Lower plasma sodium is associated with a microinflammatory state among patients with advanced chronic kidney disease

BACKGROUND/AIMS

Lower serum sodium levels have been associated with increased mortality among patients with chronic kidney disease (CKD). Our aim was to analyze the independent factors associated with lower sodium levels among nondialysis patients with advanced CKD and to evaluate the evolution of these patients in comparison to those with higher plasma sodium over a 1-year period.

METHODS

We included 72 patients with CKD stages 4 and 5 without clinically evident cardiopathy or liver disease. Bioelectrical impedance and echocardiography were performed to analyze the possible relation between plasma sodium and volume status and subclinical left ventricular (LV) dysfunction. During follow-up, we compared the evolution of patients with lower baseline plasma sodium (low quartile: <138 mEq/l) with that of patients with higher levels over a 1-year period.

RESULTS

At baseline, the independent predictors of lower plasma sodium were C-reactive protein (CRP; OR 0.96; 95% CI 0.91-0.99) and body mass index (OR 0.89; 95% CI 0.78-0.99). An inverse correlation between plasma sodium and CRP was observed (r = -0.32; p = 0.01). Plasma sodium did not correlate with extracellular water and was not different between patients with or without echocardiographic data of LV dysfunction (p = 0.7). During follow-up, patients with lower sodium at baseline showed persistently lower sodium values (p = 0.04), higher CRP (p = 0.05), lower serum albumin (p < 0.01) and higher erythropoietin-stimulating agent resistance index (p = 0.05).

CONCLUSIONS

Our results suggest an association between lower plasma sodium and a microinflammatory state among patients with advanced CKD. Inflammation could be an underlying confounding factor explaining the increased mortality in these patients.

Lack of influence of serum magnesium levels on overall mortality and cardiovascular outcomes in patients with advanced chronic kidney disease

Background. Low serum magnesium has been associated with an increased cardiovascular risk in the general population and in dialysis patients. Our aim was to analyze the influence of serum magnesium on overall mortality and cardiovascular outcomes in patients with advanced CKD not yet on dialysis. Methods. Seventy patients with CKD stages 4 and 5 were included. After a single measurement of s-magnesium, patients were followed a mean of 11 months. Primary end-point was death of any cause, and secondary end-point was the occurrence of fatal or nonfatal CV events. Results. Basal s-magnesium was within normal range (2.1 ± 0.3 mg/dL), was lower in men (P = 0.008) and in diabetic patients (P = 0.02), and was not different (P = 0.2) between patients with and without cardiopathy. Magnesium did not correlate with PTH, calcium, phosphate, albumin, inflammatory parameters (CRP), and cardiac (NT-proBNP) biomarkers but correlated inversely (r = −0.23; P = 0.052) with the daily dose of loop diuretics. In univariate and multivariate Cox proportional hazard models, magnesium was not an independent predictor for overall mortality or CV events. Conclusions. Our results do not support that serum magnesium can be an independent predictor for overall mortality or future cardiovascular events among patients with advanced CKD not yet on dialysis.

Serum alkaline phosphatase levels and left ventricular diastolic dysfunction in patients with advanced chronic kidney disease

BACKGROUND

High levels of alkaline phosphatase (ALP) have been associated with increased mortality in patients with advanced chronic kidney disease (CKD). We hypothesize that elevated ALP could be partly explained by subclinical liver congestion related to left ventricular diastolic dysfunction.

METHODS

Doppler echocardiography was performed in 68 patients with advanced CKD followed up for a median of 2.1 years. Time-averaged levels of ALP and γ-glutamyl transferase (GGT) were compared between patients with and without diastolic dysfunction. We also evaluated the effect of intensifying diuretic treatment on ALP levels in a small group of 16 patients with high ALP and signs of volume overload.

RESULTS

ALP correlated significantly (p < 0.001) with GGT but not with parathyroid hormone (p = 0.09). Patients with diastolic dysfunction showed higher ALP (p = 0.01), higher GGT (p = 0.03) and lower albumin (p = 0.04). The highest values of ALP were observed in patients with diastolic dysfunction plus pulmonary hypertension (p = 0.01). Intensifying diuretic therapy in a subgroup of patients with signs of fluid overload induced a significant reduction in body weight, GGT (p < 0.001) and ALP levels (p < 0.001).

