Source : Webster's Revised Unabridged Dictionary (1913)

Fulminant \Ful"mi*nant\, a. [L. fulminans, p. pr. of fulminare
   to lighten: cf. F. fulminant.]
   Thundering; fulminating. [R.] --Bailey.

Source : WordNet®

fulminant
     adj : sudden and severe; "fulminant pain"; "fulminant fever"