Chronic Hyponatremia and Brain Structure and Function Before and After Treatment

Area of Science:

• Neuroscience
• Endocrinology
• Radiology

Background:

• Hyponatremia is the most common electrolyte disorder, linked to significant morbidity and mortality.
• Neurologic symptoms are common in hyponatremia and may be reversible with treatment.

Purpose of the Study:

• To investigate neurocognitive impairment, brain volume, and cerebral function using MRI in patients before and after hyponatremia treatment.
• To assess the relationship between sodium levels, cognitive function, and brain activity.

Main Methods:

• Prospective cohort study involving 21 patients with chronic hyponatremia.
• Neuropsychological testing and resting-state MRI were performed before and after treatment to normalize sodium levels.
• Analysis included cognitive assessments, brain volume measurements, and assessment of neuronal activity and synchronization.

Main Results:

• Cognitive function significantly improved after hyponatremia treatment.
• MRI revealed decreased brain tissue volumes, neuronal activity, and synchronization in gray matter post-treatment.
• The hippocampus showed prominent volume reductions. Increased neuronal synchronization correlated negatively with sodium levels and cognitive function.

Conclusions:

• Hyponatremia resolution improves cognition and reduces brain activity and volumes, especially in the hippocampus.
• Impaired cognition in hyponatremia is associated with increased neuronal activity rather than solely tissue volume.
• The hippocampus is particularly susceptible to changes during hyponatremia.