Sustained low-efficiency daily dialysis with hemofiltration for acute kidney injury in the presence of sepsis

AIMS: Acute kidney injury (AKI) commonly occurs in critically ill patients with sepsis and is associated with poor outcomes. Unfortunately, the ideal mode of renal replacement therapy remains unknown. Because both higher doses of dialysis and hemofiltration have been associated with improved survival, we postulated that adding hemofiltration to the diffusive clearance achieved by sustained low-efficiency daily dialysis (SLEDD-f) would provide a survival advantage over SLEDD. METHODS: From December 2003 to October 2005, we retrospectively analyzed all patients with multisystem organ failure, vasopressor-dependent hypotension and oliguric acute kidney failure secondary to nonoperative sepsis who were treated with renal replacement therapy (RRT). After exclusionary criteria were applied, 8 patients received SLEDD-f and 13 patients received SLEDD. All treatments were for 8 - 16 h/day. SLEDD-f was continued until vasopressors were reduced to a minimal dose. Outcomes were mortality and recovery of renal function at 30 days after initiation of RRT. APACHE- II scores were calculated at the time of dialysis initiation to predict mortality. RESULTS: Despite higher APACHE II scores, 30-day survival was 100% in the SLEDD-f group and 38% in the SLEDD group. Furthermore, most of the SLEDD-f patients were able to have vasopressors weaned quickly and all patients in the SLEDD-f group recovered significant renal function to allow discontinuation of RRT. CONCLUSIONS: While the optimal treatment remains unknown, this small study raises the possibility that SLEDD-f offers a survival advantage and increases the chance of renal recovery while decreasing the need for vasopressors. A large randomized trial comparing SLEDD-f with other forms of renal replacement therapy is needed.     

Urological management of patients with von Hippel-Lindau's disease

We present our experience with 7 patients with von Hippel-Lindau's disease. Five patients had bilateral renal tumors and 2 had pheochromocytomas. Staging is accomplished best with abdominal computerized tomography and renal angiography. Computerized tomography is the preferred method to follow the patients. Because of the tendency for these patients to have bilateral renal involvement, surgical efforts should be directed toward preserving renal parenchyma without compromising adequate tumor excision. Of the 7 patients 6 are alive 4 months to 8 years postoperatively. One patient had metastatic disease at autopsy. No patient required dialysis or renal transplantation. The relationship between the multifocal renal cysts and renal carcinomas in this disease remains unknown.     

The femoral head in osteonecrosis. A quantitative study of osteocyte population

The occurrence of osteonecrosis following renal transplantation is well recognised but its pathogenesis remains unknown. We have quantified the number of empty osteocytic lacunae in the subchondral bone of femoral heads from a control group of patients, and compared these with femoral heads from a group of renal transplant recipients without evidence of overt osteonecrosis. There is a significant increase in empty osteocytic lacunae in renal transplant patients. We conclude that loss of osteocytes precedes other manifestations of osteonecrosis.     

Successful pregnancy in renal transplant recipient with previous known polyomavirus nephropathy

Pregnancy after renal transplantation has become increasingly common. Studies in non-immunocompromised patients have shown that pregnant women have increased susceptibility to infection or reactivation of latent virus such as BK virus. To what extent a renal transplant recipient is at risk for reactivation of polyoma virus during pregnancy remains unknown. We hereby report successful pregnancy outcome in a renal transplant recipient with a known history of BK virus nephropathy treated with cidofovir i.v. To our knowledge, this is the first published experience with a successful pregnancy in renal transplant recipients with known history of polyomavirus-associated nephropathy.     

C4d deposition without rejection correlates with reduced early scarring in ABO-incompatible renal allografts

C4d deposition in peritubular capillaries is a specific marker for the presence of antidonor antibodies in renal transplant recipients and is usually associated with antibody-mediated rejection (AMR) in conventional allografts. In ABO-incompatible grafts, however, peritubular capillary C4d is often present on protocol biopsies lacking histologic features of AMR; the significance of C4d in this setting remains unclear. For addressing this, data from 33 patients who received ABO-incompatible renal allografts (after desensitization) were retrospectively reviewed. Protocol biopsies were performed at 1 and/or 3 and 6 mo after transplantation in each recipient and at 12 mo in 28 recipients. Twenty-one patients (group A) had strong, diffuse peritubular capillary C4d staining without histologic evidence of AMR or cellular rejection on their initial protocol biopsies. The remaining 12 patients (group B) had negative or weak, focal peritubular capillary C4d staining. Three grafts (two in group B) were lost but not as a result of AMR. Excluding these three patients, serum creatinine levels were similar in the two groups at 6 and 12 mo after transplantation and at last follow-up; however, recipients in group A developed significantly fewer overall chronic changes, as scored by the sum of Banff chronic indices, than group B during the first year after transplantation. These results suggest that diffuse peritubular capillary C4d deposition without rejection is associated with a lower risk for scarring in ABO-incompatible renal allografts; the generalizability of these results to conventional allografts remains unknown.     