CONCLUSIONS

Elevated ALP in patients with advanced CKD could be partly explained by subclinical liver congestion related to left ventricular diastolic dysfunction, hypervolemia or both. The worse prognosis of these patients could be explained by their myocardial damage.

Exploring the opinion of CKD patients on dialysis regarding end-of-life and Advance Care Planning

Advance care planning (ACP) and the subsequent advance directive document (ADD), previously known as "living wills", have not been widely used in Spain. The Ethics Group from the Spanish Society of Nephrology has developed a survey in order to investigate the opinion of dialysis patients regarding the ADD and end-of-life care. Patients received documentation explaining ACP and filled out a survey about their familiarity with and approval of the ADD. Seven hospital dialysis centres participated in the study for a total of 416 active dialysis patients. Questionnaires were distributed to 263 patients, 154 of which answered (69.2% completed them without assistance). The rates for ADD implementation (7.9%) and designation of a representative person (6.6%) were very low. Most of the patients clearly expressed their wishes about irreversible coma, vegetative state, dementia and untreatable disease. More than 65% did not want mechanical ventilation, chronic dialysis, tube feeding or resuscitation if cardiorespiratory arrest occurred. They reported that an ADD could be done before starting dialysis but most thought that it should be offered only to those who requested it (65% vs 34%). In conclusion, patients have clear wishes about end-of-life care, although these desires had not been documented due to the very low implementation of the ADD.

Strict volume control and longitudinal changes in cardiac biomarker levels in hemodialysis patients

BACKGROUND

Our aim was to analyze the longitudinal changes in cardiac biomarker levels in hemodialysis patients with high comorbidity treated in our special hospital unit. We hypothesize that strict volume control strategy (salt-restricted diet, extended dialysis sessions and dry weight clinical assessment and reassessment in every session) could prevent progression of left-ventricular damage and, therefore, progressive increment in cardiac biomarker levels over time.

METHODS

This is a longitudinal cohort study including 46 dialysis patients in which a strategy of strict volume control has been adopted. N-terminal pro-B-type natriuretic peptide (NT-proBNP), troponin T and C-reactive protein (CRP) levels were measured at baseline and prospectively at 4, 8 and 12 months. The possible association between volume control and cardiac biomarker levels was analyzed.

RESULTS

Dry weight could be reduced (p < 0.01) over time. A reduction in systolic BP (p < 0.05) and in CRP levels (p < 0.05) was observed, whereas NT-proBNP and troponin T values remained stable. However, patients in the high quartile of NT-proBNP at baseline showed a reduction (p = 0.02) in troponin T over time with no significant trend (p = 0.08) to progressive reduction in NT-proBNP values.

CONCLUSIONS

Strict volume control in dialysis patients may prevent progressive increment in cardiac biomarker levels over time. The impact seems to be higher among patients with higher levels at baseline in whom strict volume control can even reduce cardiac biomarker levels on follow-up.

Treatment of hirudin overdosage in a dialysis patient with heparin-induced thrombocytopenia with mixed hemodialysis and hemofiltration treatment

We report a patient who developed type II heparin-induced thrombocytopenia (HIT) and accidentally received a recombinant hirudin (r-hirudin) overdosage. Treatment with hemodialysis (HD) using high-flux polysulfone dialyzer and hemofiltration was performed. Length of treatment was adjusted, monitoring activated partial thromboplastin time (aPTT) to 1.5-2.5 times the mean of the normal range. She developed deep venous thrombosis and occlusion of vascular access. Only after cessation of heparin lock catheter, platelet count began to increase. After one year of treatment with acenocoumarol and additional low-dose r-hirudin, neither bleeding nor thrombotic episodes have been reported.

