ABSTRACT Introduction: Urolithiasis causes pain, renal functional deterioration and notorious economic expenses. Objectives: To identify the clinical-epidemiological characteristics of nephrolithiasis. Methods: A descriptive, cross-sectional study was conducted in a total of 2,923 people from to three clinics of Plaza de la Revolution Teaching Community Clinic, Plaza de la Revolution municipality, Havana province, Cuba. They were selected by simple random sampling from the 16 clinics that the health area has. The data was obtained through a survey and structured interview. The information was processed automatically (IBMSPSS 22.0). Frequency distribution analysis was used, prevalence rates were calculated and the homogeneity test was used. Results: The prevalence of urolithiasis was 4.99 per 100 inhabitants, 6.3 among men and 5.7 among white-skinned men. The average age at diagnosis was 39.3 years. Among the risk factors for lithiasis, the high intake of oxalates prevailed (97.3%). Ultrasound was the most used form of diagnosis (67.8%). Phytotherapy was the most used medical treatment (69.2%). A medical permit was issued to 16.4% of the patients in the last two years. Conclusions: The prevalence of urinary lithiasis in Plaza de la Revolution Teaching Community Clinic is high, prevailing in males, in white-skinned and middle aged subjects. High oxalate intake is the most common risk factor for urinary lithiasis found. The most used form of diagnosis is ultrasound and the most used treatment is phytotherapy.

RESUMEN Introducción: Las urolitiasis ocasionan dolor, deterioro funcional renal y notorias erogaciones económicas. Objetivos: Identificar las características clínico-epidemiológicas de la nefrolitiasis. Métodos: Estudio descriptivo, transversal. Se estudiaron 2 923 personas pertenecientes a tres consultorios del Policlínico Plaza; municipio Plaza de la Revolución, provincia La Habana, Cuba., seleccionados por muestreo simple aleatorio de los 16 con que cuenta el área de salud. Los datos se obtuvieron mediante encuesta y entrevista estructurada. La información fue procesada de forma automatizada (IBMSPSS 22.0). Se utilizó análisis de distribución de frecuencias, se calcularon tasas de prevalencia, y fue empleado el test de homogeneidad. Resultados: La prevalencia de urolitiasis fue de 4,99 por cada 100 habitantes, de 6,3 entre los varones y de 5,7 en los de piel blanca. La edad promedio al diagnóstico fue de 39,3 años. Entre los factores de riesgo de litiasis predominó la alta ingestión de oxalatos (97,3 %). La ecografía fue la forma de diagnóstico más usada (67,8 %). La fitoterapia fue el tratamiento médico más utilizado (69,2 %). Al 16,4 % de los pacientes se les expidió certificado médico en los últimos dos años. Conclusiones: La prevalencia de litiasis urinaria en el Policlínico Docente “Plaza de la Revolución” es elevada, con predominio en el sexo masculino, en sujetos de piel blanca y en las edades medias de la vida. La alta ingestión de oxalato es el factor de riesgo de litiasis urinaria más frecuente encontrado. La forma de diagnóstico más utilizada es la ecografía y el tratamiento más empleado es la fitoterapia.

Abstract INTRODUCTION During the pandemic caused by the SARS-CoV-2 virus, some patients who develop severe forms of COVID-19 present thrombotic microangiopathy in the course of the disease’s clinical progression. METHODS Data came from direct patient observation and clinical records. We performed a kidney biopsy and used optical microscopy and immunofluorescence techniques. RESULTS We present the case of a 78-year-old male patient, mestizo, overweight with a history of high blood pressure, ischemic cardiopathy and chronic obstructive pulmonary disease who was first admitted to the hospital due to respiratory symptoms and diarrhea related to COVID-19, from which he recovered. He was subsequently readmitted with symptoms of acute renal dysfunction accompanied by mild anemia and thrombocytopenia; at the same time, he resulted negative for COVID-19 via a real-time polymerase chain reaction test. A kidney biopsy revealed thrombi in glomerular capillaries, acute tubular necrosis, thickening of extraglomerular blood vessel walls, and C3 deposits in the glomerular tufts. CONCLUSIONS We describe a case of thrombotic microangiopathy with kidney biopsy in a patient recovering from COVID-19. Acute renal dysfunction is a form of thrombotic microangiopathy that has been observed in patients recovering from COVID-19.

