Yolanda Foster continues to fight back against symptoms of Lyme disease.

Yolanda Foster's Husband Serves As Co-Chair During Lyme Disease Event

Just days after revealing her two youngest children, Bella and Anwar Hadid, were secretly struggling with Lyme disease, as well, the Real Housewives of Beverly Hills star shared a photo update with her fans and followers on Instagram.

"Being challenged in life is inevitable, being defeated is optional," Foster wrote on Instagram on Monday. "#InItToWinIt #FirstTryAtLDITheraphy #SearchingForACure #AffordableForAll #ChronicLymeDiseaseAwereness."

Yolanda Foster Reveals Son Anwar & Daughter Bella Also Have Lyme Disease

A photo posted by YOLANDA (@yolandahfoster) on Oct 12, 2015 at 10:15am PDT

According to a Radar Online report earlier this month, Foster claimed learning of her children's diagnosis "struck the deepest core of hopelessness inside of me."

During an event in New York City, Foster opened up about her frustrations in having to watch "my babies struggle in silence in order to support me in my journey."

"I will walk to the end of the earth to find a cure so that you can live a healthy life that you deserve," Foster told her kids at the event, before apologizing for "all the important things I have missed in your life these past four years."

"I used to be a pretty cool, smart, multi-tasking, kicka** mom -- but all three of you, all three of my children really got short-changed with a dumb blonde in the white robe, that mostly lives her life in bed," Foster admitted.

For more Yolanda Foster, tune into The Real Housewives of Beverly Hills season six, when it premieres on Bravo later this year.