Waldenström's Macroglobulinemia and Cryoglobulinemic Glomerulonephritis: An Unusual Case of Monoclonal Gammopathy of Renal Significance.

Cryoglobulins are immunoglobulins that precipitate at temperatures below 37 °C and dissolve upon reheating. They can induce small-vessel vasculitis with renal involvement. Cryoglobulinemic glomerulonephritis is a rare manifestation that occurs in patients with monoclonal gammopathy, specifically Waldenström's macroglobulinemia. We present the case of a 52-year-old patient with a history of cutaneous vasculitis and hypothyroidism, who presented with generalized edema, moderate anemia, hypercholesterolemia, nephrotic range proteinuria of 12.69 g/day, microhematuria, arterial hypertension, and hypocomplementemia via the classical pathway, without acute kidney injury and with negative serological studies and positive cryoglobulins in the second determination. Serum and urine protein electrophoresis and immunofixation studies showed a monoclonal band of IgM and kappa light chain. Renal biopsy was consistent with cryoglobulinemic glomerulonephritis. In the context of dysproteinemia and cryoglobulinemic glomerulonephritis, bone-marrow aspiration and biopsy were performed, leading to the diagnosis of Waldenström's macroglobulinemia. Monoclonal gammopathies have been described in association with type I cryoglobulinemias. This described association is uncommon, which is why we present this case, along with a review of the literature.

An Unusual Case of Seronegative Cryoglobulinemic Glomerulonephritis with Dominant Organized IgA Deposits Associated with Staphylococcal Infection: Casual or Causal Relationship?

Introduction: Cryoglobulinemia refers to the presence of cryoglobulins (CGs) in the serum, encompassing a group of diseases caused by the type of circulating GC. Cryoglobulinemic glomerulonephritis (CryoGN) is the principal manifestation of renal involvement. The diagnosis may be challenging because the hallmark of cryoglobulinemia is the detection of CG in the serum. However, cases of CryoGN without serological evidence of CGs are not uncommon in clinical practice, often diagnosed by anatomopathological findings in the renal biopsy. Case Presentation: We report the case of an 86-year-old male who developed renal impairment, nephritic syndrome, and nephrotic-range proteinuria, without serological evidence of CGs, associated with staphylococcal bacteremia without apparent focus. Renal biopsy and pathological examination showed a membranoproliferative glomerulonephritis pattern with CD61-negative pseudothrombi. Immunofluorescence microscopy showed atypical IgA-dominant deposits. Electron microscopy revealed amorphous subendothelial and mesangial deposits and organized electrodense deposits within capillary loops (pseudothrombi) with microtubular substructure measuring 20-40 nm in thickness. These findings were consistent with seronegative CryoGN and microtubular organized atypical IgA-dominant deposits. Discussion: In this report, we discuss the clinical, analytical, and histopathological findings of a rare case of CryoGN without serological evidence of CGs. Regarding the etiology that triggered the glomerular disease in our patient, we conducted an exhaustive study in order to determine the underlying cause of CryoGN. At the time of biopsy, the patient had an active staphylococcal bacteremia. There are reports that postulate that staphylococcal antigens drive activation of immune system and in consequence, could cause this rare form of IgA-dominant glomerulonephritis with cryoglobulinemic features. After ruling out other causes of cryoglobulinemia, we discuss a plausible causal relationship of the staphylococcal infection in the pathogenesis of CryoGN in our patient.

Efficacy and Safety of the Use of SGLT2 Inhibitors in Patients on Incremental Hemodialysis: Maximizing Residual Renal Function, Is There a Role for SGLT2 Inhibitors?

