Irish Journal of Medical Science (1971 -)

, Volume 185, Issue 4, pp 945–947 | Cite as

Posterior reversible encephalopathy syndrome (PRES) associated with liquorice consumption

  • K. O’ConnellEmail author
  • J. Kinsella
  • C. McMahon
  • J. Holian
  • S. O’Riordan
Case Based Review



Posterior reversible encephalopathy syndrome (PRES) is a medical emergency but prompt recognition, early institution of supportive care and identifying and removing potential triggers are associated with a good clinical outcome. We report an unusual case of PRES associated with liquorice consumption.


A 56-year-old lady presented with thunderclap headache, visual disturbance and a generalised tonic–clonic seizure. Blood pressure on admission was markedly elevated but improved within 24 h. Cranial CT and lumbar puncture were normal (no xanthochromia). She had hypokalaemia. Cranial MRI revealed abnormalities in the occipital lobes consistent with PRES. There was no evidence of restricted diffusion or vasoconstriction. Follow-up MRI 3 weeks later demonstrated complete resolution. On direct questioning she revealed in recent months she had habitually eaten liquorice sweets each day; they were “on special offer” in her local shop.

Conclusion and relevance

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.


Posterior reversible encephalopathy syndrome Liquorice Hypertension 


Conflict of interest



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Copyright information

© Royal Academy of Medicine in Ireland 2014

Authors and Affiliations

  • K. O’Connell
    • 1
    Email author
  • J. Kinsella
    • 1
  • C. McMahon
    • 2
  • J. Holian
    • 3
  • S. O’Riordan
    • 1
  1. 1.Department of NeurologySt Vincent’s University HospitalDublin 4Ireland
  2. 2.Department of RadiologySt Vincent’s University HospitalDublinIreland
  3. 3.Department of NephrologySt Vincent’s University HospitalDublinIreland

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