Chronic pyelonephritis

Pyelonephritic end-stage kidney and ureterocutaneous fistula in a Shetland pony

A 12-y-old Shetland Pony was presented with a mucus-secreting fistula in the right paralumbar fossa. Surgery was performed to unravel the origin of the fistula. The horse died under anesthesia and was forwarded to autopsy. The right kidney was markedly atrophic and fibrotic, consistent with unilateral end-stage kidney. The right ureter was markedly thickened, but with luminal continuity leading into the urinary bladder where a partial obstruction caused by nodular para-ureteral fat necrosis was evident. The lumen of the cutaneous fistula was continuous with the right ureter; therefore, we diagnosed the lesion as a ureterocutaneous fistula. Anomalies of the ureter are uncommon, and ureterocutaneous fistula formation in equids has not been reported previously to our knowledge.

Asymptomatic Bacteriuria is Harmless and Even Protective: Don't Treat if You Don't Have a Very Specific Reason

Symptom-free bacterial colonization of the lower urinary tract in an otherwise healthy individual was long misunderstood. Our current understanding is based on solid research proving that asymptomatic bacteriuria (ABU) is harmless and even protective against symptomatic urinary tract infection episodes. Thus, ABU should not be treated in patients with the exception of before endosurgery and, until we have accumulated more knowledge, in pregnant women.

Urinary tract infections. Old and new concepts

The recommendations for evaluation and management of pediatric patients with UTIs are summarized in Table 5. These recommendations were designed to minimize the risk of kidney damage in children with UTIs based on current perceptions of the pathogenesis of renal injury. The children at greatest risk for kidney damage are the infants and young children with febrile UTIs in whom effective treatment is delayed, those with gross VUR, and those with anatomic or neurogenic urinary tract obstruction. These recommendations likely will be modified as more is learned about the pathogenesis of renal injury associated with UTIs, as new therapeutic approaches are developed, and as imaging technology improves.

Reflux nephropathy: the glomerular lesion and progression of renal failure

Reflux nephropathy is the cause of 5%-10% of dialysed end-stage renal failure. Once scarring has occurred, the prognosis depends on the severity of initial damage and the presence of proteinuria, which reflects the development of glomerulosclerosis. It is independent of ongoing reflux or infection. Histological appearances highly suggestive of reflux nephropathy can occur in radiologically normal kidneys. Duplex Doppler scans of ureteric orifices suggest these patients may have lateral insertion, suggesting past reflux. Glomerular hypertrophy correlates well with reduced renal function and severe renal scarring, but poorly with focal and segmental glomerulosclerosis, which correlates with proteinuria. Increasing attention is being paid to the tubulo-interstitium and the relationships between the cellular infiltrates (mainly T4 cells) and glomerular, tubular and vascular damage. Control of hypertension, hyperphosphataemia and a low-protein diet are the only currently widely accepted treatments for slowing progression.

Natural history of "lower" urinary tract infections

Our current knowledge of the long-term outcome of uncomplicated urinary tract infections in women is based on a re-evaluation of the criteria for defining pyelonephritis at autopsy, careful description of the causes of renal disease among patients entering dialysis and transplant programs, long term observation of patients, and epidemiologic studies which have attempted to determine the association of bacteriuria with mortality. The weight of the evidence favors the conclusion that although urinary tract infections can produce severe impairment of renal function, this is rare in the absence of a major predisposing factor such as obstruction, calculus, reflux, abnormalities of the voiding mechanism or diabetes. The predisposing lesions, however, may go undetected until heralded by episodes of acute pyelonephritis or by renal failure. Unfortunately, urinary tract infections are so common that it is difficult to distinguish the population at greatest risk. The possible role of renal damage produced by autoimmune mechanisms following infection needs continued study.

A contribution to the morphology and pathogenesis of thyroid-like lesions in the kidney

The morphological variations of thyroid-like lesions in the kidney in 15 cases with chronic destructive interstitial nephritis as the basic alteration were examined with light microscopy and immunohistological methods. Reflux pyelonephritis was present in some cases. Thyroid-like lesions can develop at any age. "Mature" thyroid-like lesions possess large follicular structures and solid tubular epithelial cell complexes, whereas the follicular structures in "young" thyroid-like lesions are small. The hyaline casts are Tamm-Horsfall protein positive in between one- and two-thirds of the follicles. IgA is present in all follicular lumina. The thyroid-like lesions are the result of a regenerative process. They develop after subtotal parenchymal destruction of remaining tubular epithelial cells from the ascending limb of the loop of Henle, the distal convoluted tubules and the collecting ducts. They are pathognomonic for healed destructive bacterial interstitial nephritis, but can also be observed in analgesic nephropathy, hydronephrosis, and nephronophthisis when these basic diseases are preceded by pyelonephritis.

Renal clubbing and scarring in adults: a retrospective study of 110 cases

A urographic pattern of renal clubbing and scarring was found in 182 scarred kidneys of 110 adult patients. Homolateral vesicoureteric reflux was demonstrated by reliable techniques in 90/135 scarred kidneys. Urinary tract infections occurred in 75 patients. Hypertension developed in 20 patients with normal renal function and was not related to the extent of scarring. Chronic renal failure occurred in 30 patients with diffuse bilateral scarring. Four patients showed histologic changes of chronic pyelonephritis. Two hypertensive patients had a typical histologic pattern of Ask-Upmark kidney (segmental hypoplasia). Development of renal scars in adulthood was demonstrated in 2 cases.

