SQL & PL/SQL

I have a package that is storing values in a system context so they they can be shared by all sessions without the overhead of constantly querying a table. My question is, after I have a number of name-value pairs to the context, is there some way I can get a list of the parameter names defined withint he context?

All of the examples I have found in the docs use USERENV as the context and retrieve the values using a known list of names. I need some way to get all of the parameters without necessarily knowing the name beforehand.

Thanks