Tickborne Encephalitis in an Area of High Endemicity in Lithuania: Disease Severity and Long‐Term Prognosis

Of 250 consecutively admitted patients with central nervous system (CNS) infections who were treated during a 1-year period, all 133 patients with tickborne encephalitis (TBE) were included in a prospective follow-up study. TBE presented as mild (meningeal) in 43.6% of patients and as moderate or severe (encephalitic) in 43.6% and 12.8% of patients, respectively. Paralytic disease was observed in 3.8% of the subjects, and cranial nerve injury was observed in 5.3%. One patient died of TBE. Permanent CNS dysfunction after 1 year was found in 30.8% of patients; in 8.5% of all TBE cases, severe disabilities required adjustment of daily activities. Corticosteroid treatment did not seem to improve outcome. A progressive course of TBE was noted in 2 patients. The risk of incomplete recovery was significantly higher among patients with the encephalitic form of TBE (odds ratio, 4.066; 95% confidence interval, 1.848-8.947). In conclusion, TBE is an important pathogen in CNS infection in the Kaunas region of Lithuania, and it causes long-lasting morbidity in one-third of cases.