title: Autonomic and peripheral nervous system function in acute tick-borne encephalitis.
abstract: Tick-borne encephalitis (TBE) is an emerging flaviviral zoonosis in Central and Eastern Europe. TBE can present as meningitis, meningoencephalitis, or meningoencephalomyelitis. Dysfunction of the autonomic (ANS) and peripheral motoric and sensory nervous system (PNS) might contribute to acute and long-term complications. We aimed to examine, whether the ANS and PNS are affected in acute TBE.
  
  
  
  Fourteen patients with acute TBE, 17 with diabetic polyneuropathy (d-PNP), and 30 healthy controls (HC) were examined in our single-center, prospective study. ANS and PNS function was assessed by time- and frequency-domain parameters of the heart rate (HR) variability at rest and deep respiration, and by sural and tibial nerve neurography. Primary endpoint was the HR variability at rest measured by root mean square of the successive differences (RMSSD). Autonomic symptoms and quality of life (QoL) were assessed by questionnaires.
  
  
  
  Tick-borne encephalitis patients had a lower RMSSD at rest (TBE 13.1 ± 7.0, HC 72.7 ± 48.3; P < 0.001) and deep respiration (TBE 42.8 ± 27.0, HC 109.7 ± 68.8; P < 0.01), an increased low-frequency to high-frequency power component ratio at rest (TBE 4.0 ± 4.0, HC 0.8 ± 0.5; P < 0.001), and a higher minimal heart rate at rest (TBE 85.4 ± 7.0, HC 69.5 ± 8.5; P < 0.001), all similar to patients with d-PNP, indicating sympathovagal imbalance with increased sympathetic activation. Compared to HC, sural and tibial nerve conduction velocities and action potential amplitudes were reduced, ANS symptoms were more frequent, and QoL was lower in patients with TBE.
  
  
  
  The ANS and to a lesser degree the PNS are affected by acute TBE, which could potentially contribute to short- and long-term morbidity.
authors.affiliation: Department of Neurology University Medical Centre Regensburg Regensburg Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Neumann
authors.affiliation: Department of Neurology University Medical Centre Regensburg Regensburg Germany.
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Schulte-Mattler
authors.affiliation: Department of Neurology University Medical Centre Regensburg Regensburg Germany.
authors.forename: Sophie
authors.initials: S
authors.lastname: Brix
authors.affiliation: Department of Neurology Krankenhaus der Barmherzigen Brüder Regensburg Regensburg Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Pöschl
authors.affiliation: Department of Medical Microbiology and Hygiene University Medical Centre Regensburg Regensburg Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Jilg
authors.affiliation: Department of Neurology University Medical Centre Regensburg Regensburg Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bogdahn
authors.affiliation: Department of Neurology University Medical Centre Regensburg Regensburg Germany; Department of Neurology HELIOS Klinikum Erfurt Erfurt Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Steinbrecher
authors.affiliation: Department of Neurology St. Josef-Hospital Ruhr-University Bochum Bochum Germany.
authors.forename: Ingo
authors.initials: I
authors.lastname: Kleiter
mesh_terms: D000328:Adult; D000368:Aged; D001342:Autonomic Nervous System Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000150:complications*; D004675:Encephalitis, Tick-Borne / Q000150:complications*; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology; D011788:Quality of Life; D012119:Respiration; D013497:Sural Nerve / Q000503:physiopathology*; D013979:Tibial Nerve / Q000503:physiopathology*; D014636:Valsalva Maneuver / Q000502:physiology; D055815:Young Adult
keywords: Autonomic nervous system; central nervous system infection; encephalitis; inflammatory neuropathy; meningitis