[Sclerosing encapsulating peritonitis: a latent threat. Changes of posture in surgery treatment]

Sclerosing Encapsulating Peritonitis (SEP) is a rare but serious complication of continuous ambulatory peritoneal dialysis (CAPD) with a high morbi-mortality. We describe our experience with patients was diagnostic of SEP, their characteristics in CAPD and their clinic evolution after diagnosis. 190 CAPD patients were follow-up during 17 years. Eight patients (4.2%) developed SEP. Average age 45+/-14 years (range 29-64 years), four was male. Time in CAPD was 72+/-29 months (range 24-120 months). All patients have peritonitis previously (mean 3+/-1). We observe a change in peritoneum characteristics (D/P Cr 4), with an average of 0.6+/-0.1 at one year of CAPD, versus 0.82+/-0.08 at the end of CAPD, with statistic significance (p<0.001). There are increases in use of hypertonic bags: 53%+/-28 at beginning versus 91%+/-27 at end, with statistic significance (p<0.009). All patients show tendency to hyperphosphoremia (mean 6.7+/-0.7 mg/dl), with product calcium-phosphorus 68.4+/-8.3. Five patients (62.5%) have a previous renal transplant, one lost due to early graft thrombosis and two lost due to acute rejection. Six patients (75%) have a previous abdominal surgery, although was extra peritoneal in all cases. The diagnosis of SEP was clinic suspicion in all cases, suggestive radiological data (intestinal handle group) and laparoscopy showing SEP (cocoon) with histological confirmation (fibrosis and peritoneal calcification) in four cases. The treatment was medical in six cases associated with surgery in four of them. The medical treatment was tamoxifen and/or corticosteroids, associated with total parenteral nutrition in two patients and enteral nutrition in one. Surgery in six patients: three as urgent surgery (all died) and three as programme surgery (two live still). Etiology of died was: three for sepsis, one for peritonitis after bowel perforation, one for severe problems of nutrition. The average survival of three patients alive was 38+/-17 months, two of them had programme surgery, and one with functioning transplant we opt for conservative treatment. The actuarial survival at 24 months was 51%.

CONCLUSION

The SEP is a serious entity with high mortality. Although our short experience doesn't can indicate a concrete treatment, our personal impression is that early surgery associated with corticosteroids treatment may improve the prognostic.

[Telemedicine and follow up of peritoneal dialysis patients]

Mean-term experience in the use of Telemedicine in Peritoneal Dialisis (PD) patients is limited as well as its cost-benefit. The main objective of this work is to evaluate Telemedicine utility in mean-long term control of stable PD patients, analyzing if the televisit (TV) could substitute 50% of the programed inhospital consults (HC) the time spent in both visit modalities, the quality of patient-personel contact as well as how image and sound have been perceived. Visit resolution was analyzed taking into account the need of HC after a TV; We also have studied if it would be possible to retrain patients in the dialisis technique with telemedicine, and we have checked the patient perceived quality and calculate the real and social costs.

METHODS

during 18 months, the system has been implanted to 19 patients with 7 +/- 4 follow up (range 3-17). A Falcon videoconference kit at patient's place was used, connected to the home television set. In the hospital there was a computer with a videoconference card, webcam and software meeting point which permits the control of patient's camera from the hospital. Both are connected by a 3RDSI line system. A monthly programmed HC or TV has been made. If more controls had been required, they have been made by TV Time spent was recorded on each TV and patients and staff questionary were inquired.

RESULTS

(a)

PATIENTS

mean age 44 +/- 8 years, 13 (68%) male. 12 (63%) had elemental educational level and 7 (37%) mean-superior. 17 (89%) were actively working. The PD technique was: CAPD 6 (32%) and APD13 (68%). (b) Televisits: 103 TV have been made. 22 +/- 9 minutes were spent on each TV less than in the HC, 33 +/- 8 minutes (p < 0.01). There were technical problems related with lines in 21 TV, but only in 4 the connection was not possible. 92 TV (89%) were made on time, 99 (96%) had a good image quality and 96 (93%) had a correct sound. 100% of patients perceived TV as close to HC. In 90 TV (87%) medical treatment was modified. Only in 4 cases (3.9%) patients needed an hospital visit. According to patient's valuation, TV replaced correctly to HC in 97 instances (94%) and in 97 (97%) in staff opinion. In all cases (100%) catheter exit site could be evaluated as well as edema presence. Retraining was possible in all cases. There was a save in nurse's time and patient's time and also, a save in physical hospital space. Initial investment apart, the daily cost increment was scarce (1.5 Euro) taking into account that there is a save in time for patients and personnel, save in physical space in hospital and in sanitary transport.

CONCLUSION

Telemedicine is useful from the clinical point of view in the mean-term for stable patients in PD. Daily cost increment is scarce and there is a save in time for patients and personnel, save in physical space in hospital and in sanitary transport.

