The influence of indomethacin on renal acidification in normal subjects and in patients with sickle cell anemia

Patients with sickle cell nephropathy have been shown to have a distal type of incomplete renal tubular acidosis. We evaluated renal tubular acidification before and after indomethacin administration because prostaglandins have been shown to inhibit the transepithelial potential difference in the collecting tubule and since we previously found indirect evidence of increased prostaglandin synthesis in patients with sickle cell nephropathy. Indomethacin did not change urine pH in the sickle cell anemia (SCA) patients or in the control subjects. It induced, however, an increase in titratable acid excretion particularly in the SCA patients. Ammonium excretion decreased after indomethacin in the SCA patients while it did not change significantly in the control subjects. In the SCA patients, net acid excretion did not rise after indomethacin. In contrast there was an increase in net acid excretion after indomethacin administration in the control subjects. We conclude from our study that the inability of patients with SCA to lower urine pH to a normal extent after ammonium chloride loading is not improved by indomethacin. The decrease in ammonium excretion after indomethacin administration in SCA might be due to an effect of the prostaglandin synthesis inhibitor indomethacin on ammoniagenesis.     

Renal amyloidosis in a child with sickle cell anemia

The kidney is frequently affected in patients with sickle cell syndrome, i.e., homozygous and heterozygous patients, with a consequently large spectrum of renal abnormalities that may range from minimal functional changes to chronic renal failure. Here, we present a 13-year-old boy with sickle cell anemia (SCA) (HbSS) who was referred to our unit with nephrotic syndrome. Renal biopsy revealed AA type amyloidosis on the basis of light microscopic findings, indicating Congo red staining and immunohistochemistry. He had neither a family history of familial Mediterranean fever (FMF) nor any complaint of recurrent abdominal pain, arthritis, and fever, but frequent painful vaso-occlusive crises. The patient was found to have no MEFV gene (Mediterranean feVer) mutations either. Painful episodic attacks might provoke recurrent acute inflammation, leading to repeated stimulation of acute phase responses and cause secondary amyloidosis. To our knowledge, this boy is the first case of SCA complicated by renal amyloidosis observed in childhood.     

Autologous bone marrow transplant in a patient with sickle cell disease and diffuse large B-cell lymphoma

As the life expectancy of patients with homozygous sickle cell anemia (SCA) improves, SCA care providers are confronted with diseases of the adult SCA population rarely seen before. We report here a 40-year-old woman with SCA who developed diffuse large B-cell non-Hodgkin's lymphoma (NHL) that was treated with eight cycles of chemotherapy consisting of cyclophosphamide, doxorubicin, vincristine, prednisone, and etoposide (CHOPE), without complete remission. She subsequently underwent high-dose cyclophosphamide and total-body irradiation followed by autologous bone marrow transplantation (BMT). To reduce the risk of sickle cell crisis precipitated by G-CSF, she underwent hypertransfusion to maintain a low % hemoglobin S throughout her treatment course. Although she has required iron chelation therapy and shows no sign of modification of her underlying SCA, she remains in remission from NHL 12 years posttransplant. To our knowledge, this is the first reported case of autologous BMT in a patient with SCA. Our patient illustrates that SCA in itself does not preclude autologous stem cell transplantation for lymphoma in selected patients, and this report should encourage others to consider autologous BMT in adults with SCA where it represents a lifesaving therapy for malignant diseases.     

Beta-2-microglobulin in sickle cell anaemia. Evidence of increased tubular reabsorption

Sickle cell nephropathy is characterized by severe defects in renal medullary functions. In contrast, both proximal tubular secretion and reabsorption are found to be elevated. Since proximal tubular cells are involved in reabsorption and catabolism of beta 2-microglobulin (beta 2-m), we studied serum concentration and urinary excretion of this low molecular weight protein in sickle cell nephropathy. Serum beta 2-m concentration was higher in sickle cell anaemia (SCA) patients compared to control persons. beta 2-m excretion, however, was normal and beta 2-m clearance was not significantly decreased. Fractional beta 2-m excretion was significantly lower and therefore tubular reabsorption of beta 2-m was increased in the SCA patients. There was no correlation between serum beta 2-m concentration and the tubular reabsorption of beta 2-m and phosphate. These findings are further evidence of a particular function of the proximal tubule in sickle cell nephropathy.     

