Edema in the nephrotic syndrome: new aspect of an old enigma

Radiology of fibrosis part III: genitourinary system

Fibrosis is a pathological process involving the abnormal deposition of connective tissue, resulting from improper tissue repair in response to sustained injury caused by hypoxia, infection, or physical damage. It can impact any organ, leading to their dysfunction and eventual failure. Additionally, tissue fibrosis plays an important role in carcinogenesis and the progression of cancer.Early and accurate diagnosis of organ fibrosis, coupled with regular surveillance, is essential for timely disease-modifying interventions, ultimately reducing mortality and enhancing quality of life. While extensive research has already been carried out on the topics of aberrant wound healing and fibrogenesis, we lack a thorough understanding of how their relationship reveals itself through modern imaging techniques.This paper focuses on fibrosis of the genito-urinary system, detailing relevant imaging technologies used for its detection and exploring future directions.

Acetazolamide and Hydrochlorothiazide Followed by Furosemide Versus Furosemide and Hydrochlorothiazide Followed by Furosemide for the Treatment of Adults With Nephrotic Edema: A Randomized Trial

BACKGROUND

Nephrotic edema is considered refractory if it does not respond to maximum or near-maximum doses of loop diuretics. This condition can be treated with loop diuretics and thiazides. However, animal studies show that the simultaneous downregulation of pendrin with acetazolamide and inhibition of the sodium-chloride cotransporter with hydrochlorothiazide generates significant diuresis, and furosemide administration following a pendrin inhibitor potentiates furosemide's diuretic effect. Therefore, we performed this study to compare the efficacy of acetazolamide and hydrochlorothiazide followed by furosemide versus furosemide and hydrochlorothiazide followed by furosemide for treatment of refractory nephrotic edema.

STUDY DESIGN

Randomized, double-blind, 2-arm, parallel trial.

SETTING & PARTICIPANTS

20 patients with refractory nephrotic edema despite treatment with 80mg of furosemide daily and creatinine clearance > 60mL/min.

INTERVENTION

Patients were randomly assigned to 2 groups: group 1 (n=10) received 250mg of acetazolamide and 50mg of hydrochlorothiazide daily and group 2 (n=10) received 40mg of furosemide and 50mg of hydrochlorothiazide daily for 1 week in phase 1. In phase 2, both groups received 40mg of furosemide daily for 2 weeks.

OUTCOMES

The primary outcome was absolute change in weight before and at the end of each phase.

MEASUREMENTS

Weight and 24-hour urine volume at baseline and the end of each phase.

RESULTS

The mean weight decrease was of significantly larger magnitude in group 1 compared with group 2 at the end of phase 1 (-1.4±0.52 [SD] vs -0.65±0.41kg; P=0.001) and phase 2 (-1.6±0.84 vs -0.5±0.47kg; P=0.005). The increase in 24-hour urine volume was also significantly higher in group 1 at the end of phase 2.

LIMITATIONS

Small sample size, short follow-up duration, and lack of serum bicarbonate and chloride measurement.

CONCLUSIONS

Acetazolamide and hydrochlorothiazide followed by furosemide is more effective than furosemide and hydrochlorothiazide followed by furosemide for the treatment of refractory nephrotic edema.

Edema in Renal Diseases – Current View on Pathogenesis

Edema is a common complication of numerous renal disease. In the recent past several aspects of the pathophysiology of this condition have been elucidated. We herein present a case of nephrotic syndrome in a 30 year-old men. The discussion revolves around the following key questions on fluid accumulation in renal disease: 1. What is edema? What diseases can cause edema? 2. What are the mechanisms of edema in nephrotic syndrome? 2a. The “underfill” theory 2b. The “overfill” theory 2c. Tubulointerstitial inflammation 2d. Vascular permeability 3. What are the mechanisms of edema in nephritic syndrome? 4. How can the volume status be assessed in patients with nephrotic syndrome? 5. What are therapeutic strategies for edema management? 6. What are the factors affecting response to diuretics? 7. How can we overcome the diuretics resistance? 7a. Effective doses of loop diuretics 7b. Combined diuretic therapy 7c. Intravenous administration of diuretics 7d. Albumin infusions 7e. Alternative methods of edema management 8. Conclusion.

