Renal Morphology, Clinical Findings, and Progression Rate in Mesoamerican Nephropathy.

BACKGROUND: Mesoamerican nephropathy (MeN) is a chronic kidney disease affecting rural inhabitants in Central America. We have previously described the renal morphology in 8 patients from El Salvador. To confirm the renal pathology, we have studied kidney biopsies from patients with MeN in Nicaragua. Follow-up urine and blood samples from both biopsy studies were collected to investigate the natural history. STUDY DESIGN: Case series. SETTINGS & PARTICIPANTS: In the kidney biopsy study, 19 male sugarcane workers in Nicaragua with suspected MeN were investigated with questionnaires, kidney biopsies, and blood and urine analysis. Inclusion criteria were age 20 to 65 years and plasma creatinine level of 1.13 to 2.49mg/dL or estimated glomerular filtration rate (eGFR) of 30 to 80mL/min/1.73m2. Exclusion criteria were proteinuria with protein excretion > 3g/24 h, uncontrolled hypertension, diabetes mellitus, or other known kidney disease. In the follow up-study, blood and urine from the kidney biopsy study in Nicaragua (n=18) and our previous biopsy study of MeN cases in El Salvador (n=7) were collected 1 to 1.5 and 2 to 2.5 years after biopsy, respectively. OUTCOMES: Renal morphology, clinical, and biochemical characteristics, change in eGFR per year. MEASUREMENTS: eGFR was calculated using the CKD-EPI creatinine (eGFRcr), cystatin C (eGFRcys), and creatinine-cystatin C (eGFRcr-cys) equations. RESULTS: In the kidney biopsy study, participants had a mean eGFRcr of 57 (range, 33-96) mL/min/1.73m2. 47% had low plasma sodium and 21% had low plasma potassium levels. 16 kidney biopsies were representative and showed glomerulosclerosis (mean, 38%), glomerular hypertrophy, and signs of chronic glomerular ischemia. Mild to moderate tubulointerstitial damage and mostly mild vascular changes were seen. In the follow up-study, median duration of follow-up was 13 (range, 13-27) months. Mean change in eGFRcr was -4.4±8.4 (range, -27.7 to 10.2) mL/min/1.73m2 per year. Most patients had stopped working with sugarcane cultivation. LIMITATIONS: 3 biopsy specimens had 4 or fewer glomeruli. CONCLUSIONS: This study confirms the renal morphology of MeN: chronic glomerular and tubulointerstitial damage with glomerulosclerosis and chronic glomerular ischemia. Follow-up data show that eGFRs, on average, deteriorated.

Prevalencia de pacientes con tratamiento sustitutivo renal en El Salvador en 2014 / Prevalence of patients receiving renal replacement therapy in El Salvador in 2014

El Salvador presenta la mortalidad por fallo renal más alta de América. Cinco proveedores de servicios de salud ofrecen tratamiento sustitutivo renal (TSR) en el país. La prevalencia nacional de TSR nunca ha sido reportada. Objetivos: Conocer la prevalencia de TSR en El Salvador y algunas características básicas. Métodos: La asociación de nefrología coordinó una encuesta nacional transversal durante el tercer trimestre de 2014; 31 centros renales participaron, que cubrían el 99,5% de los pacientes. Resultados: Prevalencia nacional de TSR: 595 por millón de población (pmp), N=3.807, edad promedio 50,4 años, 67,5% hombres. Por modalidad: diálisis peritoneal (DP) 289 pmp; hemodiálisis (HD) 233 pmp; con trasplante renal funcionante 74 pmp (donante vivo solamente). La seguridad social cubre el 25% de la población, pero atiende al 49,7% de los pacientes en TSR. Generalmente observamos prevalencias más altas en municipios con centros renales, costeros o de zonas bajas. Un 95% de los pacientes en HD reciben menos de 3 sesiones semanales. Un 59% de los pacientes en DP no están en continua ambulatoria o programas automatizados y un 25% todavía utilizan catéter rígido. Etiología de la enfermedad renal crónica: no reportada/desconocida 50%, hipertensión 21,1%, diabetes 18,9%, glomerulonefritis 6,7%, obstructivas 1,2%, tubulointersticiales 0,9%, poliquísticas 0,4%, otras 0,7%. Discusión: A pesar del incremento de servicios de TSR, la prevalencia es inferior al promedio latinoamericano (660 pmp). Un 75% de los pacientes en HD y DP están infradializados. Todavía se utilizan técnicas anticuadas. La presencia de la nefropatía mesoamericana influye las características demográficas (muchos jóvenes, 2/3 hombres, alta prevalencia en zonas bajas y costeras) (AU)

