Kenneth I. Glassberg, MD

• Professor of Urology,
• Columbia University, College of Physicians and Surgeons
• Director, Division of Pediatric Urology,
• Morgan Stanley Children? Hospital of New York?Presbyterian, New York, New York

It is most commonly observed in renal transplants during the early posttransplant period erectile dysfunction treatment hypnosis safe 160 mg super viagra. Interestingly testosterone associations with erectile dysfunction diabetes and the metabolic syndrome discount super viagra 160 mg buy line, there were no significant differences in the outcome between the two groups erectile dysfunction biking 160 mg super viagra buy with amex. In early posttransplant biopsies erectile dysfunction gel treatment super viagra 160 mg order on-line, glomerular thrombi were more frequent in the C4d-positive group erectile dysfunction treatment massachusetts super viagra 160 mg order with mastercard, while arteriolar lesions were seen with higher frequency in C4d-negative cases. The difference might, in part, be attributed to clinical variables, differences in biopsy practices, as well as differences in biopsy interpretation. However, the risk of recurrence varies greatly depending on the underlying cause, most frequently genetic abnormality of the complement system. Some of these recurrences, especially those associated with factor H mutations, occur very early posttransplantation. In addition, cyclosporine but not tacrolimus induces renal hypoperfusion that can further perpetuate thrombosis in renal microcirculation (275). In these patients, rising serum creatinine can be the only abnormal laboratory finding. In some of these series, the incidence of microangiopathic anemia and thrombocytopenia was as high as 100% and 75%, respectively (231,262). The presence of complement abnormalities during pregnancy is also a risk factor for fetal loss and preeclampsia; however, the incidence of such complications appears to be relatively low (4. Since these conditions require different therapies, difficulty in differentiating these conditions from each other remains a significant clinical problem. Mutations in complement regulatory proteins also predispose to preeclampsia (280). This is in spite of the fact that the renal morphologic findings with mostly arteriolar and arterial lesions resembled those seen in malignant hypertension and scleroderma renal crisis. Clinically, this may pose a differential diagnostic challenge especially when the underlying malignancy is not readily apparent. Usual autopsy findings are tumor emboli and/or fibrin microthrombi, mostly within small pulmonary vessels, including arterioles and capillaries (306). The severity of clinical disease rests mainly on the extent of involvement and, in particular, the presence of changes in renal arteries. This difference in the renal morphologic features between classic and atypical forms may explain the poorer prognosis seen in the atypical form. We follow this approach in the microscopic description; however, some overlap between acute and chronic features may occur. Although large areas of necrosis can sometimes be seen, more often the necrosis is patchy and widespread, so the swollen kidney has a reddish, mottled appearance. Calcification may be apparent in the previously necrotic areas in patients who have survived for longer periods; this can be seen on x-ray of the abdomen. Other patients who die may have no apparent cortical necrosis, although petechial hemorrhages are seen in an enlarged, swollen kidney. Bilateral nephrectomy specimens from patients who have developed irreversible renal failure with uncontrollable hypertension may be of normal or reduced size if the patient had an extended period of hemodialysis before nephrectomy. Reduction in size is partly a consequence of the damage inflicted by the disease itself, particularly if there has been extensive arterial narrowing; however, for patients who have undergone long-term dialysis, dialysis arteriopathy may also be observed. Focal scarring or areas of calcification may be seen corresponding to previous areas of necrosis. Light Microscopy Glomeruli the glomerular morphologic features vary according to the severity and the duration of the disease and the presence or absence of arterial changes. The percentage of the glomeruli with pathologic changes may also vary; in some instances, only few glomeruli are involved, whereas in other cases, most of the glomeruli are affected. The glomerulus is slightly hypocellular, and most of the glomerular capillary lumina are closed due to thickening of the capillary walls. Fibrin is sometimes clearly detectable beneath the glomerular capillary endothelial cells. The glomerular capillary walls are thickened, and the mesangial areas blend with the capillaries. Some of the glomerular capillary tufts are permeated by eosinophilic acellular material. Some of the glomerular capillary lumina are occluded by fibrin thrombi; the rest of the capillaries are congested. The reason for this fibrillar appearance is not obvious; collapsed glomerular capillary walls and mesangial edema may be contributing factors. Mesangial cells, although often swollen and hypertrophic, are usually not increased in number during the acute phase of the disease. If mesangial cell proliferation occurs, it is usually slight, focal, segmental, and late. The term mesangiolysis was first used by Yajima (312) in 1956 in patients with nephritis associated with subacute bacterial endocarditis. However, the glomerular capillary cysts, one of the most typical features of mesangiolysis, were described earlier by Pearce (313) in an experimental model of glomerular lesion induced by Crotalus adamanteus venom. The term mesangiolysis refers to partial or complete dissolution of the mesangial matrix and cells. Most of the glomerular capillary lumina are occluded by homogenous eosinophilic thrombi. The specimen is from a 40-year-old obese African American female who died a few days after initial presentation. Focal reduplication of the glomerular capillary basement membranes is also seen (arrowhead). The dilated infundibulum is occluded by homogenous eosinophilic material (intraluminal thrombus). Extensive reduplication of the glomerular capillary basement membranes indicates developing chronicity. The borders of the dissolving mesangium are hazy, and the mesangial matrix is difficult to identify. Mesangiolysis can also be seen in diabetes mellitus, various forms of glomerulonephritis, and transplant glomerulopathy (315). In the late stage of mesangiolysis, the mesangium may be thickened by pale fibrillary (sclerotic) material. This process of healing and sclerosing may lead to a distinctive pattern of glomerular sclerosis ("bland sclerosis") characterized by loss of glomerular cells and capillary lumina but with at least partial preservation of the lobular architecture. If present, they are usually small, affecting only a few capillary loops or a segment of the glomerulus. Sometimes, the necrotizing lesion is associated with arteriolar thrombosis and/or fibrinoid necrosis of the arteriolar wall. This stage is characterized by mostly