Briana had been struggling with her health for years, which was highly documented on the reality show, and was rushed to the hospital via ambulance during a July episode of RHOC.
To be fair, Culberson has had her share of health issues aside from this new diagnosis.
Sadly, she underwent thyroid surgery back in 2011 to remove tumors, and required more than just the removal of the tumors - the procedure ended up taking her thyroid and lymph nodes, too.
Before finding out about her daughter's diagnosis, Gunvalson said, "We're still trying to get to the root of the issue so testing and the surgeries aren't over."
Condolences from around the world poured into Gunvalson's account, one of which read, "I just finished watching the season finale while home sick due to a lupus flare."
"I'm 29 and was diagnosed with Lupus 10 years ago, but was sick for four years prior to my diagnosis," the commenter explained.
"I'm so sorry to hear that Briana has been diagnosed, but also want you to remember there is hope!"
"I love Briana on the show," the woman continued. "She is such a good person and a wonderful mom. You all will get through this."
"I'm a first grade teacher and definitely have my off days," she wrote, "but I'm still a happily married, working woman."
"I know Brianna can do it too! I also hope you guys can help spread awareness," the comment continued.
"I don't have much of a platform, but you and Brianna have such a huge fan base and it helps to turn a negative into a positive."
Other fans weren't as sympathetic.
Another wrote, "Poor Briana, she's a normal girl thrown in the midst of all these crazy grannies lmao."
Yeah, LMAO over Lupus, ffs. Culberson, daughter of Real Housewives of Orange County's Vicki Gunvalson, was diagnosed with lupus on last night's season finale, and things got pretty upsetting.
In the above photo, Gunvalson wrote, "Season #11 a wrap! Enjoy the fall season and the holidays."
"Thank you to all of you who love and believe in me," she continued.
"Those of you that wish to post anything bad or negative will be blocked and deleted."
She hashtagged the post with #woohoo #rhoc #season11 #mydaughterismyworld and #mydaughter.
Keep on keeping on, Briana!