Extracorporeal regional complexing haemodialysis treatment of acute inorganic mercury intoxication

A 70-year-old white female presented approximately 24 h after ingesting three 475 mg tablets (1.425 g) of mercuric chloride in a suicide attempt. Acute renal failure necessitated the initiation of haemodialysis approximately 4 d after the ingestion. Treatment with BAL (2,3-dimercaptopropanol) resulted in only small increases in mercury output into dialysate. A new procedure involving the extracorporeal infusion of the chelating agent dimercaptosuccinic acid (DMSA) into the arterial blood line during haemodialysis was initiated. This procedure of Extracorporeal Regional Complexing Haemodialysis (ERCH) had been effective in increasing methylmercury removal in patients poisoned by contaminated grain. The first DMSA-ERCH procedure was performed 6 d after poisoning. There was a dramatic increase in mercury output into the dialysate. During three treatment sessions of 80 min each, 1189 micrograms of mercury were removed from the patient. The dialysed mercury represented the only mercury output since the patient was anuric and not producing faeces. DMSA-ERCH appears to be much more effective than BAL and haemodialysis in the treatment of acute inorganic mercury poisoning. The long interval between poisoning and initiation of treatment probably contributed to the patients ultimate demise, 28 d after poisoning. Efficacy of the DMSA-ERCH procedure for inorganic mercury poisoning is likely to be improved as the interval between exposure and treatment is reduced.