Right from the beginning till now, the news of coronavirus is so spread that you might have read every article and saw every video there. Most of those have focused on what coronavirus is doing to our society, our economy, and our lungs. But what is it doing to our brain? By now even the symptoms of COVID-19 are memorized: dry cough, fatigue, and a fever. There are some more obscure symptoms, like a sore throat, diarrhea, and aches and pains. We are learning more every day about this virus, and working out new ways to combat it in our communities.
Sometimes when the infection is really bad, patients end up with acute respiratory distress syndrome or ARDS, when their lungs are so clogged up that their bodies aren’t able to absorb enough oxygen and that they struggle to breathe. This is usually when a person ends up requiring ventilation to support their breathing- and even that doesn’t always work. But the danger isn’t only to Lungs- it’s to the whole body, including the brain. As the number of COVID-19 cases climbs, doctors and scientists have noted more and more symptoms linked to the central nervous system- severe headaches and loss of smell and taste. Other reports include seizures and strokes, and recent case reports identified COVID-19 patients suffering from acute necrotizing hemorrhagic encephalopathy, where the inflammation in the brain leading to memory loss and disorientation.
University College London (UCL) conducted research that described 43 cases of patients with COVID-19 who suffered either, strokes, temporary brain dysfunction, nerve damage, or other serious brain effects. The research adds to recent studies which also found the disease can damage the brain. Michael Zandi, from UCL’s Institute of neurology, who co-led the study said, “Whether we’ll see a plague on a large scale of brain damage linked to the pandemic- almost like sleeping sickness outbreak in the 1920s and 1930s after the influenza pandemic- remains to be seen“.
This disease is caused by a new coronavirus, which is essentially a respiratory disease that affects the Lungs, but neuroscientists and specialist brain doctors say emerging evidence of its impact on the brain is alarming. Adrian Owen, a neuroscientist at Western University in Canada, told Reuters in an interview, “I worry that we’ve many people with COVID-19 now. And if during a year we’ve 10 million recovered people, and people have cognitive deficits then that’s getting to affect their ability to figure and their ability to travel about activities of daily living“
The UCL study was published within the journal Brain where nine patients who had brain inflammation were diagnosed with a rare condition called acute disseminated encephalomyelitis (ADEM) which is more usually seen in children and may be triggered by viral infections. The team said it might normally see about one adult patient with ADEM per month at their specialist London clinic, but this had risen to a minimum of one per week during the study period, which is a concerning increase. According to a report, one-third of COVID-19 patients had neurology complications and two-third of them had a severe disease that there was a need to go to ICU.
How can the coronavirus reach the brain?
An area in the body that is supposed to be highly protected, how does the coronavirus reach the brain? More and more researches are continuing to reveal the dramatic effect that COVID-19 exerts on the central nervous system. Around 36% of COVID-19 patients show neurological symptoms. This opens a new question for not only its treatment but also its long-term effect. The impact COVID-19 has on the brain is often overlooked due to the complicated diagnostics of medically unstable patients. However, in the case of brain infection, the coronavirus can lead to several neurologic symptoms like headaches, seizures, loss of control over body movements, and loss of vital senses. Our brain is protected against viral bacterial infections, thanks to the blood-brain barrier, which is a thick natural border that separates the brain from the rest of the body. The border is made of cells that only let very small particles to pass through. However, severe inflammations that come with diseases like COVID-19 can destroy this barrier. Some viruses can even use inflammatory cells as Trojan horses to trick their way into the brain. The new coronavirus, SARS-COV-2 is thought to be one of them. Another possibility is that the cells that built the blood-brain-barrier themselves get infected and then allow the virus to pass through this border into the brain. Brains of infected COVID-19 people show the presence of the virus in endothelial and neuronal cells.
The virus, however, can use other ways to visit the central nervous system. One such way is accomplished through the axons- threadlike part of the neuron that is found all over the body. Through these axons, the virus can potentially travel to the main part of neurons in the brain or spinal cords. Brain cells that are damaged release chemicals called biomarkers, found within the spinal fluid, which may be a colorless liquid body substance found within the brain and medulla spinalis. The presence of these biomarkers in the blood of COVID-19 patients, especially patients with severe cases, indicates that brain cells have been attacked and damaged by the coronavirus. Even the host’s immune system can misdirect it attacks when faced with a viral infection in the brain and damage the central nervous system. The brain may be a fragile organ with most of its cells lacking the power to regenerate. This means that the damage to the brain is often lasting and potentially cause neurological disorders.
We might see a wave of psychiatric and neurological issues following this pandemic. Researchers at UC San Diego published a paper in April of 2020, just a couple of months after the pandemic began, to warn the scientific and medical community that patients who have been exposed to or recovered from COVID-19 should be carefully monitored for neurological issues going forward. Based on past influenza pandemics, they say we should be on the lookout for a possible increase in cases of insomnia, anxiety, and depression, in addition to the symptoms we already mentioned. And all of this doesn’t even touch on how physical isolation, the anxiety of living in a pandemic, worrying about our loved ones and our health, and the stress of financial uncertainty can all independently cause serious mental strain. We are still learning what the long-term effects of this pandemic will be, not just on brains, but on everything.