Long COVID or functional neuropathy?

A systematic review showed that the hypothesis that prolonged COVID may be associated with functional neuropathy (FND) remains untested.

Across 102 long COVID studies, the neurological symptoms were poorly characterized to support or refute a diagnosis of FND, reported Tiago Teodoro, MD, of St George’s Hospital, London, and colleagues.

Given the nature of the disorder, some FND patients may be inappropriately identified as long-term COVID patients, delaying diagnosis and treatment and potentially affecting prognosis, researchers say. writes. European Journal of Neurology.

“We are still struck by the similarities between some symptoms of long-term COVID and the impairments caused by acute illness,” Teodoro said. MedPage Today.

“Our systematic review shows that some people labeled as having long-lasting COVID may actually be experiencing a form of functional neuropathy. However, it has been largely overlooked in the medical literature.

“While this is a major problem in understanding COVID for the long haul, it is a condition that has specific diagnostic criteria and effective treatments available, so it is primarily a major problem for patient management.

What is FND? Abnormal brain signals No significant structural damage to the brain.Occurs in estimation 4-12 per 100,000 people per year.

“These are common neurological conditions caused by malfunctioning of the brain, but not directly related to structural damage,” Teodoro said.

“We have seen many patients develop functional neurological symptoms following acute events such as injuries, invasive medical procedures, and infections,” he said.

“Though these factors do not directly cause functional neurological symptoms, they are best understood as triggers that cause this condition in people with pre-existing predispositions.” medical symptoms may persist.”

The analysis by Teodoro and co-authors “seems well done, which is not surprising given that the author is a well-known and respected scholar,” said Emeritus Research Fellow at the National Institute of said Mark Hallett, M.D., former chief of medical neurology. He is a Neurological Disorders and Stroke (NINDS) physician and was not involved in this study.

“Their main conclusion is how often functional neuropathy occurs in long-term COVID, largely because the data have not been collected in sufficient detail and the diagnosis has not been generally considered. We don’t know if it will play a role,” Hallett said. MedPage Today.

“However, some long-standing COVID patients likely have FND or FND with other medical conditions,” he noted.

“The most important issue is that FND requires its own treatment, and such treatment may be successful,” Hallett said. , that the diagnosis can be made on the basis of positive features, and that proper treatment, as always, depends on making the correct diagnosis.”

Diagnosis of functional neurological symptoms is positive and not just based on ruling out other conditions, Teodoro and co-authors emphasized. This means that symptoms are often intermittent and fluctuate in severity,” they wrote.

Teodoro and colleagues reviewed 102 studies spanning 412,726 people infected with COVID-19. Of these, 31 studies recruited participants who had had COVID for a long time (11,860 patients). The remaining studies examined acute COVID patients who were screened for long-lasting acute symptoms of COVID.

Overall, 51 studies were prospective, 33 cross-sectional and 12 retrospective. Eighteen included a control group. Most (89 studies) long defined her COVID as symptoms lasting more than her four weeks.

Most studies had a mean or median age of 40 to 59 years and a similar proportion of male and female participants.

The most consistently reported neurological symptoms were cognitive impairment, headache, pain, dizziness, fatigue, sleep-related symptoms, aging or anosmia.

“Overall, we found no evidence that any author systematically searched for positive features of FND,” write Teodoro and colleagues. “Exceptions were his three studies that explained temporal discrepancies.”

“In addition, only 13 studies specifically focused on long COVID after mild infection, where confounding effects from the general effects of severe illness are mitigated,” they added.

“Increasing numbers FND case report caused by COVID-19 infection (and vaccination),” Teodoro and co-authors noted. ”

Researchers and clinicians need to be cognizant of the complexity and heterogeneity of mechanisms underlying COVID symptoms over time, the researchers said.

“This includes ensuring that neuropsychiatric and functional explanations for symptoms are considered alongside other explanations. or incapacitating, or prejudices that are less “realistic” than more traditional biological explanations for symptoms. .

“Patients are also likely to have multiple diagnoses that describe multiple symptoms. This runs the risk of being masked using long COVID-like syndrome labels.” Without understanding, patients may not receive appropriate care and the development of new treatments and services may be delayed.”