Urinary loss of thyroid hormones: An issue to remember

A 45-year-old woman suffering from primary hypothyroidism, previously well substituted with levothyroxine, was urgently referred from Primary Care to Endocrinology due to very elevated thyrotropin, free thyroxine at low limit of normality, very high cholesterol and generalised oedema. Hypothyroidism was suspected as the main aetiology of this clinical condition. A detailed examination showed nephrotic range proteinuria and the patient was finally diagnosed with lupus nephritis. Urinary loss of thyroid hormones, fundamentally linked to their transport proteins, in patients affected by nephrotic syndrome is sometimes a forgotten phenomenon and one which should be considered in patients with increased levothyroxine requirements. In this report, we present the details of this case and a brief review of the literature on this topic.

Bilateral neuroretinitis and membranous lupus nephritis: 2 infrequent manifestations in juvenile lupus

Fifteen-year-old female patient, previously healthy, referred to our center for presenting abdominal pain, vomiting, diarrhea, malar erythema, palpebral and lower limb edema, arthralgia, morning stiffness and bilateral blurred vision. Laboratory and imaging studies together with the clinic allowed the diagnosis of nephrotic syndrome secondary to systemic lupus erythematosus. Ophthalmology examination revealed a visual acuity of 8/10 in both eyes and bilateral disc edema with partial macular star, findings compatible with bilateral neuroretinitis. Renal biopsy established the diagnosis of membranous lupus nephritis. Immunosuppressive treatment was started, obtaining gradual clinical improvement. Although systemic lupus erythematosus with membranous lupus nephritis and neuroretinitis is a very infrequent association, when faced with a patient with bilateral neuroretinitis, we must consider systemic lupus erythematosus within the differential diagnoses.

[Nephrotic syndrome due to preeclampsia: Presentation, management and clinical evolution observed in 5 years experience]

INTRODUCTION

Nephrotic syndrome (NS) is rare during pregnancy. The main cause is severe pre-eclampsia (PR). Our aim was to describe the clinical presentation, analytical features, medical management, and progress of women with NS due to PE.

MATERIALS AND METHODS

A descriptive, retrospective study, conducted from 01/01/2017 to 01/01/2022 (5years). Women with a gestational age (GA) ≥20weeks were included in the study, hospitalised due to hypertensive disorders in pregnancy (HDP), with no evidence of kidney damage prior to gestation.

RESULTS

Of the 652 HDP, 452 PE and 21 NS were identified. Maternal age was 25±5.7 years, GA at diagnosis was 33.1±5.1 weeks. All the women had facial and peripheral oedema: 5 pleural effusion, 3 pericardial effusion, and 2 anasarca. Their p24 was 6.17±2.34grams (3.10-10.8), serum albumin 2.5±0.27g/dL (2.10-2.90), and serum cholesterol 281.4±21.7mg/dL (251-316). Thirteen developed maternal complications: acute kidney damage, pulmonary oedema, dilated cardiomyopathy, eclampsia, and HELLP syndrome. They all remained hypertensive postpartum, and required a combination of two to three antihypertensive drugs. They all received statins postpartum, and angiotensin converting enzyme (ACE) inhibitors to manage proteinuria. None developed hyperkalaemia or creatinine elevation. Hospital stay was 10.4±3.7days. All nephrotic range proteinuria parameters reversed prior to discharge. No deaths were recorded.

CONCLUSION

Presentation ranged from peripheral oedema to serous involvement. Severity of proteinuria varied. Use of ACE inhibitors did not precipitate hyperkalaemia or kidney failure. Maternal complications were frequent, but no deaths were recorded.

Nephrotic syndrome as a manifestation of thrombotic microangiopathy due to long-term use of sunitinib

Nephrotic syndrome in patients with cancer may be related to the primary malignancy or chemotherapeutic therapy. Solid organ cancers may cause membranous glomerulonephritis which is manifested by nephrotic syndrome; other less common histologic presentations include focal and segmental glomerulosclerosis and minimal change disease. In addition, chemotherapy agents may cause renal toxicity by affecting the small blood vessels, glomeruli, tubules, and interstitium. Tyrosine kinase inhibitors such as sunitinib may cause endothelial and podocyte damage leading to thrombotic microangiopathy affecting only the kidney and manifested by proteinuria and hypertension. We report a case of an elderly man with gastrointestinal stromal tumor (GIST) on treatment with sunitinib who had as a complication a thrombotic microangiopathy manifested with nephrotic syndrome and a hypertension of difficult control, which was finally controlled by stopping this drug but had a fatal outcome due to its malignancy.

