EUROPEAN JOURNAL OF NEUROLOGY

Sareban M, Berger MM, Pinter D, Buchmann A, Macholz F, Schmidt P, Schiefer L, Schimke M, Niebauer J, Steinacker JM, Treff G and Khalil M

Eur J Neurol. 2020 Oct 23.

DOI: https://doi.org/10.1111/ene.14606

Abstract

Background

At high altitude the brain is exposed to hypoxic stress, which may result in neurological conditions with acute mountain sickness (AMS) being the most common one. We hypothesized that rapid ascent to high altitude alters neuro‐axonal integrity that can be detected by increased concentration of serum neurofilament light (sNfL) in the blood and may be even exaggerated in subjects with AMS.

Methods

sNfL was measured by a single molecule array (Simoa) assay in 47 healthy subjects at low altitude (423m) and 44h after rapid and active ascent to high altitude (4559m). Peripheral oxygen saturation (SpO2) and partial pressures of oxygen (pO2) were obtained at low and high altitude. The Acute Mountain Sickness‐Cerebral (AMS‐C) scoring system was used to assess AMS‐incidence and ‐severity.

Results

sNfL increased from baseline to high altitude (6.34±1.96 vs 7.19±3.14 pg/mL; p=0.014) but sNfL did not correlate with SpO2 (r=‐0.19; p=0.066) or pO2 (r=‐0.19; p=0.068). The incidence of AMS at high altitude was 62%. Neither at low altitude (p=0.706) nor at high altitude (p=0.985) there was a difference in sNfL between subjects with and without AMS as measured three days following rapid ascent and 44h of high‐altitude exposure. Altitude sNfL did not correlate with AMS‐C overall‐ and single item‐scores such as headache severity.

Conclusions

Rapid ascent of healthy subjects to high altitude provokes an increase in sNfL 44h after arrival at 4559m, which is not related to the magnitude of hypoxaemia or AMS incidence and severity, suggesting that neuro‐axonal injury does not directly contribute to AMS.