Heat Stress Nephropathy: An Emerging Epidemic of Global Warming.

Climate change has led to global warming since the last century, which has adverse health consequences. Heat stress nephropathy (HSN) is such a disorder that is emerging as an epidemic because of heat exposure, dehydration, and shortage of drinking water. HSN has been suspected to occur in different parts of the world. Many cases of chronic kidney disease of unknown etiology (CKDu) such as Mesoamerican nephropathy and Sri Lankan nephropathy are now being considered as HSN. Influences of agrochemicals (e.g., pesticides), heavy metals (e.g., cadmium, lead, arsenic, and fluoride), and genetic polymorphism were suspected for causation of CKDu in those cases, but results were inconsistent in different studies from different locations. Drinking water with high silica and strontium was also found in a region with high CKDu in South India. Malnutrition and infections such as leptospirosis can also cause CKDu. It is not clear whether CKDu in different hot locations studied represents a single disease or a group of different disorders, but the common factors found are heat and related dehydration. However, combined effects may also be possible. Dehydration from heat stress increases toxin exposure of different organs because of higher blood and urine concentration, as chronically dehydrated patients may not excrete toxic substances effectively. Also, the wells and water reservoirs are more concentrated with toxic substances because of hot weather due to evaporation.