Characteristic MRI finding in severe tick-borne encephalitis in children and the effect of immunoglobulin G on the course of the disease

Aims: Severe courses and permanent neurological residua after tick-borne encephalitis (TBE) are mainly reported in children over 16 years.¹ In our patient group, we were interested in the questions: are there specific MRI findings for TBE and the effect of IgG on the disease course?

Methods: Retrospective analysis: 5 patients (2 boys; 10 10/12 – 33 years, mean age 19 5/12 years) neurorehabilitation in our clinic during 1993 to 2012 for TBE (age at disease onset [d.o.] 3 4/12 – 13 11/12 years; mean age at d.o. 8 8/12 years). First manifestation of TBE: flue-like symptoms or gastroenteritis 8 to 21 days after a tick bite (recall of tick bite in 4/5 pat.) and meningoencephalitis with positive proof for IgM antibodies against TBE. One patient: active immunization; two patients: passive immunization for TBE.

Results: All patients showed symmetrical lesions of the basal ganglia in T2-weighted images of the MRI. Two children obtained passive immunization after tick bite and showed a very severe course of the disease with aggressiveness, symptomatic-focal epilepsy, and neuropsychological deficits. Two patients received nonspecific IgG (one patient during acute treatment).

Outcome: Out of the five patients, two (40%) had symptomatic-focal epilepsy; four out of the five patients (80%) had hemiparesis. One patient (with active immunization) showed a complete remission after administration of nonspecific IgG during acute treatment. Another patient (without vaccination for TBE) and severe transitional phase showed positive effect on rehabilitation after the administration of nonspecific IgG.

Conclusion: One should consider TBE in the course of a meningoencephalitis together with symmetrical thalamus lesions in the MRI even without a positive history of a tick bite. It has to be discussed if the early administration of nonspecific IgG could have a positive influence on the outcome. Our patient group is special-as for the severe course of the disease in children under 16 years of age as well as for the positive response to nonspecific IgG treatment-in one case even later during rehabilitation. Further studies are warranted to confirm our preliminary observations.

Reference

1 Berger Ch. Mosures de tique, meningo-encephalite verno-estivale et vaccination de l'enfant contre l'encéphalite à tiques. 2011