Covid-19 patients with no respiratory symptoms may develop brain complications like delirium and stroke: Study
Scientists also detected a fatal neurological condition called ADEM, which stands for acute disseminated encephalomyelitis. The study raises concerns over long-term brain damage
Some Covid-19 patients might not show typical respiratory symptoms, but could develop brain abnormalities such as delirium, brain inflammation, stroke, and nerve damage, according to a new study. However, scientists do not yet understand how the new coronavirus causes these complications, as it does not seem to go after the brain directly.
The study from University College London (UCL) adds to the growing body of evidence that Covid-19 is more than just a respiratory disease. The research also found a new brain complication stand out: ADEM, which stands for acute disseminated encephalomyelitis. It is a deadly neurological condition, triggered by viral infections. Though rare, it most commonly strikes children. At the time of the study, the researchers were diagnosing at least one ADEM case every week. Before the Covid-19 era, it used to be once every month.
The researchers studied 43 individuals aged between 16 and 85. They either had confirmed or suspected infection. Commenting on his study, one of the authors, Dr Michael Zandi from UCL, said: “We identified a higher than expected number of people with neurological conditions such as brain inflammation, which did not always correlate with the severity of respiratory symptoms." “We should be vigilant and look out for these complications in people who have had Covid-19," he added. If the pandemic could trigger a surge in cases of brain damage -- similar to how the mysterious sleeping sickness outbreak in the 1920s and 1930s followed the 1918 influenza pandemic -- is yet to be determined. Experts believe that the influenza virus was behind both these conditions.
In this study, scientists checked for signs of neurological complications in all 43 patients. Of them, ten suffered a temporary brain dysfunction with delirium, which explains mental confusion in patients. They also saw 12 people with brain inflammation, eight with strokes, and eight others with nerve damage, mainly from Guillain-Barré syndrome. This syndrome occurs where the immune system attacks the nerves, eventually leading to paralysis of the whole body.
Among the 12 patients struggling with brain inflammation conditions, nine were diagnosed with ADEM. “Doctors need to be aware of possible neurological effects, as early diagnosis can improve patient outcomes. People recovering from the virus should seek professional health advice if they experience neurological symptoms,” UCL's Dr Ross Paterson and one of the authors of the study, said. Further, the experts did not detect traces of the virus in the brain fluid, suggesting that it might not directly invade the brain. More studies should explore why the infection leads to a range of neurological complications. However, some evidence from patients indicates that they might arise from the body's immune response, and not from the virus itself.
The UCL team suggests that patients might need a long-term follow up to understand if the virus causes lasting brain damage. "Given that the disease has only been around for a matter of months, we might not yet know what long-term damage Covid-19 can cause," Paterson said. David Strain, a senior clinical lecturer at the University of Exeter Medical School, who was not involved in the study pointed out that the disease seems to cause severe brain complications in only some patients and more studies should focus on the disease prevalence. “This is very important as we start to prepare post-Covid-19 rehabilitation programs. We’ve already seen that some people with Covid-19 may need a long rehabilitation period, both physical rehabilitation such as exercise and brain rehabilitation. We need to understand more about the impact of this infection on the brain," he told the Guardian.