A flavivirus infection of the central nervous system characterised by a biphasic meningoencephalitis.
Transmission is usually by hard ticks of the Ixodes genus. It can also be acquired from consumption of raw (unpasteurised) milk or dairy products.
Disease onset is 4 to 28 days after a bite from an infected tick. Diagnosis is made based on immune status; seasonality; geographical, animal, and arthropod exposures; clinical findings; and radiographic abnormalities.
Treatment consists of supportive care and management of complications. Aciclovir is given empirically until herpes simplex/varicella zoster infection is ruled out.
Most patients recover fully without long-term sequelae.
Vaccines are available in various countries.
Tick-borne encephalitis (TBE) is a flavivirus infection of the central nervous system, characterised by a biphasic meningoencephalitis. It is transmitted usually by hard ticks of the Ixodes genus. Disease onset is 4 to 28 days after a bite from an infected tick. TBE can also be acquired from consumption of raw (unpasteurised) dairy products.
History and exam
Key diagnostic factors
- presence of risk factors
- general malaise
- body pains
- mild meningitis
- severe encephalitis
- altered mental state
Other diagnostic factors
- cranial and spinal nerve palsies
- vestibular/hearing defects
- arms, shoulders, and head muscles paralysis
- history of recent tick bite
- summer months
- occupational exposure
- outdoors activities
- recent consumption of raw (unpasteurised) milk or dairy products
- age ≥50 years
1st investigations to order
- CT brain
- cerebrospinal fluid analysis
- cerebrospinal fluid/serum serology
Investigations to consider
- cerebrospinal fluid/serum reverse-transcription polymerase chain reaction
- MRI head
suspected viral aetiology
- Aseptic meningitis
- Encephalopathy (toxic/metabolic)
- Status epilepticus
- CDC Health Information for International Travel (the Yellow Book): viral hemorrhagic fevers
- Tickborne diseases abroad
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