Chemotherapy-induced tubulopathy: a case report series

Acquired tubulopathies are frequently underdiagnosed. They can be characterized by the renal loss of specific electrolytes or organic solutes, suggesting the location of dysfunction. These tubulopathies phenotypically can resemble Bartter or Gitelman syndrome). These syndromes are infrequent, they may present salt loss resembling the effect of thiazides (Gitelman) or loop diuretics (Bartter). They are characterized by potentially severe hypokalemia, associated with metabolic alkalosis, secondary hyperaldosteronism, and often hypomagnesemia. Tubular dysfunction has been described as nephrotoxic effects of platinum-based chemotherapy. We present 4 cases with biochemical signs of tubular dysfunction (Bartter-like/Gitelman-like phenotype) related to chemotherapy.

Diagnostic Usefulness of Antibodies Against M-type Phospholipase A2 Receptor (aPLA2R) in Primary Membranous Nephropathy in the Mexican Population

OBJECTIVE

This study aimed to determine the frequency and diagnostic performance of antibodies against M-type phospholipase A2 receptors (aPLA2R) in subjects with idiopathic membranous nephropathy (IMN).

MATERIALS AND METHODS

A diagnostic test study was conducted in a cohort of 160 patients from the nephrology outpatient clinic over a period of eight years. Serum samples were taken and analyzed from patients with a histological diagnosis of IMN with proteinuria greater than and less than 1 g in 24 hours and other glomerular diseases other than IMN with aPLA2R measurement by enzyme-linked immunosorbent assay (ELISA) (Euroimmun, Luebeck, Germany).

RESULTS

In 22 of 160 patients, an aPLA2R concentration >9 RU/mL was found, and all these cases had IMN. The prevalence of seropositivity in cases with active IMN was 78% (21/27). All these correlations were statistically significant with a p<0.001. The area under the receiver operating characteristic (ROC) curve (AB-ROC) of aPLA2R was 0.87 (95%, CI: 78-0.96).

CONCLUSIONS

The aPLA2R has adequate diagnostic usefulness to diagnose IMN in the selected population, especially in subjects with proteinuria greater than 1 gr/day, with a sensitivity of 78% and a specificity of 99%.

Scleromyositis: A Novel Entity Beyond Systemic Sclerosis and Autoimmune Myositis

Scleromyositis is a new clinical entity, which not only has clinical and histopathological components of systemic sclerosis and inflammatory myopathy but is also characterized by presenting unique characteristics, which may not be in the previously mentioned diseases. Up until now, there are no specific classification criteria proposed by the American College of Rheumatology or the European League Against Rheumatism (ACR/EULAR). This paper presents a case report of a female patient in her 60s who was admitted to our institution due to muscle weakness in her legs and dysphagia. Within her diagnosis approach, clinical characteristics compatible with autoimmune myopathy were found; however, she presented with anti-PM/Scl75 antibody-positive results. In this paper, we emphasized the clinical characteristics and forms of presentation of scleromyositis, additionally discussing the available treatment for this entity.

Advances in the Physiology of Transvascular Exchange and A New Look At Rational Fluid Prescription

The Starling principle is a model that explains the transvascular distribution of fluids essentially governed by hydrostatic and oncotic forces, which dynamically allow vascular refilling according to the characteristics of the blood vessel. However, careful analysis of fluid physiology has shown that the principle, while correct, is not complete. The revised Starling principle (Michel-Weinbaum model) provides relevant information on fluid kinetics. Special emphasis has been placed on the endothelial glycocalyx, whose subendothelial area allows a restricted oncotic pressure that limits the reabsorption of fluid from the interstitial space, so that transvascular refilling occurs mainly from the lymphatic vessels. The close correlation between pathological states of the endothelium (eg: sepsis, acute inflammation, or chronic kidney disease) and the prescription of fluids forces the physician to understand the dynamics of fluids in the organism; this will allow rational fluid prescriptions. A theory that integrates the physiology of exchange and transvascular refilling is the "microconstant model", whose variables include dynamic mechanisms that can explain edematous states, management of acute resuscitation, and type of fluids for common clinical conditions. The clinical-physiological integration of the concepts will be the hinges that allow a rational and dynamic prescription of fluids.

MO210: Anti-Receptor Type M Antibodies of Phospholipase A2 in the Diagnosis of Primary Membrane Nephropathy

BACKGROUND AND AIMS

Idiopathic membranous nephropathy (IMN) is one of the main causes of nephrotic syndrome in the adult population. Approximately between 20% and 40% of patients who suffer from it require replacement therapy in a period of 10–15 years. Recently, it has been reported that antibodies against the Type M phospholipase A2 receptor (APLA2R) are responsible for between 69% and 82% of cases with IMN in different parts of the world. Until now, the diagnosis and clinical follow-up of IMN requires the performance of a renal biopsy and proteinuria measurements.

METHOD

Diagnostic test study in a cohort of 106 patients who continued to be followed up in the nephrology outpatient clinic (EC), in the period from 1 January 2009 to 31 January 2017. Serum samples were taken and analyzed of patients with histological diagnosis of IMN with proteinuria &gt; and &lt;1 g in 24 h and other glomerular diseases other than IMN such as lupus nephritis, diabetic nephropathy, primary glomerular diseases and kidney donors (healthy subjects) with measurement of APLA2R by ELISA (EUROIMMUN ) concomitant with measurement of 24-h urine proteinuria.

