Diagnosis of Renal Tubular Acidosis and Bicarbonatemia Above Sea Level in Pediatric Patients in Mexico City

Abstract

Abstract Background Renal tubular acidosis (RTA) is most often misdiagnosed due to several factors. Altitude, which influences bicarbonate levels, is a variable that is hardly considered in diagnosing RTA, so it should be a factor to consider when diagnosing this pathology. Regarding of this, the present study established reference limits for HCO3- levels in healthy children without pathologies associated with alterations in the acid-base balance in Mexico City and the metropolitan area. Methods A total of 267 pediatric patients were included, within normal percentiles for their age, with adequate psychomotor development, normal glomerular filtration rate (GFR), and without any associated pathology of any alteration in the acid-base balance. Results Compared to older children, children younger than two years of age showed statistically higher levels of calcemia and cystatin C. On the other hand, this same group showed lower values of creatininemia, pCO2, and HCO3-. Bicarbonate levels in children under two years of age were 13.94 mEq/L and 14.9 mEq/L in those over that age. A correlation was identified between HCO3- levels and pCO2 (r = 0.68; p < 0.001). Conclusions In the study population, an effect of altitude on blood levels of pCO2 and HCO3- was observed.