Acute Boric Acid Poisoning With Chronic Renal Failure Successfully Treated With Continuous Hemofiltration

We describe an 88-year-old female with chronic kidney disease (CKD) stage 3a (baseline serum creatinine, 1.1 mg/dL) who presented with vomiting and diarrhoea after accidentally ingesting 6 g of a boric acid solution intended for eye irrigation. On admission, her blood pressure was 95/49 mmHg, and physical examination revealed mild facial and chest erythema. As the ingested dose exceeded the toxic threshold and the patient exhibited potential for hemodynamic instability, continuous hemodiafiltration (CHDF) was initiated at 16 hours post-ingestion with the following parameters: blood flow rate, 100 mL/min; dialysate flow rate, 500 mL/h; and filtration rate, 500 mL/h. Mental status and skin condition improved, and CHDF was discontinued after 48 hours. By hospital day 45, the serum creatinine level returned to baseline, and chronic kidney function remained stable. Although the ingested dose was below the lethal range (15-20 g), impaired renal clearance likely prolonged systemic exposure, resulting in toxicity. This case suggests that early CHDF can be advantageous in patients with CKD experiencing boric acid poisoning, particularly when hemodynamic instability precludes intermittent hemodialysis, and can facilitate the prevention of renal function deterioration.