"My poor baby girl Noodles is sick," the actress wrote Tuesday on Twitter. "She had a seizure and they don't know why. I'm taking her to see a specialist two hours away for a brain scan."
Osbourne, who has a nearly identical-looking black Pomeranian named Sid, welcomed Noodles in March. Nicknamed "Noody Bear," the puppy weighed less than 1 lb. and was "already ruling the house" on her first day home.
A short three months later, the puppy's health took a sad turn. "I can't even look at my baby girl without crying," Osbourne wrote. "She just looks so sick and helpless."
After the brain scan, the prognosis was bleak. Noodles was suffering from swelling in her brain.
"Noodles is not going to make it," Osbourne wrote. "She was born with a brain defect and I have to put her to sleep today. I'm devastated. I just can't believe it."
Courtesy Kelly Osbourne