[Antiproteinuric effect of renin-angiotensin system blockade in patients with normal/lower than 115 mmHg systolic blood pressure]

The renoprotective effect of renin-angiotensin system (RAAS) blockade by ACE inhibitors (ACEI) or AT1 receptor antagonists (ARA) in chronic proteinuric nephropathies is well known. Most studies have related this beneficial effect with the antihypertensive and antiproteinuric properties of these drugs, but this aspect has not been extensively analyzed in patients with normal/low values of blood pressure. We studied nineteen patients with different chronic proteinuric nephropathies that started ACEI or ARA because of proteinuria and despite systolic blood pressure (SBP) < or = 115 mmHg. Short and long-term tolerance to treatment as well as evolution of renal function parameters were recorded.

RESULTS

At baseline, SBP was 110.2 +/- 2.6 mmHg (105-115) an diastolic blood pressure (DBP) 68.6 +/- 4.3 (60-75). Initial low doses of ACEI or ARA were well tolerated. After 6 months of treatment, proteinuria decreased by 46% of baseline, from 2.1 +/- 1.8 g/day to 1.1 +/- 0.8 g/day, without significant changes in BP or renal function. After a 48 +/- 27 months follow up, proteinuria decreased to 0.7 +/- 0.6 g/day (68% of basal values). Renal function and BP did not show significant changes during follow up.

CONCLUSIONS

RAAS blockade by ACEI/ARA induces a significant antiproteinuric and renoprotective effect in proteinuric patients with normal/low levels of BP Initial doses of ACEI/ARA were well tolerated.

[Acute hyperphosphatemia secondary to phosphate administration for bowel preparation]

We report a 75-years-old woman, stable on a three-weekly hemodialysis program over a period of 3 years, who develop acute hyperphosphatemia secondary to phosphate administration for bowel preparation. The quick clinical diagnosis and the treatment with intensive hemodialysis resulted in a correction of hyperphosphatemia, hypocalcemia, acidemia and other electrolyte abnormalities. The phosphate cathartics are contraindicated in patients with severe renal insufficient or in dialysis program. Our case shows the severe side effects secondary to injudicious use of sodium phosphate cathartics.

Results of kidney transplantation in recipients over 70 years of age: experience at a single center

We performed 41 kidney transplants in patients >70 years (35 single and 6 dual), with a mean recipient age of 72+/-2 years, from January 1990 to December 2001. Mean age of the donors was 69+/-12 years. Immunosuppression used triple therapy with steroids, mycophenolate mofetil, and cyclosporine or tacrolimus. Cold ischemia time was 23+/-3 hours. The incidence of primary nonfunction was 4.8%, and delayed graft function 58.5%. Acute rejection incidence was 12%. The actuarial patient survival rates at 12, 24, and 36 months were 82.5%, 82.5%, and 75%, respectively. Actuarial survival rates of the grafts censuring for death of the recipient with a functioning graft were 89.5%, 86%, and 68%, respectively. Nine of the 18 graft losses were due to recipient death. Overall, renal transplant recipients >70 years showed good results. The principal cause of graft loss was recipient death.

[Immunoallergic interstitial nephritis vs. cholesterol atheroembolism. Differentiating characteristics]

