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Since the first official case of Covid-19 in China in December 2019, researchers have sought to unravel the mechanism of action of Sars-CoV-2 (new coronavirus), which attacks several organs in addition to the lungs and causes changes in circulation, which can lead to death. only due to pulmonary insufficiency. The National Health Service of countries in more advanced stages of the pandemic, such as the United Kingdom, believes that several physical, cognitive and psychological sequelae must persist in Covid-19 patients, especially respiratory ones if they follow the patterns of SARS (Acute Respiratory Syndrome Severe) and MERS (Middle East Respiratory Syndrome).
Recent publications in scientific journals New England Journal of Medicine e Brain document neurological symptoms in patients with Covid-19. They range from simple cognitive difficulties to mental confusion, in addition to headache, loss of smell and tingling, as well as encephalitis, hemorrhage, thrombosis, ischemic stroke, necrotic changes and Guillain-Barré Syndrome, neurological conditions not always correlated with the severity of respiratory symptoms. “What impressed the pathologists most were the signs of ischemia and hypoxemia, rather than inflammatory lesions. It's extremely intriguing and we don't know why the virus causes so many neurological problems. The olfactory pathway is a possible gateway, but not only does it justify psychiatric problems”, explains Clarissa Lin Yasuda, neurologist at the Department of Neurology and Neurosurgery at the State University of Campinas (Unicamp).
No virus was detected in the CSF in any of the studies mentioned. Clarissa comments on the case of a patient with a very serious condition of loss of motor coordination, also with the absence of the virus on magnetic resonance images and in the cerebrospinal fluid. “It appears that the effects do not occur through the direct action of the virus, but rather through more indirect mechanisms that cause damage to the nervous system. We have not seen many cases of specific or necrotizing encephalitis as serious as those reported in these studies, but rather other manifestations such as Guillain-Barré Syndrome that can evolve into very serious conditions,” she explains.
Pathologists evaluate tissue and organ injuries and help treat serious cases. “Autopsies that we have carried out in recent months on patients diagnosed with Covid-19 reveal that the virus spreads through several organs such as the heart and kidneys in addition to the lungs and reaches the brain through the olfactory nerve”, said Paulo Saldiva, pathologist at Hospital das Clinics of the Faculty of Medicine of the University of São Paulo (USP), during the Virtual Annual Meeting of the Brazilian Society for the Progress of Science (SBPC), on July 13. According to Paulo, in many cases cardiovascular changes occur even when the lung is better preserved.
The long-term behavior of Sars-CoV-2 is a worrying enigma. The varicella-zoster virus that causes chickenpox, for example, can remain inactive in the spinal cord for years and reactivate in a situation of low immunity, causing herpes zoster (shingles). Clarissa comments on two cases of patients who had already recovered from Covid-19, since April, who returned to have symptoms in July when they tested positive again in the RT-PCR, a test used to analyze the gene expression and quantification of viral RNA. “They do not have neurological changes, but symptoms of Covid-19. Infectious disease specialists do not know whether they became infected again with Sars-CoV-2 or another undetected virus, or if Sars-CoV-2 became lodged in the tissue. It is impossible to say because it is not known whether people develop immunity to this virus or not”, warns the neurologist.
Although the impact of Sars-CoV-2 on the lungs is unprecedented and frightening, lasting impacts on the nervous system may be greater and even more overwhelming due to the difficult regeneration of nervous tissue and may result in general disabilities as the nervous system coordinates the body's functions. as a whole.
Traces of Covid-19
In Brazil there is but of 1,6 million recovered from Covid-19. The Ministry of Health's Epidemiological Surveillance System indicates that 50% of the most serious patients survive. According to the World Health Organization (WHO), the chance of sequelae increases in critically ill patients who have had a prolonged stay in the ICU (Intensive Care Unit) and need to use respirators. Recovery can take three to six weeks or more.
There can be many post-intubation complications resulting from prolonged intubation (artificial respiration) followed by tracheostomy (a procedure that facilitates the arrival of air to the lungs when there are obstructions), the most common being laryngeal damage such as injuries to the vocal cords and narrowing of the larynx, and airway trauma. They can cause damage to vocalization, breathing and swallowing.
