The piglet and the trident sign in osmotic demyelination syndrome

Excerpt

A 28-year-old man with potomania was referred to the emergency department for confusion. On physical examination, he was stuporous and had mild pyramidal syndrome. His blood sodium level was 109 mmol/L. After an overly rapid correction of hyponatremia (122 mmol/L, i.e., plus 13 mmol/L, in the first 12 h), he had reduced alertness and finally developed coma on day 5. He was intubated and mechanically ventilated. Brain magnetic resonance imaging showed prominent central pontine FLAIR-hyperintensity with peripheral and corticospinal tract sparing (Fig. 1). These findings are typical of osmotic demyelination syndrome (ODS) and have been compared with a pig's snout or a trident sword (piglet sign or trident sign). One month later, he was alert with spastic teraparesis, still under mechanical ventilation.

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