Tick-borne encephalitis

Description of the disease

A virus belonging to the genus Flavivirus of the Flaviviridae family causes this meningoencephalomyelitis, or inflammation of the nervous system. Ticks, specifically Ixodes ricinus, transmit this virus. Every year, 10,000 – 13,000 people get sick with tick-borne encephalitis, of which 1000 – 2000 are in the Baltic countries. Only 30% of those infected develop symptomatic form, 3% of Lithuanian residents have had asymptomatic form. Children up to 16 years old make up 6-20% of all TBE patients. Infection occurs through tick bites (65.8%), consumption of unpasteurized or unboiled cow, goat milk or dairy products.

Symptoms

Symptoms of tick-borne encephalitis appear 1-2 weeks after infection (the earlier, the more severe the disease). The first and only symptom is fever, lasting 2-5 days, then the person feels nothing for about a week, but after a week various symptoms appear, lasting about 10-21 days.
Tick-borne encephalitis can affect the following:
a) meninges – meningitis. Manifested by headache, nausea and vomiting, fever, stiff neck, meningeal posture – head tilted back and legs bent.
b) brain – encephalitis. Various symptoms occur depending on the localization of brain damage. Typically there are speech, thinking, attention, balance disorders, tremors, less commonly – hearing, vision, movement, breathing disorders, mental/consciousness disorders, etc.
c) spinal cord – myelitis. Weakness in arms, legs, sensory disturbances, urinary/defecation disorders may occur.

Epidemiological History

• Tick bite
• Being in the forest
• Drinking unpasteurized milk

Clinical Indicators

• Clinical symptoms
• Characteristic changes in blood

Diagnostic Methods

• The main method of diagnosing TBE involves collecting cerebrospinal fluid during a lumbar puncture and detecting virus-specific IgM class antibodies in it (antibodies produced by the human body against the virus).
• The blood also shows the presence of IgM.

Treatment

Overview There is no specific treatment for tick-borne encephalitis (TBE). Antiviral drugs are ineffective.

Symptomatic Treatment

• Fluids and Electrolytes: Administer fluids with electrolytes to maintain hydration and balance.
• Glucose: Provide glucose if necessary to manage blood sugar levels.
• Antiepileptic Drugs: Use antiepileptic drugs if required to control seizures.
• Pain Management: Administer painkillers to relieve pain.

Managing Brain Edema

• Diuretics: Use diuretics to reduce brain edema.
• Fluid-Reducing Agents: Employ additional agents that reduce fluid accumulation.

Corticosteroids Opinions on the use of corticosteroids for treating TBE are controversial, and their use may vary based on individual cases and physician preference.

During the acute period, physiotherapy, massages, therapeutic exercises are applied. Vaccinations are recommended for prevention.

Source | Author Doctor Nikas Samuolis, reviewed by Prof. Virginijus Šapoka | Vilnius University | Faculty of Medicine | Head of the Department of Internal Medicine, Family Medicine, and Oncology