Infection with SARS-CoV-2 not only damage the lung but also the brain

It is well known that COVID-19 mainly damages the lung of a patient and bring about inflammatory response characterized by impairment to deep airways and alveoli. With the deepening of research, researchers have come to discover that in addition to lungs injury, COVID-19 might also incur damage to the immune system and other organs, even can break through the blood-brain barrier, and severe infections can damage the brain, causing a series of complications including inflammatory strokes, mental illness and senile dementia .

Authoritative journals such as Lancet Psychiatry^[1] and Nature ^[2]have reported the brain damage caused by COVID-19 separately.

Mortality pattern of COVID-19

After the invasion of SARS-CoV-2 into the lungs, inflammation formed on that, and inflammatory exudation, like sputum, encroached patients’ alveoli, severely damaging the respiratory function of the lungs. Patients were unable to breathe normally and further developed symptoms of respiratory failure, which was followed by increased respiratory rate, chest tightness, wheezing, dyspnea, cyanosis, and finally gradual death in pain ^[4].

  Nonetheless, there are pieces of evidence indicating that the heart, kidneys, testicles, etc. might be affected by the COVID-19. With respect to the heart, COVID-19 can lead to myocarditis, cell necrosis, heart attack, arrhythmias, and acute or delayed heart failure, in addition, infected patients with heart disease before will have a higher risk of coming down with viral myocarditis; as for the kidney, under the influence of COVID-19, blood vessel dilation caused a sharp drop in blood pressure, leading to kidney injury and even failure; studies have shown that COVID-19 may also attack male testicles and affect male reproductive function. Moreover, COVID-19 can incur sudden death through the storm of inflammatory cytokines and immune organs damage ^[5].

COVID-19 infection can cause brain damage

During admitting patients, medical staff found that some patients had neurological symptoms, which were manifested in three categories. The first was central nervous system symptoms, such as headache, dizziness, disturbance of consciousness, acute cerebrovascular disease, epilepsy, etc.; secondly, symptoms of the peripheral nervous system, such as loss of taste, loss of smell, loss of appetite, neuralgia, etc.; lastly, damage to skeletal muscles ^[6].

  Lancet Psychiatry on June 25^th analyzed detailed clinic information of 125 COVID-19 patients that developed neurological or psychiatric symptoms. Researches found that among the 125 patients, 62 percent had impairment of blood supplying to the brain; 31 percent had changes in mental status, such as confusion or prolonged unconsciousness, with an occasional bout of encephalitis.

In July, some researchers compiled the case reports of 43 COVID-19 patients with neurological complications, found that the patients had many diseases that mainly attacked the brain, and the most common symptoms were stroke and encephalitis. Encephalitis can worsen into acute disseminated encephalomyelitis, which can cause inflammation of the brain and spinal cord at the same time, leading neurons to lose myelin sheath, and then symptoms similar to multiple sclerosis appear. In light of the above, it is believed that the SARS-CoV-2 infection can cause brain damage.

Reference:

[1] Varatharaj, Aravinthan et al. “Neurological and neuropsychiatric complications of COVID-19 in 153 patients: a UK-wide surveillance study.” The lancet. Psychiatry vol. 7,10 (2020): 875-882. doi:10.1016/S2215-0366(20)30287-X [2] Marshall, Michael. “How COVID-19 can damage the brain.” Nature vol. 585,7825 (2020): 342-343. doi:10.1038/d41586-020-02599-5