orthostatic hypotension vs postural hypotension

orthostatic hypotension and postural hypotension both are nouns.

Word	Noun	Adjective	Verb	Adverb
orthostatic hypotension	Yes	No	No	No
postural hypotension	Yes	No	No	No

As nouns, orthostatic hypotension and postural hypotension are synonyms defined as:

orthostatic hypotension and postural hypotension: low blood pressure occurring in some people when they stand up

orthostatic hypotension (noun)	postural hypotension (noun)
low blood pressure occurring in some people when they stand up	low blood pressure occurring in some people when they stand up