Enterovirus encephalitis is an inflammation of brain tissue caused by pathogens of the genus Enterovirus, which includes polio viruses, Coxsackie A and B, ECHO viruses and human enteroviruses (types 68-72). The disease is manifested by fever, headaches, gastrointestinal tract damage (abdominal pain, nausea, vomiting). Also, with encephalitis, focal symptoms occur, convulsive seizures, rash on the skin and mucous membranes are possible. For diagnostic purposes, magnetic resonance imaging of the brain, analysis of cerebrospinal fluid, identification of the pathogen (PCR, RSC, virological method) is carried out. In enterovirus encephalitis, pathogenetic treatment with subsequent rehabilitation is prescribed.
ICD 10
A85.0 Enterovirus encephalitis
General information
Enterovirus encephalitis, like other viral lesions of the central nervous system, is more common in young children. According to various data, enteroviruses account for from 12% to 20% of all encephalitis. Pathology proceeds relatively favorably compared to other neuroinfections, however, with untimely medical care, there is a risk of severe neurological complications. In this regard, early detection and treatment of encephalitis is a priority task of pediatric neurology.
Causes
The causative agents of the disease are small viruses from the Picornaviridae family of the genus Enterovirus. Encephalitis is most often associated with infection with ECHO viruses or Coxsackie viruses of group A (23 serotypes), B (6 serotypes). Less often, the cause of cerebral lesions are polio viruses, which have 3 serotypes, enteroviruses of types 68-72. In 60% of cases, enterovirus disease is detected in children under 9 years of age.
The natural host of enteroviruses is a human. Pathogens are transmitted by airborne droplets from a patient with an active form of infection, by fecal-oral method from a virus carrier. Viruses have extremely small sizes — 17-28 nm. They are stable in the environment, they persist for a long time in water (even in chlorinated water) if there is a sufficient number of organic compounds in it.
Pathogenesis
At the initial stage of infection, enteroviruses multiply in the lymphoid formations of the upper respiratory tract (with airborne infection) or Peyer’s plaques and mesenteric lymph nodes (with the primary penetration of the pathogen into the intestine). This stage is accompanied by characteristic clinical signs. In the absence of a strong immune response, viruses enter the bloodstream, a generalized stage of infection occurs.
The high frequency of enterovirus lesions of the central nervous system is due to the ability of the pathogen to easily overcome the blood-brain barrier (BBB). In this case, the neurons of some brain areas are damaged with concomitant disruption or shutdown of some neurological functions. The inflammatory process in the central nervous system also leads to the accumulation of toxins, decay products of viruses, which increases the permeability of capillaries, causes petechial hemorrhages.
Symptoms
Brain inflammation manifests 3-12 days after infection. The prodromal period is poorly expressed, so enterovirus encephalitis begins suddenly, reaches its peak within a few days. The first symptom of the disease is fever (38.5-40 ° C), which has a wave-like character: the temperature normalizes by 3-6 days of the disease, then rises again for several days. On average, 2-4 fever waves are observed in children.
Typical signs of enterovirus encephalitis include diffuse headache, 20-40% of children complain of pain in the umbilical region, nausea, vomiting. Patients become lethargic, drowsy, and in severe cases there is a deep depression of consciousness. Meningeal signs (rigidity of the occipital muscles, symptoms of Kernig, Brudzinsky) are poorly expressed, they occur when the process spreads from the nervous tissue to the meninges.
With significant focal lesions in children, various manifestations of neurological deficits appear, which depend on the localization of pathology. Most often, this manifests itself with paresis, sensitivity disorders, shaky or unstable gait. Disorders of speech function, loss of the ability to read or write, tinnitus, and other hearing disorders are often noted.
Among the external signs of the disease in enterovirus infection, children have a spotty or hemorrhagic skin rash. During the examination of the oral cavity, hyperemia of the pharynx, granularity of the posterior wall of the pharynx, red rashes on the mucous membrane are revealed. Lymph nodes may also increase. In 10-30% of cases, when examining a child at a later stage of the disease, an increase in the liver and spleen is determined.
