Serum electrolyte and metabolic changes during conditioning of autologous hematopoietic stem cell transplantation in patients with autoimmune diseases: A prospective study in a single institution.

Background: A hematopoietic stem cell transplant (HSCT) includes a conditioning regimen which may cause unwanted metabolic changes. Objective: Analyze the changes in electrolytes, glucose, urea and glomerular filtration rate in patients with MS who underwent an autologous HSCT employing the “Mexican method”. Methods: Serum and urinary electrolytes, blood glucose, creatinine, uric acid and estimated glomerular filtration rate (eGFR) were prospectively assessed on days -11, - 9, and 0 in a group of 75 patients with multiple sclerosis (MS) receiving an autologous HSCT employing the “Mexican Method”, which includes high doses of both cyclophosphamide (Cy, 200 mg/Kg) and rituximab (1000 mg). Results: The median age of the patients was 46 years, with a range of 20 to 65. Baseline data were defined at day -11 of the HSCT. There were significant changes in serum and urinary electrolytes, which diminished substantially after the delivery of high-dose Cy. 12 patients (16%) developed hyponatremia and two had hyponatremiainduced seizures which resulted in hospital admissions. A comparison of baseline blood metabolites with those obtained after the full Cy dosage (day 0), revealed a significant increase in blood glucose and uric acid with an associated decrease in serum calcium, sodium, and potassium. The salient findings were drug-induced hyponatremia and hyperglycemia. Conclusion: Significant changes in serum electrolytes, blood glucose, creatinine, uric acid and estimated glomerular filtration rate (eGFR) were observed in patients given autologous HSCT for MS, employing high-dose Cy. Some of these changes may have clinical consequences, mainly those derived from iatrogenic hyponatremia. No evidence of damage to renal function was observed at day 0.