Was it a kidney infection, as is being widely reported, or something else that sidelined Mary-Kate Olsen for the past week? Did Sean Avery or Stavros Niarchos do a number on her heart, or did she merely suffer renal failure?

We may never know.

Regardless, she's been out of commission - but is now determined not to let her frail condition keep her down. Malnourished but optimistic, Mary-Kate Olsen hit the streets of New York, with huge bodyguards aiding her every step, yesterday.

Mary-Kate Olsen gets some fresh air on what may be one of her last days.

Despite fears that a rogue breeze might finish her off any second, the brittle actress forged on, determined to pick up some new thrift store designer clothes.

We urge everyone to pray Mary-Kate Olsen makes it through the week. And to put their Full House DVDs up on eBay, because they could double in value real quick.