Watch Dr. Messer on The Insider

REPORTER: But first, Rob Kardashian rushed to the ER. Let’s go inside the Kardashian health crisis.

Rob Kardashian: Getting healthy like, into the holidays, onto the New Year’s is huge for me.

Kris Kardashian: He’s gained over 100 pounds in the last year. He’s missed Christmas, he missed Kim’s wedding.

Rob Kardashian: The media is just so negative, they can say the craziest things about our family, about me. I’ve gained a lot of weight, so it’s been a lot of stress on me.

Reporter: Two years after pledging to reclaim his health, 28-year-old reclusive Rob has been hospitalized and reportedly diagnosed with diabetes. It is believed he was taken to the hospital after not feeling well over the weekend. According to a website, Rob was diagnosed with diabetic ketoacidosis, which was a shocking wakeup call.

DR. Messer: Diabetic ketoacidosis doesn’t cause diabetes, it’s a complication of uncontrolled, untreated diabetes.

Reporter: Our medical insider endocrinologist Caroline Messer who hasn’t treated rob, says taht the condition can be controlled with diet and exercise, but if left untreated, the prognosis is dire.

Dr. Messer: If diabetes is left completely untreated, and you go into diabetic ketoacidosis, that can eventually lead to a coma and death. There can be other complications, such as blindness, the need for amputations, kidney failure, and dialysis.

Kris Kardashian: Your liver is shutting down.

Rob Kardashian: It is a shock to me because at one point I'm super healthy, and I'm 26 years old, but now I'm at my worst.

Reporter: A foreshadow of what was to come, Rob has not appeared on Keeping Up with the Kardashians since 2014, though his health issues were a subplot on the show back in April, when the family staged a failed intervention.

Kris Kardashian: I'm really really worried about Rob

Kloe: Neither you, nor Courtney, nor Kim have even attempted to see him in numerous days in a row.

Reporter: June 16th would be the last time Rob was seen in public when cameras caught him at a fast food restaurant at 11 p.m. Fans grew concerned two weeks ago when Courtney posted this image alongside a healthier Rob. A day later, Kloe posted this selfie with a caption quote “if only you could see yourself through my eyes. I'll forever be obsessed with you.”

Interviewer: Knowing about Rob and everything that's happened, would you go back and do the show again?

Kloe: I would. I feel like you know, this is our life and we signed up for it, and I think like, when things are good you definitely want to talk about it, and like, you know, have everybody know about everything that’s great. When it's bad yeah, you pull back a little but you have to know that comes with the territory. Not everything is butterflies and bunnies, (laughter) sometimes you get some rain.