Diagnosis and treatment for renal and urinary tract infections

Jeng Jong Huang, Chin-Chung Tseng

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Upper urinary tract infection (UTI) or acute renal infection spans a continuum of varying severity from uncomplicated acute pyelonephritis (APN) through worsening stages of acute becterial nephritis (ABN) to frank renal abscess. It can be a focal or diffuse process in different portions of the kidney exhibiting different degrees of inflammation. In clinical practice, the distinction among the different upper UTIs must be made on radiologic grounds. APN in adults is a clinical diagnosis that does not ordinarily require special imaging studies, but more severe of complicated upper UTIs do. On the basis of postcontrast CT scan findings, we classified ABN as (1) Group I (n = 7), wedge-shaped; (2) Group II (n = 12), focal mass, may progress to abscess; and (3) Group III (n = 9), diffuse (multifocal) mass. Three (33%) of the 9 patients in Group III died. Renal ultrasonography (US) is sensitive in detecting Group II ABN lesions (positive rate, 69%), and revealed marked renal enlargement in most Group III lesions (89%). Therefore, in upper UTI patients with a critical status or those refractory to antibiotics, US studies are sensitive in detecting severe lesions, and abdominal CT scan can accurately define and delineate the extent of these lesions. Emphysematous pyelonephritis (EPN) is a rare, severe gas-forming infection of renal parenchyma and its surroundings. Four radiological classes of EPN include: (1) Class 1 (n = 5): gas in the collecting system only; (2) Class 2 (n = 11): gas in the renal parenchyma without extension to extrarenal space; (3) Class 3A (n = 7): extension of gas or abscess to perinephric space; class 3B (n = 21): extension of gas or abscess to pararenal space; and (4) Class 4 (n = 4): bilateral EPN or solitary kidney with EPN. Upper UTI caused by E. coli (69%) and K. pneumoniae (29%) in patients with DM (96%, 46/68) and/or urinary tract obstruction (22%, 10/46) is the cornerstone for EPN. Mixed acid fermentation of glucose by Enterobacteriaceae is the major pathway of gas formation. For localized EPN (Classes 1 and 2), percutaneous catheter drainage (PCD) combined with antibiotics can provide a best outcome. For extensive EPN (Classes 3 and 4) with a more benign manifestation (e.g. less than two risks, including: thrombocytopenia, acute renal impairment, disturbance of consciousness, or shock), if preservation of kidney is considered, PCD combined with antibiotics may be attempted due to its high successful rate and may preserve the kidney. Nephrectomy provide the best management outcome (90%, 9/10) and should be promptly attempted for extensive EPN with a fulminant course (e.g. two or more risks). The total mortality was 18.8% (9/48). In addition, we analyzed 25 patients with acute pyogenic iliopsoas abscess within 10 years. Pain in the flank, back or abdomen is the most common complaint, but characteristic triad of limp, fever, and pain is rare. Accurate diagnosis can be provided by early suspicion and CT scan. These patients commonly represent extensions from the infectious sources of bowel, kidney, or spine. The etiology of iliopsoas abscecces may vary with each country. In out Taiwanese series, the most probable etiology is UTI (52%) with enteric micro-organisms (E. coli: 44% and Kleb spp.: 24%) and frequently occur in older (mean age: 64 y/o), diabetic (64%) females (18:7). In the absence of adjacent involvement (such as the bowel) on the CT scan, PCD provides an alternative to surgery. Once PCD fails, subsequent surgical drainage or nephrectomy should be performed.

Original languageEnglish
Pages (from-to)250-257
Number of pages8
JournalJournal of Internal Medicine of Taiwan
Issue number5
Publication statusPublished - 2001 Dec 1

All Science Journal Classification (ASJC) codes

  • Internal Medicine


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