Endothelin-1 RS5370 gene polymorphism in primary nephrotic syndrome: A case-control study

INTRODUCTION

Primary nephrotic syndrome (NS) is a common glomerular disease in children. We assessed the genotypes and frequency of the rs5370 allelic variant of the EDN1 gene in children with primary NS.

PATIENTS AND METHODS

We conducted a case-control study in Mansoura University Children's Hospital, Egypt between December 2015 and January 2018. We recruited 50 patients with steroid-sensitive NS (SSNS) and 50 patients with steroid-resistant NS (SRNS) in addition to 100 healthy controls. The patients underwent clinical evaluations and tests including measurement of serum albumin, cholesterol, creatinine and urea levels and a 24-h urinary protein test. We used polymerase chain reaction methods to assess the genotypes of rs5370 variants of the EDN1 gene (GG, GT and TT) and alleles (T and G) in the groups under study.

RESULTS

The most frequent genotype of the EDN1 gene at the locus of interest in the control group was the GT genotype (88%; P=.001) while the GG genotype was more frequent in the NS group compared to the control group (P=.02). We did not find statistically significant differences between the NS and control groups in regard to the EDN1 rs5370 alleles (P=.69). The GG genotype was more frequent in the SSNS group compared to the SRNS and control groups (P=.03). When we compared allele frequencies between the control, SSNS and SRNS groups, we did not find significant differences (P=.89). The GT genotype was associated with normal blood pressure in children with NS (P=.007), while the GG genotype was associated with hypertension (P<.001). We did not find statistically significant differences in renal histopathology or serum cholesterol levels based on the genotype.

CONCLUSIONS

The GG genotype at the rs5370 locus of the EDN1 gene may be associated with an increased risk of primary NS and a better response to steroid therapy.

Nephrotic syndrome as a manifestation of thrombotic microangiopathy due to long-term use of sunitinib

Nephrotic syndrome in patients with cancer may be related to the primary malignancy or chemotherapeutic therapy. Solid organ cancers may cause membranous glomerulonephritis manifesting with nephrotic syndrome; other less common histologic presentations include focal and segmental glomerulosclerosis and minimal change disease. In addition, chemotherapy agents can cause renal toxicity by affecting the small blood vessels, glomeruli, tubules, and interstitium. Tyrosine kinase inhibitors such as sunitinib may cause endothelial and podocyte damage leading to renal limited thrombotic microangiopathy, manifested by proteinuria and hypertension. We report a case of an elderly man with gastrointestinal stromal tumor (GIST) on treatment with sunitinib who had as a complication of a thrombotic microangiopathy manifested with nephrotic syndrome and difficult-to-control hypertension, which was controlled by stopping this drug but with a fatal outcome due to its malignant neoplasm.

Acute myocardial infarction in a child with nephrotic syndrome

Myocardial infarction is very rare in children. It can have different etiologies such as thromboembolism caused by nephrotic syndrome (NS). We report the case of a 15 year old boy with NS, diagnosed at the age of 7 year, admitted for prolonged chest pain. The final diagnosis was ST-elevation myocardial infarction with thromboembolism in the left anterior descending artery due to hypercoagulability of NS. This association is very uncommon and the management of both conditions presents a challenge.

Antiproteinuric action of amiloride in paediatric patient with corticoresistant nephrotic syndrome

INTRODUCCION

In nephrotic syndrome, increased podocyturia accompanies pathologic proteinuria. The therapeutic regimen with enalapril, losartan and amiloride could reduce both variables.

OBJETIVES

Evaluate the anti-proteinuric effect of 2 non-immunological therapeutic regimens, the quantitative relationship between podocyturia and proteinuria.

MATERIAL AND METHODS

We included children aged 4-12 years with corticoresistant nephrotic syndrome, using 2 different schemes: group A, enalapril + losartan, and group B, enalapril + losartan + amiloride.