Glomerular involvement in adults with sickle cell hemoglobinopathies: Prevalence and clinical correlates of progressive renal failure

Patients with sickle cell anemia (SCA) may develop a glomerulopathy with proteinuria and progressive renal insufficiency, leading to ESRD. Albuminuria is a sensitive marker of glomerular damage in this population and precedes the development of renal insufficiency. For determination of the prevalence of glomerular damage in SCA and the clinical correlates of renal insufficiency, 300 adult patients with SCA were studied (hemoglobin SS = 184; and 116 with other sickling hemoglobinopathies: SC, SD, and S-beta thalassemia); albumin excretion rates (AER) and renal function (Cockroft-Gault formula) were determined, and clinical and hematologic evaluations were conducted. In hemoglobin SS disease, increased AER (micro- and macroalbuminuria) occurred in 68% of adult patients, and macroalbuminuria occurred in 26%. In other sickling disorders, increased AER occurs in 32% of adults, and macroalbuminuria occurs in 10%. The development of graded albuminuria was age dependent, so at 40 yr, 40% of patients with SS disease had macroalbuminuria. There were no differences in hematologic parameters (hemoglobin levels, white blood cell count, percentage of reticulocytes, platelet counts, or lactate dehydrogenase levels) between patients with normoalbuminuria and those with micro- or macroalbuminuria. By multivariate analysis, albuminuria correlated with age and serum creatinine in SS disease but not with BP or hemoglobin levels. In other sickling disorders, albuminuria tended to be associated with age but not with hemoglobin or BP levels. The diastolic BP was lower in patients with SCA than in African American control subjects, and the development of renal insufficiency, which was present in 21% of adults with SS disease, was not accompanied by significant hypertension. It is concluded that glomerular damage in adults with SCA is very common, and a majority of patients with SS disease are at risk for the development of progressive renal failure. The development of micro- and macroalbuminuria is not related to the degree of anemia, suggesting that sickle cell glomerulopathy is not solely related to hemodynamic adaptations to chronic anemia. In contrast to other glomerulopathies, the development of systemic hypertension is uncommon in SS disease with renal insufficiency.     

Renal abnormalities in sickle cell disease

Renal abnormalities in sickle cell disease. Sickle cell nephropathy is indicated by sickled erythrocytes, with the consequent effects of decreased medullary blood flow, ischemia, microinfarct and papillary necrosis. Impaired urinary concentrating ability, renal acidification, hematuria, and potassium secretion are also found. There may be a causal relationship between an increase in nitric oxide synthesis and experimental sickle cell nephropathy, and some studies have indicated that the progression of sickle cell nephropathy is hemodynamically mediated. Although there are many studies showing that proteinuria, nephrotic syndrome, chronic progressive renal failure, and acute renal failure syndromes are the outcome of this disease, the pathogenic mechanism(s) and potential therapies remain to be elucidated. Survival of patients with sickle cell nephropathy who progress to end-stage renal disease (ESRD) is equal to non-diabetic ESRD patients, and graft survival rates are also similar for those who undergo renal transplantation. This article presents a historical review of the glomerular and tubular disorders associated with sickle cell nephropathy, and reviews therapeutic indications to slow its progression. Further research is needed.     

Combined liver and kidney transplantation in a patient with sickle cell disease

Sickle cell intrahepatic cholestasis is a potentially fatal end-organ complication of sickle cell anemia. Renal involvement in sickle cell anemia is common, and in some cases, can present as acute renal failure. Although renal transplants have been performed in patients with sickle cell anemia since the late 1960s and a number of liver transplants have been recently performed for these complications, there has not been experience with dual organ transplantation for sickle cell anemia-related complications. We describe the case of a patient with sickle cell anemia who underwent successful combined liver and kidney transplantation after the development of acute sickle cell intrahepatic cholestasis and renal failure requiring continuous venovenous hemodialysis. The patient underwent a successful combined liver and kidney transplant with limited perioperative complications and preserved allograft function. At 22 months posttransplant, the patient expired as a result of an acute pulmonary embolus in the setting of bilateral hip fractures. Autopsy revealed no evidence of liver or kidney allograft rejection and evidence of chronic sickle cell nephropathy in the native kidney. Combined liver and kidney transplantation is a viable therapeutic option in patients with severe end-organ effects of sickle cell anemia.     

Ketorolac-induced irreversible renal failure in sickle cell disease: a case report

 Nonsteroidal anti-inflammatory drugs are often used in the management of those with acute pain secondary to sickle cell disease due to potent analgesic effects along with a lack of addictive potential, respiratory depression, and central nervous system effects, as may occur with narcotics. Caution should be observed in the use of nonsteroidal anti-inflammatory drugs in patients with compromised renal function. We present a case of a 17-year-old sickle cell disease patient with an acute painful episode and normal renal function indices who subsequently developed irreversible renal failure and a perirenal hematoma following the administration of ketorolac, despite adequate hydration. Due to its inhibitory effect on prostaglandin-mediated vasodilation, we advise caution in the use of ketorolac for the pain management of sickle cell painful episodes. We recommend following the administration guidelines for ketorolac for renal-compromised patients in those with painful episodes of sickle cell disease, and if used in this patient population, renal function must be very closely monitored. Received: 24 March 1998 / Revised: 5 June 1998 / Accepted: 10 June 1998     

Impaired creatinine secretion after an intravenous creatinine load is an early characteristic of the nephropathy of sickle cell anaemia.

