The COVID pandemic has now claimed as many American lives as World War I, the Vietnam War, and the Korean War combined. Most of these deaths are due to the well-known pulmonary complications of the coronavirus. It has become increasingly recognized, however, that the virus also attacks the nervous system. Doctors in a large Chicago medical center found that more than 40% of patients with COVID showed neurologic manifestations at the outset, and more than 30% of those had impaired cognition. Sometimes the neurological manifestations can be devastating and can even lead to death.
However, new research is now suggesting that there may be long-term neurologic consequences in those who survive COVID infections, including more than seven million Americans and another 27 million people worldwide. Particularly troubling is increasing evidence that there may be mild — but very real — brain damage that occurs in many survivors, causing pervasive yet subtle cognitive, behavioral, and psychological problems.
How COVID damages the brain
COVID can cause damage to the brain directly by encephalitis, which may have devastating or subtle consequences. In one British study of 12 patients with encephalitis, one made a full recovery, 10 made a partial recovery, and one died. This study also found that a number of patients with COVID suffered strokes. In fact, COVID infection is a risk factor for strokes. A group of Canadian doctors found that individuals over 70 years of age were at particularly high risk for stroke related to COVID infection, but even young individuals are seven times more likely to have a stroke from this coronavirus versus a typical flu virus.
Autopsy data from COVID patients in Finland suggests that another major cause of brain damage is lack of oxygen. Particularly worrisome is that several of the patients who were autopsied did not show any signs of brain injury during the course of their COVID infection — yet all had brain damage. In one patient there was loss of taste, and in two there was “minimal respiratory distress,” but none of these patients were thought to have any brain damage while alive.
According to British neurologists, COVID-19 can cause serious damage to the brain and central nervous system. Such damage can lead to psychosis, paralysis and strokes, which are often detected in their late stages.
There are numerous signs that the novel coronavirus SARS-CoV-2 not only attacks the lungs and respiratory tract, but also other organs on a massive scale.It can severely affect the heart, vessels, nerves, kidneys, and skin.
British neurologists have now published shocking details in the journal "Brain," which suggests SARS-CoV-2 can cause severe brain damage — even in patients with mild symptoms or those in recovery. Often this damage is detected very late or not at all.
Autopsy studies have yet to find clear evidence of destructive viral invasion into patients’ brains, pushing researchers to consider alternative explanations of how SARS-CoV-2 causes neurological symptoms.
ABOVE: Slice of a deceased COVID-19 patient’s olfactory bulb, illustrating an area (left) with significant leakage of fibrinogen (fluorescent green) into the tissue, likely the result of damage to small blood vessels. DRAGAN MERIC
When epidemics and pandemics washed over humanity through the ages, watchful doctors noticed that in addition to the usual, mostly respiratory ailments, the illnesses also seemed to trigger neurological symptoms. One British throat specialist observed in the late 1800s that influenza appeared to “run up and down the nervous keyboard stirring up disorder and pain in different parts of the body with what almost seems malicious caprice.” Indeed, some patients during the 1889–92 influenza pandemic reportedly became afflicted with psychoses, paranoia, stabbing pains, and nerve damage. Similarly, scholars have linked the 1918 flu pandemic to parkinsonism, neuropsychiatric disorders, and a broadly coinciding outbreak of the “sleeping sickness” encephalitis lethargica, which would often arrest patients in a coma-like state—although researchers still debate whether the two are causally connected.
That SARS-CoV-2, the culprit of the COVID-19 pandemic, is also associated with neurological symptoms isn’t entirely surprising, given some evidence that its close relatives, MERS-CoV and SARS-CoV-1, have been associated with neurological symptoms too. But the proportion of patients developing such symptoms—and their mounting collective numbers—has startled some scientists. When the news broke early last year that some 36 percent of COVID-19 patients in Wuhan hospitals were developing impaired consciousness, seizures, sensory impairments, and other neurological symptoms, “that floored me,” remarks Shibani Mukerji, a neuroinfectious disease specialist at Massachusetts General Hospital.
w ^随着流行病和大流行病的流行,人类警惕的医生注意到,除了常见的呼吸道疾病外,这些疾病似乎还引发神经系统症状。一位英国喉咙专家在1800年代后期观察到,流行性感冒似乎“在紧张的键盘上运转,使身体不同部位的疾病和痛苦激起了几乎是恶意的恶作剧”。实际上,据报道,在1889-92年的流感大流行中,有些患者患有精神病,偏执狂,刺痛和神经损伤。同样,学者们已经联系1918年的流感大流行是帕金森氏病,神经精神疾病和广泛并发的“昏睡病”性脑炎爆发,这通常会使患者陷入昏迷状态,尽管研究人员仍在争论两者是否存在因果关系。