RESULTS

In group A, 17 patients completed the study, the initial mean proteinuria was 39 mg/m²/h and mean proteinuria at the end was 24 mg/m²/h, while in group B 14 patients were treated and the initial average proteinuria was 36 mg/m²/h and the end average proteinuria was 13 mg/m²/h. The paired T test showed significant differences in the decrease in proteinuria, for patients in group B without variation in podocyturia. The 2 factors associated with an increase in proteinuria were podocyturia and the time elapsed from the diagnosis of cortico-resistant nephrotic syndrome to the start of treatment anti-proteinuric.

CONCLUSIONS

The use of amiloride decreased proteinuria, without significantly modifying podocyturia; we did not observe a positive relationship between both variables.

Acute myocardial infarction in a child with nephrotic syndrome

Myocardial infarction is very rare in children. It can have different etiologies such as thromboembolism caused by nephrotic syndrome (NS). We report the case of a 15 year old boy with NS, diagnosed at the age of 7 year, admitted for prolonged chest pain. The final diagnosis was ST-elevation myocardial infarction with thromboembolism in the left anterior descending artery due to hypercoagulability of NS. This association is very uncommon and the management of both conditions presents a challenge.

Primary membranous nephropathy in the era of autoantibodies and biological therapies

Primary membranous nephropathy is an autoimmune kidney disease and the most common cause of nephrotic syndrome in adults. About 70%-80% of cases are caused by anti-PLA2R antibodies. Its association with anti-THSD7A antibodies and other autoantibodies has also been described. Recent pilot studies and clinical trials have shown that several biological agents targeting autoantibody-producing cells are effective in controlling the disease with an acceptable safety profile. In this narrative review, we update key concepts about the pathogenesis, autoantibody-based diagnosis, and kidney biopsy findings in primary membranous nephropathy. In addition, we propose a diagnostic and therapeutic algorithm, including guidance on monitoring the response to therapy. We compare the efficacy and safety of currently available treatments, including rituximab and new biological agents, and identify unmet clinical needs.

[Antiproteinuric action of amiloride in paediatric patient with corticoresistant nephrotic syndrome]

INTRODUCCION

In nephrotic syndrome, increased podocyturia accompanies pathologic proteinuria. The therapeutic regimen with enalapril, losartan and amiloride could reduce both variables.

OBJETIVES

Evaluate the anti-proteinuric effect of 2 non-immunological therapeutic regimens, the quantitative relationship between podocyturia and proteinuria.

MATERIAL AND METHODS

We included children aged 4 to 12 years with corticoresistant nephrotic syndrome, using 2 different schemes: group A, enalapril+losartan, and group B, enalapril+losartan+amiloride.

RESULTS

In group A, 17 patients completed the study, the initial mean proteinuria was 39mg/m²/h and mean proteinuria at the end was 24mg/m²/h, while in group B 14 patients were treated and the initial average proteinuria was 36mg/m²/h and the end average proteinuria was 13mg/m²/h. The paired T test showed significant differences in the decrease in proteinuria, for patients in group B without variation in podocyturia. The 2 factors associated with an increase in proteinuria were podocyturia and the time elapsed from the diagnosis of cortico-resistant nephrotic syndrome to the start of treatment anti-proteinuric.

CONCLUSIONS

The use of amiloride decreased proteinuria, without significantly modifying podocyturia; we did not observe a positive relationship between both variables.

[Endothelin-1 rs5370 gene polymorphism in primary nephrotic syndrome: A case-control study]

INTRODUCTION

Primary nephrotic syndrome (NS) is a common glomerular disease in children. We assessed the genotypes and frequency of the rs5370 allelic variant of the EDN1 gene in children with primary NS.

PATIENTS AND METHODS

We conducted a case-control study in Mansoura University Children's Hospital, Egypt, between December 2015 and January 2018. We recruited 50 patients with steroid-sensitive NS (SSNS) and 50 patients with steroid-resistant NS (SRNS) in addition to 100 healthy controls. The patients underwent clinical evaluations and tests including measurement of serum albumin, cholesterol, creatinine and urea levels and a 24-hour urinary protein test. We used polymerase chain reaction methods to assess the genotypes of rs5370 variants of the EDN1 gene (GG, GT and TT) and alleles (T and G) in the groups under study.

