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.

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.