Audrina Patridge celebrates birthday without Lauren Conrad! GASP!

Pool party? I'll guess I'll watch.....for research...........
US:
How times have changed.
Audrina Patridge celebrated her birthday in Las Vegas Saturday night without Hills BFF Lauren Conrad.
The now 23-year-old (her actual birthday was May 9) drank Grey Goose and Red Bull and goofed off with pals — including her mom! — at club LAX..............So why didn't Conrad, 22, party with her pal in Vegas?
"Obviously there is tension and other things going on," Conrad told Usmagazine.com at the Hills season finale party in Beverly Hills last week.
"I mean there are things in our relationship, but that's how every relationship is," Conrad added. "You fight, you make up, you get along…obviously we are going to have problems, but we are still friends and we love each other."
Besides, Conrad and third roomie Lo Bosworth threw Patridge a pool party at their Hollywood Hills home, she says.
"You'll see it on the show!" Conrad teases.