CKD of Unknown Origin in Central America: The Case for a Mesoamerican Nephropathy

Abstract

An epidemic of chronic kidney disease of unknown origin has emerged in the last decade in Central America and has been named Mesoamerican nephropathy. This form of chronic kidney disease is present primarily in young male agricultural workers from communities along the Pacific coast, especially workers in the sugarcane fields. In general, these men have a history of manual labor under very hot conditions in agricultural fields. Clinically, they usually present with normal or mildly elevated systemic blood pressure, asymptomatic yet progressive reduction in estimated glomerular filtration rate, low-grade non-nephrotic proteinuria, and often hyperuricemia and or hypokalemia. Diabetes is absent in this population. Kidney biopsies that have been performed show a chronic tubulointerstitial disease with associated secondary glomerulosclerosis and some signs of glomerular ischemia. The cause of the disease is unknown; this article discusses and analyzes some of the etiologic possibilities currently under consideration. It is relevant to highlight that recurrent dehydration is suggested in multiple studies, a condition that possibly could be exacerbated in some cases by other conditions, including the use of nonsteroidal anti-inflammatory agents. At present, Mesoamerican nephropathy is a medical enigma yet to be solved.

CKD of Uncertain Etiology

“…Subsequently, this disease pattern, which was similar to that of Balkan Endemic Nephropathy (9), was reported in other countries, including Nicaragua, Costa Rica, and Sri Lanka (6,(10)(11)(12), and its prevalence is now as high as 16% in some of these areas (13). In El Salvador, ESRD that is largely attributable to CKDu has become the leading cause of hospital deaths (8), and in Sri Lanka, nearly 4% of the national health care budget is now spent on treating CKDu (14,15).…”

“…In our review, only two studies from Sri Lanka and two studies from Central America reported a significant association between agrochemical use and CKDu. Agrochemical use was not reported in studies from other regions, suggesting the possibility of a distinct etiology for CKD in agricultural communities in CKDu-endemic regions (6,(11)(12)(13)(14). These findings may reflect variation in the regional exposures being studied as well as difficulties in defining and quantifying agrochemical exposure, but they also highlight the need for more conclusive epidemiologic studies examining causation, particularly in agricultural communities in CKDu-endemic regions.…”

“…CKD of uncertain etiology (CKDu) is a term that has been used to describe CKD that is not attributable to any traditional risk factor, such as diabetes, hypertension, or HIV. CKDu is being reported with increasing frequency across the globe, and in many parts of Central America, eastern Europe, and south Asia, it is being reported in epidemic proportions (4)(5)(6).…”

A study of chronic kidney disease patients with no known risk factors coming to tertiary care hospital

“…Studies from Central America have reported a new kidney disease Mesoamerican nephropathy which primarily affects agricultural communities especially in the sugarcane fields. 1,5,6 It was reported to present with mild proteinuria and asymptomatic progressive kidney failure. Kidney biopsies showed chronic tubulointerstitital disease with secondary glomerulosclerosis and some signs of glomerular ischemia.…”

“…The authors suggested recurrent dehydration related to manual labor under very hot conditions in agricultural fields, possibly exacerbated by NSAIDs or other toxins as a likely cause. 6 Studies from Sri Lanka and India have also reported outbreaks of CKD occurring among workers in the rice paddies. They reported that CKDu (CKD of unknown etiology) had a point prevalence ranging from 2-16% among those aged >18 years.…”