다 5,6). 그러므로급성신우신염환자에서증상및징후, 혈액학적및영상학적진단결과를통하여중증임상양상 책임저자 : 김원영서울특별시송파구올림픽로 43길 88 서울아산병원응급의학과 Tel: 02-3010-3350, Fax: 02-3010-3360, E-mail: wonpia73@naver.com 접수일 : 2016년 3월 22일, 1차교정일 : 2016년 3월 22일, 게재승인일 : 2016년 5월 27일 320
양측성일측성신우신염의임상양상차이 / 321 Article Summary What is already known in the previous study Acute pyelonephritis (APN) is a common disease in the emergency department. It is important to distinguish between the complicated and uncomplicated APN. 환자를연구에포함하였고, 이중전산화단층촬영에서급성신우신염의소견이관찰되지않은환자는연구에서제외하였다. 전산화단층촬영상일측의신우신염이있는환자군과양측의신우신염이확인된환자군으로나누어두군간의임상소견및예후의차이를비교하였다. 2. 연구방법 What is new in the current study The symptom, sign, laboratory test, severity, resistant pathogen, and outcomes such as occurrence of septic shock, hospital days, and mortality of bilateral APN compared with unilateral APN were not statistically different. 으로진행할수있는고위험환자들을찾아내고자하는노력들이있어왔고고령, 당뇨, 요로결석의동반등이그위험인자로제시되었다 2,7). 한편급성신우신염은일반적으로는일측으로발생하나, 약 30% 정도에서양측으로발현되기도한다 6,8). 그러나아직일측성신우신염과양측성신우신염의임상적차이에대한연구는부족한실정이다. 한연구에서는양측성신우신염이일측성신우신염에비해급성신손상의발생빈도는더높으나쇼크발생정도및사망률등에는차이가없었다고보고하였으나, 최근 99명의양측성신우신염을대상으로한연구에서는일측성신우신염에비해임상양상, 임상화학검사결과, 예후가더불량하여급성신우신염환자에서조기에영상의학적검사의시행이필요하다고제안하였다 6,8). 하지만, 표본수가적고입원환자만을대상으로한연구이기에이러한결과를응급의료센터에내원한급성신우신염환자에적용하기에는무리가있다. 이에저자들은응급의료센터에내원한급성신우신염환자를대상으로일측성신우신염과양측성신우신염의임상양상, 검사실검사결과, 전산화단층촬영소견및예후에있어서차이점이있는지를비교연구해보기로하였다. 대상과방법 1. 연구대상본연구는 2012년 1월부터 2014년 12월까지 48개월간서울아산병원응급의료센터로내원하여급성신우신염을진단받은 18세이상의환자를대상으로의무기록을후향적으로분석하였다. 임상적으로급성신우신염을진단받은환자중내원 3일이내에복부전산화단층촬영을시행한 급성신우신염의진단은 1988년 Safrin 등 9) 의진단기준에따라 1) 배뇨통, 긴급뇨, 빈뇨, 측복통, 발열, 오한, 오심및구토등의증상, 2) 진찰소견상늑척추각압통, 3) 혈액검사상백혈구증가증 (12,000개/mL 이상 ), 4) 38.5 C 이상의고열, 5) 소변검사상농뇨또는요배양검사상양성 ( 백혈구 5개 /HPF 이상, 균 100,000 CFU 이상 ) 중에서세가지이상의소견을보이는경우로하였다. 연구기간동안응급의료센터를내원한환자의 ICD-10 진단코드 (N10C, acute pyelonephritis) 를검색하여급성신우신염을진단받은환자를추출후임상적급성신우신염유무를확인하였고, 이들중내원 3일이내의복부전산화단층촬영결과가있는환자를추출하였다. 본기관에서는급성신우신염이의심되는환자중증상, 징후또는검사실소견이명확하지않아임상적으로비특이적인양상을보이는경우, 간농양, 급성담낭염, 급성충수돌기염, 게실염등의다른질환의감별이필요한경우, 신농양의발생이의심되는경우에복부전산화단층촬영을시행하였다. 복부전산화단층촬영의결과는영상의학과전문의에의하여작성된정식판독소견을인용하였고, 기록지에언급되지않은소견에대해서는응급영상의학전문의의자문을받아분석하였다. 연구대상의성별, 나이등의인구학적인특징과기저질환, 증상, 신체검사결과및실험실검사결과를의무기록을조사하여분석하였다. 전산화단층촬영에서관찰되는급성신우신염의소견은신장실질의관류결손부위의유무와신장주위지방침윤소견으로정의하였고, 합병증으로는신농양과기종성신우신염을조사하여분석하였다 10-12). 미생물배양검사는혈액배양검사와소변배양검사의결과를분석하였고, 내성균은요로감염에가장많이사용하는항생제인 Ciprofloxacin과 Ceftriaxone에대한내성여부와광범위베타락탐계항생제분해효소 (extended spectrum beta lactamase, ESBL) 생성균의여부를조사하여분석하였다. 대상환자들의예후는입원기간동안패혈증성쇼크의발생유무, 재원기간, 그리고 28일사망률을추적조사하였다. 패혈증성쇼크는 International Sepsis Definitions Conference Criteria에따라전신염증반응증후군의기준을만족하고수액요법에도불구하고수축기혈압이 90 mmhg 미만이거나평균동맥혈압이 65 mmhg 이하인경우로정의하였다 13). 이연구는소속병원의의학윤리연구심의위원회
