Status epilepticus from an illegally imported Chinese rodenticide: "tetramine".

INTRODUCTION: The following case report demonstrates the severe consequences of refractory convulsive status epilepticus from an unfamiliar imported toxin, tetramethylenedisulfotetramine (TETS), and the difficulties of identifying the offending agent. CASE REPORT: A previously healthy 15-month-old girl was found by her parents playing with a white rodenticide powder brought from China. Fifteen minutes later, the child developed generalized seizures and was brought to an Emergency Department (ED). Her initial fingerstick blood glucose was 108 mg/dL. In the ED, the child was intubated for status epilepticus. Despite aggressive therapy with lorazepam, phenobarbital, and pyridoxine, she had 4 h of intermittent generalized seizure activity. She was extubated on the third hospital day, but appeared to have absence seizures and cortical blindness. Continuous electroencephalogram monitoring, performed weeks later, revealed severe diffuse cerebral dysfunction with multiple epileptogenic foci. The child remains developmentally delayed and is on valproic acid therapy for seizure control. Translation of the Chinese package labeling did not clarify its contents. Tetramethylenedisulfotetramine was finally confirmed by gas chromatography-mass spectrometry (GC-MS) in this rodenticide product and then quantified against a TETS standard that was synthesized in our laboratory.
CONCLUSION: Tetramethylenedisulfotetramine is grouped with other "cage convulsants," such as picrotoxin, since they have a similar intercalating cyclical molecular structure and cause seizures through non-competitive gamma-aminobutyric acid (GABA) antagonism. The oral lethal dose 50% (LD50) in humans is estimated to be as low as 100 microg/kg. Our patient has severe diffuse cerebral dysfunction likely secondary to prolonged seizure activity after exposure to TETS.