Encephalitis caused by herpes simplex virus

Encephalitis, which is caused by the herpes simplex virus , is a very common clinical manifestation of a severe generalized herpes infection that affects the entire nervous system of the human body. Occurs sporadically. The severity of this disease is associated with the necrotic nature of the process and the subsequent formation of foci of hemorrhagic decay of the brain substance. In addition to herpetic encephalitis in newborns, in most other cases the causative agent of herpetic encephalitis is the herpes virus type 1. The main route of spread of infection is airborne, but household contact is also possible.

CLINICAL PICTURE

The disease begins acutely, with a rise in body temperature. Meningeal symptoms quickly appear, and general epileptic seizures often occur. Focal symptoms are manifested by central mono- and hemiparesis, hyperkinesis. In the cerebrospinal fluid, pleocytosis with a predominance of lymphocytes (up to several hundred cells in 1 μl), an increase in protein content (up to 2-3 g/l), mild xanthochromia or a small admixture of erythrocytes is detected.

SYMPTOMS

Early clinical manifestations of encephalitis are not specific. The onset of the disease resembles an influenza infection. The first symptoms are an increase in body temperature to high levels, severe headaches, decreased or complete loss of appetite, nausea, and possibly repeated vomiting. A state of prostration appears. Further, if the source of inflammation is localized in the temporal or frontal lobes of the brain, adults and older children may experience inappropriate behavior, psychosensory disturbances, skin hyperesthesia, delirium syndrome, taste and olfactory hallucinations. All of the above symptoms in young children are almost impossible to recognize. Subsequently, the course of the disease is in many ways similar to the clinical picture of acute encephalopathy, which is expressed in an increasing disturbance of consciousness from somnolence and stupor to cerebral coma.

One of the main manifestations of encephalitis is local convulsive twitching or attacks of generalized tonic or clonic-tonic seizures, which in younger children can develop at the very beginning of the disease, which can cause errors in diagnosis. Within a few days, depending on the focus of the inflammatory process, focal neurological symptoms in the form of hemiparesis, various sensitivity disorders, and aphasia begin to intensify. In addition, symptoms such as drooping of the corner of the mouth, smoothness of the nasolabial fold on one side, unilateral blepharoptosis, anisocoria, and deviation of the tongue may be observed. As a manifestation of increasing intracranial pressure, examination of the fundus reveals a congestive optic disc. In most cases, a sign confirming the herpetic nature of encephalitis is the appearance of a vesicular rash on the skin of the body around the end of the first week of the disease. If left untreated, the disease begins to progress steadily and in most cases has a poor prognosis.

A significant number of surviving patients develop severe persistent residual effects from the neuropsychic sphere in the form of intellectual impairment and the development of paralysis, paresis and contractures.

TREATMENT

Treatment should be carried out exclusively by a neurologist. Self-medication is unacceptable. Etiotropic therapy for herpetic encephalitis includes antiviral treatment with acyclovir (Zovirax, Virolex). This therapy should be based on the results of a clinical examination of the patient. Laboratory specific examination methods are time-consuming and cannot provide early diagnosis. Therefore, treatment with acyclovir should be started as early as possible, only if the herpetic nature of the disease is suspected, as well as with encephalitis of unknown etiology. To reduce body temperature, physical cooling methods are used - applying ice to the head and on the area of large vessels, wiping the surface of the body with alcohol or a 1-2% solution of vinegar or wrapping in a wet sheet, administering antipyretic drugs such as paracetamol, aspirin, cefekon and etc., introduction of lytic mixtures.

Herpes simplex - symptoms and treatment

The incubation period for the acquired form lasts 2-14 days. Most often, it cannot be installed due to lack of manifestation.

Herpes simplex in children usually occurs as stomatitis and gingivitis - the temperature rises, fever, general intoxication, focal hyperemia (redness) of all mucous formations of the oral cavity, pain when chewing, increased salivation. Small children refuse to eat due to pain. In a short period of time, small vesicular rashes appear at the site of hyperemia, which quickly open, leaving behind painful erosions - aphthae. Regional lymph nodes enlarge and become painful. Over time, the immune system strengthens and the symptoms gradually regress without any traces of damage. Relapses are rare.