SGLT-2i are the new standard of care for diabetic kidney disease (DKD), but previous studies have not included patients on kidney replacement therapy (KRT). Due to their high risk of cardiovascular, renal complications, and mortality, these patients would benefit the most from this therapy. Residual kidney function (RKF) conveys a survival benefit and cardiovascular health among hemodialysis (HD) patients, especially those on incremental hemodialysis (iHD). We retrospectively describe the safety and efficacy of SGLT2i regarding RKF preservation in seven diabetic patients with different clinical backgrounds who underwent iHD (one or two sessions per week) during a 12-month follow-up. All patients preserved RKF, measured as residual kidney urea clearance (KrU) in 24 h after the introduction of SGLT2i. KrU levels improved significantly from 4.91 ± 1.14 mL/min to 7.28 ± 1.68 mL/min at 12 months (p = 0.028). Pre-hemodialysis blood pressure improved 9.95% in mean systolic blood pressure (SBP) (p = 0.015) and 10.95% in mean diastolic blood pressure (DBP) (p = 0.041); as a result, antihypertensive medication was modified. Improvements in blood uric acid, hemoglobin A1c, urine albumin/creatinine ratio (UACR), and 24 h proteinuria were also significant. Regarding side effects, two patients developed uncomplicated urinary tract infections that were resolved. No other complications were reported. The use of SGLT2i in our sample of DKD patients starting iHD on a 1-2 weekly regimen appears to be safe and effective in preserving RKF.

Correlación entre la proteinuria de 24 horas y el índice proteinuria/creatinina en alícuotas de orina: valor y limitaciones / Correlation between 24-hours proteinuria and proteinuria/creatinine rate in urine aliquots: value and limitations

Objetivo: Estudiar la correlación existente entre la recolección de proteinuria de veinticuatro horas y el índice proteinuria/creatinina tomada de una alícuota de la misma muestra y analizar las variables que afectan la correlación. Material y Métodos: Se seleccionaron 100 personas adultas de diversos servicios hospitalarios y ambulatorios del Hospital Nacional Cayetano Heredia a quienes se les solicitó proteinuria en 24 horas por diversas circunstancias. La proteinuria y la creatinina en orina se midieron utilizando auto-analizadores con técnicas de química seca. Resultados: Un paciente fue excluido por dudosa recolección de la muestra. Hubo 18% varones y 82% mujeres. En la muestra hubo 38% de pacientes gestantes La correlación obtenida en toda la muestra tuvo un r= 0,74 (p < 0,001), evidenciándose que la dispersión de los datos ocurrió en presencia de pacientes con proteinuria superior a 7 g/día; con volumen urinario menor a 600 ml/día y pacientes gestantes. Al excluir estos datos la correlación tuvo un r= 0,95, p < 0,001 (r2= 0,88, IC 95% 0,79-0,93, p < 0,001). Conclusión: Existe una alta correlación entre proteinuria en 24 horas y el índice proteinuria/creatinina tomada en una alícuota. Existen variables críticas que afectan la correlación entre estos dos parámetros: diuresis dudosas, gran proteinuria y pacientes gestantes.

Objective: To study the correlation between twenty-four hours proteinuria and proteinuria/creatinine index taken from an aliquot of the same sample and analyze the variables that affect the correlation. Methods: 100 people were selected from various adult inpatient and outpatient services from Hospital Nacional Cayetano Heredia who required the measurement of proteinuria in 24 hours for various reasons. Proteinuria and creatinine were measured using auto-analyzers with dry chemistry techniques. Results: One patient was excluded for doubtful collection of the sample. There were 18% male and 82% women. 38% of the sample was pregnant patients. The correlation in the entire sample had an r= 0.74 (p < 0.001), demonstrating that the scattering of data occurred in the presence of proteinuria more than 7 g/day; urine volume less than 600 ml/day and pregnant patients. By excluding these data, the correlation had an r= 0.95, p < 0.001 (r2 = 0.88, 95% CI 0.79-0.93, p < 0.001). Conclusion: There is a high correlation between 24-hours proteinuria and the proteinuria/creatinine index taken from an aliquot. There are critical variables that affect the correlation between these two parameters: doubtful diuresis, great proteinuria and pregnant patients.