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As harmful as dehydration?

Researchers uncover mechanisms of overhydration leading to hyponatremia – a common condition in patients after a traumatic brain injury

May 22, 2018

We are all familiar with the drawbacks of dehydration, but we rarely hear about the harmful effects of overhydration. It is known that excess fluid accumulation can lead to dangerously low sodium levels in the blood or hyponatremia – a life-threatening condition that can result in brain swelling. Similarly, more is known about the mechanisms in the body that detect and drive thirst while little is known about how the brain detects a state of overhydration.

"[Hyponatremia] occurs in common pathological conditions, including brain injury, sepsis, cardiac failure and in the use of drugs, such as MDMA (ecstasy),” says Dr. Charles Bourque, whose team from the Centre for Research in Neuroscience at the Research Institute of the McGill University Health Centre (RI-MUHC) uncovered a key piece to the puzzle of how our brains detect hyponatremia and regulate overhydration. The new study featured in Cell Reports unearths the fundamental mechanism of how hyponatremia is detected in the brain.

“Our specific data will be important for people studying hydromineral and fluid electrolyte homeostasis, and clinicians who treat patients faced with hyponatremia,” reports Dr. Bourque, who is a scientist in the Brain Repair and Integrative Neuroscience Program (BRAIN) at the RI-MUHC and a professor in McGill’s Department of Neurology. This condition is more common in elderly patients and can cause cognitive problems and seizures in this vulnerable group. While it remains uncertain how hyponatremia develops, a defect in the hydration sensing mechanism of the brain could be the culprit.

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