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Am J Kidney Dis. 2016 Jan;67(1):20-30. doi: 10.1053/j.ajkd.2015.08.021. Epub 2015 Oct 9.

Heat Stress Nephropathy From Exercise-Induced Uric Acid Crystalluria: A Perspective on Mesoamerican Nephropathy.

Author information

1
Division of Kidney Diseases and Hypertension, University of Colorado, Denver, CO.
2
Scientific Board, Department of Investigation, Hospital Nacional Rosales, San Salvador, El Salvador.
3
Occupational and Environmental Medicine, Sahlgrenska University Hospital and University of Gothenburg, Gothenburg, Sweden.
4
Unit of Occupational Medicine, Institute of Environmental Medicine (IMM), Karolinska Institutet, Stockholm, Sweden.
5
Research Center on Health, Work and Environment (CISTA), National Autonomous University of Nicaragua at León (UNAN-León), León, Nicaragua.
6
University of Balearic Islands, Palma de Mallorca, Spain.
7
Agencia para el Desarrollo y la Salud Agropecuaria, San Salvador, El Salvador.
8
Research Center on Health, Work and Environment (CISTA), National Autonomous University of Nicaragua at León (UNAN-León), León, Nicaragua; Department of Non-communicable Disease Epidemiology of London School of Hygiene and Tropical Medicine, London, United Kingdom.
9
La Isla Foundation, San Salvador, El Salvador.
10
Laboratory of Renal Physiopathology and Nephrology Department, INC Ignacio Chavez, Mexico City, Mexico.
11
Division of Kidney Diseases and Hypertension, University of Colorado, Denver, CO; Division of Nephrology, Eastern Colorado Health Care System, Department of Veteran Affairs, Denver, CO. Electronic address: richard.johnson@ucdenver.edu.

Abstract

Mesoamerican nephropathy (MeN), an epidemic in Central America, is a chronic kidney disease of unknown cause. In this article, we argue that MeN may be a uric acid disorder. Individuals at risk for developing the disease are primarily male workers exposed to heat stress and physical exertion that predisposes to recurrent water and volume depletion, often accompanied by urinary concentration and acidification. Uric acid is generated during heat stress, in part consequent to nucleotide release from muscles. We hypothesize that working in the sugarcane fields may result in cyclic uricosuria in which uric acid concentrations exceed solubility, leading to the formation of dihydrate urate crystals and local injury. Consistent with this hypothesis, we present pilot data documenting the common presence of urate crystals in the urine of sugarcane workers from El Salvador. High end-of-workday urinary uric acid concentrations were common in a pilot study, particularly if urine pH was corrected to 7. Hyperuricemia may induce glomerular hypertension, whereas the increased urinary uric acid may directly injure renal tubules. Thus, MeN may result from exercise and heat stress associated with dehydration-induced hyperuricemia and uricosuria. Increased hydration with water and salt, urinary alkalinization, reduction in sugary beverage intake, and inhibitors of uric acid synthesis should be tested for disease prevention.

KEYWORDS:

Central America; Mesoamerican nephropathy (MeN); chronic kidney disease (CKD); dehydration; etiology; heat stress nephropathy; hyperuricemia; hypothesis; physical exertion; rhabdomyolysis; sugarcane workers; tubular injury; uric acid crystalluria; uric acid disorder; uricosuria; urinary acidification

PMID:
26455995
DOI:
10.1053/j.ajkd.2015.08.021
[Indexed for MEDLINE]

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