Supplementary Material for: Management of severe hypercalcemia with continuous venovenous hemodialysis and regional citrate anticoagulation: a case report

Severe hypercalcemia is a potentially life-threatening condition that often requires urgent medical intervention, especially when refractory to conventional treatments. Continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA) is a therapeutic option, although data on its use in hypercalcemia is limited. We report the case of a 78-year-old woman who presented with severe hypercalcemia (4.89 mmol/l, corrected for albumin), ECG-changes, muscle weakness and acute kidney injury. She was unresponsive to standard treatments including crystalloids, diuretics, calcitonin and bisphosphonates. Imaging revealed multiple lytic bone lesions and a mediastinal mass, with biopsy confirming diffuse large B-cell lymphoma. Continuous venovenous hemodialysis (CVVHD) with RCA was initiated after other therapies failed to lower calcium levels and symptoms persisted. Initial challenges with anticoagulation were resolved by increasing the citrate dose, along with an adapted calcium supplementation rate, leading to successful normalization of calcium levels within 30 hours. Careful monitoring of post-filter calcium, systemic calcium and total-to-ionized calcium ratios, along with rapid dose adjustments, prevented complications such as hypocalcemia, citrate accumulation and rebound hypercalcemia. The patient’s calcium levels stabilized and she was transferred to a regular nursing ward to start oncological treatment. This case highlights the effectiveness of CVVHD with RCA in managing refractory hypercalcemia and underscores the importance of vigilant monitoring and individualized adjustments to prevent treatment related complications.