Danielle Collins reveals diagnosis of rheumatoid arthritis

Danielle Collins has begun treatment for rheumatoid arthritis, a chronic inflammatory condition that causes pain and swelling in the body's joints.

The American, 25, who is the WTA World No.33 and reached the Australian Open semifinals in January, becomes the second leading WTA player to be diagnosed with RA in the past two seasons following Denmark's Caroline Wozniacki.