The commonest clinical presentation of both immunoalergic interstitial nephritis (IIN) and atheroembolic renal disease (ATD) is an acute renal failure accompanied by skin lesions and eosinophilia. As a consequence, differential diagnosis between both entities is often very difficult. We have performed a comparative retrospective study of those patients diagnosed as having IIN or ATD in our Hospital in the period 1980-2000. A total of 42 patients have been diagnosed of IIN and 16 of ATD. Demographic data, as well as clinical and laboratory parameters and outcomes of every studied patient were analysed. We found a significantly higher prevalence of male sex (100% vs 57%, p < 0.01), previous history of hypertension (100% vs 55%, p < 0.01), chronic renal insufficiency (56% vs 17%, p < 0.01), ischemic heart disease (56% vs 14%, p < 0.001), peripheral ischemic disease, endovascular procedures (87% vs 7%, p < 0.001) and anticoagulant treatments (25% vs 5%, p < 0.001) among patients with ATD as compared with IIN, respectively. On the contrary, previous infections (45% vs 12%, p < 0.01) and exposure to new drugs (100% vs 40%, p < 0.001) were significantly more frequent among IIN patients in compare with ATD. ATD patients showed skin lesions consisting of livedo reticularis and digital infarcts (63% vs 31%, p < 0.05) accompanied by blood pressure increase (100% vs 24%, p < 0.001), whereas IIN patients showed fever (41% vs 19%, p < 0.05) and cutaneous rash as significant clinical manifestations, respectively. The number of ATD patients with proteinuria > 1 g/24 h was significantly higher, but no differences between both groups in the prevalence of urinary sediment abnormalities were observed. The prevalence of absolute eosinophilia was high in both groups (88% among ATD patients, 64% among IIN patients; pNS). Prognosis of both entities was clearly different: Almost all patients with ATD died (69%) or evolved to end-stage renal failure, whereas most patients with IIN showed a recovery of renal function after withdrawal of responsible drugs and steroid treatment. In summary, the analysis of clinical and laboratory data allows an initial differential diagnosis in patients suspected as having IIN or ATD.

Spontaneous improvement of the renal function in a patient with HIV-associated focal glomerulosclerosis

Collapsing glomerulopathy is a pattern of renal injury that is seen in association with human immunodeficiency virus (HIV) infection. Patients with this HIV-associated nephropathy (HIVAN) present nephrotic syndrome and rapid deterioration of the renal function. There is no proven effective therapy for HIVAN, and the majority of the patients become dialysis dependent. We report a case of biopsy-proven HIVAN that showed spontaneous improvement of the renal function.

CDMA and TDMA based neural nets

CDMA and TDMA telecommunication techniques were established long time ago, but they have acquired a renewed presence due to the rapidly increasing mobile phones demand. In this paper, we are going to see they are suitable for neural nets, if we leave the concept "connection" between processing units and we adopt the concept "messages" exchanged between them. This may open the door to neural nets with a higher number of processing units and flexible configuration.

Influence of obesity on the appearance of proteinuria and renal insufficiency after unilateral nephrectomy

BACKGROUND

Some patients develop proteinuria and progressive renal failure after unilateral nephrectomy, although the majority of patients maintain normal renal function. Reasons to explain this different evolution are not known.

METHODS

A cross-sectional study was performed in 73 patients who had undergone unilateral nephrectomy 13.6 +/- 8.6 years before. Patients with morphologic abnormalities in the remaining kidney, systemic disorders, or abnormal renal function at the time of nephrectomy were excluded. All of the 73 included patients showed normal renal function and negative proteinuria at nephrectomy. The patient's medical records were reviewed, and clinical and analytical data throughout follow-up were obtained.

RESULTS

Fifty-three out of the 73 patients (group I) showed a normal renal function and negative proteinuria at the cross-sectional study. The remaining 20 patients (group II) showed proteinuria (3.4 +/- 3.1 g/day). The time elapsed between nephrectomy and proteinuria appearance was 10.1 +/- 6.1 years. Thirteen patients of group II had developed renal insufficiency (serum creatinine at the cross-sectional study of 3.9 + 3.2 mg/dL) in addition to proteinuria. The time elapsed between proteinuria appearance and the onset of renal insufficiency was 4.1 +/- 4.3 years. Renal insufficiency showed a slowly progressive course in most of these patients. There were no significant differences between group I and group II patients in age, gender, renal function, or blood pressure at the time of nephrectomy. In contrast, group II patients showed a body mass index (BMI) that was significantly higher than group I at nephrectomy (31.6 +/- 5.6 vs. 24.3 +/- 3.7 kg/m(2), P < 0.001), at cross-sectional study (33.3 +/- 6.6 vs. 25.1 +/- 3.5 kg/m(2), P < 0.001), and throughout follow-up. Among the 14 obese (BMI > 30 kg/m(2)) patients at the time of nephrectomy, 13 (92%) developed proteinuria/renal insufficiency. In contrast, among the 59 patients with BMI < 30 kg/m(2), only 7 (12%) developed these complications (P < 0.001). Kaplan-Meier estimated probability of negative proteinuria and normal renal function 10 years after nephrectomy was 40 and 70%, respectively, in obese patients at nephrectomy. At 20 years after nephrectomy, these percentages were 8 and 35%, respectively. In contrast, in nonobese patients, the probability of negative proteinuria and normal renal function was 93 and 98%, respectively, at 10 years (P < 0.001) and 77 and 91%, respectively, at 20 years (P < 0.001). Multiple logistic regression analysis showed that the risk of developing renal disease was only statistically correlated with BMI at the time of unilateral nephrectomy (odds ratio 1.34, 1.03 to 1.76 CI).

