convulsion vs kerfuffle

convulsion and kerfuffle both are nouns.

Word	Noun	Adjective	Verb	Adverb
convulsion	Yes	No	No	No
kerfuffle	Yes	No	No	No

As nouns, kerfuffle is a hypernym of convulsion; that is, kerfuffle is a word with a broader meaning than convulsion:

Other hypernyms of convulsion include commotion, disruption, disturbance, flutter, hoo-ha, hoo-hah, hurly burly, to-do.

convulsion (noun)	kerfuffle (noun)
a physical disturbance such as an earthquake or upheaval	a disorderly outburst or tumult
violent uncontrollable contractions of muscles
a sudden uncontrollable attack
a violent disturbance