322 / 김현우외 (institutional review board) 의심사를통과하였다. 3. 통계분석대상환자의변수는평균 ± 표준편차와백분율로표현하였고정규분포를따르지않는연속변수의경우중앙값과사분위수로표현하였다. 통계분석은윈도우용 SPSS ver. 18.0 (SPSS Inc., Chicago, IL, USA) 를사용하였고, 서로다른두군간의평균값은독립표본 t 검정 (Student s t-test) 으로, 정규분포를따르지않는연속형자료는 Mann-Whitney U-test를이용하였다. 범주형자료는카이제곱검정 (chi-square test) 또는피셔의정확한검정 (Fisher s exact test) 을사용하여분석하였다. 유의수준은 0.05 미만인경우를통계학적으로유의한차이가있다고판정하였다. 결과 1. 임상적특징 2012년 1월부터 2014년 12월까지 48개월간서울아산병원응급의료센터로내원하여급성신우신염을진단받은 18세이상의성인환자 1,854명중내원 3일이내에복부전산화단층촬영을시행한환자는 388명이었다. 이중전산화단층촬영상신우신염의소견이관찰되지않은 85명 을제외한 303명을연구에포함하였다. 총 303명의연구대상중일측신장에만신우신염소견이관찰된환자는 193명 (63.7%) 이었고, 양측신장에신우신염소견이있었던환자는 110명 (36.3%) 이었다 (Fig. 1). 일측성신우신염군과양측성신우신염군을비교했을때나이는양군모두평균 57.4세로동일하였으나, 남성의이환율이양측성신우신염군 (20.0%) 이일측성신우신염군 (10.9%) 에비해의미있게많았다 (p=0.029)(table. 1). 기저질환의경우양군간에차이가없었고, 증상이나신체검사도양측신우신염군이증상발생기간이더길었던것 (4.0일 vs. 3.0일, p<0.001) 을제외하고는두군간에통계학적차이를보이지않았다. 2. 실험실검사혈액검사에서는양측성신우신염군에서백혈구수 (8.6 ±3.8 10 3 μl vs. 11.9±5.1 10 3 μl, p=0.038) 가적은반면혈소판수 (234.9±92.8 10 3 μl vs. 205.1±68.8 10 3 μl, p=0.004) 는많았고, 양측성신우신염군의알부민수치 (3.1±0.5 g/dl vs. 3.4±0.6 g/dl, p<0.001) 가일측성신우신염군에비해적었던것을제외하고는두군간에차이를보이지않았다. 또한소변검사역시농뇨, 혈뇨, 그리고소변내아질산염의유무에이르기까지두군간에통계학적차이는없었다 (Table 2). 두군간의미생물배양검사결과를비교해보았을때, 소변에서는양측성신우신염군과일측성신우신염군에서 Fig. 1. Flow diagram of the enrolled patients. A total 1,854 patients who diagnosed acute pyelonephritis in emergency department were retrospectively collected. 1,551 patients who were not performed computed tomography (CT) or did not show visible pyelonephritis in CT were excluded. Of these 303 patients, 110 patients (36.3%) were confirmed bilateral pyelonephritis by CT. CT: computed tomography
양측성일측성신우신염의임상양상차이 / 323 각각 58.2% 와 59.1% 의세균이배양되었고 (p=0.880), 혈액에서는각각 33.7% 와 34.5% 에서세균이배양되었다 (p=0.878). 또한 Ciprofloxacin, Ceftriaxone, 그리고 ESBL에대한내성균역시소변배양과혈액배양모두두군간에차이를보이지않았다 (Table 3). 3. 전산화단층촬영소견 4. 패혈증성쇼크의발생및예후패혈증성쇼크까지진행된경우는양측신우신염과일측신우신염이각각 30.9% 와 24.4% 로양측신우신염군이조금높은경향을보였으나통계학적인차이는보이지않았고 (p=0.215), 재실기간과사망률역시두군간에큰차이를보이지않았다 (Table 5). 요로감염의위험요인인신결석과요관결석그리고수신증의유무를전산화단층촬영으로확인해보았을때두군간에차이를보이지않았으며, 신우신염의진단소견인신장실질의관류결손과신장주위지방침윤소견역시두군간에차이를보이지않았다. 