chronic-type glomerular changes such as mesangial widening resulting from matrix accumulation (mesangial sclerosis), thick capillary walls with occasional double contours, segmentally sclerotic lesions, and chronic ischemic glomerular injury. Activated mesangial cells can migrate along the glomerular capillary walls between the glomerular capillary endothelium and the lamina densa of glomerular basement membranes, with resulting mesangial cell interposition. The double contour is composed of new (inner) basement membrane and the original (outer) basement membrane. Double contours of the glomerular capillary walls may apparently persist for several months or years. It should be emphasized that such extensive reduplication of the basement membranes as shown on the photograph is rarely seen. A: the glomerulus is hypercellular with closure of some of the glomerular capillary lumina. The glomerular capillary lumina are congested, but no capillary thrombi or cellular proliferation is present. The lesions closely resemble those seen in idiopathic focal segmental glomerulosclerosis with focal and segmental collapse of the glomerular capillary lumina, mesangial matrix accumulation, and visceral epithelial cell hyperplasia overlying the sclerotic segments. These segmentally sclerotic changes may represent healed necrotizing glomerular lesions. Alternatively, chronic sclerosing-type glomerular injury with segmental features can also develop as part of evolving chronicity affecting the glomeruli. Chronic ischemic-type glomerular injury is characterized by thickening and wrinkling of the glomerular capillary basement membranes, simplification of the glomerular tuft, widening of the Bowman space between the collapsed glomerular loops and the Bowman capsule, and collagen accumulation internal to the Bowman capsule replacing the Bowman space. Simplification refers to shrinkage of the glomerular capillary tuft accompanied by an apparent decrease in the number of normal glomerular lobules and by apparent loss of the mesangial matrix and cells. If the changes progress to complete glomerular ischemic obsolescence, the glomeruli appear as small, hypocellular, compact eosinophilic masses ("tombstones" or globally sclerotic glomeruli). Arteries and Arterioles Various changes occur in the renal arteries and arterioles. In the early stages, renal arterioles show swelling of the endothelial cells and subendothelial space. The arteriolar lumen may be severely narrowed and, sometimes, fragmented red blood cells are seen in the thickened arteriolar wall. The term fibrinoid necrosis is probably a misnomer because little evidence indicates that cellular necrosis is a constant feature of the lesion. Fibrinoid necrosis is thought to be related to increased vascular permeability and nonspecific trapping of plasma proteins, including fibrin in arteriolar walls. Such finding can also be associated with intraluminal thrombosis affecting arterioles and/or glomerular capillary lumina. As the disease progresses, the involved arterioles tend to become hyalinized, losing the staining reactions for fibrin. The thrombotic material in the lumen may merge with the arteriolar wall; therefore, it is often difficult to distinguish between fibrinoid necrosis of the arteriolar wall and the fibrin thrombus in the lumen. In addition, the arterioles may show proliferation of cells assumed to be endothelial cells; this change was first reported by Baehr et al. The cellular proliferation in the arterioles is sometimes a prominent feature, and the collections of cells, often concentrically arranged, may attain the size of glomeruli. Capillary channels with or without an edematous extracellular matrix can sometimes be recognized. Lipidcontaining macrophages may be present in the intima of small renal arteries undergoing proliferative changes. Because these proliferations resemble glomeruli, they are referred to as glomera, or glomeruloid structures (317). The small interlobular artery shows the edematous intima containing few myointimal cells ("mucoid intimal hyperplasia"). The patient presented with severe ("malignant") hypertension and acute renal failure. Fibrin may appear deep in the intima and may permeate the wall extensively; as in arterioles, this lesion is also called fibrinoid necrosis. This change is usually designated mucoid intimal hyperplasia; it may be severe, with marked narrowing of the lumen. Often, one sees a rapid proliferation of cells in the intima that might be regarded as organization of the intimal edema. The glomerular capillary walls are thickened; however, the glomerular capillary lumina are patent. Frank tubular epithelial necrosis may occur or acute tubular necrosis as is seen with ischemia may be present. Iron pigment and hyaline droplets in the cytoplasm of the proximal convoluted segment may be observed, with varying degrees of tubular loss. In those cases with cortical necrosis, small patchy infarcts or larger necrotic areas are seen. Rarely, calcifications of the cortex can be widespread in chronic cases of cortical necrosis. The interlobular artery shows luminal thrombus with nuclear debris in the arterial wall. The glomerulus exhibits ischemic features with thickening and wrinkling of the glomerular capillary basement membranes. Large numbers of red blood cells are present in the interstitium in areas of cortical necrosis. The arterial changes may result in severe narrowing or occlusion of the vascular lumen with consequent reduction in blood flow. These severe vascular changes are associated with a poor prognosis (318) and are responsible for the secondary ischemic glomerular changes such as shrinkage of glomerular capillary tufts and wrinkling and thickening of the capillary walls. Fibrous replacement of the thickened intima is a later change in the interlobular arteries. Changes similar to those seen in the interlobular arteries can also be present, although less frequently, in the larger (arcuate and intralobar) arteries. The glomerular capillary walls and lumina (A) and the arterial wall (B) show strong fibrinogen positivity. Platelets can sometimes be seen between the endothelial cells; occasionally, the remnants of platelets are visible within the lamina densa of the glomerular capillary basement membrane. Electrondense fibrillar fibrin wisps are sometimes a conspicuous feature in the lumina and rarely in the subendothelial space. The swollen mesangial matrix appears as a meshwork filled with electron-dense, finely granular or fibrillar material similar to the subendothelial changes. Mesangiolysis may be seen, and this progressive disintegration results in capillary ectasia. In the older lesions, wrinkling and collapse of the glomerular basement membranes may occur and are conspicuous in some cases. Small, rounded particles that are 40 nm in diameter and are limited by a thin membrane have been described in the cytoplasm of the endothelial cells. Arterioles and arteries show changes in the endothelial cells similar to those seen in the glomeruli. One sees swelling, cytolysis, and detachment of the endothelium from the underlying structures with a widening of the intima.

