Sven Kühn1, Darius Gerlach2, Hans-Jürgen Noblé1, Frank Weber1, Jörn Rittweger2, Jens Jordan2,3, Ulrich Limper2,4. 1. German Air Force Center of Aerospace Medicine, Fürstenfeldbruck, Germany. 2. German Aerospace Center (DLR), Institute of Aerospace Medicine, Cologne, Germany. 3. Institute of Aerospace Medicine, University of Cologne, Cologne, Germany. 4. Department of Anesthesiology and Intensive Care Medicine, Merheim Medical Center, Hospitals of Cologne, University of Witten/Herdecke, Cologne, Germany.
Abstract
Background: In human beings exposed to high altitude, cerebral magnetic resonance imaging (cMRI) revealed alterations ranging from subclinical cerebral edema formation to subtle brain abnormalities. Yet, brain structure after adaptation to high altitude and their recovery after return to lowlands have been rarely investigated. We, therefore, examined 10 healthy individuals by cMRI before, 12 hours after descent (R + 12h), and again 3.5 months (R + 3.5m) after a 7-day high altitude exposure at 4554 m. Results: After their 3-day lasting, stepwise ascent to 4554 m, all subjects suffered acute mountain sickness with a mean Lake Louise score of 5.8 ± 1.7 after the first night at that altitude. Acute mountain sickness completely resolved after 4 days at 4554 m. While 12 hours after descent mean white and gray matter volumes were increased compared with before altitude exposure (p = 0.045 and p = 0.002), these volumes were normalized on R + 3.5m. Moreover, we observed significant focal volume alterations likely attributed to either vasogenic or cytotoxic edema formation. Two subjects presented new brain findings after altitude exposure. In one individual the number of preexisting white matter hyperintensities (WMHI) transiently increased, in the other individual a reversible splenial lesion syndrome (RESLES) emerged. Both findings had resolved 15 and 8 days after descent, respectively. None developed structural lesions like brain atrophy, cerebral infarcts, microbleeds, or high-altitude cerebral edema. Discussion: Three days after complete recovery from acute mountain sickness and after return to low altitude, subclinical vasogenic and cytotoxic edema, RESLES and WMHI are present in high-altitude acclimatized individuals. However, these cerebral alterations are reversible within months at lowland.
Background: In human beings exposed to high altitude, cerebral magnetic resonance imaging (cMRI) revealed alterations ranging from subclinical cerebral edema formation to subtle brain abnormalities. Yet, brain structure after adaptation to high altitude and their recovery after return to lowlands have been rarely investigated. We, therefore, examined 10 healthy individuals by cMRI before, 12 hours after descent (R + 12h), and again 3.5 months (R + 3.5m) after a 7-day high altitude exposure at 4554 m. Results: After their 3-day lasting, stepwise ascent to 4554 m, all subjects suffered acute mountain sickness with a mean Lake Louise score of 5.8 ± 1.7 after the first night at that altitude. Acute mountain sickness completely resolved after 4 days at 4554 m. While 12 hours after descent mean white and gray matter volumes were increased compared with before altitude exposure (p = 0.045 and p = 0.002), these volumes were normalized on R + 3.5m. Moreover, we observed significant focal volume alterations likely attributed to either vasogenic or cytotoxic edema formation. Two subjects presented new brain findings after altitude exposure. In one individual the number of preexisting white matter hyperintensities (WMHI) transiently increased, in the other individual a reversible splenial lesion syndrome (RESLES) emerged. Both findings had resolved 15 and 8 days after descent, respectively. None developed structural lesions like brain atrophy, cerebral infarcts, microbleeds, or high-altitude cerebral edema. Discussion: Three days after complete recovery from acute mountain sickness and after return to low altitude, subclinical vasogenic and cytotoxic edema, RESLES and WMHI are present in high-altitude acclimatized individuals. However, these cerebral alterations are reversible within months at lowland.
Entities:
Keywords:
RESLES; acclimatization; cytotoxic edema; vasogenic edema; white matter lesion
Authors: Diego Iacono; Erin K Murphy; Paul M Sherman; Holly Chapapas; Bianca Cerqueira; Christine Christensen; Daniel P Perl; John Sladky Journal: Sci Rep Date: 2022-04-27 Impact factor: 4.996