Serial determination of caffeine and active metabolites in a case of severe caffeine poisoning causing recurrent cardiac arrest after hemodialysis: a case report

Caffeine is highly dialyzable, and cases of severe caffeine poisoning causing recurrent symptoms after hemodialysis (HD) and the serial evaluation of active metabolite and caffeine levels have rarely been reported. A previously healthy 17-year-old female with cardiac arrest due to ventricular fibrillation was transferred by ambulance to our emergency department. Laboratory tests revealed severe lactic acidosis and hypokalemia. As cardiac defibrillation was ineffective, veno-arterial extracorporeal membrane oxygenation was initiated after tracheal intubation. Eleven hours after admission, ingestion of highly caffeinated tablets (12.1 g of caffeine in total) was revealed, and HD was performed for 4 h, achieving hemodynamic stability. She developed recurrent cardiac arrest 26 h after admission. Return of spontaneous circulation was achieved with 1 mg of intravenous adrenaline, and continuous hemodiafiltration was performed, resulting in circulatory stability. Complications included abdominal compartment syndrome, right lower limb compartment syndrome, and hypoxic-ischemic encephalopathy. She was transferred to a rehabilitation facility on day 111. Serum concentrations of caffeine and its active metabolites were determined using liquid chromatography tandem mass spectrometry. Serum caffeine concentrations on admission and at the time of the second cardiac arrest were 233 µg/mL and 44 µg/mL, respectively, with serum concentrations of active metabolites (paraxanthine, theobromine, and theophylline) re-elevated at the time of the second cardiac arrest. It should be kept in mind that recurrence of toxic symptoms may occur due to delayed elevation of active metabolites, particularly in critically ill patients with severe complications. Delayed elevation of active caffeine metabolites may cause recurrent or delayed toxicity even after hemodialysis. In severe caffeine poisoning, sudden deterioration can occur after apparent stabilization, requiring careful monitoring following hemodialysis. Forensic evaluation of severe caffeine intoxication may require assessment of both caffeine and metabolite concentrations.