Authors :
Presenting Author: Mingyu Li, MD – Augusta University
Luis Rueda Carrillo, MD – Augusta University; Fernando Vale Diaz, MD – Augusta University; Manan Shah, MD – Augusta University; Klepper Alfredo Garcia, MD – Augusta University; Debra Moore-hill, MD – Augusta University; Nilufer Yalcin, MD – Augusta University
Rationale:
Antibodies against Glutamic acid decarboxylase 65 (GAD65) are associated with variable neurologic syndromes, including stiff-person syndrome, cerebellar ataxia, and autoimmune encephalitis (AE). In this case, we present a patient with super-refractory status epilepticus (SRSE) secondary to anti-GAD65 encephalitis with poor response to multiple antiseizure drugs (ASDs) including pentobarbital, who required a vagus nerve stimulator (VNS) to control seizures.
Methods:
A 38-year-old female was transferred to our hospital for new-onset refractory status epilepticus (NORSE). EEG reported subclinical seizures originated from the right temporal and left frontal lobes. Brain MRI showed hyperintensity on T2 FLAIR in the bilateral frontal and temporal lobes.
Results:
The patient was in SRSE and treated with multiple ASDs
, including phenytoin, levetiracetam (LEV), valproic acid, lacosamide (LCM), topiramate (TPM), perampanel (PER), clobazam (CBZ), midazolam, propofol, pentobarbital, and phenobarbital (PB). The cerebrospinal fluid (CSF) tests did not show an inflammatory response. However, IVIG and steroids were started given the high concern of autoimmune encephalitis. Anti-GAD65 antibody came back to be elevated (4.67nmol/L) eventually. She then received plasma exchange and rituximab. Repeated CSF tests showed a decrease in anti-GAD65 antibodies (1.63 nmol/L). Follow-up MRI showed significant improvement. Despite all the interventions, she was still going back to status epilepticus intermittently and requiring multiple inductions of phenobarbital coma. Therefore, a VNS was implanted on the hospital day 35. A rapid titration protocol was initiated with the increase of normal output to 2 mA and duty cycle to 51% in four days. ASDs were weaned after output reached 1.5 mA. She experienced no seizure or subclinical seizure since hospital day 33 of 55. Her final ASD regimen was PB, LCM, LEV, TPM, PER, and CBZ. She has been seizure-free since the discharge, and she is close to her baseline condition with only mild memory impairment currently.
Conclusions:
Previous literature on VNS in the treatment of refractory status epilepticus (RSE) secondary to AE is limited. Our case represents the first report of VNS being used to treat SRSE in anti-GAD65 encephalitis. VNS implantation has been shown to terminate RSE/SRSE in 74% of acute cases in a systematic review. In our case, pentobarbital coma was unsuccessful in control of seizures. However, with additional rapid VNS titration, pentobarbital and other ASDs were weaned without causing clinical or subclinical seizures. Rapid VNS titration has also been reported effective in several cases of AE-related RSE. Research has demonstrated that rapid titration of VNS leads to a significantly faster response onset and a comparable side-effect profile when compared to slower titration schedules. In conclusion, we reported a patient benefit from rapid titration of VNS in treating anti-GAD65 encephalitis with poor response to multiple ASDs. The available data is heterogeneous, and further investigations are warranted to determine the optimal timing for initiating VNS treatment and appropriate titration protocols.
Funding:
The authors have no funding to disclose.