This study showed that angioplasty was at least equivalent to the surgical procedure gluten causes erectile dysfunction cheap super viagra 160 mg without a prescription. The placement of stents during angioplasty was introduced in the 1990s to prevent repeated stenosis of the renal artery impotence at 40 effective super viagra 160 mg. However erectile dysfunction treatment massage super viagra 160 mg purchase visa, complications did arise in some patients with renal failure directly attributable to stent placement in two patients psychological erectile dysfunction young buy super viagra 160 mg on line. Thus erectile dysfunction most effective treatment discount super viagra generic, the question arose concerning whether revascularization provided additional benefit as compared to medical management. Medical treatment was ir h ta 9 9 - n U also used as appropriate during the follow-up period. Multivariate analysis showed no difference in mortality or renal survival between the two treatment groups. Angioplasty was associated with better control of blood pressure, a finding repeated in many studies. Three recent randomized trials comparing endovascular repair to medical management have been established. They found that 16% of the stent group and 22% of the medication-alone group had reached the primary end point of reduction in creatinine by 20% at the end of 2 years, but this result did not attain statistical significance (363). The primary outcome was the renal function as determined by the inverse of the serum creatinine over time with a median follow-up of 33. This trial has been criticized because the degree of stenosis was determined centrally, the intervention technique varied (not all patients received stents), and patients were enrolled only if the local physician was uncertain of the appropriate management possibly introducing selection bias (309,365). In summary, despite numerous studies comparing various therapies, we do not yet know which is optimal. One aspect of the problem is that no one knows how to determine how individual patients will fare with angioplasty. Currently, intervention may be considered in patients with bilateral renal artery stenosis and with congestive heart failure without obvious cardiac cause or with rapidly declining renal function, or with refractory hypertension (365). Hypertension may complicate any form of glomerular disease, as shown in several reviews (3,251). One potential mechanism for hypertension due to chronic renal parenchymal disease is increased intravascular volume followed by inappropriate activity of the renin-angiotensinaldosterone system leading to sodium retention, and increased sympathetic activity (3,7). This increased risk suggests additional mechanisms involving inflammation and the immune system that may link all these forms of injury. Tumors and Other Conditions Associated With Hypertension Pheochromocytoma Pheochromocytoma is a tumor of chromaffin tissues in the adrenal glands. This tumor affects the two sexes equally and has a peak incidence in the fifth decade. The first of these syndromes to be described was by Sipple (372) and included the association of carcinoma of the thyroid and pheochromocytoma. There are two variants that include pheochromocytomas: Type 2A includes medullary thyroid carcinoma with pheochromocytomas and parathyroid hyperplasia as well as cutaneous lichen amyloidosis. Type 2B refers to the combination of medullary thyroid carcinoma, pheochromocytomas, mucosal neuromas, and a marfanoid habitus (370). Most of the mutations are point mutations and lead to bilateral pheochromocytomas that are usually benign but may recur (371,373). The incidence of pheochromocytomas in the disease is 5% although autopsy studies have found up to 13% incidence (371,373). Mutations in a number of other genes have also been associated with pheochromocytomas. Paragangliomas of the head, chest, and abdomen are the most common tumors with these mutations. The tumorigenic mechanisms for each of these genes are reviewed by Welander et al. Variable clinical manifestations have been reported, but the characteristic triad on presentation of headache, tachycardia, and diaphoresis in a patient with hypertension has a high sensitivity (90. Hypertension is present in greater than 90% of patients with pheochromocytomas and is frequently paroxysmal (293,370). Screening for pheochromocytomas should be considered in patients with resistant hypertension, the classic triad described above, family history, hypertensive reaction to anesthesia, early onset of hypertension, incidentally found adrenal tumors, or those with the genetic syndromes listed above (374). Hypertension in pheochromocytomas results from release of catecholamines into the circulation. The tumor cells consistently metabolize the catecholamine to metanephrine and norepinephrine. Thus, the most sensitive techniques currently used are measurements of plasma-free metanephrines or urinary-fractionated metanephrines. The sensitivity is 99% and specificity is 89% for the plasma measurement and 97% and 86%, respectively, for the urinary determination (370,374). Newer compounds such as [18F]-fluoro-2-deoxy-d-glucose combined with positron emission tomography have further added sensitivity particularly in the evaluation of metastatic lesions (293). Genetic testing is recommended for patients with a family history, presentation at less than 50 years of age, or where there are bilateral, malignant, or recurrent tumors (293). Most pheochromocytomas are benign, but malignant tumors represent 5% to 26% of these neoplasms (375). Benign tumors may be cured by surgical excision, although recurrence has been reported (293). Malignant tumors tend to be larger, contain more necrosis, and invade local tissues. When pheochromocytomas are fixed in formalin and then are exposed to light, they turn a light brown. Immunohistochemical staining for chromogranin A is strong in pheochromocytomas and distinguishes them from nonneuroendocrine tumors such as those in the adrenal cortex (369). Histologic features such as greater cellular polymorphism and necrosis may be present more frequently in malignant tumors but do not define them. During the last decade, several classification systems have been devised combining histologic, immunochemical, and biochemical characteristics in an attempt to assess malignant potential without real success (369). The ultrastructure of pheochromocytomas is characterized by the presence of dense-core neurosecretory granules with the typical appearance of either epinephrine or norepinephrine granules or sometimes both within the same cell. Conditions Associated With Adrenal Cortical Lesions ir h ta 9 9 - n U HyPeraldosteronIsM Hypertension may result from the excess production of aldosterone, as first shown by Conn (376) in relation to removal of an adrenal cortical tumor. Hypertension is typically accompanied by hypokalemia, muscular weakness, decreased plasma renin concentration or activity, and increased plasma aldosterone. Numerous mendelian forms of human hypertension associated with hyperaldosteronism and low