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Chapter 5: TBE in adults

2004 to 2014. All patients were evaluated by of EEG pathology and clinical condition. In
high-resolution MRI. Clinical symptoms were most cases, an initially abnormal EEG
scored using the modified RANKIN Scale at normalizes within a few weeks. The EEG may
admission and at defined follow-up dates. The be of prognostic value when there is a
results indicate a strong correlation between persistence of pathological patterns or the
meningo- encephalomyelitis documented on appearance of new irregularities. 68,69
MRI and a poor outcome. Further risk factors

for a worse outcome were age, male gender,
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and preexisting diabetes mellitus. Cranial Prognosis, long-term sequelae
computed tomography (CCT) is usually
negative and not recommended for the and Postencephalitic syndrome
diagnosis of encephalitic brain lesions. In (PES)
some rare occasions CCT may show symmetric
or asymmetric bilateral hypodensities of the The case fatality rate (CFR) from infection with
thalami and/or basal ganglia. 62–65 Single TBEV-EU is reported to range between 1% and
photon emission computed tomography 2%. 2,41 In lethal cases, death occurs within 5–
(SPECT) is a highly sensitive functional imaging 10 days after the onset of neurological
method for the detection of cerebral symptoms in the context of diffuse brain
perfusion abnormalities. A SPECT study from edema and bulbar involvement.
Sweden including adult patients with TBE
(n=73), and patients with other forms of There are several retrospective and
meningoencephalitis (n=56), showed a prospective studies from different countries
decrease in regional cerebral blood flow regarding long-term morbidity of TBE patients
(rCBF). However, these findings were not (Table 1). Overall, there is a high proportion of
significantly related to the clinical course or patients with persistent post-TBE symptoms of
the outcome of TBE. 42,66 Thus, the significance different severity. However, differences in
of this reduced rCBF remains unclear. Another patient selection, age-specific exposure,
pilot study using 18F-FDG PET/CT in 10 access to medical care, and selective reporting
patients with TBE showed that glucose of more severe cases may result in bias in
hypometabolism was present in 7 out of 10 these data and may explain, in part, the
patients with TBE, reflecting neuronal discrepancies between different TBEV
dysfunction in areas prone to TBEV infiltration subtypes. 8,43,56,70–74
and responsible for the development of
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clinical signs and symptoms. PES is a condition that includes residual
(behavioral) changes following the recovery

from viral or bacterial encephalitis according
to the international classification for diseases.
EEG The symptoms are nonspecific and, in contrast
to organic disorders, are often reversible.
In the acute stage of CNS inflammation,
There may be a variety of residual neuro-
electro-encephalograms (EEGs) show patho-
logical dysfunctions, such as paralysis,
logical patterns. In a study by Lindquist, there deafness, or aphasia. Initially, doubts were
were abnormal EEG findings in 77% of patients raised whether PES after TBE exists; however,
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with TBE.
a recent study specifically assessed the
incidence and characteristics of PES after TBE.
An abnormal EEG correlates with the severity
of the clinical condition of the TBE patient; Between 1995 and 2008, 124 patients aged 16
however, there is no link between the degree – 76 years were followed for >3 years. Of

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