Meghan King Edmonds says her son Hart was recently diagnosed with a type of irreversible brain damage.
Edmonds is parent to 2-year-old daughter Aspen and twins Hart and Hayes with husband Jim Edmonds.
She immediately suspected "something was different" with Hart from his birth in June 2018.
"I always knew. I just knew..." the star wrote.
Edmonds took Hart to a number of specialists -- a chiropractor, cranial sacral therapist, pediatrician and two neurologists -- all of whom said her son was fine.Hart wasn't diagnosed until Edmonds had him undergo an elective MRI with anesthesia.
"Hart has minor Periventricular Leukomalacia on both sides of his brain (namely the white matter), but more so on his right," Edmonds wrote.
"She told me this mainly occurs in premies and since he was not a premie (he was born at 37 weeks gestation) she believes this damage somehow occurred 'a couple months before he was born.' She explained that he is at risk for being diagnosed with Cerebral Palsy and will be monitored," she said.
"Hart has irreversible brain damage, it's called PVL."
Edmonds has enrolled Hart in the Missouri First Steps program for children with disabilities or developmental delays.
She recalled how she and Jim went out to dinner the same night they informed family of Hart's diagnosis.
"I explained to Jimmy how we are not somehow compromised or punished for having a child with special needs (whatever that may or may not mean!), we are BLESSED," the star wrote.
"This doesn't mean his diagnosis isn't a challenge... or a little bit sad, or that I don't feel a little bit guilty," she qualified.
"I pray for a miracle and I grapple with how to navigate his life ... This is a heavy challenge as a mother: where do we go from here? This is where: one foot in front of the other."
Edmonds spent Fourth of July with Hart, Hayes and other family Thursday. She shared a slideshow of photos from the celebration on Instagram.
"Happy Birthday, America! We walked in a neighborhood parade, Hayes and Hart tried their first popsicles, we all went swimming, and Mimi, Papa, Aunt Cakey, and @nahocl helped me keep my head from spinning! (Daddy on the road with the @cardinals)," Edmonds captioned the post.
Edmonds is known for starring in Seasons 10-12 of "The Real Housewives of Orange County."
She also appeared as a guest in Seasons 9 and 14 of the Bravo series.