renin have now been described. Liddle syndrome is caused by mutations in the epithelial sodium channel leading to increased numbers of channels at the cell surface. This process results in increased salt and water reabsorption independent of mineralocorticoid levels (21). The syndrome of apparent mineralocorticoid excess is characterized by the deficiency of an isoform of the enzyme 11-hydroxysteroid dehydrogenase, which catalyzes the interconversion of hormonally active cortisol to inactive cortisone and dictates specificity for the mineralocorticoid receptor (21). Normally, this enzyme is expressed in the kidney, with resulting inactivation of cortisol and greater access of aldosterone to the receptor. However, when this enzyme is deficient, more cortisol is bound to the receptor in preference to aldosterone. Cortisol is both more potent and present in greater concentration than is aldosterone, and its binding to the receptor results in an apparent mineralocorticoid excess (21). Hypertension exacerbated in pregnancy results from a missense mutation in the mineralocorticoid receptor that presents with hypertension before age 20 (21). The hypertension is exacerbated during pregnancy because steroids lacking 21-hydroxyl groups, such as progesterone, which is elevated during pregnancy, are agonists of the mutant receptor. A second form of familial hyperaldosteronism that cannot be suppressed by glucocorticoids has been described and several possible candidate genes have been identified (384). These patients have either adrenal cortical hyperplasia or aldosterone-producing tumors. The first step is the determination of the aldosterone: renin ratio with additional tests of exclusion for those with borderline tests. Adrenal vein sampling is necessary to confirm lateralization of increased aldosterone synthesis. Patients may present with hypertension, salt wasting, adrenal insufficiency, or sexual development anomalies. It is manifested clinically by hypertension, truncal obesity, characteristic facies, hirsutism, disturbed glucose tolerance, easy bruisability, striae, poor wound healing, muscle wasting, and osteoporosis (387,388). Guidelines for the diagnosis of Cushing syndrome have been provided from the Endocrine Society (389). Approximately one third of the cases of hyperaldosteronism are due to hyperplasia of the zona glomerulosa (392). Such hyperplasia is characterized by increased width of the cortex and may be accompanied by either large or small nodules. By contrast, in Cushing disease, the adrenal glands are often enlarged and show bilateral diffuse cortical hyperplasia with or without nodules (391). Adrenal Adenoma Grossly, adenomas are yellow, circumscribed, and usually weigh less than 50 g (393). Currently, biomarkers have not shown consistent results for determining prognosis (398). Transcriptome analysis has also been applied to adrenocortical tumors, but the results are not yet predictive (399). Carcinomas may produce different steroids at various times during their development (388). An area with nuclear pleomorphism is present in the upper left portion of the micrograph. Other cell types include a hybrid form of small, lipid-rich cells resembling a mixture of cells from zona glomerulosa and zona fasciculata, cells resembling those of the zona glomerulosa alone, and some that are similar to those of the zona reticularis. Ultrastructural studies in tumors that produce aldosterone show the typical cytoplasmic features of cells of the zona glomerulosa (394). These changes include mitochondria with plate-like cristae, smooth endoplasmic reticulum, lipid droplets, polyribosomes, and Golgi complex. In addition, spironolactone bodies may be identified by the concentric, dense lamellae, which resemble myelin figures. High concentrations of aldosterone are present within these tumors (395), but, on occasion, other substances may be detected. The incidence of adrenal tumors is not known, but they are found incidentally in 4% of patients who undergo highresolution abdominal imaging studies (396). Once an adrenal incidentaloma is discovered, hormonal evaluation for increased production of aldosterone, corticosteroids, or epinephrine/norepinephrine should be undertaken. If the tumor is nonfunctional and less than 3 cm in diameter, it can be monitored safely by repeat radiologic studies (396). Surgical removal of these tumors frequently results in cure, unlike the results of adrenalectomy in cases of pure hyperplasia (392). Predictors of cure include young age, ability to localize aldosterone secretion to one side, and lower plasma renin activity. This syndrome and its variants occur in an autosomal recessive pattern and are due to a mutation in any one of six genes involved in salt resorption in the thick ascending limb of Henle (401). The increased sodium delivery to the distal tubule results in hypokalemic alkalosis. Liddle syndrome is due to mutations in the epithelial sodium channel of the cortical collecting duct (403). Gordon syndrome is due to mutations in with-no-lysine kinases, which regulate the function of the sodium chloride cotransporters of the distal convoluted tubule. In some cases, the macula densa is more prominent, but usually, the entire apparatus is enlarged. Immunocytochemical techniques demonstrate increased numbers of cells containing renin, especially in the afferent arterioles (404). Hypertension Associated With Assorted Tumors Adrenal Carcinoma the incidence of adrenal carcinomas is approximately one case per million. In general, adrenal carcinomas are large, usually greater than 6 cm in diameter and may show necrosis grossly (391). The 16-year-old patient presented with malignant hypertension (250/150 mm Hg), papilledema, and low serum potassium. Histologically, the tumor had sheets of large epithelioid cells with prominent vascular spaces. The tumor cells converged into the muscular walls of the arterioles within the substance of the tumor. Granules present in the cells stained with the Bowie stain, a finding indicative of renin. The renin secretion from these tumors is autonomous such that the hypertension may be difficult to control (407). Grossly, these tumors are usually less than 5 cm in diameter, circumscribed, and gray or yellow white (406,408). Renin has been detected in the tumor cells using both immunohistologic and immunoelectron microscopic techniques (406). Hypertension in patients with nephroblastoma is fairly common and is usually secondary to intrarenal ischemia due to compression on the renal vessels by the tumor (414). Immunohistochemical examination revealed renin in ovoid cells near tumor vessels in areas of well-differentiated mesenchyme, a finding suggesting that the tumor cells themselves produced the renin. Immunohistochemistry demonstrated renin in atrophic glomerular structures in both cases. Forty-one had hypertension; however, resection of the tumors led to normalization of blood pressure in only six of these patients. These six patients also had high plasma renin activity in the ipsilateral renal vein and higher renin levels in the tumor tissue than in the remaining kidney.

