Dados do Trabalho

Título

Presence of newly-onset epileptic seizures may discriminate autoimmune encephalitis from other causes of rapidly progressive dementia

Introdução

Rapidly progressive dementia (RPD) is characterized by an accelerated course of cognitive decline. The causes of RPD are multiple, including disorders like prion diseases, nonprion neurodegenerative diseases and vascular dementia, though many cases are attributable to potentially reversible conditions. Autoimmune encephalitis (AIE) is one of the potentially reversible etiologies of RPD. According to Graus’ 2016 criteria, possible AIE is defined as a clinical disorder fulfilling three criteria: 1) Subacute onset of working memory deficits, altered mental status or psychiatric symptoms; 2) At least one of: a) new focal central nervous system findings, b) seizures not explained by a previous disorder, c) cerebrospinal fluid pleocytosis, d) magnetic resonance (MR) features suggesting encephalitis; 3) Reasonable exclusion of alternative causes. It is important to distinguish AIE from other causes of RPD, as AIE may respond to specific immunotherapies.

Objetivo

To analyze the sensitivity and specificity of newly-onset epileptic seizures (NOES) for distinguishing AIE from other causes of RPD.

Método

Medical records of a sample of 68 patients with RPD from three tertiary centers in Florianópolis, Santa Catarina, were reviewed and searched for history of NOES. RPD was defined as any disorder fulfilling the National Institute on Aging – Alzheimer’s Association criteria for dementia that progressed from symptom onset to dementia in 2 years or less. The prevalence of NOES among AIE and non-AIE patients was compared. Sex, age and time from onset to dementia were also compared. Fisher’s exact test and Student’s t-test were used for hypothesis testing, as appropriate.

Resultados

Of the 68 RPD patients, 46 (67.6%) were male. Six patients were diagnosed with AIE (8.8%). Among the AIE patients, 3 (50.0%) had NOES, while the same was true for 8 (12.9%) of the non-AIE patients. The presence of NOES was able to distinguish AIE from non-AIE patients with 50.0% sensitivity and 87.0% specificity (p = 0.049). AIE patients were also younger (53.3 x 66.7 years; p = 0,041) and had a shorter clinical course (51.7 x 238.8 days; p < 0,001). There was no sex difference between AIE and non-AIE patients (p = 1.000).

Conclusão

The presence of NOES may differentiate AIE from other etiologies among patients with RPD with low sensitivity but high specificity. The diagnosis of AIE as a cause of RPD should be made according to published criteria.

Palavras-chave

New-onset epilepty seizures; Rapidly progressive dementia; Autoimmune encephalitis