Magnetic resonance neuroimaging findings in high-altitude cerebral edema (HACE) and probable correlation with its temporal evolution and pathogenesis.

Abstract

Background: High-altitude illness (HAI) is a spectrum continuum ranging from innocuous high-altitude headache
(HAH) to severe, potentially fatal high-altitude cerebral edema (HACE) with acute mountain sickness (AMS) and high
altitude pulmonary edema (HAPE) in the middle of the gamut. MRI brain findings in such patients have prognostic
implications, especially the diffusion and susceptibility-weighted imaging.
Methodology: Twenty-one devotees visiting a high-altitude cave temple, in whom there was a clinical suspicion of
high-altitude cerebral edema after the ascent, were included in this study. All the patients met the criteria for diagnosis of
acute mountain sickness (AMS) as well as HACE. MRI brain was done in all 21 patients with special emphasis on
diffusion and susceptibility-weighted imaging.
Results: Diffusion restriction with T2/FLAIR hyperintensity was present in the splenium of the corpus callosum in all
21 patients. Other sites involved were centrum semiovale and deep white matter (90.5%), middle cerebellar peduncles
(66.7%), and posterior limb of the internal capsule (57%). SWI revealed multiple tiny cerebral microbleeds in the splenium,
deep white matter, and middle cerebellar peduncles.
Conclusion: This study suggests the evolution of diffusion restriction, T2/FLAIR hyperintensity, and cerebral
microbleeds in the splenium of the corpus callosum and white matter in HACE correspond well with the temporal
evolution of cytotoxic, ionic, and vasogenic cerebral edema underpinning the role of brain water dyshomeostasis, central
to the pathogenesis of HACE.