Luciana Castilho de Figueiredo, physiotherapy supervisor at the ICU of the Hospital de Clínicas (HC) at Unicamp, emphasizes the need for multidisciplinary and interdisciplinary rehabilitation of severe post-Covid-19 patients, involving physiotherapists, speech therapists, doctors, nutritionists and others. “Symptoms such as loss of taste and smell were already signs of something very serious in relation to eating habits and are made worse by dysphagia (difficulty swallowing) resulting from prolonged intubation and tracheostomy”. Swallowing changes not adequately treated; They can lead to malnutrition, dehydration, bronchopneumonia and even lead to death. “Talking and eating are part of happy habits, they are part of what is worthy of people”, highlights the physiotherapist.
Embolic processes may occur when weaning from mechanical ventilation or due to an exaggerated inflammatory response. Small clots break off and are transported by the blood to various organs where they can obstruct vessels and make it impossible for cells to oxygenate. The consequences can be pulmonary embolism, thrombosis, heart attacks and ischemic stroke. “An ischemic stroke can generate an infinite number of impairments, such as paralysis of movement and loss of speech”, emphasizes Luciana.
“We noticed a polyneuropathy (nerve disorder) that appears very acutely, quickly and severely, encompassing muscle weakness and loss of muscle and motor skills”, comments the physiotherapist. Less severe patients are showing gradual development of signs of polyneuropathy: tingling and numbness, burning-like pain and inability to feel vibrations or the position of limbs and joints. This is what Alessandra Alday, 48 years old, reported. “Two months ago I had the first symptoms of Covid-19 and I still feel weakness, muscle pain in my body and severe discomfort, like chronic fatigue. Only then did the sensations of tingling and heaviness in the legs come. The doctor suspects a peripheral neurological disorder similar to Guillain-Barré Syndrome”, reveals Alessandra, who tested positive for the disease in May.
Luciana highlights that physiotherapeutic intervention has a huge impact on the rehabilitation of severe Covid-19 patients. “It aims to make the patient relearn how to breathe on their own in a spontaneous and safe way, as only then will they be able to leave the ICU for the ward. Assists in early mobilization throughout hospitalization to assist with movement. In persistent respiratory sequelae that do not progress to fibrosis (replacement of functional lung tissue by non-functional tissue, scar) marked by oxygen dependence, physiotherapy in cardiovascular rehabilitation that involves a physiological adaptation to exercise is essential”.
How long will they persist?
The scenario is still unclear and it will be necessary to monitor complications in Covid-19 victims. HC-Unicamp is evaluating implementing a telemedicine and telerehabilitation program. “The first step would be to evaluate the respiratory impairment demonstrated by fatigue in the pulmonary function test, followed by an individualized rehabilitation program in which the patient could receive a kit with a communication device, a respiratory exerciser and an activity program that he can do it at home”, informs the physiotherapist.
Preliminary data collected by neurologist Clarissa through online quiz point out that around 67% of patients recovered from Covid-19 without hospitalization present some persistent neurological symptom: chronic fatigue (30%), memory problems (25%), loss of smell (20%), headaches (15% ) and loss of taste (10%). Only 33% consider themselves without symptoms. “It is very serious to say that only 33% consider themselves healthy and without symptoms, and none of these patients were hospitalized. Imagine what the situation of seriously ill patients will be like”, emphasizes Clarissa.
The Neuroimaging Laboratory at HC-Unicamp, associated with Cepid Brainn (Brazilian Institute of Neuroscience and Neurotechnology linked to the Fapesp Research, Innovation and Diffusion Centers program) will carry out an MRI study on patients with post-Covid-19 neurological conditions and who had neurological changes in the acute phase, in patients with few neurological changes or only changes in smell and taste, and in those who were asymptomatic from a neurological point of view. “In image processing we can detect subtle brain changes. My hypothesis is that the virus could cause structural changes or even changes in brain function, or even some degree of atrophy”, explains the neurologist. Monitoring these patients will allow us to assess the long-term impact of Sars-CoV-2 on the nervous system.
Currently, Brazil has lost over 82 thousand Brazilians to Covid-19 and there are more than 1,6 million recovered, many of whom may still need medical care. “It is difficult to talk about the marks of Covid-19. The number of deaths is an impact that is immeasurable. The denial of science and disregard for lives impresses me. I felt sadness, discouragement, fear of transmitting the virus to my family, fear of dying or having consequences. I'm learning a new way of living by enjoying my flowers and rediscovering little things that give me joy. The prospect of resignification gives me hope. There is life here and it is flourishing”, reflected Alessandra Alday hopefully.