CONCLUSIONS

Obese patients are at risk for developing proteinuria and chronic renal failure after unilateral nephrectomy. Regular and long-term follow-up are recommended in these patients.

Double versus single renal allografts from aged donors

BACKGROUND

The age limit of the cadaver kidney donors is increasing in response to the growing demand for renal transplantation. Simultaneous double kidney transplantation (SDKT) with kidneys obtained from elderly adults has been proposed to increase the transplantation number and improve its results. However, if SDKT is performed when there are no clear indications, a negative effect could be produced on the total number of transplanted patients as both kidneys would be used for only one recipient.

MATERIAL AND METHODS

In December 1996 we designed a transplantation protocol to be able to extend the selection of cadaver kidney donors with normal serum creatinine levels without establishing any age limit. A pregraft renal biopsy was always performed to analyze the glomerulosclerosis (GE) percentage whenever the donors were 60 years of age or older. A SDKT was performed in a single recipient when the donor age was 75 years or older or when the donors between 60 and 74 years old had a GE rate of more than 15%. On the contrary, a single kidney transplantation was performed in two different recipients for kidneys from donors between 60 and 74 years of age with a GE rate of less than 15%. Kidneys having GE rates of more than 50% were discarded for transplantation. Donor kidneys from subjects younger than 60 years of age were always used for a single kidney transplantation.

RESULTS

Based on the above mentioned protocol, from December 1996 to May 1998, 181 patients received a kidney transplantation in our hospital. These patients were divided into three groups: group I which included the SDKT recipients (n=21), group II or single kidney recipients from 60- to 74-year-old donors (n=40), and group III or recipients from <60-year-old donors (n=120). The mean follow-up time was 15+/-5 months (range 6-24). Mean donor age was 75+/-7 years in group I, this was significantly higher than in group II (67+/-4, P<0.001) and group III (37+/-15, P<0.001). The primary nonfunction rate was low in the three groups, there being no statistically significant differences (5, 5, and 4%, respectively). A significantly greater percentage of patients from group I (76%) presented immediate renal graft function as compared with group II (43%, P<0.01) and III (50%, P<0.05). The acute rejections rate was very low in all three groups (9.5, 7.5, and 22%, respectively) with significant differences between groups II and III (P<0.05). No significant differences between the different groups were observed for one year actuarial patient survival (100, 95, and 98%, respectively) or graft survival rates (95, 90, and 93%, respectively). The 6-month serum creatinine levels were excellent in the three groups, although there were significant differences between groups I and II (1.6+/-0.3 vs. 1.9+/-0.6 mg/dl, P<0.05), II and III (1.9+/-0.6 vs. 1.4+/-0.4 mg/dl, P<0.001), and I and III (P<0.05).

CONCLUSIONS

Simultaneous double kidney transplantations make it possible to use kidneys from extremely elderly donors (>75 years) or those whose GE>15%. In addition, kidneys from donor 60-74 years old in which the GE<15% can be used for single kidney transplantations in two different recipients with excellent results.

Immunosuppression in older renal transplant patients

Renal transplantation procedures in patients older than 60 years of age have clearly improved in recent years. In the cyclosporin era, graft and patient survival are good. However, older patients exhibit a higher mortality, especially from infectious and cardiovascular causes, than young patients. In this article we review the immunosuppressive treatment in older patients, analyse what drugs can be used and finally propose several immunosuppressive combinations to treat this group of patients. Currently, new immunosuppressive drugs enable more flexible immunosuppressive protocols. Nevertheless, to avoid overimmunosuppression, elderly patients should be treated with lower doses and fewer immunosuppressive drugs.

