Marked improvement in febrile infection-related epilepsy syndrome after lidocaine plus MgSO4 treatment in a 12-year-old girl

Abstract

Purpose: This report sheds light on a successful treatment in febrile infection-related epilepsy syndrome (FIRES) with the combined use of lidocaine and MgSO4.

Methods: We report a 12-year-old previously healthy girl who experienced an upper respiratory infection with fever and headache for 2 days, then suddenly went into a coma followed by repetitive status epilepticus. All tests for CNS infection, metabolic and toxic diseases, and autoimmune encephalitis were negative. Hence, the diagnosis of FIRES was made. During 5 weeks of hospital treatment, various antiepileptic drugs were administered at different times without success. To achieve seizure control, we then attempted the use of lidocaine first, then followed by MgSO4.

Results: The SE was successfully controlled when lidocaine plus MgSO4 was introduced. At follow-up, almost no neurological sequelae remained.

Conclusion: This is the first report describing the combined use of lidocaine and MgSO4 with successful treatment outcomes. This experience has indicated that even FIRES can be controlled if treated promptly with certain agents. However, more studies are needed to explore the mechanisms and effects of lidocaine and MgSO4 in FIRES.

Keywords: FIRES; Febrile infection-related epilepsy syndrome; Lidocaine; MgSO4; Status epilepticus.

Fig. 1

(A) On Day 1 of admission, the patient was in a state of deep coma; electroencephalography (EEG) background consisted of slow delta waves (3–4 Hz, 25–50 μV). (B) On Day 2, the EEG pattern shifted to a slow background mixed with numerous spikes or sharp-wave activity from both hemispheres. (C and D) On Day 3, 8–9 s before the generalized seizure occurred, the EEG pattern in the right frontal–temporal region transformed into fast low-voltage activities (C) and quickly entered a state of generalized fast low-voltage activities. In the clinical setting, generalized tonic–clonic seizure appeared (D). (E) On Day 31 of admission (3 days of lidocaine use prior to the introduction of MgSO₄), the EEG background consisted of a slow theta wave (4–5 Hz, 25–50 μV) interspersed with paroxysmal spike activities. (F) On Day 35, after the introduction of lidocaine for 7 days and MgSO₄ for 4 days, neither clinical seizures nor epileptiform activities on EEG were noted.

Fig. 2

Timeline of clinically observed seizures and treatment with various intravenous-type AEDs. AEDs = antiepileptic drugs; GTCs = generalized tonic–clonic seizures; PBT = pentobarbital; PHB = phenobarbital; PHT = phenytoin; PROP = propofol; VPA = valproic acid.

Fig. 3

(A) Initial magnetic resonance imaging (MRI) images: T2-weighted (T2W) fluid-attenuated inversion recovery (FLAIR) images (taken on Day 3 of admission) showing symmetrical edema and hyperintensities of the bilateral external capsules and medial temporal lobes along with the hippocampi and posteromedial thalami (arrow). (B) Follow-up MRI images: T2W FLAIR images (taken on Day 21 of admission) showing mild remission of abnormal cortical swelling in the bilateral medial temporal lobes, hippocampi, thalami, basal ganglia, and external capsules (arrow).