Urinary tract infections in infants under six months of age

6개월 미만 영아의 요로 감염

  • Kang, Min Joo (Department of Pediatrics, College of Medicine, Korea University) ;
  • Shin, Hye Kyung (Department of Pediatrics, College of Medicine, Korea University) ;
  • Yim, Hyung Eun (Department of Pediatrics, College of Medicine, Korea University) ;
  • Je, Bo-Kyung (Department of Radiology, College of Medicine, Korea University) ;
  • Eun, So Hee (Department of Pediatrics, College of Medicine, Korea University) ;
  • Choi, Byung Min (Department of Pediatrics, College of Medicine, Korea University) ;
  • Park, Jong-Tae (Department of Occupational and Environmental Medicine, College of Medicine, Korea University) ;
  • Eun, Baik Lin (Department of Pediatrics, College of Medicine, Korea University) ;
  • Yoo, Kee Hwan (Department of Pediatrics, College of Medicine, Korea University)
  • 강민주 (고려대학교 의과대학 소아과학교실) ;
  • 신혜경 (고려대학교 의과대학 소아과학교실) ;
  • 임형은 (고려대학교 의과대학 소아과학교실) ;
  • 제보경 (고려대학교 의과대학 영상의학교실) ;
  • 은소희 (고려대학교 의과대학 소아과학교실) ;
  • 최병민 (고려대학교 의과대학 소아과학교실) ;
  • 박종태 (고려대학교 의과대학 산업의학교실) ;
  • 은백린 (고려대학교 의과대학 소아과학교실) ;
  • 유기환 (고려대학교 의과대학 소아과학교실)
  • Received : 2005.09.14
  • Accepted : 2005.10.25
  • Published : 2006.03.15

Abstract

Purpose : Although suprapubic bladder aspiration(SBA) is the most reliable technique for identifying bacteriuria in young infant, no report has been published about the clinical manifestations of urinary tract infection(UTI) diagnosed by aspirated urine in Korea. This study was performed to examine clinical manifestations and related factors of UTI confirmed by a positive urine culture obtained by SBA in young infants. Methods : We reviewed medical records of 159 infants younger than six months of age, who had been admitted for UTI to Korea University Ansan Hospital from January 2002 to June 2005. Results : The male:female ratio was 5.1 : 1. The most common pathogen in urine culture was Escherichia coli(92.5 percent). Most of the gram-negative pathogens had high sensitivity to amikacin, or third generation cephalosporins and had low sensitivity to ampicillin, trimethoprim-sulfamethoxazole, or gentamicin. Hydronephrosis and vesicoureteral reflux(VUR) were present in 32.7 percent and 27.7 percent respectively. Renal cortical defects observed on DMSA scans were detected in 37.1 percent. Prolonged fever duration and hospital day, high erythrocyte sedimentation rate(ESR) and C-reactive protein(CRP) levels, hydronephrosis and VUR were related to the renal cortical defects(P<0.05). Rates of UTI-associated bacteremia and aseptic meningitis were 8.3 percent and 6.6 percent. Conclusion : Early differential diagnosis is very important in infants younger than 6 months of age with UTI because the clinical findings are non-specific and UTI-associated bacteremia and aseptic meningitis are concomitantly found. Because prolonged fever and higher ESR and CRP levels are risk factors of the renal cortical defects, radiologic evaluations and nephrologic follow-up were needed in identifying the predisposing congenital abnormalities and chronic renal scarring.

목 적 : 신생아를 비롯한 어린 영아의 요로 감염에 대한 국내 보고는 많지 않으며, 특히 위양성률이 낮은 방광 천자법으로 요로 감염을 진단한 보고는 없다. 본 연구자들은 방광 천자법으로 얻은 소변으로 진단된 어린 영아의 요로 감염에 대한 임상 양상을 알아보았다. 방 법 : 2002년 1월부터 2005년 6월까지 고려대학교 의료원 안산병원 소아과에 발열과 같은 감염 증상이 있어 내원한 6개월 미만의 영아에서 방광 천자를 시행하여 요 침사 현미경 검사에서 백혈구수가 5개 이상인 농뇨가 있으면서 배양 검사에서 세균이 자란 요로 감염 환아 159명을 대상으로 연령 및 성별 분포, 임상 증상 및 징후, 임상 검사 소견, 요로계 영상 검사 소견을 후향적으로 분석하여 동반된 요로 기형, 급성 신우신염과 신반흔과 같은 신피질 손상, 그리고 병발된 균혈증과 뇌수막염 여부와 그 관련 인자를 알아보았다. 결 과 : 남아 133명, 여아 26명이었고 1개월 미만의 신생아가 35명(22.0%)이었다. 소변 배양 검사에서 158례(99.4%)에서 단일 균주가 배양되었으며, Escherichia coli 148주, Klebsiella pneumoniae 5주, Enterobacter cloacae 4주, Enterobacter aerogenes 1주, Enterococcus faecalis 1주 그리고 Streptococcus agalactiae 1주가 배양되었다. 수신증이 있었던 경우는 32.7%(49/150)로 신생아는 41.2%(14/34)였다. 방광 요관 역류가 있었던 경우는 27.7%(31/112)로 신생아는 22.7%(5/22)였다. 신 스캔검사에서 신피질 손상이 37.1%(52/140)에서 관찰되었고 이 중 신생아는 37.5%(12/32)였다. 급성 신우신염 소견을 보인 경우가 29.3%(41/140)였고 신반흔 소견을 보인 경우는 7.9%(11/140)였다. 신피질 손상이 있었던 군이 신피질 손상이 없었던 군에 비해 평균 발열기간과 입원 기간이 길었으며, ESR과 CRP 농도, 수신증과 방광 요관 역류의 빈도가 높았다(P<0.05). 균혈증이 병발된 경우는 8.3%(13/158)였으며 신생아는 11.4%(4/35)였다. 나이 등 여러 임상 인자들에 있어 균혈증이 병발된 군과 균혈증이 없었던 군 사이에 유의한 차이가 없었다. 무균성 뇌수막염이 병발된 경우는 6.7%(5/75)였으며, 신생아는 7.7%(2/26)였다. 결 론 : 신생아를 비롯한 어린 영아의 요로 감염에서는 비특이적인 임상 양상을 나타내며, 특히 패혈증과 무균성 뇌수막염이 병발하기 쉬우므로 조기에 감별 진단하는 것이 중요하겠다. 또한 고혈압이나 만성 신부전과 같이 영구적인 신손상을 일으킬 수 있는 신피질 손상이 상당수에서 발견되므로, 발열 기간이 길고 염증 반응 수치가 높은 경우 신 스캔과 요로 기형을 찾기 위한 요로계 영상 검사와 추적 관찰이 꼭 필요하겠다.

Keywords

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