Clinical characteristics and outcomes of patients with autoimmune encephalitis at a tertiary center in Saudi Arabia.

BACKGROUND

Autoimmune encephalitis (AE) is an important cause of subacute encephalopathy and seizure. Regional cohort-level data are limited. We aimed to characterize the clinical presentation, antibody profiles, neuroimaging findings, treatment, and outcomes of patients with AE managed at a tertiary referral center in Saudi Arabia.

METHODS

This single-center retrospective study included patients who fulfilled the 2016 Graus diagnostic criteria for AE. Patients were identified using the EPIC platform, and clinical, serological, magnetic resonance imaging, treatment, and modified Rankin scale data were reviewed.

RESULTS

Among 148 patients screened, 18 met the inclusion criteria, including 12 with antibody-positive AE, 5 with seronegative limbic encephalitis (LE), and 1 with probable AE. Anti-N-methyl-D-aspartate receptor encephalitis (n=9) occurred exclusively in young women (mean 17.2 years), with orofacial dyskinesia (44.4%) and one ovarian teratoma. Two patients with anti-glutamic acid decarboxylase 65 (GAD65)-associated disease presented after 2 to 8 years with refractory status epilepticus and mesiotemporal abnormalities. One patient with dual antibdies anti-gamma-aminobutyric acid B receptor encephalitis with anti-GAD65 had small cell lung cancer. Seronegative AE (n=5, mean 40.4 years) presented acutely (<14 days) with mesiotemporal abnormalities, and all patients received pulse steroids. One patient with seronegative LE died from cyclophosphamide toxicity. At ≥3 months, 77.8% achieved a modified Rankin scale score of 0 to 2.

CONCLUSION

This single-center Saudi cohort included seropositive and seronegative AE. Anti-GAD65-associated disease was characterized by delayed presentation and refractory seizures, whereas seronegative LE showed a uniform acute mesiotemporal pattern responsive to first-line immunotherapy. Outcomes were comparable with those of international cohorts, supporting early recognition and larger regional studies.