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Chapter 5: TBE in adults

depending on the affected parts of the CNS, Patients with meningoencephalomyelitis may
such as meninges (meningitis), brain experience paresis of the arms, back, and legs,
(encephalitis), cranial, or spinal nerves with the upper extremities affected more
(meningoencephalomyelitis). The specific often than the lower extremities. Bilateral
clinical symptoms in the second stage of TBE paresis is a rare symptom (Photo 1 and 2).
result from the affinity of the virus for distinct Involvement of the medulla oblongata and the
CNS regions, producing additional clinical central parts of the brainstem (bulbar) is
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symptoms like chorea, parkinsonism, associated with the poor prognosis (Photo
mutism, nystagmus, and others. Encephalitic 3). Occasionally, TBE can be associated with
symptoms are classified as mild to severe. autonomic dysfunction including reduced
heart rate variability and tachycardia.
Meningitis presents with headache, nausea,
vomiting, vertigo, and neck stiffness. Signs of Flaccid paralysis arises, very similar to that
meningeal irritation (neck stiffness, Brudziński, seen in poliomyelitis, due to the viral
Kernig’s signs) have a low clinical sensitivity preference for the anterior horn of the
and could even be absent, leaving headache cervical spinal cord. In contrast to
and febrile temperatures as the only poliomyelitis, mono-, para-, or tetraparesis
symptoms. In a study from Poland, 10% of the develops in 5–10% of patients. Paralysis of
TBE patients with CSF pleocytosis were respiratory muscles may also occur, neces-
without objective meningeal symptoms. 53,54 In sitating ventilatory support. Cranial nerve
pediatric TBE patients, fever without neuro- involvement is associated mainly with ocular,
logical symptoms is more often the chief facial, and pharyngeal motor functions.
complaint compared with adult patients. Hearing defects may also occur. Brainstem
involvement (particularly of the medulla
Meningoencephalitis is observed in adults in oblongata) can lead to bulbar syndrome, with
50% of TBE cases. 55,56 Symptoms are the risks of sudden respiratory and circulatory
cerebellar signs and typically include ataxia. failure. 6,7,41,42,57
The most common neurological symptom is
altered mental state, ranging from Chronic TBE – chronic TBEV infection
somnolence to coma with 12% of TBE patients
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in this phase exhibiting a GCS score below 7. Some peculiarities in the course of TBE are
Disorientation, excitation, seizures, and observed in Western Siberia. The onset of
confusion are also observed, as well as illness is more often gradual than acute, with a
hyperkinesia of limbs and facial muscles, prodromal phase including fever, headache,
cranial nerve involvement with paresis of anorexia, nausea, vomiting, and photophobia.
facial and ocular nerves, cerebellar ataxia, and These symptoms are followed by a stiff neck,
autonomic disturbances of the bladder and sensorial changes, visual disturbances, and
intestines. Spinal nerve paralysis has been variable neurological dysfunctions, including
documented in 11-15% of patients. Depending paresis, paralysis, sensory loss, and convul-
on the extent of the CNS affection, meningo- sions. In fatal cases, death occurs within the
encephalitis can be moderate or severe. first week after onset. The case-fatality rate is
Severe myalgia in the extremities sometimes approximately 20%, compared with 1–2% for
precedes the development of paresis. Involve- the European form. However, these findings
ment of the cranial nerve nuclei and motor may be biased by the different types of
neurons of the spinal cord causes flaccid medical treatment available in Western and
paralysis of neck and upper extremity muscles Eastern Europe. It is supposed that, in contrast
(Photo 1). to the European form, the disease caused by
TBEV-FE is more severe in children than in

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