When the skin is affected (mainly in adults), vesicular rashes often appear around the mouth, wings of the nose, and sometimes on the torso and buttocks. The rash consists of small vesicles with serous contents on a slightly hyperemic skin background. Subsequently, they open and dry out, after which crusts form without a trace.

Sometimes the bubbles merge into quite large bubbles. Often their contents fester, oozing forms, and a secondary streptococcal or staphylococcal infection (staphylo- and streptoderma) occurs.

General health, as a rule, does not change. Sometimes the regional lymph node may be slightly enlarged and painful. In general, the process rarely lasts more than a week.

With severe immunodeficiencies, the infection may take a more widespread (generalized) course. In this case, a syndrome of general infectious intoxication occurs and internal organs are affected: the liver and spleen are enlarged, the nervous system is affected (meningoencephalitis, encephalitis and meningitis), as well as the lungs, kidneys and other organs. With relapses of a chronic infection, patients sometimes feel mild discomfort and tingling in the area of future rashes.

With genital herpes, rashes appear on the skin and mucous membranes in the genital area and perineum. They are usually accompanied by soreness, hyperemia of the surrounding tissue, enlargement and tenderness of the inguinal lymph nodes. The frequency of relapse depends on the individual characteristics of the immune system.

With ophthalmoherpes - eye herpes - unilateral lesions are more often observed due to the transition of the primary process to the organ of vision, i.e., a secondary lesion occurs. Keratitis, blepharoconjunctivitis, iridocyclitis, uveitis, chorioretinitis, optic neuritis and other manifestations may be observed.

A very unusual form of manifestation of herpes simplex is known as Kaposi's eczema herpetiformis - eczema herpeticum. As a rule, it occurs in people who have any skin disease or predisposition to it (dermatosis or “problem skin”). In this case, intoxication and high body temperature are observed, herpetic blisters appear everywhere, quite abundant and closely spaced, periodically merging, sometimes with hemorrhagic impregnation. In some cases, they suppurate, then they open, dry out and form a solid crust. When the rash is completely treated with green paint, the patient’s skin takes on the appearance of crocodile skin. The disease is often quite severe and can lead to death.

During pregnancy, the child becomes infected:

before birth - in 5% of cases (primary infection and ascending infection during this period are rare);
during childbirth, i.e. when passing through the natural birth canal - in 95% of cases.

With primary infection of a pregnant woman in the first trimester or with ascending infection of the fetus, malformations often develop that are incompatible with life, or a miscarriage occurs, especially when infected with type II herpes virus, which is the infecting agent most often - up to 80% of cases.

When a pregnant woman is infected in the second and third trimesters, the risk of injury to the child is about 50%. At the same time, the liver and spleen enlarge, specific inflammation of the lungs, jaundice, metabolic disorders, malnutrition, meningoencephalitis, anemia and more occur. After birth, it can occur either in an asymptomatic subclinical form or have severe disabling consequences - blindness, severe damage to the central nervous system, deafness [1][2][6][8][11].

The main factors causing viral encephalitis

The most common source that can begin to activate inflammation in the body is the herpes simplex virus. In addition to it, various other infections become the mechanism of manifestation:

Cytomegalovirus.
Chicken pox.
Mononucleosis.
Enteroagents.
Adenoviruses and others.

The ways of spreading the disease are:

Airborne method.
Contact.
Fecal-oral.
Transmissible.
Vaccination.

The development of this disease often occurs in newborns and people of retirement age. And also in patients suffering from HIV and other conditions that impair the functioning of the immune system.