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These findings were interpreted as an indication that hyperfiltration and normofiltration are distinct physiologic states impotence at 17 160 mg super viagra buy fast delivery. Another study by the same group of investigators showed that the dependence on vasodilator prostaglandins in type 1 diabetes is greater in women than in men (252) erectile dysfunction causes of discount super viagra american express. This finding is consistent with recent evidence that sex hormones may contribute to the pathogenesis of diabetic nephropathy (253) erectile dysfunction pills cost purchase super viagra 160 mg on line. This alteration could make these patients more susceptible to hyperfiltration in response to alterations in glomerular hemodynamics beer causes erectile dysfunction order super viagra with amex. Treatment with insulin normalized glomerular pressure and renal hypertrophy (262 erectile dysfunction doctors in nc discount 160 mg super viagra overnight delivery,263). Some of the glomerular hemodynamic changes have been attributed to the effects of diabetes on afferent arteriolar resistance resulting in vasodilation. However, the precise mechanisms for the changes in glomerular hemodynamics remain undefined. Some data also suggest that these events might be further modulated by proinflammatory mediators and cytokines (276). In summary, hyperfiltration occurs early in the course of diabetes, and some data indicate correlation with the later appearance of diabetic nephropathy. The mechanism responsible for the increased filtration is not well defined, although several humoral factors, including hormones, growth factors, and prostaglandins, have been implicated. However, other factors are probably also necessary for the development of diabetic glomerulosclerosis in any particular patient. Excess glucose is also channeled into the polyol pathway resulting in changes in the polyol-inositol metabolism important in the pathogenesis of some diabetic complications (279). However, as much as 30% of the glucose could be channeled through this pathway in diabetes (279). Although there are several mechanisms that have been proposed to explain the role of polyol pathway in the diabetic renal complications, the precise pathogenetic mechanism(s) remains unclear. In addition to induction of oxidative stress, osmotic-induced vascular damage has also been postulated. Glucose competes with the high-affinity transporters of myoinositol into cells, thus depleting tissue levels of this substrate during periods of hyperglycemia (281). The decrease in myoinositol leads to a reduction in certain sodium-potassium adenosine triphosphatases through a decline in phosphoinositide metabolism. Although the exact effect on the development of renal disease is unknown, investigators have hypothesized that changes in sodium-potassium adenosine triphosphatase may lead to alterations in the mesangial cells and smooth muscle cells of arterioles with alteration of vascular tone or modification of the responses to neurotransmitters and hormones (282). However, no pathologic changes in other organs were observed, and the renal changes were not typical for diabetic nephropathy. While most published studies point toward activation of the polyol pathway and sorbitol accumulation in diabetes, there are also some conflicting results. They also used dietary supplementation with myoinositol, which also resulted in reduction of glomerular hyperfiltration. The relationship between control of blood glucose levels and amount of glycosylated hemoglobin was discerned by Koenig et al. Since that time, investigators have shown that many intracellular, extracellular, and plasma proteins, including hemoglobin, albumin, lipoprotein, myelin, tubulin, lens protein, and various matrix proteins such as collagen may become glycosylated with varying physiologic effects (300). This is a relatively slow process that, under physiologic conditions, occurs predominantly in long-lived proteins such as collagen and lens proteins. In diabetes, hyperglycemia and oxidative stress favor the reversible glycosylation of proteins, lipids, and nucleic acids with the attachment of glucose to the amino groups forming Schiff bases at a rate proportional to the serum glucose concentration. Additional chemical rearrangement forms the more stable but still a reversible early glycosylation product known as the Amadori product. Cross-linking of matrix proteins may also increase permeability of basement membranes perhaps via reducing their electronegativity (270,307). Expression of growth factors may promote synthesis of matrix proteins by mesangial cells (311). These findings were interpreted as suggestive of local oxidative stress playing a role in the pathogenesis of diabetic glomerular lesions. Aminoguanidine reduced urinary protein excretion; however, the trial was terminated due to side effects including hepatic toxicity and apparent lack of efficacy to prevent diabetic nephropathy. Several experimental animal studies addressed the effects of dietary treatment with aminoguanidine, a substance that interferes with the formation of reactive intermediate glycosylation products (168,295,301,333­335). These effects took place without impact on body weight, blood glucose, insulin levels, or food consumption. Experimental evidence suggests that both of these mechanisms have relevance in the pathogenesis of diabetic nephropathy (353). Brownlee (352) proposed that hyperglycemia-induced overproduction of superoxide by mitochondrial electron transfer chains may play a central role in the development of diabetic complications. Several studies, both experimental and clinical, tested the efficacy of various antioxidants such as vitamins C and E, lipoic acid, antioxidative enzymes, taurine, and others to prevent or delay the onset of diabetic renal complications. The findings of these studies lend some support for the relevance of oxidative stress in the pathogenesis of diabetic nephropathy; however, the findings are not conclusive. The role of TrAnsforminG GrowTh fAcTor­ And oTher GrowTh fAcTors Several growth factors have been implicated in the pathogenesis of diabetic nephropathy. These investigators found that both the protein and the gene were increased in the kidneys of each model in association with renal hypertrophy. These mice showed reduced renal expression of collagen and fibronectin, better preservation of podocytes, reduced urinary protein, and decreased serum creatinine levels. There is a growing body of evidence indicating that grem1 might be a potential modifier of renal disease in diabetic nephropathy. Ang-1, constitutively expressed by the podocytes of a fully developed kidney, promotes endothelial cell survival, while Ang-2 is a competitive inhibitor of Ang-1 (398). Ang-1 exerts its effects via autocrine/paracrine action with its receptor (Tie-2) expressed primarily on endothelial cells and podocytes (399). In both experimental models and humans, dysregulation of Ang-1 and Ang-2 expression in diabetic kidneys has been associated with a decreased Ang-1­to­Ang-2 ratio (400,401). As described earlier, the early changes in diabetic nephropathy include glomerular hyperfiltration and renal hypertrophy. However, growth hormone seems to be also necessary for this early growth (368,415). In addition, these dwarf rats showed a slower progression of hypertrophy and other changes of diabetic nephropathy. However, these last three substances were not sufficient to produce diabetic nephropathy in the absence of growth hormone. In other words, an intact growth hormone axis is required for the development of diabetic renal disease. The Role of Inflammation and Tubulointerstitial Injury More and more data support the notion that inflammation and tubulointerstitial injury play an important role in the pathogenesis of diabetic nephropathy (425,426). This is in concordance with the pathologic changes of advanced diabetic nephropathy featuring not only glomerular