[Severe PERM syndrom mimicking tetanus].

We report the case of a 55-year-old man without significant medical history admitted to the ICU for a progressive paralysis mimicking life-threatening tetanus. Evolution with classical tetanus treatment was negative, with the need for ventilator support and worsening condition being life threatening. Uncommon evolution revealed a rare glycin antibody-associated hyperekplexia (progressive encephalomyelitis with rigidity syndrome). Patient dramatically improved with immunosuppressive therapy including plasmatic exchanges, cyclophasmid and high dose corticoid infusions. Intensivists should be aware of this very rare syndrome whose treatment is the opposite of tetanus while presentation is very close. Optimal and treatment could lead to prolonged survival.