Varicella zoster infection

Varicella-zoster virus causes chickenpox and herpes zoster. The source of infection for chickenpox can only be a person with chickenpox or herpes zoster, including the last 24-48 hours of the incubation period. Convalescent chickenpox remains infectious for 3-5 days after the skin rash stops. The disease cannot be transmitted through a third party. Intrauterine infection with chickenpox is possible in the case of a pregnant woman. Chickenpox can occur at any age, but in modern conditions the maximum number of patients occurs in children aged 2 to 7 years. Herpes zoster develops after primary infection with the Varicella-zoster virus, after the infection passes into a latent form, in which the virus is localized in the spinal, trigeminal, sacral and other nerve ganglia. Endogenous reactivation of the infection is possible.

Etiology

Herpes viruses contain double-stranded DNA and have a glyco-lipoprotein envelope. The sizes of viral particles are from 120 to 220 nm.

Today, 8 types of herpes viruses that have been identified in humans have been described:

two types of herpes simplex virus (HSV-1, HSV-2),
varicella zoster virus (VZV or HHV-3),
Epstein-Barr virus (EBV or HHV-4),
cytomegalovirus (CMV or HHV-5), HHV-6, HHV-7, HHV-8.

Based on the biological properties of viruses, 3 subfamilies of herpes viruses have been formed: (alpha herpes viruses, beta herpes viruses and gamma herpes viruses). A-herpesviruses include HSV-1, HSV-2, VZV.

Betaherpesviruses include CMV, HHV-6, HHV-7. They, as a rule, multiply slowly in cells, cause an increase in the affected cells (cytomegaly), are capable of persistence, mainly in the salivary glands and kidneys, and can cause congenital infections. Gammaherpesviruses include EBV and HHV-8.

Symptoms

The first stage of the anomaly is distinguished by such complaints as:

Feverish condition.
Manifestation of malaise.
Painful sensations in the muscles.
Sore throat.
Loose stools.
Compression in the abdominal area.

The second stage involves the following problems:

Pain in the head area.
Nausea unrelated to eating.
Gag reflexes.
Particular sensitivity to bright light.
Dizziness.
Psychosensory disturbances.
General lethargy.
Epileptic seizures and more.

Simultaneously with these manifestations, focal neuralgic disorders progress. At the same time, the person begins to experience:

Impaired sensitivity of the limbs.
Difficulties in coordinating voluntary muscle activity.
Problems with the speech apparatus.
Sources of damage to FM neurons.
Change in gait.
Tremor.

The described symptoms can be diagnosed in various forms of the disease. But some manifestations of viral inflammation have a special type of severity, for example:

Serious disturbances in consciousness.
Hallucinations.
Psychomotor seizures, etc.

Epstein-Barr virus infection

An infectious disease caused by the Epstein-Barr virus (EBV) and characterized by a systemic lymphoproliferative process with a benign or malignant course.

EBV is isolated from the body of a patient or virus carrier with oropharyngeal secretions. Transmission of the infection occurs through airborne droplets through saliva, often when a mother kisses her child, which is why EBV infection is sometimes called the “kissing disease.” Children often become infected with EBV through toys contaminated with the saliva of a sick child or a virus carrier, when using shared utensils and linen. Blood transfusion and sexual transmission of the infection are possible. Cases of vertical transmission of EBV from mother to fetus have been described, suggesting that the virus may be the cause of intrauterine developmental anomalies. Contagiousness during EBV infection is moderate, which is probably due to the low concentration of the virus in saliva. The activation of infection is influenced by factors that reduce general and local immunity. The causative agent of EBV infection has a tropism for the lymphoid-reticular system. The virus penetrates the B-lymphoid tissues of the oropharynx and then spreads throughout the body's lymphatic system. Infection of circulating B lymphocytes occurs. The DNA virus penetrates into the nuclei of cells, while the proteins of the virus give infected B-lymphocytes the ability to continuously multiply, causing the so-called “immortality” of B-lymphocytes. This process is a characteristic feature of all forms of EBV infection.

EBV can cause: infectious mononucleosis, Burkitt's lymphoma, nasopharyngeal carcinoma, chronic active EBV infection, leiomyosarcoma, lymphoid interstitial pneumonia, hairy leukoplakia, non-Hodgkin's lymphoma, congenital EBV infection.