Autonomic and peripheral nervous system function in acute tick‐borne encephalitis

Abstract

ObjectivesTick‐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.MethodsFourteen 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.ResultsTick‐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.ConclusionsThe ANS and to a lesser degree the PNS are affected by acute TBE, which could potentially contribute to short‐ and long‐term morbidity.

Potential molecular mechanisms of chronic fatigue in long haul COVID and other viral diseases

“…Interestingly, one of the most common clinical manifestations of POWV encephalitis is muscle fatigue. Encephalitis is often associated with increased demyelination [ 57 ] of peripheral nerves [ 58 ] that in turn causes impairment of ion conduction through sensory neurons [ 59 ] resulting in abnormalities in neuromuscular function [ 60 ].…”

The epidemiology, clinical presentation, and predictors of severe Tick-borne encephalitis in Lithuania, a highly endemic country: A retrospective study of 1040 patients

“…Pathological studies from human post mortem CNS tissue revealed that TBEV selectively affects neurons in the brainstem, cerebellum, basal ganglia, and spinal cord. TBEV antigens were found in >50% of fatal cases in the medullar tegmentum and the pons, including its raphe nuclei and the locus coerulus, which are parts of the central ANS [ 23 ].…”

EAN consensus review on prevention, diagnosis and management of tick‐borne encephalitis

“…The myelitic form is rare (4%-15%), usually being associated with meningoencephalitis, and manifests with flaccid paralysis when motoneurons, radices or peripheral nerves are involved (poliomyelitic or polyradiculoneuritic forms, commonly seen in upper limbs and neck), or rarely with spastic pareses [5,30,[118][119][120][121][122][123]. Occasionally, autonomic disorders have been described in patients with TBE [124,125]. In endemic areas, concomitant TBE and Lyme neuroborreliosis may occur with more severe clinical course [126][127][128].…”