Frequency and characteristics of functional neurological disorder in the emergency department.

Background: Functional neurological disorders (FND) are common yet frequently under-recognized in emergency settings. Reliance on diagnostic coding alone (e.g. ICD-10 diagnoses F44 and F45) likely underestimates their true prevalence and healthcare impact. This study aimed to assess the frequency and characteristics of FND among adult neurological emergency department (ED) presentations using a hybrid case-finding strategy.

Methods: We conducted a retrospective analysis of all neurological ED presentations (n = 5504) to a tertiary university hospital in 2023. A full-text keyword search of 184,279 ED documentation entries was followed by manual review to check the FND-related keywords' relevance to acute ED presentations. Additional cases were identified from neurological inpatient discharge records. Clinical and demographic variables, presenting symptoms, diagnostic classification, and management pathways were analyzed.

Results: We identified 199 cases of functional symptoms as chief presenting complaints, representing 3.6% of all neurological ED presentations. The patients' median age was 33 years, and 71% were female. Functional seizures were the most common presentation (54%), followed by motor or sensory deficits (21%). Most patients (75%) were discharged directly from the ED, while 19% were admitted. Discharge against medical advice occurred in 4.5% of FND cases, compared to 1.5% overall. Only 39% of ED-discharged FND cases received F44 or F45 diagnostic codes.

Conclusions: FND is a common cause of neurological emergency presentations. Epidemiological analyses that rely on diagnostic codes risk substantially underestimating its true prevalence. Our findings underscore the need for improved recognition, diagnostic clarity, and structured care pathways for FND in emergency settings.