Secondary (AA-type) amyloidosis in patients with polymyalgia rheumatica

Several cases of systemic amyloidosis associated with polymyalgia rheumatica (PMR) or giant-cell arteritis (GCA) have been described. Nevertheless, the type of amyloid deposit has not been characterized in most of them. Here we report on two patients with PMR (one with associated GCA) who developed nephrotic syndrome and end-stage renal failure caused by massive amyloid deposition. Immunohistochemical analysis showed that the amyloid deposits were of AA type (secondary amyloidosis) in both cases.

Absence of hypoalbuminemia despite massive proteinuria in focal segmental glomerulosclerosis secondary to hyperfiltration

We observed that some patients do not develop hypoalbuminemia despite the presence of massive proteinuria. To investigate whether the absence or presence of hypoalbuminemia could be a marker in the distinction between idiopathic focal segmental glomerulosclerosis (FSG) and FSG secondary to hyperfiltration, we reviewed all our patients with biopsy-proven FSG and persistent nephrotic-range proteinuria (>3.5 g/24 h). Patients who met these conditions were then separated into those with hypoalbuminemia (serum albumin level <3 g/dL; group I; n = 19) and those with normoalbuminemia (>3.5 g/24 h; group II; n = 18). All group I patients had nephrotic edema in contrast with the absence of edema in all group II patients. Serum cholesterol and triglyceride levels were significantly greater in group I. All group I patients had been diagnosed with idiopathic FSG. The diagnoses of group II patients were FSG secondary to massive obesity in eight patients (44%), vesicoureteral reflux in five patients (27%), and renal mass reduction in three patients (16%); only two patients (11%) in this group had idiopathic FSG. The case histories of 19 other patients with nephrotic-range proteinuria associated with hyperfiltering disorders (reflux nephropathy, massive obesity, renal mass reduction), but without renal biopsy, were also reviewed; despite massive proteinuria (5.8 +/- 3.1 g/24 h), serum albumin and total protein levels were always within normal values. In conclusion, patients with FSG secondary to hyperfiltration do not develop hypoalbuminemia or the other characteristic complications of nephrotic syndrome, despite the presence of massive proteinuria values.

Association of thin basement membrane nephropathy with hypercalciuria, hyperuricosuria and nephrolithiasis

BACKGROUND

Familial persistent microhematuria with normal renal function is the most common presentation of thin basement membrane nephropathy (TBMN). Gross hematuria episodes and loin pain attacks are other manifestations of the disease. On the other hand, it has been shown that hypercalciuria (HC) and hyperuricosuria (HU) can produce both gross or microscopic non-glomerular hematuria, in addition to their role in renal stone formation.

METHODS

We studied the prevalence of HC, HU and nephrolithiasis in a group of 27 biopsy-proven TBMN as well as in 19 non-biopsied first-degree relatives with persistent microhematuria and 25 first-degree relatives without microhematuria. A group of 27 patients with IgA nephropathy (IgAN) and persistent microhematuria, and another group of 20 healthy subjects without known renal diseases were selected as control groups.

RESULTS

Ten (37%) patients with TBMN and 8 (42%) relatives with microhematuria showed HC and/or HU at presentation; relatives without microhematuria, IgAN patients and normal controls showed a significantly lower prevalence of HC and HU. The prevalence of previous nephrolithiasis among TBMN patients (25%) was significantly higher than in IgAN patients (3%; P < 0.05). Family history of nephrolithiasis was recorded in 14 (51%) of the 27 TBMN families, in contrast with 2 of 27 (7%) with IgAN and 1 of 20 (5%) in normal controls (P < 0.05). The prevalence of nephrolithiasis, gross hematuria bouts and loin pain episodes among TBMN patients and microhematuric relatives showing HC and/or HU at presentation (44%, 44% and 27%, respectively) were significantly higher than those of TBMN patients and microhematuric relatives with normal calcium and uric acid urinary excretions (10%, 7% and 3%, respectively; P < 0.05). At the end of follow-up (8.8+/-4.1 years in TBMN patients and 9.1+/-4.2 years in relatives with microhematuria), all the cases maintained normal renal function.

CONCLUSIONS

We found a high prevalence of HC, HU, and nephrolithiasis among TBMN patients and relatives with microhematuria. Our study also shows a significant relationship between the presence of HC and/or HU and the prevalence of nephrolithiasis, gross hematuria bouts and loin pain episodes.