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Images in Neurology
June 2009

Polyradiculitis as a Predominant Symptom of Tick-Borne Encephalitis Virus Infection

Arch Neurol. 2009;66(7):904-905. doi:10.1001/archneurol.2009.117

A 58-year-old man had rapidly progressive and painful paresis of the left leg. He described a tick bite 3 weeks prior to admission without having been vaccinated for tick-borne encephalitis virus (TBEv). Neurological examination showed pronounced diffuse paresis, hypesthesia, and diminished tendon reflexes of the left lower extremity. Analysis of cerebrospinal fluid demonstrated lymphoplasmacellular moderate pleocytosis (cell count, 44/μL; protein [total], 0.260 g/dL [to convert to grams per liter, multiply by 10.0]; glucose, 58 mg/dL [to convert to millimoles per liter, multiply by 0.0555]; lactate, 18.0 mg/dL [to convert to millimoles per liter, multiply by 0.111]) and detected IgM and IgG against TBEv. In the cerebrospinal fluid, oligoclonal bands were present, but identical bands were identified in the blood. In the serum, IgM against TBEv were also detected, and the IgG titer was elevated (94 U/mL). Titers and polymerase chain reaction evaluation for Lyme borreliosis were negative. Peripheral nerve electrophysiological studies were normal except for damage to the left peroneal nerve against the background of a past trauma. An electromyogram provided no evidence of florid damage in the gastrocnemius or tibialis anterior muscles. Motor evoked potentials to the left lower limb were abnormal, suggesting damage to the nerve root, plexus, or ischiadic nerve. Lumbar spine magnetic resonance imaging finally helped establish the diagnosis of TBEv polyradiculitis (Figure 1 and Figure 2).