RESULTS

The most frequent genotype of the EDN1 gene at the locus of interest in the control group was the GT genotype (88%; P=.001) while the GG genotype was more frequent in the NS group compared to the control group (P=.02). We did not find statistically significant differences between the NS and control groups in regard to the EDN1 rs5370 alleles (P=.69). The GG genotype was more frequent in the SSNS group compared to the SRNS and control groups (P=.03). When we compared allele frequencies between the control, SSNS and SRNS groups, we did not find significant differences (P=.89). The GT genotype was associated with normal blood pressure in children with NS (P=.007), while the GG genotype was associated with hypertension (P<.001). We did not find statistically significant differences in renal histopathology or serum cholesterol levels based on the genotype.

CONCLUSIONS

The GG genotype at the rs5370 locus of the EDN1 gene may be associated with an increased risk of primary NS and a better response to steroid therapy.

Predictors of poor outcome in children with steroid sensitive nephrotic syndrome

BACKGROUND AND OBJECTIVE

Nearly 50% of the children with steroid sensitive nephrotic syndrome (SSNS) have a frequently relapsing (FR) or steroid dependent (SD) course, experiencing steroid toxicities and complications of immunosuppression. The study aimed to compare parameters between children with infrequent relapsing (IFR) and FR/SD nephrotic syndrome and to identify the factors associated with a FR/SD course.

METHODS

A retrospective analysis of medical records from 2009 to 2014, of children with SSNS attending the pediatric nephrology clinic in a tertiary care medical college and hospital.

RESULTS

Out of 325 children (226 males) with SSNS, 213 were IFR and 112 were FRNS/SDNS. The median age of onset was 34 (IQR 24-48) months. The median time to the first relapse was 4 (IQR 3-7) months and 6 (IQR 4-12) months in FR/SD and IFR group respectively. Multivariate logistic regression analysis showed "adequate treatment (≥12 weeks) of the first episode" (odds ratio 0.56, 95% CI 0.34-0.91; p value=0.02) and "shorter median time to the first relapse" (odds ratio 1.04, 95% CI=1.01-1.08; p value=0.04) to be independent predictors of FR/SD course. An ROC curve was constructed which showed that time to first relapse <5.5 months was associated with a sensitivity of 69% and specificity of 60% in predicting a FR/SD course.

CONCLUSION

Adequate treatment of the first episode is associated with less chance of an FR/SD course. After treatment of first episode, the first relapse occurring within 5.5 months may predict a frequently relapsing or steroid dependent course.

The role of bioelectrical impedance analysis, NT-ProBNP and inferior vena cava sonography in the assessment of body fluid volume in children with nephrotic syndrome

BACKGROUND

Assessment of volume status and differentiating "underfill" and "overfill" edema is essential in the management of patients with nephrotic syndrome (NS).

OBJECTIVES

Our aim was to evaluate the volume status of NS patients by using different methods and to investigate the utility of bioelectrical impedance analysis (BIA) in children with NS.

METHODS

The hydration status of 19 patients with NS (before treatment of NS and at remission) and 25 healthy controls was assessed by multifrequency BIA, serum N-terminal-pro-brain natriuretic peptide (NT-proBNP) levels, inferior vena cava (IVC) diameter, left atrium diameter (LAD) and vasoactive hormones.

RESULTS

Renin, aldosterone levels, IVC diameter and LAD were not statistically different between the groups. NT-proBNP values were statistically higher in the attack period compared to remission and the control group (p=0.005 for each). Total body water (TBW), overhydration (OH) and extracellular water (ECW) estimated by the BIA measurement in the attack group was significantly higher than that of the remission group and controls. There were no significant correlations among volume indicators in group I and group II. However, significant correlations were observed between NT-proBNP and TBW/BSA (p=0.008), ECW/BSA (p=0.003) and ECW/ICW (p=0.023) in the healthy group. TBW was found to be higher in patients with NS in association with increased ECW but without any change in ICW. NT-proBNP values were higher in patients during acute attack than during remission.

CONCLUSIONS

Our findings support the lack of hypovolaemia in NS during acute attack. In addition, BIA is an easy-to-perform method for use in routine clinical practice to determine hydration status in patients with NS.

