Development of the clinical assessment scale in autoimmune encephalitis

Abstract

We read with great interest the study by Lim et al, 1 which aimed to develop an easily applicable scale to grade the severity of autoimmune encephalitis (AE). Nine key clinical features were identified and included in the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). CASE showed good interobserver and intraobserver reliability, and internal consistency, as well as a high correlation with the modified Rankin Scale (mRS).We applied CASE retrospectively to a cohort of 60 patients with AE, admitted to our institution between 2012 and 2018, and prospectively in 3 additional patients. Median age at onset was 55 years (range = 3 months-88 years), in 13 of 63 (21%) onset was before 18 years of age, and 34 of 63 (54%) were female. All patients fulfilled the clinical diagnostic criteria for AE 2 : definite AE was diagnosed in 16 of 63 patients (25%), definite anti-NMDA receptor encephalitis in 11 of 63 (17%), definite autoimmune limbic encephalitis in 6 of 63 (10%), antibody-negative probable AE in 4 of 63 (6 %), possible AE in 25 of 63 (40%), and Hashimoto encephalopathy in 1 of 63 (2%). At the disease nadir, median mRS score was 4 (range = 3-5). We applied CASE at maximum clinical severity (median CASE score = 9, range = 3-24). In our cohort, CASE significantly correlated with mRS (p < 0.0001, r 2 = 0.5025; Fig), although the correlation strength was weaker than that reported by Lim et al. However, we encountered several issues when CASE was applied to our patients that need to be clarified. Severe clinical conditions, such as coma and status epilepticus, make other items hardly assessable (eg, gait instability, language). In such cases, it is not specified what score should be given to items that are not directly assessable (we gave the maximum score). Postictal state after seizures also interferes with the evaluation of most items. The authors should clarify how to apply the scale in these situations and whether this score is meant to be used only in clinically stable patients. Furthermore, when applying CASE to a pediatric population, some items, such as memory and language, were not easily assessable. We think that the scale is more suitable for adult patients. Moreover, it would be appropriate to develop a different scale for patients with altered consciousness.CASE is potentially a useful tool and addresses the unmet need of clinical scales to grade AE severity, as mRS is quite coarse in evaluating this condition. However, CASE needs further improvement and validation to be employed in clinical trials.

The autoantibody-mediated encephalitides: from clinical observations to molecular pathogenesis

“…The role of white matter abnormalities hints at effects via glia or perhaps bystander inflammation, and indeed oligodendrocytes do express NMDARs [57]. Alongside these, the development of simple predictive clinical tools such as the anti-NMDAR Encephalitis One-year Functional Status (NEOS) Score and the Clinical Assessment Scale in Autoimmune Encephalitis (CASE), to predict outcomes and trajectories, respectively, is an important step to clinically ground a potentially molecular approach [58,59]. Collectively, these studies set the scene for precision brain-targeted therapies, in both acute and convalescent phases.…”

Grading the severity of autoimmune encephalitis: Advances and pitfalls

“…We read with great interest the study by Lim et al, which aimed to develop an easily applicable scale to grade the severity of autoimmune encephalitis (AE). Nine key clinical features were identified and included in the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).…”

Reply to “Grading the severity of autoimmune encephalitis: Advances and pitfalls”

“…As shown in the Figure, total CASE scores were widely distributed in patients within the same consciousness level, such as stupor and coma (total n = 88, including both the development and validation cohorts). This means that even comatose patients have different CASE scores.…”

“…We thank Drs Spagni and Iorio for their interest in our paper, and for raising important issues to improve the Clinical Assessment Scale in Autoimmune Encephalitis (CASE).…”