BACKGROUND: The capacity to increase the tubular secretion of creatinine (TS(cr)) after an intravenous creatinine load (stimulated TS(cr)) has been found to be impaired in subclinical reduction of renal mass. We decided to investigate if this response was impaired in sickle cell anaemia (SCA) patients before there was evidence of deterioration of renal function. METHODS: Studies were done in 16 patients with homozygous SCA who had normal or supranormal glomerular filtration rate (GFR) and in 20 normal controls of similar median age (23 years). The tubular stress test (TST) consisted of 30-min clearance periods ([(125)I]iothalamate and creatinine) done before (baseline) and after (three successive post-stimulation periods) the intravenous infusion of 88.4 micromol (10 mg) of creatinine per kg of body weight. RESULTS: Baseline studies showed that the SCA patients had higher GFR and lower serum creatinine concentration. After stimulation there were no changes in GFR. In contrast, creatinine clearance increased 2.3 times in normal but not in SCA patients (P<0.001) and the TS(cr) in the first post-stimulation period was 161+/-83 nmol/kg/min in SCA patients vs 286+/-93.2 in normal controls (P<0.001). The mean TS(cr) post-stimulation was also reduced in patients with SCA (123+/-52 nmol/kg/min vs 179+/-50 in normal controls, P<0.001). Since SCA patients had lower P(cr) values, separate analysis was made of post-load clearance periods in which P(cr) was comparable in patients and in normal controls (range 177-265 micromol/l or 2-3 mg/dl) and the reduction in TS(cr) was also present in SCA patients in these study periods. CONCLUSION: Patients with SCA have impaired response to the TST before there are reductions in glomerular filtration. Therefore, a reduction in the tubular secretory reserve capacity represents an early event in the nephropathy of this condition.     

Renal function in children with sickle cell anemia

BACKGROUND: Patients with sickle cell anemia have various forms of renal dysfunction. SUBJECTS, MATERIALS AND METHODS: The purpose of this study is to demonstrate the abnormalities of HbSS patients' renal function in childhood. Renal function studies were performed in 55 patients with homozygote sickle cell anemia and compared with 13 healthy children. The blood and timed urine samples were obtained for hematological and biochemical determinations. RESULTS: Mean serum creatinine, sodium, phosphorus and calcium levels were not statistically different between patients and controls. Mean serum potassium and uric acid levels were significantly higher in patients than in controls. Mean tubular phosphate reabsorption (p < 0.001) and fractional excretion of potassium (p < 0.05) were lower in patients than in the control. There were no significant differences in fractional excretion of sodium and uric acid between patients and controls. Patients had significantly higher urine pH and significantly lower specific gravity and osmolality than controls. Also, there were no significant differences in urinary protein/ creatinine, urinary N-acetyl-beta-D-glucosaminidase/creatinine and urinary malondialdehyde/creatinine between patients and controls. CONCLUSION: Thus, significant proximal tubular dysfunction is not a common feature but distal tubular abnormality is the most consistent renal functional derangement of patients with SCA in childhood.     

Renal disease in adult Nigerians with sickle cell anemia: a report of prevalence, clinical features and risk factors

Renal abnormalities in adult Nigerians with sickle cell anemia (SCA) have not been extensively studied. To determine the prevalence, pattern and the associated risk factors of renal disease, 72 subjects with SCA from two centers in the southwestern Nigeria were investigated. Socio-demographic data, body mass index and clinical findings were documented. The urine analysis, serum bio-chemistry, hemogram and renal factors attributable to SCA were determined. Presence of albuminuria of at least 1+ or microalbuminuria in those negative with dipstick; and the estimated glomerular filtration rate (eGFR) using the Cockcroft-Gault formula categorized subjects to various stages of chronic kidney disease (CKD). Subjects with and without albuminuria were compared to determine the relative risk associated with renal disease. Four (5.6%) subjects had macro-albuminuria, while 32 (44.4%) had micro-albuminuria and 30 (41.7%) had hemoglobinuria. In the subjects with albuminuria, age, hematocrit, systolic blood pressure, serum creatinine, urea and creatinine clearance were numerically higher while the eGFR was numerically lower. There was no significant difference in the clinical parameters studied in the two groups of subjects. The diastolic blood pressure was significantly higher in the albuminuric group. Based on eGFR, 22 (30.6%) subjects had hyperfiltration (GFR > 140 mL/min/1.73 m2), of whom 36.4% had albuminuria, 18 (25.0%) had stage 1 CKD, 30 (41.7%) had stage 2 CKD and two (2.7%) subjects had stage 3 CKD with albuminuria. None had stage 4 and 5 CKD. We conclude that renal abnormalities, importantly albuminuria, is common in adult Nigerians with SCA and the pattern and incidence are similar to those reported from other parts of the world. Regular blood pressure monitoring, early diagnosis and active intervention are advocated to delay progression to end-stage kidney disease in view of poor outcomes of renal replacement therapy in SCA patients with nephropathy.     

