On the Brain: The Neurologic Effects of COVID-19
“What I will really take away from this pandemic is this idea of unity in critical care. ...We had pulmonary critical care, anesthesia critical care, surgical critical care, neurocritical care and emergency medicine critical care providers working side by side on the same unit, caring for the same patients.”
COVID-19 is multifaceted . While we often hear of its associated respiratory complications, we are also seeing its reach extend beyond the lungs. Many symptoms of COVID-19 are actually neurologic in nature—from a loss of smell and taste, to even strokes. To learn more about how the virus may be affecting the brain, we reached out to MCIRCC member and Michigan Medicine neurointensivist Dr. Venkatakrishna Rajajaee.
While COVID-19 is currently a situation in progress, what are we learning about how this disease may be affecting the brain?
Through this pandemic, we have learned that the COVID-19 virus impacts much more than the lungs. We know for example that it can cause cardiomyopathy, widespread clotting and acute kidney injury. Its impact on the brain appears to be a much more serious problem than we first thought.
Venkatakrishna Rajajaee, MD, MBBS
I think the first clue that this virus could cause serious problems in the brain were the reports of loss of smell as an early symptom. This suggests that the virus causes injury to olfactory nerve endings, and perhaps uses these nerves as a portal into the brain. The virus impacts the brain in several ways. Most starkly, there are case reports of direct viral invasion of the brain, causing an encephalitis and serious neurological injury visible on Magnetic Resonance Imaging (MRI). There are also case series, covered in the lay press, of acute ischemic stroke caused by the occlusion of large vessels, possibly as a result of the clotting disorder induced by the infection. In addition, there are case series of the Guillain Barre syndrome occurring in association with COVID-19 infections.
However, I would say that the most common problem we see in critically ill patients with COVID-19 is that they are not waking up as we would expect them to. They are profoundly encephalopathic on presentation and while intubated, often require high doses of sedatives, and do not wake up consistently when sedatives are weaned down. MRIs on these patients have demonstrated a variety of findings, from small regions of restricted diffusion suggesting ischemic stroke, to nonspecific changes suggesting cerebral edema and injury in certain parts of the brain. What we do not know is why this is happening. Profound hypoxia prior to presentation to medical care? Clotting of smaller cerebral blood vessels? Direct brain invasion? I think there is a lot to be learned about what this deadly new virus does to the brain.
While COVID-19 brings many challenges to the table, what victories are being celebrated in the Neuro ICU?
I would say the greatest victories we have had in the Neuro ICU are very similar to the victories in every other unit. Several of our critically ill COVID patients were eventually extubated and discharged. Patients were extubated in the third week of illness, after being desperately ill. I think the basic principle we have long applied to acute neurological injury was very relevant with these patients—be patient, don’t give up too easily.
As a neurointensivist, what is on your wish list when working with COVID-positive patients?
My number one wish is for technology that minimizes the risk to healthcare providers who provide care to these patients. This does not just protect healthcare workers and those they come in contact with, including other patients- it also potentially improves the care the COVID patient receives. Currently, healthcare workers must minimize room entry and bundle care, restricting the ability to perform interventions such as insulin infusions and bronchoscopy. Also, fewer infected healthcare workers means lower concern for hospital-acquired COVID infections, as hospitals ramp up elective care.
In terms of the neurological issues faced by these patients, we need to establish whether, and if so to what extent, the virus directly invades the brain. Limited cerebrospinal fluid testing has been performed, but this needs to be done more widely. We also need to establish how serious the cerebrovascular clotting issues are, and to what extent this may impact patients beyond large vessel occlusions. Knowing the answers to these questions may permit the use of early aggressive therapy to prevent devastating neurological complications, such as systemic anticoagulation, antiinflmmatory therapy or antiviral medications.
What do you think your area of care, or the field of critical care in general, might look like post-pandemic?
From a neurological standpoint, when we see a patient who is encephalopathic and hypoxic, or a young patient with an ischemic stroke who has had symptoms of the flu, we will ask ourselves: is this COVID?
COVID will be with us for a while, and we as intensivists will practice our trade knowing this. Just as some measures of social distancing are likely here to stay for the foreseeable future—I’m not about to shake hands anytime soon—the measures that critical care healthcare workers use to protect themselves are also here to stay. We will default to using personal protective equipment when performing aerosol generating procedures on hypoxic patients whose infection status is unknown. We will intubate using video laryngoscopy, not direct laryngoscopy. A generation of critical care providers has learned invaluable lessons in pandemic preparedness and, more generally, the fundamentals of disaster management.
But what I will really take away from this pandemic is this idea of unity in critical care. For a period of a few months, many of the differences between intensivists from a variety of backgrounds became much less important and we were unified, focused on a common goal. Of course there was a lot of variation in practice, but we had pulmonary critical care, anesthesia critical care, surgical critical care, neurocritical care and emergency medicine critical care providers working side by side on the same unit, caring for the same patients. Perhaps this can be an opportunity for critical care providers of different stripes to come together and to empower the field, to provide the best possible care to these patients and to be a force to reckon with.