Immunopathology of the glomerular changes in chronic pyelonephritis

To investigate the presence of intraglomerular immunoprotein deposition in chronic pyelonephritis (CPN), 29 renal specimens from patients with various urological diseases were examined by immunofluorescence. The relationship between immunohistological findings and types of glomerular changes which were classified according to Heptinstall's criteria was studied. Only type 2 glomeruli, which were considered to be ischemic changes, demonstrated granular and globular depositions of IgM and C3 in the collapsed and solidified shrunken tufts. IgM was positive in 117 of 258 (45.3%), and C3 in 122 of 264 (46.2%) type 2 glomeruli. The distribution patterns of IgM and C3 were much the same. IgG and IgA were rarely observed and neither fibrinogen nor albumin was observed in the tufts of type 2 glomeruli. Normal glomeruli and other types of glomerular changes in CPN showed few or no intraglomerular immunoprotein deposition.

Renin-dependent hypertension in children with reflux nephropathy

In children with reflux nephropathy renin-dependent hypertension may develop. Two girls with reflux nephropathy, hypertension, elevated plasma renin activity, but normal (Case I) and near normal (Case 2) serum creatinines are described. These cases suggest that reflux nephropathy can activate the renin-angiotensin system and that the renin inhibitors, methyldopa and propranolol, an useful in managing this type of hypertension.

Loss of renal tissue in the elderly

Eighty-eight kidneys obtained at necropsy from normotensive subjects aged over 50 years were examined histologically and by post-mortem pyelography and angiography. Moderate or severe scarring was present in 50%. Its distribution and the absence of calyceal deformity make pyelonephritic scarrig unlikely. Its extent was related to the severity of change in the renal vessels, but not to age. On pyelograms, scarring was difficult to distinguish from fetal lobation. Kidneys with the most severe histological changes in the vessels tended to show the most marked angiographic distortion, though in general the two techniques examine different parts of the renal vascular bed. Total renal area and "cortical" area, measured from the angiograms, were not significantly correlated with age, thouth both tended to be smaller in older subjects. These dimensions, particularly cortical area, were significantly correlated with vascular changes, being smallest when vessels were most markedly affected. Results suggest that the loss of renal tissue which occurs in the elderly, particularly selective loss of cortex, is more closely related to events in the renal vasculature than to age itself.

Host factors and infectious diseases in the elderly

Because of declining function of their immunologic and other organ systems, elderly individuals are more susceptible to certain types of infections of their heart valves, meninges, urinary tract, and skin. They may develop serious sepsis with subtle clinical signs and symptoms, which makes accurate diagnosis difficult. The antimicrobial agents of choice for use against the organisms most commonly responsible for these septic symdromes are listed in Tables 2, 3, and 4. Some methods of preventing these infections are discussed, but further studies to verify old techniques and establish new ones are needed.

Single nephron study of intrarenal urea handling in experimental pyelonephritis

Micropuncture experiments were carried out in 20 rats with bilat. experimental chronic pyelonephritis. Inulin and urea concentrations were estimated in the late proximal, early distal and latte distal nephron segment. Proximal urea reabsorption did not differ from that in control animals. Fractional amount of filtered urea in the early distal segment was significantly lower in the pyelonephritic rats, urea reabsorption in the distal tubule approcimated zero. The data indicate that intrarenal urea recirculation is abolished by the experimental lesion, thus determining maximal urine urea concentration. It is suggested that the concentrating defect of experimental pyelonephritis is not only a result of an adaptational increase in individual nephron GFR; an additional intrinsic lesion seems to be present, located in the renal medulla.

Diseases causing end-stage renal failure in New South Wales

The nature of the original renal disease was determined in 403 consecutive cases of end-stage renal failure, in 317 of which the clinical diagnosis was corroborated by histological examination of the kidney. Five diseases accounted for 20 or more cases--glomerulonephritis (31% of the total), analgesic nephropathy (29%), primary vesicoureteral reflux (8%), essential hypertension (6%), and polycystic kidneys (5%). In only four cases did renal failure result from chronic pyelonephritis without a demonstrable primary cause. Greater use of micturating cystography and cystoscopy and routine urine testing for salicylate are advocated for earlier diagnosis of the major causes of "pyelonephritis". The incidence of end-stage renal failure in people aged 15-55 in New South Wales was estimated to be at least 34 new cases per million of total population each year.

Hypertension, asymmetric renal parenchymal defect, sterile urine, and high E. coli antibody titre

During an 11-year period four children were seen with asymmetric renal parenchymal reduction, arterial hypertension, and sterile urine. The history and radio-logical or histological findings, or both, were consistent with "abacterial pyelonephritis" induced by bacterial infection in early childhood. All four had raised antibody titres to Escherichia coli. Three possibilities may explain the high antibody titres and insidious course of the renal damage-the presence of bacterial variants or amorphous bacterial antigen in the kidneys or the fact that because of cross-reactivity between certain E. coli O antigens and renal tissue the "E. coli antibodies" were, in fact, autoantibodies.