Relation between circadian blood pressure rhythm and serum albumin level in non-diabetic patients with proteinuria

It remains unclear whether the abnormal circadian blood pressure (BP) rhythm in non-diabetic chronic kidney disease (CKD) is related to hypoalbuminemia. We evaluated relationships between circadian BP rhythm and serum albumin concentration (SAC) and also examined autonomic nervous activities. Non-diabetic CKD patients with proteinuria (n = 197; 105 men, 92 women; aged 47.0 ± 13.3 years; estimated glomerular filtration rate ≥30 ml/min) were divided into nephrotic syndrome (NS: n = 46, SAC ≤ 30 g/l), hypoalbuminemia (n = 65, 30 < SAC < 40 g/l) and normoalbuminemia (n = 86, SAC ≥ 40 g/l) groups. Non-proteinuria subjects (n = 97, urinary protein/creatinine ratio < 30 mg/g creatinine) were enrolled as the non-proteinuria group. Ambulatory 24 h BP monitoring was conducted in all subjects. Simultaneously, power spectral analysis of heart rate was performed to evaluate the sympathovagal balance. Waking BP was lower in the hypoalbuminemia and NS groups than the other groups. Sleeping/waking mean BP ratio was not different between non-proteinuria (0.87 ± 0.07) and normoalbuminemia (0.89 ± 0.08) groups, but increased significantly (p < 0.05) in the hypoalbuminemia (0.92 ± 0.08) and NS groups (0.96 ± 0.08). Significant reverse correlations were observed between SAC and sleeping/waking mean BP ratio (r = -0.274, p < 0.001) in all patients. Multivariate regression analysis identified SAC and sympathovagal balance as predictors of increased sleeping/waking BP ratios as the dependent variable. In non-diabetic CKD patients with proteinuria, disturbed circadian BP rhythms were related to SAC and 24 h sympathovagal imbalance.

The proteinuria-hypertriglyceridemia connection as a basis for novel therapeutics for nephrotic syndrome

The development of new and specific treatment options for kidney disease in general and glomerular diseases in specific has lagged behind other fields like heart disease and cancer. As a result, nephrologists have had to test and adapt therapeutics developed for other indications to treat glomerular diseases. One of the major factors contributing to this inertia has been the poor understanding of disease mechanisms. One way to elucidate these disease mechanisms is to study the association between the cardinal manifestations of glomerular diseases. Because many of these patients develop nephrotic syndrome, understanding the relationship of proteinuria, the primary driver in this syndrome, with hypoalbuminemia, hypercholesterolemia, hypertriglyceridemia, edema, and lipiduria could provide valuable insight. The recent unraveling of the relationship between proteinuria and hypertriglyceridemia mediated by free fatty acids, albumin, and the secreted glycoprotein angiopoietin-like 4 (Angptl4) offers a unique opportunity to develop novel therapeutics for glomerular diseases. In this review, the therapeutic potential of mutant forms of Angptl4 in reducing proteinuria and, as a consequence, alleviating the other manifestations of nephrotic syndrome is discussed.

Steroid-sensitive nephrotic syndrome in children: triggers of relapse and evolving hypotheses on pathogenesis

Nephrotic syndrome remains the most common manifestation of glomerular disease in childhood. Minimal change nephropathy is the most common cause of the syndrome in children. Despite its initial high response rate to corticosteroids and its favorable prognosis, relapses are common leading to increased morbidity and cost of treatment.This review seeks to appraise the common triggers of relapse and to highlight the evolving hypotheses about the pathogenesis of the syndrome. Literature search was conducted through PubMed, Google web search and Cochrane Database of Systematic reviews using relevant search terms.Acute respiratory infections and urinary tract infections are the most frequent infectious triggers of relapse. Targeted interventions like initiating corticosteroid or its dose-adjustment during episodes of acute respiratory infection and zinc supplementation are reportedly effective in reducing relapse rates. Hypotheses on pathogenesis of the syndrome have evolved from the concepts of 'immune dysregulation', 'increased glomerular permeability' to 'podocytopathy'.Although development of drugs which can regulate the pathways for podocyte injury offers future hope for effective and targeted treatment, the relapse-specific interventions currently contribute to significant reduction in disease morbidity.

Nephrotic syndrome: components, connections, and angiopoietin-like 4-related therapeutics

Nephrotic syndrome is recognized by the presence of proteinuria in excess of 3.5 g/24 h along with hypoalbuminemia, edema, hyperlipidemia (hypertriglyceridemia and hypercholesterolemia), and lipiduria. Each component has been investigated individually over the past four decades with some success. Studies published recently have started unraveling the molecular basis of proteinuria and its relationship with other components. We now have improved understanding of the threshold for nephrotic-range proteinuria and the pathogenesis of hypertriglyceridemia. These studies reveal that modifying sialylation of the soluble glycoprotein angiopoietin-like 4 or changing key amino acids in its sequence can be used successfully to treat proteinuria. Treatment strategies on the basis of fundamental relationships among different components of nephrotic syndrome use naturally occurring pathways and have great potential for future development into clinically relevant therapeutic agents.

