Covid-19

How Covid-19 affects the brain

From The Carlat Report by Paul Riordan, MD

Beyond the stress-related conditions, from grief to depression to PTSD, the novel coronavirus can potentially invade neurons, and the immune response to the virus can affect the brain as well. Similar viruses like SARS-CoV-1 and MERS-CoV have been implicated in psychiatric disorders, and the first reports of similar problems with COVID-19 are starting to come in (Troyer EA metal, Brain Behav Immun ;87:34-39).

One group has created a neuropsychiatric staging system:

Stage	Pathology	Neuropsychiatric Presentation
1	The virus has penetrated the epithelial cells of the nose and mouth	Decreased smell or taste
2	The virus has invaded the bloodstream, causing inflammation, hypercoagulation, and possible stroke	Fatigue, sensory loss, double vision, paralysis, or ataxia
3	The virus has crossed the blood-brain barrier into the CNS, where it may cause demyelination or neurodegeneration	Seizure, confusion, delirium, coma, loss of consciousness, or death

Neurologic complications are more common in severe than mild COVID-19 cases (6%-15% vs 1%-2%). Among patients who died from COVID-19, 1 in 5 had evidence of encephalopathy. These complications can appear after recovery from the respiratory syndrome and have even been observed in patients with no respiratory symptoms (Rogers JP et al, Lancet Psych 2020;S2214-0366(20)30203-); Mao L et al, JAMA Neurol 2020;3201127.