Limbic Encephalitis Associated with Anti-γ-aminobutyric Acid B Receptor Antibodies

Abstract

Background:Autoimmune encephalitis associated with antibodies against γ-aminobutyric acid B receptor (GABAB R) in patients with limbic encephalitis (LE) was first described in 2010. We present a series of Han Chinese patients for further clinical refinement.Methods:Serum and cerebrospinal fluid (CSF) samples from patients referred to the program of encephalitis and paraneoplastic syndrome of Peking Union Medical College Hospital were tested with indirect immunofluorescence. Clinical information of patients with anti-GABAB R antibody positivity was retrospectively reviewed, and descriptive statistical analysis was performed.Results:All eighteen anti-GABAB R antibody-positive cases had limbic syndromes, and electroencephalogram (EEG) or neuroimaging evidence fulfilled the diagnostic criteria of LE. Four patients had additional antibodies against Hu in serum and one had anti-N-methyl-d-aspartate receptor antibody in both sera and CSF. Seventeen (17/18) patients presented with new-onset refractory seizure or status epileptics. Twelve (12/18) patients had memory deficits, 11 (11/18) patients had personality change, 7 (7/18) patients had disturbance of consciousness, and 3 (3/18) patients showed cerebellar dysfunction. One patient with LE had progressive motor and sensory polyneuropathy. Lung cancer was detected in 6 (6/18) patients. Ten (10/18) patients showed abnormality in bilateral or unilateral mediotemporal region on magnetic resonance imaging. Ten (10/18) patients had temporal lobe epileptic activity with or without general slowing on EEG. Seventeen patients received immunotherapy and 15 of them showed neurological improvement. Four patients with lung cancer died within 1–12 months due to neoplastic complications.Conclusions:Our study demonstrates that most Han Chinese patients with anti-GABAB R antibody-associated LE have prominent refractory epilepsy and show neurological improvement on immunotherapy. Patients with underlying lung tumor have a relatively poor prognosis. Testing for anti-GABAB R antibodies is necessary for patients with possible LE or new-onset epilepsy with unknown etiology.

Clinical characteristics and long-term follow-up of seven cases of anti-GABABR encephalitis in patients of Han Chinese descent

“…Our study showed that memory deficit is common in these patients and that complete recovery is difficult, which may be closely related to damage to the marginal lobe. Psychiatric disorders are common (64.7%) [7] in patients with anti-GABABR encephalitis, and this result is roughly in line with our finding. Mental disorders are also common symptoms that tend to persist until the patient is discharged.…”

“…Epilepsy is a prominent and critical clinical manifestation of anti-GABABR encephalitis, and epilepsy or refractory epilepsy is often the first symptom [6]. In a previous study by Guan et al, 17 of the 18 patients presented with new refractory epilepsy or status epilepticus [7], while all the patients in our study had epilepsy. Herpes simplex encephalitis is perhaps most frequently associated with epilepsy, of the types of sporadic viral encephalitis, with an incidence of about 50% in cases of combined epilepsy [8].…”

Anti-GABAB Receptor Encephalitis in China

“…To the best of our knowledge, there were 48 cases [5][6][7] reported in China, and the average age was about 56 years old, which was smaller than that reported in 2010 (62 years) [2]. And most of them were middle-aged and old men (about 65%).…”

“…It has been reported that patients with SCLC might have unfavorable treatment outcomes if using the immunotherapy. And the main causes of death in patients with anti-GABA B R encephalitis were lung tumor progression and chemotherapy related complications [2,6,10]. Therefore, it is necessary to attach great importance to the detection of tumor or paraneoplastic biomarkers.…”

Comparisons between Psychiatric Symptoms of Patients with Anti-NMDAR Encephalitis and New-Onset Psychiatric Patients

“…Surprisingly, despite the prominent psychiatric symptoms and the importance of psychiatric involvement in its treatment, the psychiatric literature on the disease is relatively scarce [5,6]. Even more surprisingly, there are few reports on anti-NMDAR encephalitis from the perspective of psychiatrists in China [11,12,13]. It is largely unknown whether there are differences in psychiatric symptoms between patients with anti-NMDAR encephalitis who initially present with psychiatric symptoms and new-onset psychiatric patients.…”