Chronic interstitial nephritis of nontraditional causes in Salvadoran agricultural communities.

In El Salvador, a form of chronic kidney disease (CKD) of nontraditional causes (CKDnt) affecting farmers is being reported. Its behavior has been epidemic and is responsible for tens of thousands of deaths. This article summarizes the results obtained from a series of studies conducted to identify the epidemiology and clinical behavior of this disease, proposing a case definition and an etiopathogenic hypothesis. Methods included a survey of CKD in agricultural communities studying 2,388 people ≥ 18 years and 1,755 < 18, a descriptive clinical study followed by histopathological assessment conducted in 46 possible cases of CKDnt ≥ 18 years, and a national survey to study the prevalence of CKD and associated risk factors in 4,817 participants ≥ 20 years followed by a nested case-control study. In the agricultural communities, the prevalence of CKD in adults was 18% (men: 23.9%, women: 13.9%), 26.8% in agricultural workers (non-agricultural 13.8%), CKDnt accounted for 51.9% of cases. CKD in the population < 18 years was 3.9% (mean estimated glomerular filtration rate > 160 mL/1.73m2). The national CKD prevalence was 12.6% (urban: 11.3%; rural: 14.4%; males: 17.8%, females 8.5%), and CKDnt was only 3.8%; with associations between CKD and exposure to agrochemicals. The clinical study revealed the presence of markers of kidney damage (A3 albuminuria: 80.4%; β2-microglobulin: 78.2%), urine electrolyte anomalies (100% hypermagnesuria, 45.7% hypernatriuria, 43.5% osmotic polyuria), abnormal osteotendinous reflexes (45.7%), sensorineural hearing loss (56.5%), and damage of the tibial arteries by Doppler imaging (66.7%). Biopsies revealed a chronic tubulointerstitial nephropathy. The etiopathogenesis of CKDnt is possibly multifactorial, including environmental contamination by agrochemicals, heat stress, and dehydration.