또한신우신염의합병증인신농양과기종성신우신염의발생률도두군간에의미있는차이가없었다 (Table 4). 고찰신우신염은대표적인상부요로감염으로주로하부요로에서상부로감염원이파급되면서발생하는것으로알려져있다 14). 양측의신장은모두방광과요관으로연결되어있고, 양측신장모두하부요로감염이파급될위험에노출되어있다. 급성신우신염이발생한경우이환된신장측의늑척추각압통이발생하나 Lee 등 8) 의연구에서는신체검사만으로신우신염의위치를정확히알수없었다고보고 Table 1. Demographic and baseline characteristics Demographics Age, yr 57.4±16.20 57.4±18.100 1.000 Male 021 (10.9) 22 (20.0) 0.029 Co-morbidities Hypertension 058 (30.1) 32 (29.1) 0.860 Diabetes 046 (23.8) 28 (25.5) 0.752 Liver cirrhosis 004 (2.1)0 03 (2.7)0 0.707 Immunocompromise 005 (2.6)0 05 (4.5)0 0.505 Neoplasm 016 (8.3)0 04 (3.6)0 0.117 Chronic renal failure 003 (1.6)0 04 (3.6)0 0.260 Urinary procedure PCN or JP catheterization 004 (2.1)0 02 (1.8)0 1.000 Urinary catheter 002 (1.0)0 03 (2.7)0 0.357 Symptoms and signs Symptom duration, day 00 3.0 (1.0-5.0) 0.4.0 (2.0-7.0) 0.000 Fever or chills 168 (87.0) 91 (82.7) 0.305 Flank pain 066 (34.2) 33 (30.0) 0.454 Abdominal pain 047 (24.4) 33 (30.0) 0.284 Urinary symptoms 097 (50.3) 51 (46.4) 0.514 URI symptoms 013 (6.7)0 14 (12.7) 0.078 Glasgow coma scale 000.15.0 (15.0-15.0) 00.15.0 (15.0-15.0) 0.662 CVAT 0.501 Unilateral 109 (56.5) 55 (50.0) Bilateral 032 (16.6) 23 (20.9) Abdominal tenderness 058 (30.1) 31 (28.2) 0.701 Abdominal rebound tenderness 002 (1.0)0 01 (0.9)0 1.000 Values are presented as mean±standard deviation, n (%) or median (interquartile range). APN: acute pyelonephritis, PCN: percutaneous nephrostomy, JP: Jackson-Pratt, URI: upper respiratory infection, CVAT: costovertebral angle tenderness
324 / 김현우외 Table 2. Laboratory test Blood tests White blood cell count, 10 3 11.9±5.1000000 08.6±3.8000000. 0.038 Hemoglobin, g/dl 12.1±1.7000000 12.2±1.6000000. 0.427 Platelet 205.1±68.8000000 234.9±92.8000000. 0.004 Prothrombin time, INR 01.1±0.3000000 01.1±0.2000000. 0.810 D-dimer 2.55 (1.07-4.24) 3.49 (1.19-4.79)0 0.669 Total bilirubin 00.9±1.2000000 00.8±0.5000000. 0.272 Albumin 03.4±0.6000000 03.1±0.5000000. 0.000 AST 25.0 (18.0-37.0) 26.0 (19.0-39.3)0 0.500 ALT 19.0 (12.5-29.0) 22.0 (15.8-38.3)0 0.145 BNP 136.0 (48.8-287.5) 82.0 (29.5-132.5) 0.144 Troponin-I 00.010 (0.006-0.034) 0.009 (0.006-0.039) 0.936 Initial lactic acid 01.4±1.2000000 01.4±1.2000000. 