Nephrotic syndrome: components, connections, and angiopoietin-like 4-related therapeutics

Nephrotic syndrome is recognized by the presence of proteinuria in excess of 3.5 g/24 h along with hypoalbuminemia, edema, hyperlipidemia (hypertriglyceridemia and hypercholesterolemia), and lipiduria. Each component has been investigated individually over the past four decades with some success. Studies published recently have started unraveling the molecular basis of proteinuria and its relationship with other components. We now have improved understanding of the threshold for nephrotic-range proteinuria and the pathogenesis of hypertriglyceridemia. These studies reveal that modifying sialylation of the soluble glycoprotein angiopoietin-like 4 or changing key amino acids in its sequence can be used successfully to treat proteinuria. Treatment strategies on the basis of fundamental relationships among different components of nephrotic syndrome use naturally occurring pathways and have great potential for future development into clinically relevant therapeutic agents.

Role of sodium during formation of edema in children with nephrotic syndrome

BACKGROUND

The pathogenesis of edema in nephrotic syndrome is not entirely understood. The aim of this study was to contribute to the discussion on edema pathogenesis in nephrotic syndrome by following changes in volume and sodium retention for the course of the disease in children with steroid-sensitive nephrotic syndrome (SSNS).

METHODS

Forty-one children with SSNS were included in the study. The patients were divided into three groups (group I: relapse-edematous; group II: relapse-edema free; group III: remission). We investigated the value of the significance and area of sodium retention and vasoactive hormones. In addition, we measured parameters such as inferior vena cava collapsibility index, left atrium diameter, and total body water (TBW) to determine the volume load and cause of edema in children with SSNS.

RESULTS

TBW increased in the relapse-nephrotic syndrome group and the difference was statistically significant among groups (P < 0.001). However, inferior vena cava collapsibility index and left atrium diameter were not different among groups. Fractional sodium excretion was lower in children with relapse nephrotic syndrome (P < 0.05).

CONCLUSION

Although TBW increases in children with SSNS, intravascular volume is normal. In addition, hypoalbuminemia and sodium retention of the proximal tubule cause edema in children with SSNS.

[41-year-old female patient with ST-elevation myocardial infarction and multiple arterial emboli]

A 41-year-old woman presented with acute angina in the emergency unit. Additionally, she reported pain in both legs and a weight loss of 5 kilograms within the last 10 days. ECG revealed an acute anterior myocardial infarction. However, immediate coronary angiography showed open arteries with minimal arteriosclerosis. A characteristic rise of cardiac enzymes together with an akinesis of the anterior wall and an adjacent mural thrombus was highly suggestive of a transient coronary thrombosis. Further investigations showed occlusion of multiple arteries in both legs and a splenic infarct. Although there was a typical risk profile including smoking, hyperlipidemia and regular estrogen medication, a further work-up was started. Urin analysis was decisive for the presence of proteinuria and a severe nephrotic syndrome. The definite diagnosis was made by direct biopsy of the kidney that revealed the characteristic findings of a minimal change glomerulopathy. Rapid remission could be induced by high-dose oral steroids. During routine work-up of coronary syndromes, especially in those with normal coronaries, rare but treatable causes of myocardial infarction and coagulopathy have to be thought of and should carefully be excluded.

Randomized cross-over trial comparing albumin and frusemide infusions in nephrotic syndrome

The contribution of hypoalbuminemia to impaired diuretic responsiveness can be overcome by administering larger doses of loop diuretics. However, the clinical efficacy of the combination of loop-acting diuretics with human albumin remains controversial. In the study reported here, 16 children with nephrotic syndrome and refractory edema were randomized in a cross-over trial to receive either the combination of 20% human albumin and frusemide infusion (HA+FU infusion group) or frusemide infusion alone (FU infusion group). At the end of study, median urine volume was 3.27 [95% confidence interval (CI) 2.04-4.50] ml/kg per hour in the HA+FU infusion group and 1.33 (95% CI 0.79-1.88) ml/kg per hour in the FU infusion group (P = 0.01); the median daily sodium excretion was 58 (95% CI 30-366) mEq and 30 (95% CI 10-122) mEq (P = 0.08), respectively The changes in other variables included weight loss [HA+FU 5.2% (95% CI 3.1-8.8); FU 0.8% (95% CI -1.9 to 4.1); P = 0.006]; urine osmolality [HA+FU 315 (95% CI 220-426) mOsm/kg; FU 368 (95% CI 318-446) mOsm/kg; P = 0.13]; osmolal clearance [HA+FU 1600 (95% CI 916-4140) ml/day; FU 880 (95% CI 510-2105) ml/day; P = 0.01; free water clearance [HA+FU -190 (95% CI -960 to 280) ml/day; FU -162 (95% CI -446 to -70) ml/day; P = 0.18]. The findings from this study suggest that the co-administration of albumin and frusemide infusions is more effective than the administration of frusemide infusion alone in inducing diuresis and natriuresis in patients with nephrotic syndrome.