El Salvador has the highest renal failure mortality rate in the Americas. Five healthcare providers offer renal replacement therapy (RRT) in the country. The national RRT prevalence has never been reported. Aims: To determine the RRT prevalence in El Salvador and some basic characteristics. Methods: The association of nephrology coordinated a nationwide cross-sectional survey during the third quarter of 2014. 31 renal centres participated in the survey, covering 99.5% of patients. Results: National RRT prevalence: 595 per million population (pmp), N=3807, average age 50.4 years, 67.5% male. By modality: peritoneal dialysis (PD) 289 pmp, haemodialysis (HD) 233 pmp, with functioning kidney transplantation 74 pmp (living donor only). Social security covers 25% of the population but treats 49.7% of RRT patients. Generally, higher prevalence was observed in municipalities with renal centres or located on the coast or lowlands. Ninety-five percent of HD patients receive fewer than 3 weekly sessions. Of PD patients, 59% do not belong to a continuous outpatient or automated programme, and 25% still use rigid catheter. Aetiology of chronic kidney disease: unavailable/undetermined 50%, hypertension 21.1%, diabetes 18.9%, glomerulonephritis 6.7%, obstructive causes 1.2%, tubulointerstitial 0.9%, polycystic 0.4% and other 0.7%. Discussion: Despite the increase in RRT services, the prevalence is lower than the Latin American average (660 pmp). Three quarters of HD and PD patients are under-dialysed. Obsolete RRT techniques are still used. The presence of Mesoamerican nephropathy influences the demographic characteristics (many young patients, two-thirds male, high prevalence in lowlands and coastlands) (AU)

Confirmed clinical case of chronic kidney disease of nontraditional causes in agricultural communities in Central America: a case definition for surveillance / Caso clínico confirmado de enfermedad renal crónica de causas no tradicionales en comunidades agrícolas de Centroamérica: una definición de caso para la vigilancia

Over the last 20 years, many reports have described an excess of cases of chronic kidney disease (CKD) in the Pacific coastal area of Central America, mainly affecting male farmworkers and signaling a serious public health problem. Most of these cases are not associated with traditional risk factors for CKD, such as aging, diabetes mellitus, and hypertension. This CKD of nontraditional causes (CKDnT) might be linked to environmental and/or occupational exposure or working conditions, limited access to health services, and poverty. In response to a resolution approved by the Directing Council of the Pan American Health Organization (PAHO) in 2013, PAHO, the U.S. Centers for Disease Control and Prevention, and the Latin American Society of Nephrology and Hypertension (SLANH) organized a consultation process in order to expand knowledge on the epidemic of CKDnT and to develop appropriate surveillance instruments. The Clinical Working Group from SLANH was put in charge of finding a consensus definition of a confirmed clinical case of CKDnT. The resulting definition establishes mandatory criteria and exclusion criteria necessary for classifying a case of CKDnT. The definition includes a combination of universally accepted definitions of CKD and the main clinical manifestations of CKDnT. Based on the best available evidence, the Clinical Working Group also formulated general recommendations about clinical management that apply to any patient with CKDnT. Adhering to the definition of a confirmed clinical case of CKDnT and implementing it appropriately is expected to be a powerful instrument for understanding the prevalence of the epidemic, evaluating the results of interventions, and promoting appropriate advocacy and planning efforts

En los 20 últimos años, en muchos informes se ha descrito un número inusual de casos de enfermedad renal crónica (ERC) en la costa del Pacífico de Centroamérica, que afecta principalmente a trabajadores agrícolas varones y señala un grave problema de salud pública. La mayoría de estos casos no se asocia con los factores de riesgo tradicionales de ERC, como envejecimiento, diabetes mellitus e hipertensión. Esta ERC de causas no tradicionales (ERCnT) podría estar vinculada con la exposición laboral o ambiental o las condiciones de trabajo, el escaso acceso a los servicios de salud y la pobreza. En respuesta a una resolución aprobada por el Consejo Directivo de la Organización Panamericana de la Salud (OPS) en el 2013, la OPS, los Centros para el Control y la Prevención de Enfermedades de los Estados Unidos y la Sociedad Latinoamericana de Nefrología e Hipertensión (SLANH) organizaron un proceso de consulta para ampliar los conocimientos sobre la epidemia de ERCnT y elaborar instrumentos apropiados para la vigilancia. El Grupo Clínico de Trabajo de la SLANH tuvo la responsabilidad de consensuar una definición de caso clínico confirmado de ERCnT. En la definición resultante se establecen criterios obligatorios y criterios de exclusión necesarios para clasificar un caso como de ERCnT. La definición incluye una combinación de definiciones de ERC universalmente aceptadas y las principales manifestaciones clínicas de ERCnT. Sobre la base de los mejores datos científicos disponibles, el Grupo Clínico de Trabajo también formuló recomendaciones generales acerca del manejo clínico, que se aplican a cualquier paciente con ERCnT. Se espera que la adopción de la definición de caso confirmado de ERCnT y su aplicación adecuada sean una herramienta poderosa para conocer la prevalencia de la epidemia, evaluar los resultados de las intervenciones y promover acciones apropiadas de sensibilización y planificación.

