Anaesthesia and the development of functional neurological disorder: A systematic review and case series

There are reports of functional neurological disorder (FND) developing after anaesthesia, though separating any aetiological role from other possible factors is challenging. We aimed to systematically review all published cases of post-anaesthetic FND to see if any common factors supported an anaesthetic role. We also aimed to identify all cases of post-anaesthetic FND arising in our FND clinic, to obtain an estimate of its frequency.

For the review, a systematic search for published cases of FND developing within 48 h of anaesthesia was conducted in June 2022. For the case series, the medical records of all patients attending an FND clinic in Melbourne between 2017 and 2019 were examined, and all cases with FND within 48 h of anaesthesia extracted.

36 published cases were identified for the review. Sixteen described preceding stressors and 16 psychiatric diagnoses, including 8 with previous FND. Thirty-two (92%) had undergone general anaesthesia, most commonly for obstetric procedures. Motor/sensory loss was the most common presentation, followed by seizures and coma. Most (80.5%) developed symptoms immediately on induction or cessation of anaesthesia. For the case series, 8 of 107 clinic patients (7.5%), developed FND within 48 h of anaesthesia. All had previous psychiatric diagnoses, including 3 with previous FND. Three underwent general anaesthesia and 3 procedural sedation, with seizures the most common presentation. All developed symptoms immediately on induction or cessation of anaesthesia.

These cases provide some support for an aetiological role for anaesthesia: there is evidence for an anaesthetic 'model' for the symptoms of FND that arise, they largely arise with the onset or termination of anaesthesia, and they arise most frequently during general anaesthesia or sedation.