ABSTRACT Introduction: Urolithiasis has increased in recent decades. Autosomal dominant polycystic kidney disease (ADPKD), the most common of all hereditary kidney diseases, occupies a predominant position in terms of incidence. Objectives: Identify the frequency of occurrence of urinary metabolic disorders in Cuban urolithiasis patients with and without ADPKD. Methods: A descriptive cross-sectional study was conducted of 579 adult patients without ADPKD selected by simple random sampling, and 21 patients with ADPKD, from the total urolithiasis patients undergoing renal metabolic evaluation at the Renal Physiopathology Laboratory of the Institute of Nephrology in the period 2010-2015. Data were obtained from medical records and reports of renal metabolic studies. Information was processed with the statistical software SPSS version 22.0. Average and standard deviation were estimated and use was made of frequency distribution analysis and homogeneity testing. Results: A predominance was found of female sex among patients with ADPKD (57.1%) and male sex among patients without ADPKD (63.4%). The most common disorders were hypercalciuria (45.3%) and hypophosphatemia (17.1%) in the non-polycystic population, and increased uric acid clearance (38.1%) and hypercalciuria (23.8%) in polycystic patients. Statistically significant differences were found in uric acid clearance increase (p = 0.01) and hyperphosphatemia (p = 0.04). Conclusions: The main metabolic disorders of lithiasis patients, polycystic as well as non-polycystic, are increased uric acid clearance, hypercalciuria, hyperuricosuria and hypophosphatemia, with a varying order of presentation. Increased uric acid clearance and hyperphosphatemia are more common in polycystic lithiasis patients.

RESUMEN Introducción: La urolitiasis se ha incrementado en las últimas décadas. La enfermedad renal poliquística autosómica dominante (ERPAD), enfermedad renal hereditaria más frecuente, ocupa un lugar preponderante. Objetivos: Identificar la frecuencia de presentación de los trastornos metabólicos urinarios en pacientes litiásicos cubanos con ERPAD y sin ella Métodos: Estudio descriptivo, transversal. Fueron estudiados 579 pacientes adultos sin ERPAD, seleccionados por muestreo simple aleatorio y los 21 pacientes con ERPAD, del total de pacientes con litiasis urinaria que se realizó estudio metabólico renal en el Laboratorio de Fisiopatología Renal del Instituto de Nefrología, en el periodo 2010-2015. Los datos fueron tomados de la historia clínica y del informe de estudio metabólico renal. La información se procesó de forma automatizada (SPSS 22.0). Se utilizó el promedio, desviación estándar, análisis de distribución de frecuencias y el test de homogeneidad. Resultados: En los pacientes con ERPAD predominó el sexo femenino (57,1 %), mientras que en los pacientes sin ERPAD, el masculino (63,4 %). Los trastornos más frecuentes en la población no poliquística fueron hipercalciuria (45,3 %) e hipofosfatemia (17,1 %). En los poliquísticos, aclaramiento aumentado de ácido úrico (38,1 %) e hipercalciuria (23,8 %). Se encontraron diferencias estadísticamente significativas para aumento del aclaramiento de ácido úrico (p = 0,01) e hiperfosfatemia (p = 0,04). Conclusiones: Los principales trastornos metabólicos de los pacientes litiásicos, tanto poliquísticos como no poliquísticos, son el aclaramiento de ácido úrico aumentado, hipercalciuria, hiperuricosuria e hipofosfatemia, aunque el orden de presentación es diferente. El aclaramiento de ácido úrico aumentado y la hiperfosfatemia se presentan con mayor frecuencia en los pacientes litiásicos poliquísticos.

ABSTRACT Introduction: Chronic kidney disease mainly affecting male farmers and not associated to traditional causes has been present in Central America for twenty years. The condition is characterized by the presence of chronic interstitial nephritis, but its ultrastructural features are not fully known. Factors suggested as responsible for its occurrence include the use of agrochemicals and other nephrotoxic agents, chronic dehydration and medicine consumption. Objective: Describe the ultrastructural characteristics of chronic interstitial nephritis in farming communities. Method: A cross-sectional descriptive study was conducted of renal biopsy samples from eight patients diagnosed with chronic interstitial nephritis in farming communities. Results: Of the eight patients studied, two (25%) were farm workers and five (62.5%) were female. Two of the patients (25%) had stage 2 and six (75%) stage 3 chronic kidney disease. In five patients evidence was found of phagolysosomes with lipid component mixed with electrodense material in distal tubule cells. An equal number of patients had myeloid bodies with laminated areas and central nucleus in proximal tubule and blood vessel cells. Conclusions: Evidence of phagolysosomes and myeloid structures of unknown content and origin was found in renal tubules and vessels of patients from farming communities diagnosed with chronic interstitial nephritis.

