Rapid calcium loss may cause arrhythmia in hemofiltration with regional citrate anticoagulation: a case report

BACKGROUND: Renal replacement therapy (RRT) with regional citrate anticoagulation (RCA) is an important therapeutic approach for refractory hypercalcemia complicated with renal failure. However, RCA has the potential to induce arrhythmia caused by rapid calcium loss. We report a case of arrhythmia associated with rapid calcium loss during RCA-RRT. CASE PRESENTATION: A 51-year-old man with hypercalcemia, primary hyperparathyroidism, and acute kidney injury was treated by predilutional-RCA-hemofiltration at a rate of 4.3 L/h. The effect of lowering serum calcium was unsatisfactory despite reducing calcium substitution gradually from 5.3 to 2.2 mmol/h in the first 8-h session of RCA-hemofiltration. New-onset sinus tachycardia with a prolonged QT interval occurred when calcium substitution was infused at rate of 1.1 mmol/h after 15 min of starting the second RCA-hemofiltration session (estimated net calcium loss was 7.54 mmol/h). When the calcium substitution was increased to usual rate of 5.6 mmol/h, the arrhythmia disappeared after 2 min. Arrhythmia did not recur when the calcium substitution rate was 2.2 mmol/h during the third session (estimated net calcium loss was 6.44 mmol/L). After the third RCA-hemofiltration session, the patient underwent parathyroidectomy and serum calcium returned to normal. CONCLUSIONS: This case indicated that rapid calcium loss may cause arrhythmia in RCA-hemofiltration, and the rate of net calcium loss should be limited below a threshold value to prevent similar adverse effect during RCA-RRT.