Complications
About 10% of cases of enterovirus encephalitis have serious negative consequences. In the acute period of pathology in children, there is a possibility of impaired cerebrospinal fluid dynamics, brain edema, which is fraught with trunk wedging, the development of life-threatening neurological disorders. Damage to the cerebral nervous tissue can be accompanied by generalized convulsive seizures, turning into an epileptic status.
In the recovery period after enterovirus encephalitis or meningoencephalitis, fibrous changes in the structures of the central nervous system are possible, which causes the appearance of paresis and paralysis, hypertension syndrome, epileptiform disorders. Often, children have residual symptoms in the form of increased fatigue, decreased learning ability, memory and concentration disorders. Emotional lability persists for a long time.
Diagnostics
During a clinical examination of a patient, a pediatric neurologist identifies symptoms typical of encephalitis, but he cannot accurately determine the enterovirus or other etiology of inflammation. It is important to collect an epidemiological history. To diagnose the disease in children, a full range of studies is needed, which includes the following methods:
- Neuroimaging. To verify the diagnosis, an MRI of the brain is prescribed, which shows foci of demyelination, signs of inflammation, changes in the basal nuclei. If MRI is not possible, as well as to exclude hydrocephalus or cerebral edema, a CT scan of the brain is performed.
- Lumbar puncture. The study determines an increase in the pressure of the cerebrospinal fluid (up to 300-400 mm of water and above), neutrophil pleiocytosis in the first 2-3 days of the disease, which is then replaced by a lymphocytic cell reaction. The protein level increases slightly, the glucose content is within the normal range.
- Laboratory diagnostics. To confirm the enterovirus etiology of the inflammatory process, virological examination of fecal masses is carried out in children, serological diagnostics (neutralization reaction) is performed with paired blood sera with a 14-day interval. PCR is considered an informative method, and RSC is recommended for express analysis.
Treatment
Specific etiotropic drugs for enterovirus brain lesions have not been developed, so pathogenetic therapy is used in children. The treatment regimen is selected individually, taking into account the severity, the period of the disease, the presence of complications or concomitant pathologies. The following groups of drugs are used for encephalitis:
- Infusion solutions. Intravenous infusions of crystalloid and colloidal solutions in a ratio of 3:1 are necessary to restore systemic blood flow, prevent shock, detoxification of the body.
- Diuretics. Dehydration therapy is indicated to eliminate intracranial hypertension, prevent edema-swelling of the brain. For this purpose, osmodiuretics, saluretics, oncodehydrants are introduced.
- Corticosteroids. Hormones are recommended as decongestants, anti-inflammatory agents, stabilizers of the blood-brain barrier. In children, they are used in age-related doses with constant monitoring of the condition.
- Neurometabolites. To relieve oxidative stress, replenish energy deficiency, and protect brain tissue from further damage, nootropics, B vitamins, and antioxidants are included in the therapeutic regimen.
- Immunomodulators. Interferon preparations, interferon inducers, synthetic immunostimulants are used to enhance the immune response against enterovirus infection.
An important point in the treatment of enterovirus encephalitis is adequate oxygen support. With an uncomplicated course of the disease, the absence of cerebral edema, inhalation of moistened oxygen is effective. With a pathological type of breathing or impaired consciousness, a ventilator is indicated in the mode of moderate hyperventilation, which contributes to the restoration of cerebral tissue perfusion.
After the elimination of the acute encephalitis clinic and stabilization of the general condition, the patient needs rehabilitation therapy in the pediatric neurological department. In addition to metabolic drugs, physical therapy, physiotherapy, and massage are prescribed as you recover. If necessary, rehabilitation is supplemented with classes with a children’s speech therapist.
Prognosis and prevention
Enterovirus encephalitis has a more favorable course in comparison with bacterial or fungal brain inflammations. About 90% of children successfully recover without severe residual consequences, but the rest have neurological deficits. The prognosis of the disease is largely determined by the localization and size of the cerebral tissue lesion, the completeness of medical care provided, and the volume of the rehabilitation program.
Specific prevention has been developed only for polio — mandatory vaccination of children in the first year of life. Non-specific preventive measures include careful processing of food products, the use of high-quality drinking water, teaching the child the rules of personal hygiene. Public prevention includes control of environmental pollution by sewage waste, disinfection of wastewater.