RESUMEN Introducción: Desde hace 20 años se presenta en Centroamérica una enfermedad renal crónica que fundamentalmente afecta a hombres agricultores y no asociada a las causas tradicionales. Se caracteriza por presentar una nefritis intersticial crónica, en tanto las características ultraestructurales no se conocen con exactitud. En su origen se invoca el uso de agroquímicos y otros agentes nefrotóxicos, la deshidratación crónica, el consumo de medicamentos, entre otros factores. Objetivo: Describir las características ultraestructurales de la nefritis intersticial crónica en comunidades agrícolas. Método: Se realizó un estudio descriptivo de corte transversal. Se estudiaron muestras de biopsias renales de ocho pacientes con diagnóstico de nefritis intersticial crónica de las comunidades agrícolas. Resultados: De los ocho pacientes estudiados, dos (25 %) trabajaban en labores agrícolas y cinco eran del sexo femenino (62,5 %). Dos de los pacientes (25 %) presentaban una enfermedad renal crónica estadio 2, y seis (75 %) estadio 3. En cinco pacientes se hallaron fagolisosomas con presencia de componente lipídico entremezclado con material electrodenso en células del túbulo distal. En igual cantidad de pacientes se observaron cuerpos mieloides con zonas laminadas y núcleo central en células de túbulo proximal y de los vasos sanguíneos. Conclusiones: En pacientes de comunidades agrícolas que padecen nefritis intersticial crónica se evidencian fagolisosomas y estructuras mieloides en túbulos y vasos renales, cuyo contenido y origen se desconocen.

In El Salvador, chronic kidney disease had reached epidemic proportions towards the end of this century’s first decade. In 2011–2012, the Ministry of Health reported it was the leading cause of hospital deaths in men, the fifth in women, and the third overall in adult hospital fatalities. Farming was the most common occupation among men in dialysis (50.7%). By 2017, chronic kidney disease admissions had overwhelmed hospital capacity. In 2009, El Salvador’s Ministry of Health, Cuba’s Ministry of Public Health and PAHO launched a cooperative effort to comprehensively tackle the epidemic. The joint investigations revealed a total prevalence of chronic kidney disease in the adult population of farming communities higher than that reported internationally (18% vs.11%–14.8%), higher in men than in women (23.9% vs 13.9%) and higher in men who were farmers/farmworkers than in men who were not (31.3% vs. 14.8%). The disease was also detected in children. An association was found between chronic kidney disease and exposure to agrochemicals (OR 1.4–2.5). In 51.9% of all chronic kidney disease cases, traditional causes (diabetes, hypertension, glomerulopathies, obstructive nephropathies and cystic diseases) were ruled out and the existence of a particular form of chronic kidney disease of nontraditional etiology was confirmed (whose initial cases were reported as early as 2002). In the patients studied, functional alterations and histopathologic diagnosis confirmed a chronic tubulointerstitial nephritis; most presented with neurosensory hearing loss, altered tendon reflexes and tibial artery damage. The main results of this cooperation were the epidemiologic, physiopathologic, clinical and histopathologic characterization of chronic kidney disease of nontraditional etiology. This characterization facilitated case definition for the epidemic and led to the hypothesis of systemic toxicity from agrochemicals (e.g., paraquat, glyphosate), which particularly affect the kidneys and to which farmers/farmworkers (who may also become dehydrated in the fields) are most exposed. The research thus also laid the foundations for design of comprehensive intersectoral government actions to reduce cases and put an end to the epidemic. Chronic kidney disease; chronic renal failure; tubulointerstitial nephritis; epidemiology; histopathology; international cooperation; agrochemicals; environmental pollutants, noxae, and pesticides; occupational health; PAHO; El Salvador; Cuba

Tubulointerstitial nephritis syndrome and uveitis is an uncommon cause of acute renal dysfunction in adults. The diagnosis can be difficult, as ocular and renal symptoms often do not coincide temporarily. Two cases of tubulointerstitial nephritis syndrome and uveitis in adults, with favorable evolution with systemic steroid treatment are presented in this paper.

El síndrome de nefritis tubulointersticial y uveítis es una causa infrecuente de disfunción renal aguda en los adultos. El diagnóstico puede hacerse difícil, pues con frecuencia no coinciden temporalmente los síntomas oculares y renales. Se presentaron dos casos de síndrome de nefritis tubulointersticial y uveítis en adultos, con evolución favorable con tratamiento esteroideo sistémico.