Fatal hyponatraemic brain oedema due to common gastroenteritis with accidental water intoxication.

Acute symptomatic hyponatraemia is a life-threatening emergency which must be diagnosed and treated promptly. The initial symptoms are often dramatic, with seizures and coma, and there is therefore a risk that the diagnosis and the urgent sodium correction therapy may be delayed by procedures such as computed tomography (CT) of the brain. As the most common aetiological factors are psychotic polydipsia and different iatrogenic causes, this condition usually develops in hospitalised patients. Water intoxication alone is very unlikely to cause severe hyponatraemia in a person with normal renal function, unless for some reason the antidiuretic hormone secretion is increased. We describe a case in which dehydration due to common gastroenteritis in combination with excessive intake of water caused the death of a young, previously healthy woman. Increased awareness of this potentially fatal condition is recommended.