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@ARTICLE{Surez:1027034,
author = {Suárez, Victor and Picotin, Rosanne and Fassbender, Ronja
and Gramespacher, Hannes and Haneder, Stefan and Persigehl,
Thorsten and Todorova, Polina and Hackl, Matthias Johannes
and Onur, Oezguer A. and Richter, Nils and Burst, Volker},
title = {{C}hronic {H}yponatremia and {B}rain {S}tructure and
{F}unction {B}efore and {A}fter {T}reatment},
journal = {American journal of kidney diseases},
volume = {84},
number = {1},
issn = {0272-6386},
address = {Philadelphia, Pa.},
publisher = {Elsevier Saunders},
reportid = {FZJ-2024-03600},
pages = {S0272638624000015},
year = {2024},
abstract = {Rationale $\&$ objective: Hyponatremia is the most common
electrolyte disorder and is associated with significant
morbidity and mortality. This study investigated
neurocognitive impairment, brain volume, and alterations in
magnetic resonance imaging (MRI)-based measures of cerebral
function in patients before and after treatment for
hyponatremia.Study design: Prospective cohort study.Setting
$\&$ participants: Patients with presumed chronic
hyponatremia without signs of hypo- or hypervolemia treated
in the emergency department of a German tertiary-care
hospital.Exposure: Hyponatremia (ie, plasma sodium
concentration [Na+]<125mmol/L) before and after treatment
leading to [Na+]>130mmol/L.Outcomes: Standardized
neuropsychological testing (Mini-Mental State Examination,
DemTect, Trail Making Test A/B, Beck Depression Inventory,
Timed Up and Go) and resting-state MRI were performed before
and after treatment of hyponatremia to assess total brain
and white and gray matter volumes as well as neuronal
activity and its synchronization.Analytical approach:
Changes in outcomes after treatment for hyponatremia
assessed using bootstrapped confidence intervals and Cohen d
statistic. Associations between parameters were assessed
using correlation analyses.Results: During a 3.7-year
period, 26 patients were enrolled. Complete data were
available for 21 patients. Mean [Na+]s were 118.4mmol/L
before treatment and 135.5mmol/L after treatment. Most
measures of cognition improved significantly. Comparison of
MRI studies showed a decrease in brain tissue volumes,
neuronal activity, and synchronization across all gray
matter after normalization of [Na+]. Volume effects were
particularly prominent in the hippocampus. During
hyponatremia, synchronization of neuronal activity was
negatively correlated with [Na+] (r=-0.836; $95\%$ CI,
-0.979 to-0.446) and cognitive function (Mini-Mental State
Examination, r=-0.523; $95\%$ CI, -0.805 to-0.069; DemTect,
r=-0.744; $95\%$ CI, -0.951 to-0.385; and Trail Making Test
A, r=0.692; $95\%$ CI, 0.255-0.922).Limitations: Small
sample size, insufficient quality of several MRI scans as a
result of motion artifact.Conclusions: Resolution of
hyponatremia was associated with improved cognition and
reductions in brain volumes and neuronal activity. Impaired
cognition during hyponatremia is closely linked to increased
neuronal activity rather than to tissue volumes.
Furthermore, the hippocampus appears to be particularly
susceptible to hyponatremia, exhibiting pronounced changes
in tissue volume.Plain-language summary: Hyponatremia is a
common clinical problem, and patients often present with
neurologic symptoms that are at least partially reversible.
This study used neuropsychological testing and magnetic
resonance imaging to examine patients during and after
correction of hyponatremia. Treatment led to an improvement
in patients' cognition as well as a decrease in their brain
volumes, spontaneous neuronal activity, and synchronized
neuronal activity between remote brain regions. Volume
effects were particularly prominent in the hippocampus, an
area of the brain that is important for the modulation of
memory. During hyponatremia, patients with the lowest sodium
concentrations had the highest levels of synchronized
neuronal activity and the poorest cognitive test
results.Keywords: Hyponatremia; cerebral edema; functional
MRI; neuropsychological assessment.},
cin = {INM-3},
ddc = {610},
cid = {I:(DE-Juel1)INM-3-20090406},
pnm = {5251 - Multilevel Brain Organization and Variability
(POF4-525)},
pid = {G:(DE-HGF)POF4-5251},
typ = {PUB:(DE-HGF)16},
pubmed = {38184092},
UT = {WOS:001260318200001},
doi = {10.1053/j.ajkd.2023.11.007},
url = {https://juser.fz-juelich.de/record/1027034},
}