Neurocovid is an unofficial name for lesions of the central and peripheral nervous system in COVID–19. The condition is caused by both the direct damaging effect of the coronavirus and indirect systemic disorders of the body. Pathology has polymorphic manifestations: asthenic syndrome, psychoemotional disorders, cognitive deficits. Severe forms of neurocovid are characterized by disorders of cerebral circulation. Diagnosis requires neuroimaging (CT, MRI), EEG, ultrasound of the vessels of the head and neck. Methods of pharmacotherapy, physiotherapy, psychotherapy, lifestyle correction are used to treat the neurological consequences of COVID-19.
ICD 10
U09.9 Condition after COVID-19 unspecified
General information
According to American studies, 49% of patients in the USA, 50% in the UK, 35-45% in Germany face neurological consequences of a new coronavirus infection. On average, more than a third of patients who have had COVID-19 present complaints typical of brain and peripheral nerve damage. The situation is complicated by the fact that the symptoms are superimposed on other manifestations of the acute period of coronavirus and postcovid syndrome. Neurological aspects of the coronavirus pandemic require further study and selection of optimal medical care schemes, including long-term rehabilitation.
Causes
Damage to the nervous system occurs in any clinical form of COVID-19, including asymptomatic or low-symptomatic course. Since damage to the central nervous system and peripheral nervous structures does not always have a direct connection with coronavirus disease, further large-scale studies and meta-analyses are required. At the same time, establishing exact cause-and-effect relationships is difficult, especially in patients with concomitant diseases.
SARS-CoV-2 is tropic not only to the respiratory epithelium, but also to neurons, cells of the neuroglia and endothelium. The most likely way of virus penetration into the brain is called trans-synaptic transfer along the fibers of the olfactory nerve. The contact spread of the virus through the endothelium is important in pathogenesis. It is assumed that viral particles can also penetrate macrophages and pass through the BBB unhindered by the “Trojan horse” mechanism.
Predisposing factors
The probability of the appearance of a neurocovid depends on the severity and clinical variant of the coronavirus infection. Acute complications from the central nervous system are 2-3 times more likely to occur in patients with severe COVID-19 who receive treatment in intensive care units. Long-term neurological consequences are possible with any variant of the disease, including infection with omicron, which is considered less dangerous among all strains of coronavirus.
An important risk factor for late neurocovid is long–term and massive drug treatment. The use of high doses of systemic corticosteroids, monoclonal antibodies and vascular drugs negatively affects cerebral blood flow. The situation worsens with polypragmasia and in patients with comorbid conditions requiring maintenance therapy. There is a tendency to increase the frequency and severity of neurocovid among elderly patients.
Pathogenesis
Recent studies show that SARS-CoV-2 is able to overcome the blood-brain barrier (BBB). This is implemented by three main mechanisms. Firstly, the virus interacts with angiotensin converting enzyme receptors, which are actively expressed on the endothelium of cerebral vessels. Secondly, viral protein S directly damages the BBB. Thirdly, the pathogen activates the vascular inflammatory reaction and disrupts microcirculation.
SARS-CoV-2 infection causes direct damage to nerve cells. The viral genome is embedded in the mitochondrial matrix of neurons, after which the replication of the pathogen is activated. Oxidative stress develops in infected cells, the influx of calcium ions is activated and mitochondrial dysfunction increases. Such changes result in necrosis or apoptosis of neurons in different parts of the brain.
The development of a neurocovid is closely related to systemic inflammatory reactions and mitochondrial disorders. With a “cytokine storm”, the level of interleukins 6 and 12, a tumor necrosis factor, sharply increases. Substances increase vascular permeability in the central nervous system, contribute to the formation of microthrombs and disrupt the blood supply to the brain. All this accelerates the passage of the virus through the BBB.
Symptoms
Headache is the most common neurological manifestation of coronavirus infection, which occurs in most patients in the acute period and worries more than 13% of patients during post-covid. The symptom is often accompanied by dizziness, muscle pain, increased fatigue. Anosmia and dysgeusia occur in 85-88% of people in the initial period of the disease, in 10% of cases they persist for more than 6 months after the COVID-19.
A serious problem is the asthenic syndrome in neurocovid, which is manifested by a decrease in working capacity, rapid fatigue after minor loads, lack of vigor even after a long rest. The situation is aggravated by cognitive impairments: deterioration of short-term and long-term memory, decreased concentration, thinking disorders.
Neurological complications of coronavirus infection include disorders of the autonomic nervous system that controls the activity of internal organs. Fluctuations in blood pressure and pulse are characteristic, especially during verticalization and physical exertion. There are orthostatic and reflex fainting, non-systemic dizziness. Postural hypoxemia develops, which is manifested by shortness of breath when getting out of bed.
