Clinical and Pathological Characterization of Mesoamerican Nephropathy: A New Kidney Disease in Central America

Background: An endemic of chronic kidney disease (CKD) of unknown cause among rural inhabitants in Central America has been identified. Young and otherwise healthy men working in plantations are frequently affected. The name Mesoamerican nephropathy (MeN) has been suggested. Clinically, MeN presents with low-grade proteinuria and progressive kidney failure. The renal pathology of this disease has not yet been described. Study Design: Case series. Setting & Participants: 8 male patients with CKD of unknown cause and clinically suspected MeN were recruited from a nephrology unit in El Salvador. All recruited patients had been working on plantations. Kidney biopsies, blood, and urine samples were collected. Outcomes & Measurements: Renal morphology examined with light microscopy, immunofluorescence, and electron microscopy; clinical and biochemical characteristics. Results: A similar pattern was seen in all 8 biopsy specimens, with extensive glomerulosclerosis (29%-78%) and signs of chronic glomerular ischemia in combination with tubular atrophy and interstitial fibrosis, but only mild vascular lesions. Electron microscopy indicates podocytic injury. Biochemical workup showed reduced estimated glomerular filtration rate (27-79 mL/ min/ 1.73 m2 with the CKD Epidemiology Collaboration [CKDEPI] creatinine equation), low-grade albuminuria, and increased levels of tubular injury biomarkers. Hypokalemia was found in 6 of 8 patients. Limitations: Small number of patients from one country. Conclusions: This study is the first report of the biochemical and morphologic findings in patients with MeN. Our findings indicate that MeN constitutes a previously unrecognized kidney disease with damage to both glomerular and tubulointerstitial compartments. (C) 2013 by the National Kidney Foundation, Inc.