Translations for convulsively in French

Here are paragraphs from public domain books translated:

From time to time I felt my companion’s arm tremble convulsively, as if he shivered from head to feet. I looked at him. He understood the look, and smiled at me; we had not exchanged a word since leaving the house.	De temps en temps, je sentais tressaillir convulsivement le bras de mon compagnon, comme si des frissons l'eussent parcouru tout à coup. Alors, je le regardais; il comprenait mon regard et me souriait, mais, depuis que nous étions sortis de chez lui, nous n'avions pas échangé une parole.
The Lady with the Camellias, by Alexandre Dumas son	La Dame aux Camélias, de Alexandre Dumas fils