INTRODUCTION For two decades, various countries have experienced an epidemic of chronic kidney disease unexplainable by traditional causes. Typically a chronic tubulointerstitial nephritis, it predominantly affects young male agricultural workers and has been reported in several countries in Central America, as well as in Sri Lanka, India and Egypt. Recent studies in El Salvador have also reported the disease in male nonagricultural workers and in women, both those working in agriculture and not. Epidemiological information on whether this condition affects pediatric populations is virtually nonexistent. Globally, estimates of chronic kidney disease prevalence in pediatric populations range from 21 to 108 per million population.
OBJECTIVE Determine the prevalence of urinary markers of renal damage and of chronic kidney disease in persons aged <18 years in rural Salvadoran communities.
METHODS Pediatric NefroSalva was a descriptive epidemiologic study in three agricultural regions with known high prevalence of chronic kidney disease of uncertain etiology: Bajo Lempa, Guayapa Abajo and Las Brisas. Demographic and health data were collected and physical measurements were taken for 2115 persons aged <18 years, 1058 boys and 1057 girls. Urine samples were tested for markers of renal damage and blood samples analyzed to measure creatinine for estimating glomerular filtration rate (Schwartz formula). Median glomerular filtration rate was compared with reference values for age groups 2–12 and 13–17 years; mean glomerular filtration rate trends were assessed for age groups 2–5, 6–12 and 13–17 years. Positive test results were confirmed after three months.
RESULTS Prevalence of urinary markers of renal damage was 4%, 4.3% in girls and 3.8% in boys. Microalbuminura (albumin:creatinine ratio 30–300 mg/g) was detected in both sexes and all age groups in all three regions, with prevalences of 2.6%–3.8% in boys and 3.3%–3.8% in girls. Macroalbuminuria (albumin:creatinine ratio >300 mg/g) was detected only in girls in Las Brisas, 2.3%. Glomerular hyperfiltration (compared to international norms) was found in all age–sex groups in all three regions. Prevalence of chronic kidney disease was 3.9%—4.1% in girls and 3.6% in boys. The prevalence of chronic renal failure was 0.1%.
CONCLUSIONS High prevalence of chronic kidney disease in children and adolescents calls attention to the need for primary prevention from very early ages. This finding in children in areas where chronic kidney disease of uncertain etiology is common in adults is consistent with a contribution of environmental toxins to the epidemic observed in these areas.
KEYWORDS Chronic kidney disease, chronic renal failure, chronic tubulointerstitial nephropathy, interstitial nephritis, glomerular hyperfiltration, child health, adolescent health, environmental health, El Salvador
The following error has been corrected in all online versions of this article.
Page 19, Table 4. The first two rows of data were misaligned by column. The corrected table is:
|
Variable (n) |
|
CKD status |
|||||
|
No CKD |
Stage 1 |
Stage 2 |
Stages 3–5 |
Total |
|||
| Total (1623) |
n
|
1560
|
56
|
5
|
1(3a) + 1(5)
|
63
|
|
|
%
|
96.1
|
3.5
|
0.3
|
0.1
|
3.9
|
||
|
95% CI
|
95.2–97.1
|
2.6–4.3
|
0.0–0.6
|
0.0–0.3
|
2.9–4.8
|
||
| Age | 2–5 years (312) |
n
|
296
|
14
|
2
|
0
|
16
|
|
%
|
94.9
|
4.5
|
0.6
|
|
5.1
|
||
|
95% CI
|
92.4–97.3
|
2.2–6.8