0.750 C-reactive protein 12.2 (6.8-19.4)0 13.1 (7.8-20.1)00 0.144 Procalcitonin 1.3 (0.4-5.3)0 1.1 (0.3-6.6)00 0.233 Blood urea nitrogen 14.0 (10.0-23.0) 15.0 (10.8-22.0)0 0.960 Creatinine 0.85 (0.71-1.14) 0.88 (0.73-1.16)0 0.666 Urinalysis Urine ph 06.2±1.1000000 06.1±1.1000000. 0.340 Urine white blood cell 0.741 Trace 02 (1.0)0000 02 (1.8)00000 + 23 (11.9)000 18 (16.4)0000 ++ 48 (24.9)000 29 (26.4)0000 +++ 79 (40.9)000 41 (37.3)0000 Urine nitrite 77 (39.9)000 38 (34.5)0000 0.356 Urine red blood cell 0.297 Trace 22 (11.4)000 15 (13.6)0000 + 14 (7.3)0000 14 (12.7)0000 ++ 29 (15.0)000 20 (18.2)0000 +++ 45 (23.3)000 27 (24.5)0000 ++++ 61 (31.6)000 27 (24.5)0000 Values are presented as mean±standard deviation, median (interquartile range) or n (%). APN: acute pyelonephritis, INR: international normalized ratio, AST: aspartate transaminase, ALT: alanine transaminase, BNP: B type natriuretic peptide Table 3. Comparison of the bacteriologic manifestations between the unilateral and bilateral APN Bacterial culture Bacteriuria 114 (59.1) 64 (58.2) 0.880 Bacteremia 065 (33.7) 38 (34.5) 0.878 Resistant pathogen in urine culture Ciprofloxacin 027 (14.0) 21 (19.1) 0.242 Ceftriaxone 021 (10.9) 10 (9.1)0 0.621 ESBL 022 (11.4) 08 (7.3)0 0.248 Resistant pathogen in blood culture Ciprofloxacin 018 (9.3)0 12 (10.9) 0.657 Ceftriaxone 011 (5.7)0 07 (6.4)0 0.814 ESBL 011 (5.7)0 07 (6.4)0 0.814 Values are presented as n (%). APN: acute pyelonephritis, ESBL: extended spectrum beta-lactamase
양측성일측성신우신염의임상양상차이 / 325 Table 4. Comparison of the computed tomography finding between the unilateral and bilateral APN Urinary tract lithiasis Ureter stone 009 (4.7)0 04 (3.6)0 0.775 Renal stone 016 (8.3)0 05 (4.5)0 0.217 Hydronephrosis 023 (11.9) 08 (7.3)0 0.200 Infection signs Perirenal fat infiltration 096 (49.7) 50 (45.5) 0.473 Renal perfusion defects 163 (84.5) 96 (87.3) 0.505 Complications Renal abscess 010 (5.2)0 08 (7.3)0 0.459 Renal emphysema 002 (1.0)0 00 (0.0)0 0.536 Values are presented as n (%). APN: acute pyelonephritis Table 5. Comparison of the prognosis between the unilateral and bilateral APN Septic shock 047 (24.4) 34 (30.9) 0.215 Acute kidney injury 026 (13.5) 23 (20.9) 0.091 Admission 140 (72.5) 86 (78.2) 0.278 Hospital days 8.7±10.9 7.8±5.500 0.440 28 days mortality 001 (0.5)0 00 (0.0)0 0.450 Values are presented as n (%) or mean±standard deviation. APN: acute pyelonephritis 하였다. 