Slow recovery from severe inorganic arsenic poisoning despite treatment with DMSA (2.3-dimercaptosuccinic acid)

A 39-year-old woman was hospitalized for nausea, diarrhea, vomiting, and weakness of unknown etiology. Her condition progressively deteriorated and she developed multiple organ failure and tetraplegia. The diagnosis of inorganic arsenic poisoning was established by measurements of arsenic in urine and serum, showing 2,000 mu g/L (normal < 10 mu g/L) and 290 mu g/Kg (normal < 2 mu g/Kg), respectively. Hair arsenic was 57 mg/kg (normal < 0.2 mg/kg). Chelating therapy with 2.3-dimercaptosuccinic acid (DMSA) 600 mg three times daily was given for a period of 45 days with three abruption periods during a total of 13 days. The clinical manifestations of arsenic toxicosis disappeared very slowly and five years after the hospitalization she still suffers from peripheral neuropathy. Although the use of DMSA was associated with increased urinary elimination of arsenic and a decrease in blood arsenic concentrations, DMSA treatment probably had no significant effect on the total body clearance in our patient. The source of the poisoning was never detected, nor the motivation behind it. Criminal intent was suspected, but no verdict was given.