CKDu or Chronic Kidney Disease of Unknown etiology/Uncertain cause is a type of chronic kidney disease that mainly affects marginalized agricultural communities in specific areas of the world where a large number of people develop an unexplained, deadly form of kidney disease (Figure 1/Distribution in the world).
Because the populations affected are some of the world’s poorest and are exposed to a high degree of occupational and environmental hazards, and because the disease is considered a ‘medical mystery,’ CKDu has received significant attention in scientific magazines and the media.
Currently, CKDu occurs chiefly in Sri Lanka and Central America, although additional hotspots are identified almost daily. In Central America, CKDu is also/predominantly referred to as Mesoamerican Nephropathy.
CKDu is a devastating and deadly phenomenon in affected regions:
Initial surveys conducted in Central America, demonstrate that up to 20-30% of adults in ‘endemic communities’ show a high prevalence of decreased kidney function of unknown origin, possibly of environmental or occupational origin.
In certain countries in Latin America, the issue has become a severe public health crisis. Hospitalizations for CKD in El Salvador increased by 50% between 2005 and 2012, making CKD the leading cause of hospitalization in the country. Nearly 1,500 of these hospitalized patients were under 19 years old (out of a total 40,000 hospitalized patients of all ages during the same period).
Most patients affected by CKDu are males between the ages of 20 and 60 who often live in rural or agricultural settings and may be exposed to extreme working conditions. Many experience a rapid loss of kidney function.
Figure 1. Proportion of men vs. women: Decline in eGFR
Regional kidney epidemics have occurred throughout the world in the past (Figure 2). Balkan endemic nephropathy is perhaps the most prominent historical example. After it was first described in the early 1940s, Balkan nephropathy was linked decades later to Aristolochia clematitis, a weed growing in wheat fields that infiltrated the flour mix consumed by farming families living along the Danube river.
 Cecilia Torres et al. (2019, October 9). Decreased Kidney Function of Unknown Cause in Nicaragua: A Community-Based Survey. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S027263860901587X
 (2019, October 9). Kidney disease of unknown causes in agricultural communities in Central America is declared a serious public health problem