Risus Sardonicus

A classical sign of Wilson’s disease, risus sardonicus is a form of facial dystonia producing a fixed smiling or grinning expression in the absence of any mirth or humor. It has been described as an “evil-looking” grin. This patient was a 27 year old man with a 10 year history of Wilson’s disease, who also had a striatal toe. Risus sardonicus also occurs in MSA, thalamic hemorrhage, tetanus and strychnine poisoning.

References

Cetlin RS, Rodrigues GR, Pena-Pereira MA, Oliveira DS, Souza CP, Tumas V. Teaching video neuroimages: excessive grinning in Wilson disease. Neurology 2009; 73(14):e73.

Cohen R. Risus sardonicus. Int J Infect Dis 2014 Mar;20:79

Sibon I, Burbaud P. Risus sardonicus after thalamic haemorrhage. Mov Disord. 2004;19:829-31.

Wenning GK, Geser F, Poewe W. The 'risus sardonicus' of multiple system atrophy. Mov Disord 2003;18:1211.