Drinking too much water can kill you say doctors

DRINKING too much water can be deadly – but doctors do not know how much is too much, it has emerged.

Experts say the advice that sick people are given to “drink plenty of fluids” could kill them.

Doctors at King’s College Hospital in London questioned the recommendation after treating a 59-year-old woman who had drunk so much water she became gravely ill.

She effectively overdosed on water after developing symptoms of a urinary tract infection (UTI). She recalled being told by a doctor to drink lots of water – half a pint every 30 minutes – though she said she had consumed more to “flush out her system”.

The woman was admitted to Accident and Emergency where doctors found she was suffering from acute hyponatraemia, which is caused by low salt levels in the blood.

It can occur if too much water is drunk over a short period of time. Symptoms include vomiting and headaches.

In serious cases the brain can swell which can lead to confusion, seizures, coma and death.

Tremulous

A death rate of almost 30 per cent has been reported in patients with low salt levels.

Writing in the journal BMJ Case Reports, doctors described how the woman got worse, explaining: “During her visit to the emergency department, she became progressively shaky and muddled. She vomited several times, was tremulous and exhibited significant speech difficulties.”

Although doctors were able to save her life with treatment, they described another case in which a young woman suffering from gastroenteritis died after consuming too much water.

The doctors said: “We frequently advise patients to ‘drink plenty of fluids’ and ‘keep wellhydrated’ when they are unwell.

“But, what do we mean by that? Are there potential risks of this apparently harmless advice?

“The harmful effects of increased fluid intake include confusion, vomiting and speech disturbance – and the potential for catastrophic outcomes due to low blood sodium concentrations.”

Dr Marynn Noronha of the Royal London Hospital, who wrote to the BMJ raising the issue, said: “When people get common illnesses like UTIs and food poisoning, they often selfmedicate by drinking lots of water.

“But we actually have no idea how our body – which is already busy fighting off an illness – reacts to such a fast intake of fluid.

“The risk of drinking too much water isn’t well established and it’s really important that we try to get a better picture of this so we can better inform patients.”

She added that early signs of water intoxication include a headache and slurring of speech.

“If you have drunk lots of water and are displaying those symptoms, you should go to A&E immediately,” she said.