I don't see galls either. If there is/was anything decent going back toward the base of the plant, I would not cut back completely, but only cut off the bad stuff. If you could leave some good nodes that would be more beneficial.
It could be a combination of several things. Sometimes when one thing hits - e.g. aphids, mites et cetera it makes the plant susceptible to other things - i.e. fungus.
That may be what happened here.
When you first saw this did you spray with anything? There are products that are triple cides and will treat insects, fungus etc.
