Studies on Clinical Characteristics, Urovirulence Factor and Host Susceptibility Gene in Pediatric Acute Lobar Nephronia

Urinary tract infections (UTIs) have been described as one of the most common serious bacterial diseases affecting infants and young children. Approximately 3% of prepubertal girls and 1% of prepubertal boys are diagnosed with UTIs (Riccabona 2003; Ma and Shortliffe 2004). The clinical severity of acute renal bacterial infection spans continuously from an uncomplicated lower urinary tract infection (i.e. cystitis) to frank abscess formation (Soulen et al., 1989). Among these UTIs, renal parenchymal infections, including uncomplicated acute pyelonephritis (APN), acute lobar nephronia (ALN), and intrarenal
abscess, are considered to be more serious forms of UTI. Acute lobar nephronia (ALN), also known as acute focal bacterial nephritis, is an acute localized bacterial renal infection presenting as an inflammatory mass without liquefaction
(Rosenfield et al., 1979; Zaontz et al., 1985; Kline et al., 1988; Klar et al., 1996, Uehling et al., 2000). The typical clinical presentations include fever, flank pain, leukocytosis, pyuria and bacteriuria, similar to presentations of patients with renal abscess or acute pyelonephritis (Zaontz et al., 1985; Soulen et al., 1989). It has previously been indicated as a complicated form of acute renal infection, representing the progression of the inflammatory process of APN (Nosher et al., 1988). ALN may also represent a relatively early stage of the development of renal abscess (Shimizu et al., 2005). The management of these renal parenchymal infections differs widely. Most patients with renal abscess require intensive medical therapy with or without surgical intervention, whereas treatment of those with ALN, like uncomplicated APN, entails only intravenous and oral antibiotics (Zaontz et al., 1985; Rathore et al., 1991; Klar et al., 1996). Hence it is important to differentiate these renal parenchymal infections. In this Chapter, we would like to review the diagnosis scheme, treatment modality, bacterial urovirulence factors, host susceptibility gene and the renal scar outcome of ALN.