A study just published in the Journal of Neurology, conducted at 5 hospitals (4 Germany, 1 Austria) reported admission diagnosis in AE patients is still proving a challenge. The physicians attributed this to the fact that initial symptoms vary widely, causing the correct diagnosis to be delayed or even missed. They looked back at 50 adult patients who eventually had AE firmly diagnosed (by positive antibodies and other criteria) over a 10-year period.
Eighty percent of the patients were considered to have a typical presentation of AE, including memory problems, personality changes, and/or psychiatric symptoms, or at least one seizure. Atypical presentations occurred in 20% of patients, most commonly isolated headache or cerebellar dysfunction. Of the 50 patients, only 32% had encephalitis of some origin suspected at admission, of which 18% were suspected to be infectious, and only 14% AE. The original admission diagnoses considered or given to 68% of study patients was quite varied and included: epilepsy, psychiatric disease, transient ischemic attack, dementia, meningitis, dissociative disorder, myoclonus, ADEM and cerebellitis.
Another interesting fact reported by the authors was the widely used Graus et al (2016) clinical diagnostic criteria for “possible AE” was not met in almost 15% of the total group of patients later discovered to have AE. If this criteria is used for determining whether to order antibody testing, the authors stated that diagnoses will be missed. In the anti-NMDA subgroup, about 17% did not meet the criteria for “possible AE,” and 25% did not meet the criteria for “probable anti-NMDA AE.” These findings lead the researchers to conclude that there may be a need for validation and/or modification of the diagnostic criteria proposed for AE. The physicians also stated that “antibody testing should not be limited to patients with typical clinical signs but should also be performed in patients with rapidly progressive psychiatric diseases and neurological symptoms that are not in accordance with a common neurological disease.”
It is widely accepted in the medical community that correct and early diagnosis is an important factor as earlier immunotherapy has been proven to improve patient outcomes. We thank the authors of this study for pressing forward the need for prompt and accurate diagnosis. The abstract of this article may be read here.