|
0.0–1.5
|
2.7–7.6
|
|||
| 6–12 years (756) |
n
|
728
|
26
|
1
|
1(5)
|
28
|
|
|
%
|
96.3
|
3.4
|
0.1
|
0.1
|
3.7
|
||
|
95% CI
|
94.9–97.6
|
2.1–4.7
|
0.0–0.4
|
0.0–0.4
|
2.4–5.1
|
||
| 13–17 years (555) |
n
|
536
|
16
|
2
|
1(3a)
|
19
|
|
|
%
|
96.6
|
2.9
|
0.4
|
0.2
|
3.4
|
||
|
95% CI
|
95.1–98.1
|
1.5–4.3
|
0.0–0.9
|
0.0–0.5
|
1.9–4.9
|
||
| Sex | Male (800) |
n
|
771
|
23
|
5
|
1(3a)
|
29
|
|
%
|
96.4
|
2.9
|
0.6
|
0.1
|
3.6
|
||
|
95% CI
|
95.1–97.7
|
1.7–4.0
|
0.1–1.2
|
0.0–0.4
|
2.3–4.9
|
||
| Female (823) |
n
|
789
|
33
|
0
|
1(5)
|
34
|
|
|
%
|
95.9
|
4.0
|
|
0.1
|
4.1
|
||
|
95% CI
|
94.5–97.2
|
2.7–5.4
|
0.0–0.4
|
2.8–5.5
|
|||
| Region | Bajo Lempa (866) |
n
|
831
|
31
|
4
|
0
|
35
|
|
%
|
96.0
|
3.6
|
0.5
|
|
4.0
|
||
|
95% CI
|
94.6–97.3
|
2.3–4.8
|
0.0–0.9
|
2.7–5.4
|
|||
| Guayapa Abajo (412) |
n
|
399
|
10
|
1
|
1(3a) + 1(5)
|
13
|
|
|
%
|
96.8
|
2.4
|
0.2
|
0.5
|
3.2
|
||
|
95% CI
|
95.2–98.5
|
0.9–3.9
|
0.0–0.7
|
0.0–1.2
|
1.5–4.8
|
||
| Las Brisas (345) |
n
|
330
|
15
|
0
|
0
|
15
|
|
|
%
|
95.7
|
4.3
|
|
|
4.3
|
||
|
95% CI
|
93.5–97.8
|
2.2–6.5
|
2.2–6.5
|
||||
INTRODUCCIÓN Hace más de una década se ha reportado una enfermedad renal crónica de causa desconocida en las comunidades agrícolas salvadoreñas la cual no está asociada a diabetes mellitus, hipertensión arterial ni a ninguna de las enfermedades tradicionales que con más frecuencia la causan.
OBJETIVO Caracterizar histopatológicamente la enfermedad renal crónica de causa desconocida en pacientes de comunidades agrícolas salvadoreñas, describir la asociación del daño renal con cada estadio de la enfermedad y evaluar la asociación entre las alteraciones histopatológicas y las variables sociodemográficas.
MÈTODOS Se estudiaron 46 pacientes de ambos sexos con una edad >18 años. Después de haber sido evaluados desde el punto de vista clínico, analítico e imagenológico, se les realizó biopsia renal, las que se clasificaron teniendo en cuenta la fibrosis intersticial, la atrofia tubular, el infiltrado inflamatorio intersticial, la esclerosis, el aumento de tamaño glomerular, y las lesiones vasculares extraglomerulares, según la clasificación de Banff 97, que se emplea para el rechazo del injerto renal. Para ello se realizaron las coloraciones especiales: ácido peryódico de Schiff, tricrómica de Masson, plata metenamina y se hicieron técnicas de inmunofluorescencia para evaluar el depósito de IgA, IgG, IgM, C3, C1q, fibrina, cadenas ligeras kappa y lambda
RESULTADOS El hallazgo fundamental fue la fibrosis intersticial y la atrofia tubular con o sin infiltrado inflamatorio de células mononucleares. Se observó además esclerosis global, aumento de tamaño glomerular, colapso del ovillo en algunos glomérulos, lesiones de los vasos sanguíneos extraglomerulares como la proliferación de la capa íntima y el engrosamiento y la vacuolización de la capa media. La fibrosis intersticial y la glomeruloesclerosis se asociaron con el sexo masculino. Los trabajadores de la caña de azúcar mostraron más fibrosis intersticial y atrofia tubular y menos glomerulomegalia que el resto de los grupos.
CONCLUSIÓN El patrón morfológico evidente encontrado en todas las biopsias fue el de una nefropatía tubulointersticial crónica con daño glomerular y vascular secundario, en diferentes estadios de evolución de la enfermedad renal crónica, independientemente de la edad, el sexo, el lugar de residencia y la ocupación.