Sickle cell nephropathy: an update on pathophysiology,diagnosis, and treatment

Sickle cell nephropathy is a major complication of sickle cell disease. It manifests in different forms, including glomerulopathy, proteinuria, hematuria, and tubular defects, and frequently results in end-stage renal disease (ESRD). Different pathophysiologic mechanisms have been proposed to explain the development of nephropathy in SCD, where hemolysis and vascular occlusion are the main contributors in the manifestations of this disease. Markers of renal injury, such as proteinuria and tubular dysfunction, have been associated with outcomes among patients with sickle cell nephropathy and provide means for early detection of nephropathy and screening prior to progression to renal failure. In small-sized clinical trials, hydroxyurea has demonstrated to be effective in slowing the progression to ESRD. Dialysis and renal transplantation represent the last resort for patients with sickle cell nephropathy. Nevertheless, despite the availability of diagnostic and therapeutic strategies, sickle cell nephropathy remains a challenging and under-recognized complication for patients with sickle cell disease.     

Prognosis of the nephrotic syndrome in sickle glomerulopathy. A retrospective study

Of 240 adults with sickle cell anemia seen over 11 years, 12 had the nephrotic syndrome. In 9 (75%) the glomerular lesion, sickle glomerulopathy, consisted of mesangial expansion and basement membrane duplication. Six patients had type IV renal tubular acidosis. Four of the 9 Patients died within 24 months (17 +/- 5; mean +/- SD), while 5 survived 36 months or longer (80 +/- 49); no significant differences were seen between the former and the latter in age, admission serum creatinine and C3 levels, urinary protein excretion, or the frequency of renal tubular acidosis. Chronic azotemia developed in 3 and acute renal shutdown in another 2. Of 22 patients with sickle glomerulopathy (our 9 added to 13 from the literature) 11 died within 2 years. Ten of these (91%) had developed renal failure, compared to only 5 of the 11 (45%) who survived longer than 2 years (p less than 0.05). The 5-year mortality in the general population of sickle cell anemia is 3.75%, and 75% of patients aged 15 years or older survive 18 years or longer. The nephrotic syndrome, most often caused by sickle glomerulopathy, occurs in 4% of patients with sickle cell anemia, leading to renal failure in two-thirds and death in 2 years in half the patients. The development of chronic azotemia correlates strongly with early mortality. The prognosis is much worse than that in the general population of sickle cell anemia.     

Glomerular hyperfiltration and albuminuria in children with sickle cell anemia

Early manifestations of sickle nephropathy include glomerular hyperfiltration and proteinuria, typically microalbuminuria. Over time, a subset of patients develops histologic changes, decreased glomerular filtration, and ultimately renal failure. This study was designed to determine the rate of glomerular hyperfiltration and prevalence of albuminuria in a cross-sectional analysis of untreated children with sickle cell anemia (SCA), and to identify correlates of both complications. Measured glomerular filtration rate (GFR) by plasma clearance of 99-technetium diethylenetriaminepentaacetate was compared to GFR estimates calculated from published formulas. Eighty-five children (mean age 9.4 ± 4.8 years) were studied; 76% had glomerular hyperfiltration with mean GFR = 154 ± 37 ml/min/1.73 m². GFR declined in teenage years and was significantly correlated with increased serum cystatin C levels and higher systolic blood pressure. Measured GFR had only modest correlations with GFR estimates (Pearson correlation coefficients ≤0.5). Albuminuria, usually microalbuminuria, occurred in 15.9% and was associated with higher diastolic blood pressure and lower white blood cell and absolute neutrophil counts. Cystatin C levels inversely reflect GFR changes and are associated with albuminuria; serial monitoring may provide a sensitive and accurate marker of nephropathy in children with SCA.     

Surgery in children with homozygous sickle cell anaemia.

