Tick-borne encephalitis: diagnosis

Diagnosis of tick-borne encephalitis is based on anamnestic, clinical epidemiological and laboratory data. Great importance in endemic regions is attached to visits to forests, a park, summer cottage in the spring and summer, the fact of sucking a tick, and eating unboiled goat or cow's milk.

Indications for consultation of other specialists

All patients with tick-borne encephalitis are subject to mandatory consultation with a neurologist. Patients with a progressive course of tick-borne encephalitis are provided with out-patient and in-patient care by a neurologist, and, if necessary, for infectious disease doctors.

Indications for hospitalization

All patients with suspected tick-borne encephalitis are hospitalized in a specialized infectious department with an intensive care unit.

Clinical diagnosis of tick-borne encephalitis

Early clinical diagnostic symptoms of tick-borne encephalitis - fever to 39-40 ° C, chills, headache, dizziness, nausea, vomiting, general weakness, pain in the muscles, joints, lower back.

On examination, attention is drawn to the presence of hyperemia of the face, neck and upper body, injection of vessels of sclera, conjunctivitis and hyperemia of the oropharynx. Patients are flaccid, adynamic. It is necessary to carefully inspect the skin, since spots or different sizes of hyperemic spots may remain at the site of suction of the mites. All patients need to explore the neurological status.

[1], [2], [3], [4], [5], [6],

Specific and nonspecific laboratory diagnostics of tick-borne encephalitis

In the peripheral blood there is a moderate lymphocytic leukocytosis, sometimes a shift to the left with an increase in the number of stab wedges, an increase in ESR.

In the two-wave course of the disease, the first wave in most patients is accompanied by leukopenia with relative lymphocytosis. During the second wave - leukocytosis with neutrophil shift and an increase in ESR. When meningeal and focal forms of the disease in the spinal cord fluid, lymphocytic pleocytosis is detected, from several tens to several hundred cells in 1 μl.

Laboratory diagnosis of tick-borne encephalitis is based on the detection of antibodies in the blood of the diseased. Use RSK, RTGA ,. RN and other methods.

Standard for diagnosis of tick encephalitis

The diagnostic standard is ELISA which allows to separately determine the total pool of antibodies to the virus, immunoglobulins of class G and M. Determination of class M immunoglobulins is important for the diagnosis of not only acute cases of the disease but also exacerbations of chronic course. Immunoglobulins of class G - the consequence of the transferred disease or effective vaccination. Serological studies are carried out in paired sera taken at the beginning and end of the disease. In the absence of antibodies, it is possible to study the third blood sample taken 1.5-2 months after the onset of the disease.

In recent years, the PCR method has been introduced into clinical practice, which makes it possible to detect specific fragments of the virus genome in the blood and spinal fluid on the early stages of the disease. The method allows you to diagnose within 6-8 hours.

Example of the formulation of the diagnosis

A84.0. Tick-borne encephalitis, meningeal form, moderate severity (PCR of the cerebrospinal fluid is positive).

[7], [8], [9], [10]

Differential diagnosis of tick-borne encephalitis

Differential diagnosis of tick-borne encephalitis is carried out with three main groups of diseases:

• other transmissible infections carried by ixodid mites;
• infectious diseases with acute onset and expressed common infection manifestations;
• other neuroinfections.

In regions endemic for tick-borne encephalitis, as a rule, there are other vector-borne infections: systemic tick-borne borreliosis and tick-borne rickettsiosis. The common for these infections is a tick bite in the anamnesis, approximately the same incubation periods and the presence of symptoms of intoxication in the acute period.

Simultaneous infection (from 0.5 to 5-10%) by the causative agents of tick-borne encephalitis and borrelemia of ticks I. Persulcatus determines the existence of conjugated natural foci of these infections and the possibility of developing in one patient the signs of both diseases, i.e. Mixed infection. To diagnose a mixed infection, it is necessary to have clinical signs of two infections. The diagnosis of tick-borne encephalitis is based on the characteristic clinical picture of the disease and the detection of IgM in the serum or the growth of IgG titres to tick-borne encephalitis virus. The diagnosis of tick-borne borreliosis is based on the clinical picture (migratory erythema, Bannwart's syndrome, facial nerve neuritis, polyradiculoneuropathy, myocarditis, polyarthritis) and serum determination of IgM titres to Borrelia burgdorferi or IgG titres increase with ELISA.

Differential diagnosis of tick-borne encephalitis with influenza should take into account the seasonality of the disease, visiting the forest, the presence of contact with mites or the fact of hypothermia, as well as the results of laboratory studies.

Hemorrhagic fever with renal syndrome from tick-borne encephalitis is characterized by painful pain in the lumbar region, marked changes in the clinical analysis of blood (from the 3-5th day of the disease neutrophilic leukocytosis, shift of the leukocyte formula to the left, the appearance of plasmocytes, an increase in ESR up to 40-60 mm / h ) and the development of renal insufficiency, characterized by oliguria. Low relative density of urine, proteinuria.

In carrying out differential diagnosis of meningeal forms of tick-borne encephalitis with meningitis caused by other viruses (Coxsackie viruses, ECHO, mumps, influenza, herpesviruses), it is first of all necessary to pay attention to seasonality of the disease and indication of a history of visiting the forest, bites and attack of ticks. Along with the clinical symptoms of the disease, great importance is the methods of virological and serological studies of blood serum.

For tuberculous meningitis is characterized by a prodromal period, the gradual development of meningeal symptoms involving the process of cranial nerves. With the growth of meningeal symptoms, lethargy and adynamia increase, the patients gradually fall into a co-morbid state. Excitation is rare. Headache is pronounced. Spinal-cerebral fluid flows under high pressure; lymphocytic pleocytosis; the protein content is increased, glucose - reduced. Characteristic is the formation in the cerebrospinal fluid of a gentle film, sometimes with the presence of mycobacteria tuberculosis, which finally clarifies the diagnosis. When X-ray examination is often observed various changes in the lungs of a tubercular nature. In the anamnesis, there is often a tuberculosis in the patient himself or in his environment.

[11], [12], [13]