Prevalence of patients receiving renal replacement therapy in El Salvador in 2014. / Prevalencia de pacientes con tratamiento sustitutivo renal en El Salvador en 2014.

El Salvador has the highest renal failure mortality rate in the Americas. Five healthcare providers offer renal replacement therapy (RRT) in the country. The national RRT prevalence has never been reported. AIMS: To determine the RRT prevalence in El Salvador and some basic characteristics. METHODS: The association of nephrology coordinated a nationwide cross-sectional survey during the third quarter of 2014. 31 renal centres participated in the survey, covering 99.5% of patients. RESULTS: National RRT prevalence: 595 per million population (pmp), N=3807, average age 50.4 years, 67.5% male. By modality: peritoneal dialysis (PD) 289 pmp, haemodialysis (HD) 233 pmp, with functioning kidney transplantation 74 pmp (living donor only). Social security covers 25% of the population but treats 49.7% of RRT patients. Generally, higher prevalence was observed in municipalities with renal centres or located on the coast or lowlands. Ninety-five percent of HD patients receive fewer than 3 weekly sessions. Of PD patients, 59% do not belong to a continuous outpatient or automated programme, and 25% still use rigid catheter. Aetiology of chronic kidney disease: unavailable/undetermined 50%, hypertension 21.1%, diabetes 18.9%, glomerulonephritis 6.7%, obstructive causes 1.2%, tubulointerstitial 0.9%, polycystic 0.4% and other 0.7%. DISCUSSION: Despite the increase in RRT services, the prevalence is lower than the Latin American average (660 pmp). Three quarters of HD and PD patients are under-dialysed. Obsolete RRT techniques are still used. The presence of Mesoamerican nephropathy influences the demographic characteristics (many young patients, two-thirds male, high prevalence in lowlands and coastlands).

Confirmed clinical case of chronic kidney disease of nontraditional causes in agricultural communities in Central America: a case definition for surveillance.

Over the last 20 years, many reports have described an excess of cases of chronic kidney disease (CKD) in the Pacific coastal area of Central America, mainly affecting male farmworkers and signaling a serious public health problem. Most of these cases are not associated with traditional risk factors for CKD, such as aging, diabetes mellitus, and hypertension. This CKD of nontraditional causes (CKDnT) might be linked to environmental and/or occupational exposure or working conditions, limited access to health services, and poverty. In response to a resolution approved by the Directing Council of the Pan American Health Organization (PAHO) in 2013, PAHO, the U.S. Centers for Disease Control and Prevention, and the Latin American Society of Nephrology and Hypertension (SLANH) organized a consultation process in order to expand knowledge on the epidemic of CKDnT and to develop appropriate surveillance instruments. The Clinical Working Group from SLANH was put in charge of finding a consensus definition of a confirmed clinical case of CKDnT. The resulting definition establishes mandatory criteria and exclusion criteria necessary for classifying a case of CKDnT. The definition includes a combination of universally accepted definitions of CKD and the main clinical manifestations of CKDnT. Based on the best available evidence, the Clinical Working Group also formulated general recommendations about clinical management that apply to any patient with CKDnT. Adhering to the definition of a confirmed clinical case of CKDnT and implementing it appropriately is expected to be a powerful instrument for understanding the prevalence of the epidemic, evaluating the results of interventions, and promoting appropriate advocacy and planning efforts.

Clinical and pathological characterization of Mesoamerican nephropathy: a new kidney disease in Central America.

BACKGROUND: An endemic of chronic kidney disease (CKD) of unknown cause among rural inhabitants in Central America has been identified. Young and otherwise healthy men working in plantations are frequently affected. The name Mesoamerican nephropathy (MeN) has been suggested. Clinically, MeN presents with low-grade proteinuria and progressive kidney failure. The renal pathology of this disease has not yet been described. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: 8 male patients with CKD of unknown cause and clinically suspected MeN were recruited from a nephrology unit in El Salvador. All recruited patients had been working on plantations. Kidney biopsies, blood, and urine samples were collected. OUTCOMES & MEASUREMENTS: Renal morphology examined with light microscopy, immunofluorescence, and electron microscopy; clinical and biochemical characteristics. RESULTS: A similar pattern was seen in all 8 biopsy specimens, with extensive glomerulosclerosis (29%-78%) and signs of chronic glomerular ischemia in combination with tubular atrophy and interstitial fibrosis, but only mild vascular lesions. Electron microscopy indicates podocytic injury. Biochemical workup showed reduced estimated glomerular filtration rate (27-79 mL/min/1.73 m(2) with the CKD Epidemiology Collaboration [CKD-EPI] creatinine equation), low-grade albuminuria, and increased levels of tubular injury biomarkers. Hypokalemia was found in 6 of 8 patients. LIMITATIONS: Small number of patients from one country. CONCLUSIONS: This study is the first report of the biochemical and morphologic findings in patients with MeN. Our findings indicate that MeN constitutes a previously unrecognized kidney disease with damage to both glomerular and tubulointerstitial compartments.