During the 25 years 1952--77 31 surgical procedures were performed on children aged up to 16 years with sickle cell anaemia (SCA). Six emergency operations were carried out, all for complications of SCA indistinguishable from the acute surgical conditions they mimicked. Seventeen minor operations were well tolerated and major surgery was undertaken 8 times, including 5 splenectomies for hypersplenism and increased transfusion requirements. The preparation for surgery by planned multiple transfusions and the indications for splenectomy are discussed. Recommendations are made for the preparation of patients for acute and routine surgery.     

Sickle cell nephropathy: challenging the conventional wisdom

This review explores the current model of sickle cell nephropathy and the limitations of the model. Renal abnormalities are common complications of sickle cell disease (SCD). Beginning in childhood, patients with SCD develop a urinary concentrating defect resulting in polyuria and a predisposition to nocturnal enuresis and dehydration. The current model of sickle cell nephropathy suggests that destruction of the renal medulla induces production of renal vasodilating substances that feedback to the glomerulus causing hyperfiltration. Hyperfiltration leads to glomerulosclerosis and proteinuria, with eventual reduction in kidney function. The crucial steps of vasodilating substance production and hyperfiltration in children with SCD have not been proven. Treatment of sickle cell nephropathy is aimed at the reduction of proteinuria with angiotensin converting enzyme inhibitors or angiotensin receptor blockers. Hydroxyurea and chronic transfusion therapy may also alter the progression of sickle cell nephropathy in children. Further studies are needed to identify an accurate model and effective treatments for sickle cell nephropathy.     

Screening for sickle trait among potential live kidney donors: policies and practices in US transplant centers.

Sickle cell trait is common in the United States (US) and associated with abnormalities of renal function. Little is known, however, about the potential risk of sickle cell trait to live kidney donors. Using an original questionnaire, we assessed the policies and practices of US renal transplant centers with regard to screening for sickle trait among potential live kidney donors. Fifty-four percent (137/252) of centers responded. Eighty-three percent (113/137) of transplant centers had no policy to screen donors for sickle trait. Thirty-four percent (46/135) of centers reported actually screening donors for sickle trait in practice. Thirty-seven percent (39/105) of centers reported excluding donors with sickle trait always or most of the time. High volume centers (>100 live donor transplants/year) were more likely to screen for sickle trait (Fisher's exact, P = 0.03), but not more likely to exclude potential donors with sickle trait from donating. Most US renal transplant centers do not screen donors for sickle trait. Wide variation is evident in center practice regarding exclusion of donors on the basis of sickle trait. Research into the potential impact of sickle trait on renal function after donation is needed to guide transplant clinicians.     

Renal transplantation in sickle cell disease

A 49 year old West Indian man with sickle cell disease and chronic renal failure was maintained on hemodialysis for 10 months before receiving a cadaveric renal transplant. Nine months post-transplant his renal function is good. His main problem has been high HbS levels needing repeated exchange transfusions. We conclude that hemodialysis and transplantation may be use successfully performed in patients with sickle cell disease with end-stage renal failure.     

Unilateral Renal Venous Thrombosis Secondary to the Use of Vibration Belt in a Young Woman

We report on the isolated unilateral renal venous thrombosis (RVT) detected in a young patient who used vibration belt to stay thin. Apart from her sickle cell trait, the patient presented no other clinical situations associated with RVT.     

Genitourinary complications of sickle cell disease

PURPOSE: In the last half century the molecular biology, pathophysiology and natural history of sickle cell disease have been well defined. Sickle cell disease causes microvascular occlusion, which is manifested in most organ systems. The genitourinary tract is most commonly affected by hematuria, urinary tract infection and priapism but other more serious sequelae have been identified. MATERIALS AND METHODS: We performed a computerized MEDLINE search from 1965 to the present and a bibliographic review of cross references. These references were analyzed for meaningful findings and case reports. RESULTS: The diagnosis and management of sickle cell disease have advanced rapidly with a significant increase in the life expectancy of affected patients and recognition of a greater number of genitourinary complications. Renal function may be mildly altered or lost completely. Patients with sickle cell disease are at increased risk for urinary tract infection. Priapism is a painful complication of sickle cell disease that is poorly understood and challenging to treat and prevent. Testicular infarction has also been noted. Furthermore, renal medullary carcinoma, a highly lethal tumor, develops almost exclusively in young patients with sickle cell trait. CONCLUSIONS: Heightened awareness of the genitourinary complications of sickle cell disease may prevent end stage disease, including renal failure and impotence. New forms of therapy for sickle cell disease, such as hydroxyurea, may prevent these complications in the future.