Abdominal aortic coarctation and segmental hypoplasia.

Functionally significant, nonatherosclerotic, noninflammatory, concentric and tubular stenoses of the abdominal aorta, 4 to 16 cm in length, were encountered in five male and five female patients 11 to 49 years old. Seven patients were younger than 19 years of age. Aortic branch stenoses were common, affecting splanchnic vessels in seven patients and renal arteries in eight patients. The pathogenesis of the aortic constrictive lesions remains unknown, but it may be related to developmental error or aortic growth arrest. Existence of multiple renal arteries in 70% of these patients lends support to the developmental hypothesis. Intimal fibroplasia characterized stenotic aortic tissue. Severe hypertension was common, with the mean preoperative arterial pressure being 200/119 mm Hg. Thoracoabdominal bypass was undertaken in eight patients, being combined with renovascular reconstruction on five occasions. Two patients underwent patch graft aortoplasty with bilateral renal revascularization. Therapeutic results were classified as excellent six times and as good four times. Single-stage arterial reconstructions are the preferred method of treatment for abdominal aortic coarctation or segmental hypoplasia with associated aortic branch disease.     

Evaluation of renal function in human visceral leishmaniasis (kala-azar): a prospective study on 50 patients from Brazil

BACKGROUND: There are few studies of renal function evaluation in visceral leishmaniasis (kala-azar). The aim of this study was to evaluate glomerular filtration rate (GFR) and tubular function as urinary acidification capacity and maximal urinary concentration, in patients with the chronic form of kala-azar. PATIENTS AND METHODS: This is a cross-sectional study of 50 consecutive patients with kala-azar. GFR was calculated by 24-hour creatinine clearance. Urinary pH, titratable acidity and urinary ammonia excretion were measured after acid-loading with NH4Cl. Urine to plasma osmolality ratio (U/Posm) was evaluated after water withdrawal and vasopressin administration. All parameters were also measured in 20 healthy volunteers (control group). RESULTS: GFR was normal in 44% of the patients, elevated in one third, and decreased in the remaining 28%. Decreased GFR was attributed to fluid loss, hypotension and immunological glomerular disease. Urinary concentrating capacity was abnormal in 68% of the patients with kala-azar after pitressin administration. A urinary pH higher than 5.5 was seen in 64% of cases after ammonium chloride acidification test. There was decreased formation of titratable acidity in 64% and low formation of ammonia urinary excretion in 30% of cases. Complete distal renal tubular acidosis was observed in 30% of patients and an incomplete form was found in 34%. CONCLUSION: Abnormalities in glomerular filtration, urinary concentration and acidification are consistently associated to the chronic form of kala-azar and can be a consequence of the immunological system dysregulation that occurs in this disease.     

