What Causes Bilateral Edema And Incontinence?

I m a home health nurse t& have patient who 2months ago had a shunt placed for hydrocephalus. wnen I began seeing her she had no problems other than incison pain now, she has htn with bp s from 190/98 -178/88, intermittent headaches on one side of her head (occipital), right flank pain & is only urinating 3 x s a day w/scant amt of urine and no stream. her md has added benicar and clonidine daily in addition to her norvasc. she has a dx of type 1 dm and mod htn but other than the hydrocelphalus no other sig health hx. I believed it was a issue with the shunt but they have checked the shunt and i s fine. now the is presenting with bilateral le edema and incontinence. the md seems to think this is because of the norvasc (she has been taking norvasc for several years), I think it is her shunt or kidneys- am I wrong? what else could this possibly be related to?