To the OP:
I would advise you to ask your doctor about your renal function if you are concerned. I don't know your age, but a very significant number of older folks have moderate renal impairment and yet have a normal or very minimally elevated creatinine level. Some docs may note this but not necessarily mention it to the patient.
Interesting article. I took a peek at a couple of other related ones. The mechanism for this toxicity is not known, but does not appear to have anything to do with oxalic acic or nephro/ureterolithiasis (kidney stones). One article mentions a suspected "excitatory neurotoxin." Scary as hell, really, with a significant mortality rate. Bottom line, if your renal function is normal, you probably have no worries but if you have moderate or worse renal impairment (estimated GFR < 60) you should be careful.