Objective:

To identify clinical and systemic variables associated with mimickers of Autoimmune Encephalitis (AE).

Background:

The classical presentation of AE includes acute or subacute onset of impaired memory and cognition, in combination with progressive neurologic symptoms which may include abnormal movements, seizures, psychosis, and balance, speech, or vision problems. However, diagnosis can be challenging due to broad differential diagnoses and variable presentations of patients with suspected AE. Greater awareness of AE has led to increased consideration of AE as a potential etiology of neurologic symptoms, and accordingly, misattribution of symptoms to AE in some instances.

Design/Methods:

We performed a single-center retrospective chart review of 212 patients from the University of Utah Health identified by query of the ICD-10 code G04.81: Other encephalitis and encephalomyelitis between January 2012- August 2022, which is the diagnostic code inclusive of AE and other related or nonspecific encephalitis.

Results:

We describe the patient demographics of this cohort, as well as relevant clinical data including the predominant presenting symptom(s), cerebrospinal fluid characteristics, electroencephalography and neuroaxis imaging findings, suspected initial diagnosis, timing and duration of treatment interventions (including immunomodulatory therapy), final diagnosis, and outcomes.

Conclusions:

The diagnosis of AE remains challenging, especially in patient presentations with a predominant psychiatric phenotype at onset, or in those with atypical features. Recognition of the most common pitfalls to diagnosis and disease mimics may improve timely and accurate recognition of causative etiologies and help to direct the most appropriate treatments and interventions.