RESULTS

In 22 of 106 patients, an APLA2R concentration &gt;9 RU/mL was found and all these cases had IMN (21 active IMN, Proteinuria &gt;1 g in 24 h and 1 inactive IMN, Proteinuria &lt; 1 g in 24 h). The prevalence of seropositivity in cases with active IMN was 78% (21/27). APLA2R concentrations were positively correlated with 24-h urine proteinuria (r = .68) and serum cholesterol (r = .42) and negative with serum albumin (r = −0.34). All these correlations were statistically significant with a P &lt; .001. The area under the ROC curve (AB-ROC) of APLA2R was 0.87 (95% CI 78–0.96). When comparing subjects with active IMN versus other subjects with glomerular diseases, with a cut-off point of 9 RU/mL, the sensitivity was 78% and the specificity 99%.

CONCLUSION

The APLA2Rs have an adequate diagnostic utility to diagnose IMN in the selected population; especially in subjects with proteinuria greater than 1 g/day, with a sensitivity of 78% with a specificity of 99%. The APLA2Rs are useful for the diagnosis of idiopathic membranous nephropathy, especially when there is proteinuria greater than 1 g in 24 h. The APLA2Rs measured by ELISA with titers greater than 9 RU/mL exclude other glomerular diseases and are highly specific for the diagnosis of IMN, which could prevent the performance of a renal biopsy.

MO974: Post-Transplant Glomerulonephritis: A Comparative Cohort Study

BACKGROUND AND AIMS

Post-transplant glomerulonephritis (GMNPTR) is considered the third cause of graft loss. This entity is associated with worse outcomes when compared with the rest of the transplanted population; however, it is little explored whether this risk is maintained despite comparing it with a similar immunological risk.

METHOD

Retrospective cohort study of 12-year kidney transplant recipients (KT) with active follow-up and biopsy-proven diagnosis of GMNPTR. The objectives were to describe the incidence of GMNPTR, describe the frequency of histological diagnoses, and perform a comparative analysis of outcomes with 1: 1 matched controls by: gender, age ± 3 years, shared haplotypes, and year of RT ± 3 years. Kaplan–Meier was used for the analysis of time-dependent variables and Mann–Whitney U was used for comparison of graft function.

RESULTS

In the study period, 632 TR were performed, 54 cases of GMNPTR were found for an incidence of 8.5%. Of these 44 (81.5%) correspond to primary nephropathies, the most frequent being the mesangioproliferative pattern (n = 14, 25.9%), IgA nephropathy (n = 10, 18.5%), focal and segmental glomerulosclerosis (n = 7,12.9%); 10 cases of secondary GMNPTR were reported, of which the most frequent were: diabetic nephropathy and lupus nephritis, in 9.3% and 7.4% respectively. Of the total cases, 4 (7.4%) correspond to true recurrence, 4 (7.4%) to de novo disease and 46 (85%) to graft glomerulonephritis with unknown primary disease. The median time for the diagnosis of GMNPTR was 10 months (IQR: 3–14), the eGFR by CKD-EPI was 67.4 (± 21.2) mL/min/1.73 m2 and proteinuria 231 mg/24 h (IQR: 100–600 mg/day). Fifty-four controls were selected with the previously described matching criteria: age at the time of RT was 38.6 (± 12) years, female gender was 57.4% and the median time on dialysis was 45 months (IQR: 35–61), similar between both groups. The haplotypes shared with the donor were: 0 (n = 33, 61%), 1 (n = 13, 24%), 2 (n = 8, 15%) and 0 (n = 32, 59%), 1 (n = 14, 26%), 2 (n = 8, 15%) for cases and controls, respectively, P = NS. Renal transplantation from a deceased donor was 41% for both groups; the median follow-up for the cases was 43 months (IQR: 24–90) and for the controls 53.5 (IQR: 33–85), P = 0.5. An overall incidence of rejection of 31.8% was observed at a median of 140 months (95% CI: 28–252), log-rank P = 0.27, it was striking that the median time for the appearance of cellular rejection showed a tendency to be higher in the cases of GMNPTR (168 versus 123 months), log-rank P = 0.08; the overall incidence of graft loss was 7.5% at a median follow-up of 149 months (95% CI: 130.5–168.3) log-rank P = 0.91. Finally, when comparing eGFR by CKD-EPI in the last follow-up, no difference was observed (eGFR 64.6 ± 26 versus 60.9 ± 27 mL/min/1.73 m2 P = 0.4).

CONCLUSION

In this study the incidence of GMNPTR is similar to that reported in other cohorts, the most frequent were the primary ones and those with a mesangioproliferative pattern; After adjusting for immune risk factors, GMNPTR did not affect survival compared to a homogeneous immune risk population. On the contrary, and as is well known, the presence of rejection was associated with lower graft function. Maintenance with triple therapy could modulate the severity of GMNPTR, and therefore we see histological diagnoses of little clinical impact.