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

TLDR

A prospective follow‑up study included all 133 tick‑borne encephalitis patients identified among 250 consecutive central nervous system infection admissions over one year. Among these patients, 43.6% had mild meningeal disease, 43.6% moderate, and 12.8% severe; 3.8% developed paralytic disease, 5.3% cranial nerve injury, one death occurred, and 30.8% had permanent CNS dysfunction after one year, with severe disabilities in 8.5%; corticosteroid treatment did not improve outcomes, and the encephalitic form carried a four‑fold higher risk of incomplete recovery, underscoring that TBE causes long‑lasting morbidity in about one‑third of cases.

Abstract

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.