따라서신체검사상으로일측의신우신염이라고진단한환자도양측의신장이모두이환되었을가능성을배제할수없다. 기존의연구에서도전산화단층촬영결과에따라급성신우신염을신장비침범, 25% 이하침범, 50% 이하침범, 50% 이상침범으로분류하여임상적중증도와의관련을비교한연구는있었으나여러연구에서상반된결과를보여추가적인연구가필요한상황이며, 양측성신우신염의발생빈도및일측성신우신염과의임상적차이에대해서는연구된바가거의없었다 8,10,15,16). 최근에국내에서급성신우신염으로입원한환자들을대상으로일측성신우신염과양측성신우신염을비교한연구에서는양측신우신염이 33.4% 에서동반되며일측성신우신염에비해급성신손상과쇼크가더잘동반된다고보고하였다 (40.4% vs. 11.2%, 24.2% vs. 6.1%, p<0.001) 8). 그러나이연구는모든신우신염환자를전산화단층촬영으로확인한것이아니기에선택편견을고려해야만한다. 급성신우신염에대한전산화단층촬영은임상적인적응증에따라선택적으로시행되어야만하며, 일반적으로비특이적인임상양상을보이거나통상적인치료에실패하였을경우시행하게된다 17). 특히입원후에전산화단층촬영검사를시행하는경우는임상경과가호전되지않는중증의환자들에서합병증발생여부를알아보기위해시행되었을가능성이있기에더욱더그해석에주의가필요하다 18). 본연구에 서는연구기간에급성신우신염으로내원한 1,854명의환자중 303명에서전산화단층촬영을시행하였고 110명의양측성신우신염환자를확인하였기에양측성신우신염의발생빈도는최소 5.9% (110/1,854) 에서최대 36.3% (110/303) 였다. 또한 81.2% 의환자가내원당일전산화단층촬영을실시하였고, 97% 의환자가내원 2일이내에촬영을하였다. 양군을비교해보아도, 일측성신우신염군의 81.3% 와양측성신우신염군의 80.9% 가내원당일검사를하여전산화단층촬영의지연으로인한영향은미미하다고볼수있다. 다만본연구에서도증상이발생한후늦게내원한환자에서양측성신우신염이많이확인된것을보았을때 (Table 1) 하부요로에서상부로파급되는요로감염의특성상시간이오래될수록양측성신우신염의발생빈도가증가하는것으로생각된다. 그리고기존 Lee 등 8) 의연구결과가본연구의결과보다높은백혈구수치와 C 반응성단백질수치를보이며, 미생물배양검사의높은양성률을보인것은보다임상양상이심각한환자들이입원을하였고이들을대상으로시행한연구이기때문으로생각된다. 본연구에서는대상자의 74.6% 만이입원을하였고, 일측성신우신염군이양측성신우신염군보다입원율이낮은경향을보였지만통계학적차이는보이지않았다 (72.5% vs. 78.2%, p=0.278). 그리고대상자의실험실소견은두군모두기존의연구에비
326 / 김현우외 해양호한결과를보였으며혈소판과알부민수치를제외하고는양군의차이를보이지않았다 (Table. 2). 이는역시입원환자들을대상으로하였을때양측성신우신염의경우가일측성에비해급성신손상이더많이발생한다고보고한 Jang 등 6) 의연구결과와차이를보였다. 그러나이들의연구역시라이플 (RIFLE) 분류상위험 (risk) 에해당하는경우는일측성과양측성신우신염두군간에차이가없었고 (28.5% vs. 29.8%, p=0.853) 신부전 (failure) 에해당하는환자는통계학적차이는있었지만 (1.5% vs. 8.5%, p=0.044) 그숫자가적어 (2/130 vs. 4/47) 추가적인연구가필요하다 6). 본연구에서는전산화단층촬영소견, 합병증과요로결석의여부그리고미생물학적검사결과및항생제감수성결과에대해서도두군간에차이를보이지않았다. 균뇨증의경우는기존의연구에서도두군간에차이가없었고, 균혈증에대해서는연구별로다른결과를보고했는데 Jang 등 6) 의연구에서는본연구와같이일측성신우신염과양측성신우신염이차이를보이지않았으나 (34.6% vs. 36.1%, p=0.981) Lee 등 8) 의연구에서는양측성신우신염이더많았다고보고하였다 (34.1% vs. 53.5%, p=0.001). 그러나내성균의배양여부는모든연구에서동일하게양군의차이가없었다 6,8). 따라서단순히양측신을침범했는지여부가신우신염의중등도를반영한다고볼수없다. 그러나이와같은결과는전산화단층촬영을시행하는기준이다른기관에서는또다른결과를보일수있기에다른환경의환자에게일반화하여적용할수는없을것이다. 본연구는두가지중요한한계를지닌다. 첫번째로단일기관의후향적연구이기때문에정보의누락등연구설계의한계를지닌다. 두번째는연구의특성상전산화단층촬영을모든신우신염환자에게적용할수없어선택편견이작용할수밖에없다는한계를가지고있다 19). 이는신우신염에대한전산화단층촬영소견을후향적으로조사한모든연구에적용되는한계이다. 결론초기응급실로내원한환자를대상으로전산화단층촬영통해확인된양측성신우신염은일측성신우신염에비해검사실검사결과, 전산화단층촬영소견및예후에있어서쇼크의발생과급성신손상이많이동반되는경향을보였으나통계학적차이가없었기에, 단순히양측성신장침범의정도로임상적질환의중증도를평가해서는안될것으로생각된다. 