PALABRAS CLAVE Enfermedad renal crónica, nefropatía tubulointersticial crónica, nefritis tubulointersticial, glomeruloesclerosis, histopatología, El Salvador
INTRODUCCIÓN En El Salvador, la enfermedad renal crónica es un serio y creciente problema de salud pública. La insuficiencia renal crónica fue la primera causa de muerte hospitalaria en los hombres y la quinta en las mujeres en 2011.
OBJETIVO Determinar la prevalencia de los factores de riesgo de la ERC (tradicionales y no tradicionales) y los marcadores de daño renal en la población adulta de áreas rurales específicas en El Salvador; medir la función renal y su distribución en la población e identificar los factores de riesgo asociados en los pacientes detectados con ERC.
MÉTODOS Se realizó un estudio epidemiológico transversal y analítico basado en la pesquisa activa de enfermedad renal crónica y factores de riesgo en personas de edades >18 años durante 2009- 2011. Se recogieron los datos epidemiológicos y clínicos a través de la historia clínica personal, así como los análisis de orina para los marcadores de daño renal y vascular, las determinaciones de creatinina sérica y glucosa, y la estimación de la tasa de filtración glomerular. Se confirmaron los casos de enfermedad renal crónica a los tres meses. Se utilizó la regresión logística múltiple para el análisis estadístico.
RESULTADOS La prevalencia de enfermedad renal crónica fue 18% (23.9% para los hombres y 13.9% para las mujeres) en 2 388 personas: 976 hombres y 1 412 mujeres de 1 306 familias estudiadas. Predominó la enfermedad renal crónica sin diabetes, ni hipertensión arterial, ni proteinuria >1 g/L (51.9%). La prevalencia de insuficiencia renal crónica fue 11% (17.1% en los hombres y 6.8% en las mujeres). La prevalencia de marcadores de daño renal fue 12.5% (mayor en los hombres): microalbuminuria, 6.9%; proteinuria (0.3 g/L), 1.7%; proteinuria (1g/L), 0.6%; proteinuria (2 g/L), 0.4%; y hematuria, 1.5%. La prevalencia de factores de riesgo de la enfermedad renal crónica fue: diabetes mellitus 9%; hipertensión, 20.9%; la historia familiar de enfermedad renal crónica, 16.5%; la historia familiar de diabetes mellitus, 18.5%; la historia familiar de hipertensión, 30.6%; la obesidad, 21%; la obesidad central, 24.9%; el consumo de AINEs, 84.2%; la proporción de fumadores, 9.9%; el consumo de alcohol, 15%; la ocupación en la agricultura, 31.2%; y el contacto con agroquímicos, 46.7%. La enfermedad renal crónica se asoció significativamente con el sexo masculino, las edades más avanzadas, la hipertensión, la ocupación en la agricultura, la historia familiar de enfermedad renal crónica y el contacto con el agroquímico metil paratión.
CONCLUSIONES Los resultados de este estudio apoyan las sugerencias propuestas por otras investigaciones con respecto a que enfrentamos una nueva forma de enfermedad renal que podría denominarse nefropatía agrícola.
PALABRAS CLAVE Insuficiencia renal crónica, enfermedad renal crónica no diabética, nefrotoxicidad, nefropatía tubulointersticial crónica, El Salvador.
INTRODUCTION For at least a decade, a chronic kidney disease unassociated with diabetes mellitus, hypertension or any of the more common traditional causes, has been reported in Salvadoran agricultural communities.
OBJECTIVE Characterize histopathology of chronic kidney disease of unknown etiology in patients from Salvadoran agricultural communities, describe renal damage associated with each disease stage, and assess associations between histopathological alterations and sociodemographic variables.