Traumatic bilateral renal infarction

Published examples of unilateral and bilateral renal artery thrombosis attest to their usual subjection to nephrectomy at diagnosis or soon thereafter, eliminating the opportunity for spontaneous improvement which would enlighten the issue of how often late recovery may occur, and under what circumstances. Seven cases of renal artery thrombosis and five patients with renal artery embolization extracted from the literature have included documentation of patchy histologic viability within otherwise total infarction. Conversely, 47 reports of renal artery thrombosis culminating in nephrectomy or examined post mortem include no reference to any of these histologic features. Presumptions are speculative regarding whether these features were absent, overlooked, or unexamined. Their incidence cannot be estimated--only the possibility of recoverable renal function in an unknown number of involved patients. It may be presumed that the majority of kidneys exposed to sustained arterial interruption will undergo irreversible infarction, with an undefined small subgroup later developing renal hypertension. An unknown number, however, may fortuitously possess arterial collateralization competent to support sufficient numbers of viable nephrons to sustain adequate renal function. It is further speculated that shared pathophysiologic features establish the opportunity for misdiagnosis of renal cortical necrosis, which carries a documented potential for spontaneous recovery. Impulsive bilateral nephrectomy may therefore be unjustified, particularly in consideration of the minimal potential hazards of nonremoval. In the event of convalescent problems of renal origin, delayed nephrectomy remains an option. The requirement for interval hemodialysis is further influenced by the advantages accruing from retention of the native kidneys relative to calcium metabolism and blood product replacement. A final consideration relates to the advisability of secondary revascularization of spontaneously recovered kidneys for the purpose of further improving renal perfusion and renal function. It may be argued that stable renal function at levels compatible with a tolerable or uncompromised lifestyle is best undisturbed, with the intention of avoiding iatrogenic mishap. A more objective consideration relates to the observed late, progressive deleterious influences of hyperfiltration imposed upon the reduced population of surviving nephrons (3); would this process been exaggerated by improved perfusion? Dietary protein restriction has been advocated for patients at risk. Identification of late functional deterioration would initiate a reconsideration of therapeutic revascularization.     

Optimizing the timing of renal replacement therapy in burn patients with acute kidney injury

Acute kidney injury is a common complication in burn ICU patients and is associated with a high mortality rate. The optimal timing for starting renal replacement therapy (RRT) remains unknown; there is no established universal definition for early and late RRT initiation. The aims of the present narrative review are to briefly analyze the available recently published data on the timing of initiation of RRT in critically ill patients and to discuss the optimal timing of RRT in critically ill burn patients with acute kidney injury. When considering renal replacement therapy for acute kidney injury patients, physicians face the dilemma of balancing the hazards of starting too early, exposing patient to an unnecessary therapy with possible complications and costs related to treatment, and preventing a significant proportion of patients from spontaneous recovery of their renal function against the potential life-threatening harm of initiating RRT) too late. Evidence suggests that with appropriate care up to 80% of burn patients experience recovery of kidney function and the need for RRT seems to be very rare after hospital discharge. In the absence of life-threatening complications, the optimal time and thresholds for starting RRT in burn patients are uncertain. High heterogeneity exists between studies on RRT timing in burn patients.     

The Effects of Acute Renal Failure on Long-Term Renal Function

The relationship between acute renal failure (ARF) and long-term renal function remains unknown. We therefore undertook a study of patients at the Baltimore VA Hospital to examine the effects of a bout of acute renal injury on long-term renal function. We retrospectively reviewed the relationship between serum creatinine and time of observation for 6058 individuals who had values greater than 1.4 mg/dL in any two consecutive years. Individuals were stratified according to total years of observation with a minimum of two years. Severity of acute renal injury was divided into mild, moderate, and severe with elevations in baseline creatinine of <50%, 50–300% and >300% respectively. Sporadic elevations in creatinine were evident in 8–15% of the population. There were a total of 1328 episodes of acute renal failure in 916 patients that were suitable for analysis. Mild ARF on a substrate of normal or mildly abnormal renal function resolved without long-term sequelae. Moderate and severe ARF occurred more frequently on a background of reduced renal function but baseline function was retained in at least 60% of patients. We conclude that ARF is more frequent in patients with chronic kidney disease but it is not invariably associated with an accelerated course to end-stage renal disease or death. Overall, the majority of ARF events resolved without adverse long-term effects suggesting appropriate management in the majority of instances.     

The effects of acute renal failure on long-term renal function

The relationship between acute renal failure (ARF) and long-term renal function remains unknown. We therefore undertook a study of patients at the Baltimore VA Hospital to examine the effects of a bout of acute renal injury on long-term renal function. We retrospectively reviewed the relationship between serum creatinine and time of observation for 6058 individuals who had values greater than 1.4 mg/dL in any two consecutive years. Individuals were stratified according to total years of observation with a minimum of two years. Severity of acute renal injury was divided into mild, moderate, and severe with elevations in baseline creatinine of < 50%, 50-300% and > 300% respectively. Sporadic elevations in creatinine were evident in 8-15% of the population. There were a total of 1328 episodes of acute renal failure in 916 patients that were suitable for analysis. Mild ARF on a substrate of normal or mildly abnormal renal function resolved without long-term sequelae. Moderate and severe ARF occurred more frequently on a background of reduced renal function but baseline function was retained in at least 60% of patients. We conclude that ARF is more frequent in patients with chronic kidney disease but it is not invariably associated with an accelerated course to end-stage renal disease or death. Overall, the majority of ARF events resolved without adverse long-term effects suggesting appropriate management in the majority of instances.     

