LAUSR

Thallium poisoning is rare but associated with considerable morbidity and mortality, with lethal doses reported between 8 and 12mg/kg [1]. We report a case of full recovery following treatment of an ingestion of thallium sulfate 1,500mg (21.4mg/kg). The United Kingdom National Poisons Information Service was consulted regarding a 34-year-old man with a background of Asperger’s syndrome presenting four days after ingesting thallium sulfate 1,500 mg purchased online with the intention of achieving euphoria. He complained of pain and numbness in his feet which made it difficult to walk and sleep. The patient had experimented on five previous occasions with much lower doses of thallium and selfadministered riboflavin believing this would offset symptoms of toxicity. The patient was transferred the same day to the West Midlands Poisons Unit. His admission whole blood thallium concentration was 1,788mg/L (8,721 nmol/L). We started chelation with Prussian Blue 10 g twice daily together with amitriptyline for neuropathic pain. We did not arrange extracorporeal treatment for the patient due to his delayed presentation. The patient reported that his symptoms of neuropathic pain started to improve on day 2 of treatment. He was able to stand and walk on day 4. On day 3 he developed tachycardia (150 beats/min). A 12lead ECG revealed a prolonged QT interval (QT/HR pair of 416/99). An echocardiogram confirmed an incidental finding of Ebstein’s anomaly. Electromyography and nerve conduction studies demonstrated demyelinating distal motor neuropathy affecting the lower limbs and reduced volitional effort of the left extensor digitorum brevis muscles. The patient developed constipation by day 8, with excessive colonic faecal loading confirmed on CT abdomen. He received polyethylene glycol laxative. His serum sodium concentration fell to 119 mmol/L on day 10. We stopped the laxative on day 11, and his serum sodium concentration returned to 134 mmol/L on day 16. Other complications included hypertension (170/101mmHg) on admission treated with perindopril, stomatitis (day 10), and alopecia (day 15). On day 28 his whole blood thallium concentration was 44.28 mg/L (216 nmol/L) and due to problems sourcing Prussian blue, we started multiple-dose activated charcoal 50 g four times a day for 24 h followed by 50 g twice daily. The patient made an uneventful recovery and was discharged on day 58 with a blood thallium concentration of 5 mg/L (27 nmol/L). A total of 57 daily whole blood measurements of thallium concentrations were obtained (Figure 1). The calculated mean whole blood apparent half-life of thallium was 110 h and 239 h while receiving Prussian blue and multiple-dose activated charcoal treatment respectively. Three months post-exposure he reported complete recovery.