Encephalitis With Antibodies Against the GABAB Receptor: High Mortality and Risk Factors

Abstract

Objective: To measure mortality, identify predictors of death and investigate causes of death in patients with anti-gamma-aminobutyric-acid B receptor (anti-GABA_BR) encephalitis. Methods: Prospective analysis of anti-GABA_BR encephalitis cases diagnosed between June 2013 and August 2018 in West China Hospital of Sichuan University, with assessment of factors associated with mortality. Results: A total of 28 patients (11 females) with anti-GABA_BR encephalitis were included in this study. After a maximum time of 52 months (median 11 months, range 2-52) of follow-up, 9 (32.1%) patients died, with a median survival time of 6.5 months. Five patients died of tumor progression, one patient died of convulsive status epilepticus, one patient died of septic shock, and two patients died of severe pneumonia. Predictors of death were older age at onset (P = 0.025), presence of a tumor (66.7 vs. 15.8%, P = 0.013), the number of complications (2.6 vs. 1.0, P = 0.009) and deep venous thrombosis (33.3% vs. 0, P = 0.026). Conclusion: Patients with GABA_BR encephalitis have a high mortality rate within 5 years. Older age at onset, presence a tumor, the number of complications, and deep venous thrombosis are associated with death.

Keywords: anti-GABABR encephalitis; mortality; predictors of death; prognosis; tumors.

Figure 1

Distribution of initial symptoms and cumulative symptoms during disease course. (A) Initial symptom at disease onset according to patients' age. The most common initial symptoms were seizures. In older patients (age at onset ≥ 45 years), 10.0% patients started with behavior changes and 5.0% patients presented with memory deficits as the initial symptom. Seizure as first symptoms occurred in all younger patients (age at onset <45 years). (B) Accumulative symptom presentation during disease course in different age groups. No significant statistical differences were found in two different age groups.

Figure 2

Clinical outcome. The modified Rankin scale (mRS) of the patients with anti-GABA_BR encephalitis at different follow-up point.

Figure 3

Analysis of Kaplan-Meier survival curve for survival. (A) Kaplan-Meier survival curves show that patients with age at onset ≥45 years had an increased risk of death compared to those with age at onset <45 years (Log rank P = 0.035). The estimated median survival time was 10 months for the group with age at onset ≥45 years and 14 months for the group with age at onset <45 years. (B) Kaplan-Meier survival curves show that patients with tumors had a greater risk of death than patients without tumors (P = 0.024). The estimated median survival time was 10 months for the group with tumor and 12 months for the group without tumor.