P488: Acute brachial plexus neuropathy with involvement of cranial nerves IX, X, XI and XII: diagnostic value of MRI

Abstract

During first three days, he gradually got comatose. EEG showed generalized continuous slow waves. We started potent antibiotics and added antiepileptic drugs in the suspicion of non-convulsive status epilepticus (NCSE). Full work up to find causative etiology including viruses, bacteria, rickettsia, fungus, auto-antibodies was done, but none of them was positive. After 10 days, he remained comatose and quadriplegic despite full dose of antimicrobial treatment. 2 weeks after admission, intravenous immunoglobulin was given in 0.4g/kg for 5 days, but there was no neurologic improvement. Follow up EEG showed no change. Case 2: A 16 year old previously healthy man suffered from drowsiness preceded by fever and headache from 5 days ago. CSF analysis showed pleocytosis with predominate lymphocytes. Initial MRI image was normal. We started acyclovir 10mg/kg three times a day. After two days, his gradually got comatose and quadriparetic. EEG showed generalized continuous slow waves. We added antibiotics and antiepileptic drugs, and checked up for possible etiologies, but nothing was positive. Follow up MRI image showed T2 high signal in bilateral thalamus, basal ganglia, and brainstem. At the fifth day of admission, we started intravenous steroid 1g for 5 days and intravenous immunoglobulin 0.4g/kg for 5 days, successively. After administration of steroid, the patient got alert and oriented, and general weakness gradually diminished. Follow up EEG also returned to normal. Discussion: High proportion of etiology-unidentified encephalitis is due to incomplete study or late seroconversion. We suggest that most of encephalitis classified as by unknown cause are undiagnosed cases of major etiologies, such as HSV encephalitis, or ADEM. So we should consider inducing immune-modulation simultaneously with the antimicrobial therapy, if neurologic status deteriorates despite improvement of CSF profile. And the response can be followed up by EEG. P488 Acute brachial plexus neuropathy with involvement of cranial nerves IX, X, XI and XII: diagnostic value of MRI