and vascular changes but also interstitial fibrosis, tubular atrophy, and interstitial inflammation. Furthermore, the amount of tubular epithelial cells with phenotypical features of epithelial-mesenchymal transdifferentiation is associated with changes in serum creatinine (428). These observations underlie the significance of the tubulointerstitial compartment in maintaining the functional integrity of the kidney. During the early stages of diabetic nephropathy featuring glomerular hyperfiltration and glomerulomegaly, significant tubular hypertrophy is also present, and it accounts for the vast majority of renomegaly. Strong evidence links tubular hypertrophy to later development of tubular atrophy and renal functional impairment. Furthermore, interstitial inflammation, a common finding in diabetic nephropathy, plays an active role in the progression of tubulointerstitial injury. Others, like the effects of proteinuria, hypoxemia, and inflammation, seem to be more significant in promoting Chapter 21 Diabetic Nephropathy 923 tubulointerstitial injury especially during the later stages of diabetic nephropathy (432­436). Proteinuria can mediate tubulointerstitial injury by various mechanisms (277,437), such as via high content of profibrogenic cytokines (433,438), excessive protein reabsorption by the tubular epithelial cells, induction of tubular epithelial-mesenchymal transdifferentiation (439,440), and activation of the complement system (432,441). The significance of inflammation in diabetic nephropathy is also supported by renal biopsy studies documenting macrophage accumulation as being predictive of declining renal function (443,444). Chronic hypoxemia due to vasoconstriction or structural abnormalities of the vasculature such as arteriosclerosis or loss of the interstitial capillaries can lead to chronic ischemic injury within the tubulointerstitial compartment (434­ 436). Hypoxic injury can also develop secondary to capillary endothelial dysfunction mediated by oxidative stress in the diabetic microenvironment (266,445). Impaired mitochondrial function due to hypoxemia might be a significant contributor to apoptotic tubular epithelial cell loss observed in human diabetic nephropathy (130). Endothelial Dysfunction and Structural Abnormalities There is evidence of widespread endothelial damage and dysfunction in diabetes. The term endothelial dysfunction encompasses a number of abnormalities including disturbances in the barrier function of the endothelium, impaired antithrombotic properties, and perturbed synthetic functions (449). Albuminuria in patients with diabetic nephropathy has been viewed as a sign of global vascular-endothelial dysfunction (70). In patients with incipient or overt diabetic nephropathy who present with microalbuminuria or macroalbuminuria, significant increases of von Willebrand factor serum levels have been observed compared with diabetic patients without microalbuminuria (451). Endothelial dysfunction in diabetes may result from complex pathogenetic mechanisms. Several lines of experimental evidence, both in vitro and in vivo, also support the notion that glomerular endothelial cells, along with mesangial cells, podocytes, tubular epithelial cells, interstitial cells, and vascular endothelial cells, are directly affected by hyperglycemic injury. The fenestrated glomerular endothelium is one of the three main structural components of the glomerular filtration barrier. Podocyte loss is considered to be a significant contributor to the pathogenesis of diabetic nephropathy. However, recent morphologic studies demonstrating loss of glomerular endothelial fenestrations in both type 1 and type 2 diabetic patients (159,161) support the notion of a more active role of the endothelial cells in the development of diabetic nephropathy. Systemic Hypertension the renoprotective effects of systemic blood pressure reduction in diabetic patients are well documented (463,464). Prospective cohort studies in normoalbuminuric patients with type 1 and type 2 diabetes of 4- to 10-year duration indicated that elevated blood pressure, along with hyperfiltration, poor glycemic control, retinopathy, and smoking, contributes to the development of persistent microalbuminuria and overt diabetic nephropathy (19,468­471). The presence of hypertension and also the visit-to-visit variability of blood pressure are risk factors for the development and progression of diabetic nephropathy in patients with type 2 diabetes (472). Lowering blood pressure in patients with type 2 diabetes provides renoprotection (473). The impact of hypertension on the progression of diabetic nephropathy was further discussed in the clinical presentation part of this chapter. Experimental (animal) studies also confirm the role of hypertension in hastening the development of diabetic nephropathy. Diabetic renal lesions in the unclipped kidney developed more rapidly and were more severe than in diabetic rats without hypertension. Hemodynamic changes induced by the clip hypertension were postulated as the underlying cause for the differences. Poor Metabolic Control systemic hypertension to these hemodynamic alterations worsens the glomerular damage, particularly in combination with impairment of autoregulation, which is commonly present in diabetes. The degree of metabolic control affects the development of diabetic glomerulosclerosis. Finally, the interplay among various growth factors clearly contributes to the progression of these lesions. Several clinical studies have demonstrated that hyperglycemia is an extremely important factor in the initiation and progression of diabetic nephropathy, as discussed in the clinical presentation part of this chapter. Additional evidence for the potential role of poor metabolic control of blood sugar in the pathogenesis of diabetic nephropathy has come from in vitro studies in which mesangial cells are grown in vitro in high-glucose environments (476­479). Cosio (477) demonstrated that an increase in matrix synthesis was accompanied by inhibition of cellular proliferation. A high glucose content in the media of cultured mesangial cells reduced the activity of the collagenases and other enzymes responsible for degrading matrix (480). This combination of increased synthesis and decreased degradation leads to increased accumulation of matrix substances. A few studies in experimental animals investigated the effects of insulin treatment on the renal lesions. One study using continuous subcutaneous insulin infusion failed to demonstrate a beneficial effect on glomerular lesions in rats (482). Similar results were recorded in a mouse model of type 2 diabetes treated with an oral hypoglycemic drug (484). Clinical Course, Progression, Therapy, and Prognosis Summary of Pathogenesis the pathogenesis of diabetic nephropathy is complex and involves the interplay of many different factors. A genetic predisposition to hypertension is definitely an important factor, although the exact nature of the gene product or functional alteration is not yet known. Hemodynamic alterations such as hyperfiltration occur in the kidneys of diabetic patients and thus may cause structural injury. Changes in the intrarenal renin-angiotensin axis, alterations in the polyol pathway, changes in prostaglandin synthesis, or increased reactivity to nitric oxide may be directly responsible for the hyperfiltration. The risk of renal function decline increases to 31% with the presence of microalbuminuria (92). Reversion to normoalbuminuria reduced the rate of microalbuminuria to 24% at the end of the study (90). Review of additional such studies supported a rate of progression from microalbuminuria to proteinuria at 15% to 30% over 5 to 10 years (486). These patients had normal renal function and mild proteinuria (range of albumin creatinine ratio 434 to 1304 mg/g) at enrollment. This constant rate of loss in individuals with variability of rates of loss between individuals suggests an important genetic component as explanation (487).

