Documenting Disease in the Undocumented Migrants: A Case Report of Chronic Kidney Disease of Unknown Origin in a Central American Migrant.

Mesoamerican nephropathy (MeN) or chronic kidney disease of unknown origin (CKDu) is a rising epidemic in hotspot regions of El Salvador and Nicaragua. MeN is often defined in patients who exhibit a clinically reduced estimated glomerular filtration rate (eGFR) but lack a defining etiology such as diabetes or hypertension. A multitude of risk factors for MeN have been identified, including physical labor demands in a hot climate, exposure to pesticides, and poverty. Additionally, social determinants such as limited access to health care and the cost of disease burden often contribute to overall poor prognosis and progression of the disease. We present a case of a 39-year-old male with a past medical history of gout who presented to the emergency room with abdominal pain radiating to the flanks and bilateral great toe pain. Social history revealed the patient recently moved to the United States from Central America (Nicaragua), was unemployed, and did not have health insurance. Prior to the presentation, the patient admitted he was not compliant with his gout medications for about one month. The symptoms first began two to three weeks prior to his evaluation in the emergency department; the patient also endorsed decreased oral intake during this time period. He was noted to have abnormally elevated creatinine along with elevated uric acid levels, low potassium and magnesium levels. Abdominal imaging revealed nephrolithiasis without hydronephrosis. Initial differentials included acute kidney injury (AKI) from dehydration, non-steroidal anti-inflammatory drug (NSAID) induced nephropathy, and uric acid nephropathy. This patient was eventually found to have a biopsy-proven findings of CKDu. We want to highlight the need to keep MeN high in the differential with a low threshold to perform a renal biopsy for accurate diagnosis and management of the disease, especially in the rising immigrant population in the United States.