The mental aspects of the neurocovid are of concern. The psychoemotional state of patients worsens against the background of quarantine, self-isolation, a large number of frightening news. The coronavirus pandemic is characterized by a special “headline stress disorder” syndrome – severe stress and constant anxiety, which is complemented by somatic manifestations in the form of palpitations, insomnia, discomfort in the heart and stomach.
Complications
In elderly people and patients with other risk factors, cerebrovascular consequences may develop: ischemic stroke, venous sinus thrombosis, hemorrhage in brain tissue. The risk of stroke in the acute period of coronavirus infection varies from 2.8% to 8.7%. Mortality in the group of patients with COVID-19 with ONMC is 5-6 times higher than the average in the population.
In the period of neurocovid, the debut of autoimmune polyradiculoneuropathies (Guillain-Barre and Miller-Fisher syndromes), leukoencephalopathy, multiple sclerosis is possible. Severe complications include meningoencephalitis, acute necrotizing encephalopathy. About 50% of people with hyperthermia and decreased saturation have signs of encephalopathy: ataxia, confusion, mental symptoms.
Diagnostics
Examination of patients with acute manifestations of neurocovid requires the participation of a neurologist, an infectious disease specialist, and resuscitators. In case of chronic consequences of COVID-19, patients undergo diagnosis and therapy in the neurological department. An important role is played by collecting complaints, clarifying the infectious and epidemiological history, the status of vaccination against coronavirus infection. The complete diagnostic program includes the following methods:
- Examination by a neurologist. Assessment of neurological status is the basic method of research in neurocovid. During physical examination, the level of consciousness, the preservation of superficial and deep sensitivity, the state of motor and higher mental functions are determined. According to the indications, the diagnosis is supplemented with a consultation of a psychiatrist.
- MRI of the brain. The images show multifocal lesions in the white matter, signs of spot hemorrhages. In acute disorders of cerebral circulation, in 80-90% of cases, areas of hyperintensivity are visible, which appear in the first hours and allow for a quick differential diagnosis.
- Ultrasound Dopplerography. The study quickly reveals blood flow disorders in extra- and intracranial vessels, indicates the localization and extent of pathological changes. UZDG also shows the parameters of venous outflow, the state of collateral circulation, the presence of arteriovenous malformations.
- EEG. The study of the electrical activity of the brain is carried out in cognitive disorders, convulsive paroxysms, insomnia. By the shape and ratio of different types of waves, it is possible to judge the functional state of nerve structures, determine the localization and degree of pathological changes.
- Laboratory diagnostics. Analyses of the cellular and biochemical composition of blood are necessary to assess the general state of health. Additionally, the study of acute phase indicators, autoimmune markers is carried out. If shortness of breath persists, a blood gas analysis is required.
The main task of differential diagnosis is to distinguish the manifestations of neurocovid and neurological problems that arise for other reasons. To do this, patients undergo a complete laboratory diagnosis with PCR examination, analysis for antibodies of classes M and G. Also, patients need to consult a cardiologist, pulmonologist, immunologist to exclude other manifestations of postcovid syndrome.
Treatment
The therapeutic program is selected taking into account the nosological form of the neurocovid, the severity of the patient’s condition and the presence of concomitant diseases. In case of critical neurological complications, treatment is carried out in an intensive care or neurological hospital. Chronic symptoms require long-term outpatient therapy followed by neurorehabilitation.
Drug treatment of neurocovid includes vasoactive drugs, neuroprotectors and nootropics, vitamin complexes. Sedatives, antidepressants and light tranquilizers are used to stabilize the mental state. With ONMC, thrombolytic, anticoagulant and antiplatelet therapy is necessary. The manifestation of autoimmune processes requires the intake of steroid hormones and immunosuppressants.
To restore health, non-drug methods play an important role: lifestyle changes, gradual expansion of physical activity, balanced and fortified nutrition. After improving well-being, spa treatment, thalassotherapy, speleotherapy and balneotherapy are recommended. Patients are assisted at individual and group psychotherapy sessions, art therapy and music therapy methods are used.
Prognosis and prevention
When conducting a comprehensive therapeutic program, it is possible to fully restore neurological functions in most patients. However, recovery and rehabilitation take time: in 20% of people, pathological symptoms persist for more than 5 weeks, in 10% – longer than 3 months. A less favorable prognosis for the development of ischemic or hemorrhagic stroke with neurocovid, after which residual neurological changes remain.
Anti-epidemic measures aimed at combating the spread of COVID-19 form the basis for the prevention of neurocovid. In the absence of contraindications, it is strongly recommended to undergo a full course of vaccination against SARS-CoV-2, which is the most reliable protection against infection and the development of severe complications. Non-specific measures are also important: physical distancing, wearing personal protective equipment, limiting social contacts.