Britney Spears Rushes to Vet in Medical Emergency During Birthday Celebration

Britney Spears got super upset Friday night, after her dog had an apparent medical emergency … TMZ has learned.

Britney was out in L.A. for a pre-birthday celebration — she turned 42 today — at her manager/best friend Cade Hudson’s home, along with her brother Bryan and several others.

At 2 AM, Britney, Cade and Bryan left Cade’s home and got in a car. An agency photog at the scene says she had her dog in the car and they rushed to a 24-hour veterinary clinic. We never see the dog, but the photog claims they brought it in.

Britney and crew then went to a gas station convenience store on the Sunset Strip, and from the photos you can tell this was some sort of emergency. Cade is in his PJs with no shoes.

They then went back to the vet, and it’s unclear whether they had the dog when they left.

Bryan seems to be the only family member with whom Britney has a face-to-face relationship. He’s been with her fairly regularly over the last few months.