A Constellation of Neuropsychiatric Symptoms
In early June, Dr. McAlpine gave a presentation of her research at the Demystifying Long COVID North American Conference 2024 in Boston. She’s been hard at work in extrapolating the causes of neuropsychiatric long COVID, a tangled web of symptoms seen in patients with long COVID that range from cognitive dysfunction to headaches, neuropathy, mental health, and the aforementioned dysautonomia.
Amid the sea of neurologic long COVID symptoms, she said “symptoms that are mixing and matching are very similar. So, I wanted to specifically look at a symptom that I could definitely isolate to the brain, and that is brain fog and cognitive dysfunction and impairment.”
In September 2021, the journal Translational Psychiatry published a study titled “Neuropsychiatric manifestations of COVID-19, potential neurotropic mechanisms, and therapeutic interventions.”
Going back all the way to the first cases of COVID in March 2020, the initial symptoms most patients complained of during an acute viral infection were around the respiratory system. Yet delirium, confusion, and neurocognitive disorders were also reported, puzzling experts and inciting a well-founded fear among many.
Even worse, after recovery, these neuropsychiatric symptoms persisted. The study found that coronavirus was able to invade the central nervous system through blood vessels and neuronal retrograde pathways, leading to brain injury and dysfunction of the cardiorespiratory center in the brainstem.
The study concluded by reporting that neuroimaging and neurochemical evidence indicated neuroimmune dysfunction and brain injury in severe patients with COVID-19. Suggested treatments included immunosuppressive therapies, vaccines to target the coronavirus’ spike protein, and pharmacological agents to improve endothelial integrity.
But there was still much that was unknown, and the study’s authors stressed the need for multidisciplinary research going forward.
How Immune Dysfunction Plays a Role
Similarly, Dr. McAlpine and her research team are still trying to sift their way through this opaque web to see why long COVID can cause autoimmune flare-ups.
In a study published in April, Dr. McAlpine and others found that small fiber neuropathy (SFN) after COVID is autoimmune-mediated and a dysfunction of the immune system.
Notably, they found that SFN could be a key pathologic finding in long COVID. SFN before the pandemic had been linked to ME/CFS and POTS, and the basic hypothesis revolved around an inflammatory immune response during a viral illness that may lead to immune dysregulation (dysimmunity) and damage to small fiber nerves.
But much still remains to be answered.
“We’ve seen quite a bit of that, but we still haven’t figured it out,” Dr. McAlpine said. “My big question is, how is this autonomic dysfunction related to the immune dysfunction, and how is that related to the vascular inflammation? There’s quite a bit of overlap in individuals with autoimmune disease and those who go on to develop this long COVID,” she added.
Still, a large portion of patients with long COVID don’t show autoimmune dysfunction, and those patients lack common biomarkers for an autoimmune condition.
“When we look at the spinal fluid in those individuals [with multiple sclerosis or a neuroinfectious disease], there’s inflammation going on ... the white blood cell count is elevated, the protein is elevated, the antibodies, the bands are elevated. I’ve been seeing long COVID patients now for 4 years, and their presentation is so distinctly different compared to my individuals that I see my patients with MS, or a neuroinfectious disease,” she said.
The mechanisms behind how all of this is interlaced remain unclear, and there may not be a one-size-fits-all treatment or definite pathogenesis for everyone.
“It’s that intersection of the immune system and the vessel wall ... Next is to figure out what do we treat, what are the targets, all of that, but there’s so many different presentations, and everybody has kind of a unique case,” she said.