Focal segmental glomerulosclerosis

Over the last 2 decades, we have learnt that focal segmental glomerulosclerosis (FSGS) is a ubiquitous phenomenon underlying the progressive deterioration of many different types of renal diseases in both pediatric and adult populations. FSGS may also be the primary renal lesion, whether in new disease entities such as glycogen storage disease and human immunodeficiency virus infection, or in idiopathic FSGS. Although the mechanism which triggers the development of primary FSGS still remains unknown, laboratory and clinical studies have identified several key pathophysiological events leading to end-stage renal disease. While therapeutic modalities have not changed remarkably, a recent study, although uncontrolled, demonstrated an impressive efficacy of intravenous steroid pulse therapy in inducing remission. Nevertheless, it remains largely unknown whether such a forced remission decreases the overall risk of developing chronic renal failure. Studies have revealed an important pathophysiological role of angiotensin and the therapeutic efficacy of angiotensin converting enzyme inhibitors in progressive loss of renal function in diseases where glomerulosclerosis is secondary; however, it remains to be verified whether these results hold true in primary FSGS. As a result of the improvement in allograft survival rate, the benefit of renal transplant outweighs the risk of recurrence of FSGS, hence transplantation continues to be a vital therapy for FSGS patients who have reached renal failure. Thus, FSGS is not one disease, but rather a range of lesions seen in many settings. The type of lesions and the patient's unique genetic factors contribute to prognosis, and also may dictate choice of optimum therapy.     

Renal agenesis and unilateral nephrectomy: what are the risks of living with a single kidney?

The long-term outlook for patients with unilateral renal agenesis or following unilateral nephrectomy in childhood is controversial. Animal studies suggest that the resultant compensatory increase in glomerular filtration might lead to progressive damage to the remaining renal tissue and may generate hypertension. Human studies addressing these concerns are limited in number and are difficult to interpret because they are small, retrospective, or cross sectional with significant variations in duration and completeness of follow-up. The published studies suggest that renal function remains stable for several decades in the majority of subjects. The clinical significance of mild-grade proteinuria and hypertension seen in some patients is unknown. Longitudinal studies are needed to understand the long-term effect and significance of the several pathophysiological changes observed in the solitary kidney.     

Familial juvenile nephronophthisis and renal transplantation in two siblings.

Familial juvenile nephronophthisis (FJN) is a hereditary renal disease, characterized by a juvenile onset and the development of medullary cysts and progressive renal damage. The pathogenesis of FJN remains unknown, and at present, no rational therapy other than renal transplantation is available. We describe two cases in siblings in whom there were no extrarenal complications, such as retinopathy or central nervous system involvement. Both patients display juvenile onset of the disease and end-stage renal failure. The brother received a kidney from his father, and the sister received a kidney from her mother. Recurrence of the underlying disease has not so far been found in the transplanted kidney.     

Lymphatic drainage in renal cell carcinoma: back to the basics

Lymphatic drainage in renal cell carcinoma (RCC) is unpredictable, however, basic patterns can be observed in cadaveric and sentinel lymph node mapping studies in patients with RCC. The existence of peripheral lymphovenous communications at the level of the renal vein has been shown in mammals but remains unknown in humans. The sentinel lymph node biopsy technique can be safely applied to map lymphatic drainage patterns in patients with RCC. Further standardisation of sentinel node biopsy techniques is required to improve the clinical significance of mapping studies. Understanding lymphatic drainage in RCC may lead to an evidence‐based consensus on the surgical management of retroperitoneal lymph nodes.     

Spontaneous perirenal hematomas. Report of 3 cases]

Spontaneous retroperitoneal hemorrhage is an uncommon affection, the diagnosis was recognized by sonography and CT scan, but the etiology remains unknown and exploration for diagnosis may become necessary. In the absence of an apparent etiology, patients with spontaneous renal bleeding should undergo radical nephrectomy, because of the extremely high incidence of small undetectable occult tumors. Three further cases were reported by the authors, who made a review of the literature.     