[Increased lipoprotein(a) in a paediatric patient associated with nephrotic syndrome]

A common complication in paediatric patients with nephrotic syndrome (NS) is hyperlipidaemia. About 20% of children do not respond to treatment with corticosteroids, presenting with a cortico-resistant NS (CRNS), which can progress to kidney failure. It has been observed that paediatric patients with CRNS have an elevated low density lipoprotein cholesterol (LDL-c), very low density lipoprotein cholesterol (VLDL-c), and triglycerides levels, as well as elevated Lipoprotein-a [Lp (a)] levels. The case is presented of a 5 year old boy, diagnosed with CRNS, presenting with dyslipidaemia with increased LDL-c, Apo-B100, and Lp(a) levels. After the poor prognosis of the renal function, immunosuppressant treatment was started with tacrolimus and atorvastatin to control dyslipidaemia. Although tacrolimus causes an elevation of total cholesterol and LDL-c, the significant alterations of the children lipid profile suggest the existence of a high cardiovascular risk. In these cases, it would be interesting to have reference values in children in our health area.

[NPHS2 Mutation analysis study in children with steroid-resistant nephrotic syndrome]

Podocin is a protein located in the glomerular slit diaphragm where it takes part in the regulation of glomerular filtration. Mutations of the NPHS2 gene that codes podocin are the main cause of autosomal recessive steroid resistant nephrotic syndrome (SRNS).

OBJECTIVES

To identify the NPHS2 mutations in Chilean children with SRNS, and to determine the prevalence of the most common variants in a group of healthy adults.

PATIENTS AND METHODS

Mutation analysis of NPHS2 in 34 Chilean children with SRNS. Once the two most common variants of NPHS2 were identified, screening for these mutations was performed on 233 healthy adults. The mutation analysis was performed by the direct sequencing of the eight coding exons by polymerase chain reaction amplification. The DNA sequencing was performed using a fluorometric method, and then evaluated with SeqPilot software. The relationship between the presence of NPHS2 variants and SRNS was calculated by comparing the allele frequency between patients with SRNS and those of the healthy volunteers using the exact Fisher test. A P<.05 was considered significant.

RESULTS

Pathogenic NPHS2 mutations were detected in 7 (21%) of the 34 patients studied, of which 6 were heterozygotes for p.R229Q and p.A284V. The presence of p.R229Q was 2.46% in the healthy volunteers.

CONCLUSIONS

This study shows that p.R229Q and p.A284V are the most frequent variants in Chilean children with SRNS. It is the first time that this relationship has been reported in Chilean children. Based on this, a screening strategy is proposed for the genetic study in patients with SRNS and their families. A parallel or sequential search strategy for p.R229Q and p.A284V in these patients is proposed.

[Idiopathic Nephrotic Syndrome: recommendations of the Nephrology Branch of the Chilean Society of Pediatrics. Part One]

Idiopathic nephrotic syndrome is the most common glomerular disease in childhood, affecting 1 to 3 per 100,000 children under the age of 16. It most commonly occurs in ages between 2 and 10. Its cause is unknown and its histology corresponds to minimal change disease in 90% of cases, or focal segmental glomerulosclerosis. 80 to 90% of cases respond to steroids (steroid-sensitive nephrotic syndrome) with good prognosis and long-term preservation of renal function over time. 70% of patients with SSNS have one or more relapses in their evolution, and of these, 50% behave as frequent relapsing or steroid-dependent, a group that concentrate the risk of steroid toxicity. Patients with steroid-resistant nephrotic syndrome have a poor prognosis and 50% of them evolve to end-stage renal disease. The goal of therapy is to induce and maintain remission of the disease, reducing the risk secondary to proteinuria while minimizing the adverse effects of treatments, especially with prolonged use of corticosteroids. This paper is the result of the collaborative effort of the Nephrology Branch of the Chilean Society of Pediatrics with aims at helping pediatricians and pediatric nephrologists to treat pediatric SNI. In this first part, recommendations of steroid-sensitive nephrotic syndrome are discussed.

Clinical features, course and prognosis of idiopathic membranous nephropathy depending on the presence of antibodies against M-type phospholipase A2 receptor

In membranous nephropathy, the presence of antibodies against M-type phospholipase A2 receptor is considered highly specific for idiopathic forms. However, no specific association to a particular clinical profile has been found for such antibodies.

OBJECTIVE

To assess potential differences in initial clinical profile, course and prognosis of idiopathic membranous nephropathy depending on the presence of anti-PLA2R antibodies.

