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Daily liquorice habit caused woman's visual disturbances and "thunderclap headache"

The woman told doctors the sweets were on “special offer” in her local shop, and that she ate them every day.

Image: Shutterstock/Francisco Javier Gil

DOCTORS BELIEVE THAT a daily liquorice habit was the most likely cause of a woman developing a syndrome that gave her a “thunderclap headache” and led to her experiencing visual disturbances.

Posterior reversible encephalopathy syndrome (PRES) is regarded by medics as a medical emergency.

However, a good clinical outcome can be achieved through a range of measures, including removing potential triggers.

According to a report by doctors from St Vincent’s in Dublin, a 56-year-old woman who presented at the hospital with the symptoms described above said she had habitually eaten liquorice sweets each day, and they were “on special offer” at her local shop.

Their report in the Irish Journal of Medical Science states:

“Liquorice contains a biologically active compound glycyrrhizic acid which inhibits 11β hydroxysteroid dehydrogenase.


Excessive liquorice consumption can cause mineralocorticoid excess and has been recently reported to cause PRES.

“We propose that in the absence of other triggers, frequent liquorice consumption precipitated the development of PRES in our patient and should be considered as a possible cause of this condition.”

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The woman’s symptoms, including “markedly elevated” blood pressure, eased within 24 hours.

A follow-up MRI three weeks later “demonstrated complete resolution”.

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About the author:

Daragh Brophy

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