A wide range of other bacterial and fungal organisms has been found in those patients treatment erectile dysfunction faqs purchase 160 mg super viagra with visa. Pulmonary hemorrhage as an initial symptom (at first clinically confused with Goodpasture syndrome) has been reported (490) erectile dysfunction emedicine buy super viagra 160 mg fast delivery. A study from Birmingham erectile dysfunction gene therapy generic super viagra 160 mg without a prescription, England erectile dysfunction what age safe 160 mg super viagra, examined 20 renal biopsy specimens and 42 autopsy specimens from patients with endocarditis (470) doctor for erectile dysfunction in delhi order super viagra 160 mg otc. Interestingly, only 9 patients in the renal biopsy group had acute glomerulonephritis and, according to those authors, 6 of them did not have immune complex deposits, but only crescent formation and necrosis (a pauci-immune pattern). The second most common morphologic pattern in the renal biopsies was acute interstitial nephritis. The most common findings in the autopsy material were localized infarction (19 cases), acute tubular damage (8 cases), glomerulonephritis (7 cases), and cortical necrosis (6 cases). Unfortunately, the morphologic description of the biopsies and of the autopsy specimens is not detailed, and no ultrastructural studies were performed (470). In the section on subacute endocarditis, we briefly addressed the diagnostic challenge in patients with pauci-immune crescentic glomerulonephritis related to endocarditis (336,472). Treating a patient with infectious endocarditis with immunosuppressive medications can have disastrous consequences. The clinical picture may be dominated by the underlying infectious process, but oliguria may herald the onset of renal involvement. Gross hematuria may stem from glomerulonephritis, renal infarction, or drug-related interstitial nephritis. Hypertension is unusual; when it is found, it may have been present before the acute onset of infective endocarditis (485,493). These laboratory findings may show considerable resolution or improvement (within days to weeks) after the institution Chapter 10 Acute Postinfectious Glomerulonephritis and Glomerulonephritis Caused by Persistent Bacterial Infection 423 of antibiotic therapy. Renal insufficiency may be relatively mild or may lead to the need for dialysis (483). The degree of renal insufficiency does not correlate with the clinical duration of infective endocarditis. In most patients, the serum creatinine level reaches its peak at or just into the beginning of successful antibiotic therapy and soon declines with therapy. Patients who show signs of renal failure fare less well than those in whom it is absent (483). One group (494) has suggested that addition of plasmapheresis and steroids aids in renal recovery, but additional studies are needed to confirm these findings. Although a transient worsening of renal function may occur before recovery (495), mild to moderate renal insufficiency almost always resolves with proper antibiotic therapy (461,495). Even severe renal failure may heal with antibiotic therapy, although it may take weeks or months to achieve (37). Subsequent biopsies have shown almost complete morphologic resolution in those patients with clinical recovery; the only renal parenchymal changes noted were persistence of mesangial sclerosis and the presence of globally sclerotic glomeruli. Occasionally, renal insufficiency may persist despite proper antibiotic therapy and dialysis (459,483). Marked residual morphologic changes have been noted long after apparent cure (459). Progressive renal failure and uremic deaths have been reported occasionally even today, when antibiotics are commonly administered (459,483). This is not a typical outcome, and once infectious endocarditis has been effectively treated, complete renal healing should take place. There may be persistent proteinuria or hematuria in some patients despite effective therapy (146,483­485). She also had pneumonia, and by the time of blood cultures, she was already on vancomycin and gentamicin. All glomeruli showed similar prominent proliferative changes, but she fully recovered with antibiotic treatment. Immunofluorescence studies have confirmed the presence of bacterial antigens in the glomerular deposits in patients with infective endocarditis owing to S. As pointed out, a proportion of patients have few or no glomerular immune complex deposits. Glomerular subendothelial deposits Pathologic Findings liGhT microscoPy Acute diffuse proliferative glomerulonephritis is the pattern of injury observed most often with acute bacterial endocarditis. The light microscopic changes closely resemble those already described in patients with acute postinfectious (poststreptococcal) glomerulonephritis. The incidence in patients with focal glomerulonephritis and acute endocarditis is not known. There appears to be a high rate of activation of the alternative complement pathway in patients with S. Several pieces of evidence suggest that there may be nonimmune activation of the alternative complement pathway by staphylococcal cell wall antigens in acute endocarditis caused by S. These include an inability to find evidence of circulating immune complexes in some of these patients (463,483), an absence of prolonged illness before evidence of glomerulonephritis, and deposition of complement without accompanying immunoglobulins in immunofluorescence studies. Other organisms have been associated with endocarditis, such as Neisseria gonorrhoeae (365) and Coxiella burnetii (496). Coagulasenegative staphylococcus sometimes forms a biofilm around the catheter tips in vivo, which is thought to shield the organism from the effects of antibiotics (378). Other reported organisms include Listeria monocytogenes (503), peptococcus (509), Corynebacterium bovis, Bacillus subtilis, micrococcus, diphtheroid species, and gram-positive anaerobic rods, such as Propionibacterium acnes (375­379,505­507,511). Between 6% and 27% of ventriculoatrial shunts have evidence of bacterial colonization (375,509), and low-grade bacteremia may persist for years before the onset of clinical symptoms (497). Cultures of the blood and cerebrospinal fluid may be sterile, and bacterial identification may be achieved only on removal of the shunt (497). Clinically overt glomerulonephritis occurs in approximately 4% to 5% of infected patients (377). The true incidence is not known and would require prospective urinalysis to identify patients with subclinical renal involvement. The latent period between shunt placement and the onset of clinical symptoms ranges from 1 month to 15 years (mean, 4 years). Renal involvement is noted almost exclusively in patients with ventriculoatrial or (483) and mesangial deposits also occur (483,484). Mesangial deposits often predominate in later biopsies studied months after the initial onset of the disease (461). The persistence of these humps suggests either that immune complexes containing staphylococcal antigens disappear more slowly than those of streptococcal origin or that the source of the antigen has not been completely eliminated. Etiology and Pathogenesis Immunofluorescence and electron microscopic findings, along with the depression of serum C3, suggest an immune complex etiologic source and pathogenesis. Most of the cases of infective endocarditis now seen stem from drug addiction (455,492). Between 40% and 78% of intravenous drug abusers with acute endocarditis owing to S. The reason for the high incidence in this group is not known, but it may be related to existing antibodies to staphylococcal antigens or to the nonimmune activation of the alternative complement pathway by staphylococcal cell wall antigens. Chapter 10 Acute Postinfectious Glomerulonephritis and Glomerulonephritis Caused by Persistent Bacterial Infection 425 ventriculojugular shunts. Renal symptoms