METHODS

Eighty-five patients with idiopathic membranous nephropathy were included (55 anti-PLA2R-positive and 30 anti-PLA2R-negative). Clinical, biochemical and pathological variables were recorded at the time of diagnosis. Frequency of spontaneous remission, incidence of response to first-line therapy, frequency and number of recurrences, survival of renal function free from renal replacement therapy, survival of renal function free from chronic renal insufficiency and frequency of occurrence of malignant, infectious or autoimmune diseases during follow-up were recorded.

RESULTS

At the time of diagnosis, anti-PLA2R-negative patients were significantly older and had a higher frequency of spontaneous remission. No differences were noted in the response to first-line treatment, frequency and number of recurrences, survival of renal function free from renal replacement therapy, or survival of renal function free from chronic renal insufficiency.

CONCLUSIONS

Anti-PLA2R-negative patients with idiopathic membranous nephropathy were older and experienced spontaneous remission more often than anti-PLA2R-positive patients. No differences in terms of treatment response, recurrences, and final prognosis were observed between both groups of patients.

[Nephrotic proteinuria in hypertensive nephrosclerosis: clinical and evolution characteristics]

BACKGROUND AND OBJECTIVE

Nephrotic range proteinuria can occur in patients with biopsy proven hypertensive nephrosclerosis (HN). We analysed the differential clinical and evolution characteristics of these patients compared with other glomerular diseases.

MATERIAL AND METHOD

This is a case-control descriptive analysis obtained from the renal pathology registry of our hospital. Clinical features, treatment and evolution of these patients (cases) were compared with nephrotic patients with other glomerular diseases (controls).

RESULTS

Five point one percent of biopsies with HN diagnosis. Case/control characteristics were: proteinuria 4.7 [3-11.4] versus 5.5 [3-28.1] g/24h/1.73m(2) (P=NS). Normal albumin compared with controls (39.5 [6.4] versus 29.4 [10] g/dL; P=.001), significant oedemas only in 10 versus 63% of controls. HN were older (58.8 [12.6] versus 45.5 [19.6] years), had longer hypertension duration before renal biopsy and more previous cardiovascular events (39 versus 16%). Mean blood pressure was higher (166/90 versus 133/75mmHg; P=.01) and had worse renal outcome.

CONCLUSIONS

HN must be included in the differential diagnosis of nephrotic range proteinuria in hypertensive patients. The absence of oedema and normal serum albumin are distinctive clinical characteristics that can help in decision-making before performing a renal biopsy.

Predictive risk factors for failure to induction therapy of lupus nephritis in a cohort of Colombian patients

OBJECTIVES

To determine the predictors of failure to obtain remission after induction therapy for proliferative lupus nephritis in a group of northwestern Colombian patients.

MATERIAL AND METHODS

A retrospective study was conducted. We included patients with systemic lupus erythematosus according to the American College of Rheumatology criteria who had nephritis confirmed by renal biopsy.

RESULTS

We followed 84 patients: 88.1% female, and 11.9% male. The mean age at diagnosis of systemic lupus erythematosus was 27.5±11.8 years (9-70). The average time between diagnosis of systemic lupus erythematosus and proliferative nephritis onset was 13.6 months (0-168). Histopathologic type: iv (78.57%), iii (15.47%), iii-iv/v (5.96%). Activity index: 6.7±4.6. Chronicity index: 2±2.7. 24-hour proteinuria (mg): 6,164 (130-18,100). Baseline creatinine: 1.14 mg/dL (0.43-7.4). Induction therapy: Steroids (100%), cyclophosphamide (76.2%) and mycophenolate mofetil (23.8%). At six months, 56% of individuals failed to achieve partial or complete remission. Predictors of failure to induction therapy were, in accordance with the bivariate analysis (OR; 95%CI): creatinine level more than 1.2mg/dL (10.8; 3.18-36.84; P<.005), nephrotic range proteinuria (11.9; 3.09-45.8; P<.001), and an activity index above 8 (5.04; 1.7-14.3; P<.001). In the multivariate analysis, only baseline creatinine higher than 1.2mg/dL (10.92; 2.65-45.02; P=.001), and nephrotic range proteinuria (9.81; 1.85-52.04; P=.007) were significant.

CONCLUSIONS

A significant percentage of Colombian patients fail to achieve remission of proliferative lupus nephritis after six months of treatment.