Toxic leukoencephalopathy due to transdermal fentanyl overdose.

Children with altered mental status who present to the emergency department have a broad differential diagnosis. We report a case of a 19-month-old girl who presented in coma and who was later found to have a fentanyl patch adhered to her back. She was found to have changes on brain magnetic resonance imaging consistent with a toxic spongiform leukoencephalopathy but had a good neurologic outcome. This case report illustrates the importance of a thorough physical examination in children in coma and a rarely reported magnetic resonance imaging finding that has been seen in opioid intoxication and is usually associated with severe morbidity and mortality.