Neurotoxic manifestations of high-dose intrathecal gadolinium administration for CT myelogram

Use of intrathecal gadolinium for contrast-enhanced myelography and cisternography remains off-label and is currently not FDA-approved. We report a 70-year-old male who underwent CT myelogram utilizing off-label high-dose intrathecal gadolinium who developed altered mental status and bilateral hearing loss. Workup ruled out meningitis (infectious and aseptic), infectious encephalopathy, encephalitis, and hypothyroidism. MRI of the brain and lumbar spine without contrast displayed fluid collection in L4-5 interspace and diffuse cerebrospinal fluid (CSF) hyperdensity consistent with intrathecal gadolinium. The patient eventually improved with high-dose IV dexamethasone and supportive care and resolution of diffuse CSF hyperdensity was observed on repeat MRI. There are limited data demonstrating the safety of low-dose intrathecal gadolinium due to which usage remains off-label. Our case highlights the need for caution when using substances for off-label indications and reinforces the usage of less invasive and noninvasive diagnostic modalities when possible.