Phosphate binder therapy for attainment of K/DOQI bone metabolism guidelines

Hyperphosphatemia in patients with chronic kidney disease leads to secondary hyperparathyroidism and renal osteodystrophy, and it is independently associated with mortality risk. The exact mechanism by which hyperphosphatemia increases mortality risk is unknown, but it may relate to enhanced cardiovascular calcification. The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) Clinical Practice Guidelines for Bone Metabolism and Disease in Chronic Kidney Disease recommends maintenance of serum phosphorus below 5.5 mg/dL, calcium-phosphorus (Ca x P) product less than 55 mg(2)/dL(2), intact parathyroid hormone (iPTH) 150 pg/mL to 300 pg/mL, and bicarbonate (HCO(3)) greater than 22 mEq/L. Although calcium-based phosphate binders (CBPB) are cost effective, there are long-term safety concerns pertaining to their postulated role in the progression of cardiovascular calcification. Sevelamer hydrochloride has been recommended as an alternative noncalcium phosphate binder. Results from the Calcium Acetate Renagel Evaluation (CARE) study indicate that calcium acetate is more effective than sevelamer hydrochloride in controlling serum phosphorous, Ca x P product, and HCO(3) in hemodialysis patients. In the Treat-to-Goal study, dialysis patients treated with sevelamer hydrochloride had slower progression of coronary and aortic calcification than patients treated with CBPB. The mechanism underlying the beneficial effect of sevelamer hydrochloride is unknown but may relate to decreased calcium loading, or to dramatic reductions in low-density lipoprotein (LDL) cholesterol in sevelamer hydrochloride-treated patients. At present, evidence incriminating CBPB in the progression of cardiovascular calcification in end-stage renal disease (ESRD) remains largely circumstantial. As calcium acetate is more efficacious and cost effective than sevelamer hydrochloride, it remains an accepted first-line phosphate binder. This review examines these issues and provides rational guidelines for the use of CBPB in patients on maintenance hemodialysis.     

Bilateral progressive cystic nephroma in a 9-month-old male infant requiring renal replacement therapy

We report the case of a 3-year-old boy who presented at 9 months of age with abdominal distension and was found to have a triad of bilateral cystic nephroma, pleuropulmonary blastoma (PPB) and juvenile intestinal polyps. There have been three previous reported cases of patients with the same associated diagnoses. Our patient is the first reported patient with PPB who received renal replacement therapy and progressed to successful renal transplantation. The potential increased risk of progression of malignancy of PPB (type 1) with immunosuppression following transplantation remains unknown.     

Clinical study of the relationship between unknown etiology of renal hematuria and serum zinc concentrations

The relationship between red blood cell counts in urine of 165 patients with unknown etiology of renal hematuria and serum zinc levels was examined. There was a significant negative correlation between red blood counts in urine and serum zinc levels. The clinical course and changes of serum zinc levels of 2 cases (case 1: 21 years old female, case 2: 46 years old male) with unknown etiology of renal hematuria are reported. Serum zinc levels showed the clinical stage of unknown etiology of renal hematuria. Renal biopsy should be done in patients with low serum zinc levels and renal hematuria continuing for a long time. Clinically, serum zinc level could be used as a marker of effect of treatment for unknown etiology of renal hematuria. Serum zinc levels were low in 165 patients with renal hematuria.     

Renal transplantation after endovascular repair of abdominal aortic aneurysm

An increasing number of abdominal aortic aneurysms (AAA) occur in renal failure patients because of strong association between atherosclerosis and chronic kidney disease. Endovascular aneurysm repair (EVAR) has proven to be an effective modality to treat AAA, particularly in patients with renal disease, because of its several advantages over the standard open procedure, including lower morbidity, shorter operative time, and shorter hospital stay. A Medline search showed a single publication on renal transplantation (RT) following EVAR of AAA. In this context, we report our case of successful RT in a patient who had undergone EVAR 2 years prior for a 5.7-cm AAA. No stent-related complications, such as graft occlusion, dislodgement, dissection, or endoleak, were observed in the perioperative period. The transplanted kidney had primary function leading to a stable serum creatinine of 115 micromol/L at 6 months. Although the long-term outcome of RT after endovascular repair of AAA remains unknown, currently available evidence shows favorable outcomes of EVAR in the normal population, in patients with renal diseases, and in RT recipients; hence, RT should not be denied to renal failure patients who have undergone EVAR in the past.