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Query: UMLS:C0920646 (renal ischemia)
 2,515 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Escherichia coli is the most frequent cause of pyelonephritis. Its possible virulence factors include the ability to adhere and colonize the urinary tract, an important initiating factor in all urinary tract infections (UTIs). The importance of P fimbriae in this adhesion is stressed and the evidence for its importance in pyelonephritis is presented in epidemiologic studies of patients, as well as in animal studies. It appears that both host receptor density and the nonsecretor state is responsible for susceptibility to urinary tract infection. Vesicoureteral reflux can be responsible for ascending upper tract infection, but infection with P-fimbriated E coli may lead to ascending pyelonephritis without reflux because of the paralytic effect of lipid A on ureteral peristaltic activity. Renal ischemia leads to renal damage following infection by reperfusion damage due to the release of superoxide. Experimentally, this ischemic damage can be prevented by allopurinol, a xanthine oxidase inhibitor. The acute inflammatory response can produce renal damage because of the respiratory burst of phagocytosis, which while killing phagocytosed bacteria also damages renal tubules. An amelioration of the inflammatory response by treatment with superoxide dismutase or corticosteroids has been shown to modulate renal damage. Vaccination with P fimbriae has been shown experimentally to prevent the initiation of the disease. However, since vaccines are not clinically available, the clinical and animal studies on therapy of acute disease are stressed. Acute pyelonephritis during the first 3 years of life more often produced the renal damage that could lead to end-stage renal disease.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Etiology and pathophysiology of pyelonephritis. 167 Sep 5

Vesicoureteral reflux (VUR) is mainly a primary phenomenon due to incompetence of the ureterovesical junction, mostly affecting a pediatric population. During micturition cystourethrography (MCU) reflux into the kidney--intrarenal reflux (IRR)--is occasionally seen. In areas with IRR the kidney surface may subsequently be depressed and the papillae retracted (reflux nephropathy (RN]. VUR may lead to hypertension and/or end-stage renal failure. Most commonly, VUR is discovered during evaluation for urinary tract infection, but it may also be present in patients with hypertension, toxemia of pregnancy, chronic renal failure and proteinuria, and it may be found in siblings of patients with VUR. For the time being VUR is demonstrated at radiographic MCU, whereas RN is diagnosed by demonstration of focal scars and of abnormal parenchymal thickness at urography. In children with VUR and no abnormalities of calyces or parenchymal defects standardized measurement of the parenchymal thickness at three sites may identify kidneys which are likely to develop focal scars. Quantitation of focal scarring should be performed in connection with a measure of the overall kidney size. The occurrence of IRR is dependent of the papillary morphology, intrapelvic pressure and urine flow. There may be an important relationship between renal ischemia and IRR in producing a 'vicious circle of deleterious effects' which, combined with parenchymal extravasation, may lead to RN. Treatment of VUR includes medical and surgical management. Since renal scarring may occur in infancy, prevention should focus on infants and young children. Infants and young children with severe VUR may have normal urograms. Therefore a MCU should also be performed, preferably with the recommended standardized technique.
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PMID:Vesicoureteral reflux and reflux nephropathy. 388 98