panencephalitis vs phrenitis

panencephalitis and phrenitis both are nouns.

Word	Noun	Adjective	Verb	Adverb
panencephalitis	Yes	No	No	No
phrenitis	Yes	No	No	No

As nouns, phrenitis is a hypernym of panencephalitis; that is, phrenitis is a word with a broader meaning than panencephalitis:

panencephalitis: diffuse inflammation of the entire brain
phrenitis: inflammation of the brain usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever (`phrenitis' is no longer in scientific use)

Other hypernyms of panencephalitis include cephalitis, encephalitis.

panencephalitis (noun)	phrenitis (noun)
diffuse inflammation of the entire brain	inflammation of the brain usually caused by a virus; symptoms include headache and neck pain and drowsiness and nausea and fever (`phrenitis' is no longer in scientific use)