참고문헌 01. Kumar S, Dave A, Wolf B, Lerma EV. Urinary tract infections. Dis Mon. 2015;61:45-59. 02. Kumar S, Ramachandran R, Mete U, Mittal T, Dutta P, Kumar V, et al. Acute pyelonephritis in diabetes mellitus: single center experience. Indian J Nephrol. 2014;24:367-71. 03. Morello W, La Scola C, Alberici I, Montini G. Acute pyelonephritis in children. Pediatr Nephrol. 2016;31:1253-65. 04. Ki M, Park T, Choi B, Foxman B. The epidemiology of acute pyelonephritis in South Korea, 1997-1999. Am J Epidemiol. 2004;160:985-93. 05. Wi YM, Kim SW, Chang HH, Jung SI, Kim YS, Cheong HS, et al. Predictors of uropathogens other than Escherichia coli in patients with community-onset acute pyelonephritis. Int J Clin Pract. 2014;68:749-55. 06. Jang SH, Lee CS, Lee MY, Hwang WM, Yun SR. Clinical differences in acute kidney injury between unilateral acute pyelonephritis and bilateral acute pyelonephritis. Korean J Med. 2012;82:696-703. 07. Chang UI, Kim HW, Noh YS, Wie SH. A comparison of the clinical characteristics of elderly and non-elderly women with community-onset, non-obstructive acute pyelonephritis. Korean J Intern Med. 2015;30:372-83. 08. Lee YJ, Cho S, Kim SR. Unilateral and bilateral acute pyelonephritis: differences in clinical presentation, progress and outcome. Postgrad Med J. 2014;90:80-5. 09. Safrin S, Siegel D, Black D. Pyelonephritis in adult women: inpatient versus outpatient therapy. Am J Med. 1988;85:793-8. 10. Paick SH, Choo GY, Baek M, Bae SR, Kim HG, Lho YS, et al. Clinical value of acute pyelonephritis grade based on computed tomography in predicting severity and course of acute pyelonephritis. J Comput Assist Tomogr. 2013;37:440-2. 11. Mitterberger M, Pinggera GM, Colleselli D, Bartsch G, Strasser H, Steppan I, et al. Acute pyelonephritis: comparison of diagnosis with computed tomography and contrastenhanced ultrasonography. BJU Int. 2008;101:341-4. 12. Yang WS, Kim WY, Sohn CH, Seo DW, Lee JH, Kim W, et al. Clinical Feature and Prognostic Factors of Emphysematous Pyelonephritis. Korean J Crit Care Med. 2012;27:89-93. 13. Levy MM, Fink MP, Marshall JC, Abraham E, Angus D, Cook D, et al. 2001 SCCM/ESICM/ACCP/ATS/SIS international sepsis definitions conference. Crit Care Med. 2003;31:1250-6. 14. Kleeman CR, Hewitt W, Guze LB. Pyelonephritis. J Am
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