METHODS The study involved 46 patients of both sexes, aged =18 years. After clinical, laboratory and imaging examinations, kidney biopsies were performed and renal tissue assessed for interstitial fibrosis, tubular atrophy, interstitial inflammatory infiltration, sclerosis, increase in glomerular size and extraglomerular vascular lesions (according to the Banff 97 classification used for kidney transplant rejection). Special staining was done: Schiff periodic acid, Masson trichrome and methenamine silver. Immunofluorescence techniques were used to evaluate IgA, IgG, IgM, complement C1q and C3, fibrin, and kappa and lambda light chain deposits.
RESULTS The main findings were interstitial fibrosis and tubular atrophy with or without inflammatory monocyte infiltration. In addition, generalized sclerosis, increased glomerular size, collapse of some glomerular tufts, and lesions of extraglomerular blood vessels (such as intimal proliferation and thickening and vacuolization of the tunica media) were observed. Interstitial fibrosis and glomerulosclerosis were associated with male sex. Sugarcane workers showed more interstitial fibrosis and tubular atrophy and less glomerulomegaly than other occupational groups.
CONCLUSION The morphological pattern in all biopsies was one of chronic tubulointerstitial nephropathy with secondary glomerular and vascular damage, in different stages of evolution of chronic kidney disease, independent of age, sex or occupation.
KEYWORDS Chronic kidney disease, chronic tubulointerstitial nephropathy, tubulointerstitial nephritis, glomerulosclerosis, histopathology, El Salvador
INTRODUCTION In El Salvador, chronic kidney disease is a serious and growing public health problem. Chronic renal failure was the first cause of hospital deaths in men and the fifth in women in 2011.
OBJECTIVE Determine prevalence of CKD, CKD risk factors (traditional and nontraditional) and renal damage markers in the adult population of specific rural areas in El Salvador; measure population distribution of renal function; and identify associated risk factors in CKD patients detected.
METHODS A cross-sectional analytical epidemiological study was conducted based on active screening for chronic kidney disease and risk factors in persons aged =18 years during 2009–2011. Epidemiological and clinical data were gathered through personal history, as well as urinalysis for renal and vascular damage markers, determinations of serum creatinine and glucose, and estimation of glomerular filtration rates. Chronic kidney disease cases were confirmed at three months. Multiple logistical regression was used for statistical analysis.
RESULTS Prevalence of chronic kidney disease was 18% (23.9% for men and 13.9% for women) in 2388 persons: 976 men and 1412 women from 1306 families studied. Chronic kidney disease with neither diabetes nor hypertension nor proteinuria =1 g/L (51.9%) predominated. Prevalence of chronic renal failure was 11% (17.1% in men and 6.8% in women). Prevalence of renal damage markers was 12.5% (higher in men): microalbuminuria, 6.9%; proteinuria (0.3 g/L), 1.7%; proteinuria (1g/L), 0.6%; proteinuria (2 g/L), 0.4 %; and hematuria, 1.5%. Prevalence of chronic kidney disease risk factors was: diabetes mellitus, 9%; hypertension, 20.9%; family history of chronic kidney disease, 16.5%; family history of diabetes mellitus, 18.5%; family history of hypertension, 30.6%; obesity, 21%; central obesity, 24.9%; NSAID use, 84.2%; smoking, 9.9%; alcohol use, 15%; agricultural occupation, 31.2%; and contact with agrochemicals, 46.7%. Chronic kidney disease was significantly associated with male sex, older age, hypertension, agricultural occupation, family history of chronic kidney disease and contact with the agrochemical methyl parathion.
CONCLUSIONS The results of this study support suggestions from other research that we are facing a new form of kidney disease that could be called agricultural nephropathy.
KEYWORDS Chronic renal failure, nondiabetic chronic kidney disease, nephrotoxicity, chronic tubulointerstitial nephropathy, El Salvador
Errata:
The following errata have been corrected in all online versions of this article.
Page 25, Table 1, units of measurement for albuminuria are mg albumin per g creatinine.
Page 26, fi rst complete paragraph, the last line should read, “Most CKD patients (51.9%) had no DM, HT or proteinuria.”
In El Salvador, end-stage renal disease is the leading cause of hospital deaths in adults, the second cause of death in men and the fifth leading cause of death in adults of both sexes in the general population.
