con·vulse 
(kən-vŭls)
(kən-vŭls)v. con·vulsed, con·vuls·ing, con·vuls·es
v.tr.
1. To shake or agitate violently: tremors that convulsed the countryside. See Synonyms at agitate.
2. To disturb or upset severely: Strikes and riots convulsed the nation.
3. To affect with irregular and involuntary muscular contractions; throw into convulsions.
4. To cause to shake with laughter or strong emotion.
v.intr.
1. To become affected by convulsions; shake.
2. To be disturbed or upset: The region convulses with change.
[Latin convellere, convuls-, to pull violently : com-, intensive pref.; see COM- + vellere, to pull.]