Serious reactions can occur with inadvertent [[intrathecal]] injection (e.g. for [[myelography]], [[cisternography]], [[ventriculography]]...) of [[iodinated contrast media]] that are not specifically indicated for intrathecal use (including ionic contrast agents as well as some non-ionic agents (e.g. Optiray®, Reno-60...)). This can cause uncontrollable seizures, [[intracerebral hemorrhage]], cerebral edema, coma, paralysis, arachnoiditis, myoclonus (tonic-clonic muscle spasms), rhabdomyolysis with subsequent renal failure, hyperthermia, and respiratory compromise, with a significant fatality rate.