in patients with ventriculoperitoneal shunts are uncommon, but they have been reported and are similar to those seen with ventriculoatrial shunts (499,511,512). Ventriculoatrial shunts have been almost totally replaced by ventriculoperitoneal shunts as a form of therapy for hydrocephalus. Although shunt nephritis is becoming a rare diagnosis, we encounter occasional patients with glomerulonephritis associated with infected central venous catheters (513­515). Although the published cases are still limited, this glomerulonephritis appears very similar to shunt nephritis. Patients have symptoms of acute glomerulonephritis with low serum complement (C3) levels. Most of the patients are children, although cases among adults have been reported (age ranges from 2 months to older than 50 years). Patients usually show signs and symptoms of bacteremia and sepsis, although renal involvement may be the first manifestation (375). Purpura, arthralgias, lymphadenopathy, hepatosplenomegaly, hypergammaglobulinemia (IgA, IgM, and IgG), and anemia are common. Less common manifestations are leukocytosis, leukopenia (499), thrombocytopenia (502,516), elevation of the erythrocyte sedimentation rate (375), cryoglobulinemia, and hypertension. Renal findings include edema, hematuria (gross in half of patients), and proteinuria (375,489,502­505,509,512,517,518). The proteinuria may be pronounced, and the nephrotic syndrome has been described in about half of patients. Apparent recovery takes place in most patients whose infected shunts or central venous catheters are removed (375,497,499,502,504,505,513­515), although there may be persistent proteinuria or hematuria (499,505). Death may result from complications following removal of the shunt or from the original neurologic disease for which the shunt was inserted (502). Focal segmental proliferative glomerulonephritis and crescentic glomerulonephritis have been noted, but less commonly (497). Immunofluorescence Microscopy Immunofluorescence shows a granular to coarse broken linear pattern along the glomerular capillary walls and in the mesangial regions (497­499,501,503,504,509). Peripheral glomerular capillary wall immunofluorescent deposits are noted in more than four fifths of patients, whereas mesangial deposits are seen in slightly more than one half. IgG is found in about two thirds of patients (497), but IgM is sometimes the predominant immunoglobulin (377,499,520). IgA, usually less intense than IgG or IgM, is present in less than one half of cases (497). There is typically an increase in the amount of mesangial matrix (498,499,504), and one reported case was referred to as lobular glomerulonephritis (499). A membranoproliferative glomerulonephritic pattern is found in approximately one half of patients, diffuse (nonlobular) proliferative glomeru- Ultrastructural studies demonstrate discrete electron-dense immune-type deposits on the subendothelial portions of the glomerular capillary walls and in the mesangial regions (499,501,503,504). Glomerular intramembranous and subepithelial deposits also have been detected, but they are rare (497,509). Increased mesangial matrix and circumferential mesangial cell interposition with creation of a new inner basement membrane­like material also can be identified. Subsequent renal biopsy, after successful treatment, reveals complete disappearance of the deposits found by electron microscopy and immunofluorescence techniques (518). Etiology and Pathogenesis There is evidence that the renal disease is caused by immune complex deposition. As noted previously in the case of other infectious diseases, there is frequently a depression of the serum complement level (375,499,503,504). Half of patients with acute glomerulonephritis have reduced levels of C4, indicative of activation of the classic complement pathway. Evidence of activation of the alternative pathway is noted in only a few patients (499,503,516). Patients with shunt infections without glomerulonephritis do not have hypocomplementemia. If therapy is inadequate and the glomerulonephritis persists, the serum complement level remains depressed (516). Circulating immune complexes and rheumatoid factors are found in most patients (521). Circulating immune complexes, serum cryoglobulins, and serial titers of antibody to bacterial antigen all abate with removal of the shunt, control of the infection, and remission of the glomerulonephritic process (522). IgG, IgM, and C3 are present in the cryoglobulins, and there was evidence in one study of the presence of both antibody to the bacterial organism and the bacterial antigen (503). It is of considerable interest that there can be complete clinical cure following eradication of shunt infection. Acute postinfectious glomerulonephritis in the modern era, experience with 86 adults and review of the literature. Transactions of a Society for the Improvement of Medical and Chirurgical Knowledge, vol. Cases and observations illustrative of renal disease accompanied with the secretion of albuminous urine. Acute glomerulonephritis following skin infection due to streptococci of M-type 2. Changing perspectives in children hospitalized with poststreptococcal acute glomerulonephritis. Circulating immune complexes and complement levels in relation to the clinical presentation of Nigerian children with acute poststreptococcal glomerulonephritis. Clinical Course and Outcome Serial renal biopsies have been performed before and after removal of the shunt; complete resolution of the glomerulonephritic process has been confirmed (518). The only residual may be mild mesangial hypercellularity (523) or focal global glomerular sclerosis (523). In most patients, the immunofluorescent and electron microscopic deposits completely disappear (504,523). However, disease in patients in whom crescentic glomerulonephritis develops may not resolve despite adequate therapy (523,524). Full clinical recovery with normalization of the serum and urine abnormalities is noted in about two thirds of patients, sometimes within a month or two (519); renal disease persists in the remaining third, as manifested by proteinuria, microhematuria, hypertension, or renal insufficiency. Rarely, complete clinical recovery can take place after several months of proteinuria or hematuria (485). Delay in diagnosis and treatment may prevent complete recovery (500) and lead to irreversible renal insufficiency (489). The glomerulonephritic process may develop as long as 5 years after the apparent colonization of a shunt and the onset of low-grade bacteremia (498,502,509,522).

References

• Seifert BL, Snyder MS, Klein AA, et al. Development of obstruction to ventricular outflow and impairment of inflow in glycogen storage disease of the heart: serial echocardiographic studies from birth to death at 6 months. Am Heart J 1992;123:239.
• Mori E, Yamadori A. Acute confusional state and acute agitated delirium: Occurrence after infarction in the middle cerebral artery territory. Arch Neurol 1987;4:1139.
• Cannom DS. Prevention of sudden cardiac death. J Cardiovasc Electrophysiol 2005;16: S21-S24.
• Lethbridge- Cejku M, Helmick C, Popovic J. Hospitalizations for arthritis and other rheumatic conditions: data from the 1997 National Hospital Discharge Survey. Med Care 2003; 41(12):1367-73.
• Illerhaus G, Wirth K, Dwenger A, et al. Treatment and prophylaxis of severe infections in neutropenic patients by granulocyte transfusions. Ann Hematol. 2002;81:273-281.
• Gupta AK, Knowles SR, Gupta MA, et al: Lithium therapy associated with hidradenitis suppurativa: case report and a review of the dermatologic side effects of lithium, J Am Acad Dermatol 32:382n386, 1995.
• Winston DJ, Yeager AM, Chandrasekar PH, et al. Randomized comparison of oral valacyclovir and intravenous ganciclovir for prevention of cytomegalovirus disease after allogeneic bone marrow transplantation. Clin Infect Dis. 2003;36:749-758.