Functional Neurological Disorder Emerges After COVID Infection, Vaccines

Patients with functional neurologic disorder (FND) after SARS-CoV-2 infection had different symptoms than people with FND after COVID vaccines, retrospective data showed.

Patients with post-COVID FND tended to be older, had more insidious onset, and had higher disability, according to Araceli Alonso-Canovas, MD, PhD, of Hospital Universitario Ramón y Cajal in Madrid, and co-authors.

Those with FND after COVID vaccination more closely resembled classic FND: they were younger, had an acute onset, and tremor was the most common phenotype, the researchers reported in Journal of Neurology, Neurosurgery & Psychiatry.

“We show for the first time evidence from a multicenter national study that FNDs after COVID-19 infections and vaccines are more common than previously reported and have distinct clinical profiles,” Alonso-Canovas told MedPage Today.

The findings point to a need to consider FND when diagnosing patients with post-COVID neurologic symptoms, she added.

“Long COVID is an umbrella term and many different circumstances have to be considered,” Alonso-Canovas said. “If there are neurological symptoms, a careful history and examination is mandatory to rule out FND, as it is a well-defined clinical condition that is potentially treatable.”

FND refers to disorders caused by an abnormality in brain signaling with no significant structural brain damage. It occurs in an estimated four to 12 people per 100,000 per year and accounts for about 6% of outpatient neurology visits.

Vaccinations can trigger FND, as can other stressors including infections. While experts maintain some people with FND might be long COVID patients, little research has been conducted to evaluate this.

“Long COVID can manifest with a range of features diagnostic of FND,” noted Alberto Espay, MD, MSc, of the University of Cincinnati, who wasn’t involved with the study.