Prolonged high-dose isoflurane for refractory status epilepticus: is it safe?

Isoflurane is an alternative treatment for refractory status epilepticus. Little is known regarding human toxicities caused by isoflurane. We present 2 patients with prolonged refractory status epilepticus treated with high concentrations of isoflurane who developed signal abnormalities on magnetic resonance imaging. Patient 1 was treated with isoflurane for 85 days with 1975.2% concentration-hours. Patient 2 was treated with isoflurane for 34 days with 1382.4% concentration-hours. Serial brain magnetic resonance images in both showed progressive T2 signal hyperintensity involving thalamus and cerebellum, which improved after discontinuation of isoflurane. These cases suggest that isoflurane may be neurotoxic when used in high doses for long time periods.