Can UC turn into Crohns?

Hi! I'm new to the forum, here's a little background on myself.

I was diagnosed with UC about 11 years ago at the age of 23. Over the past 11 years, I've only had about 3 flare ups, until THIS year came around. I've already had 3 flares and with one I ended up in the ER. I had a colonscopy back in April that said I had inflammation in my terminal ileum, at the time I wasn't having any symptoms so the doctor said it could be something else (like an infection) and brushed it off....well fast forward to this last flare I had. It was DIFFERENT than anything I've ever experienced ( I was on pentasa at the time) My symptoms usually are painful cramps, frequent bowel movements with blood (no diarrhea), well this last flare that sent me to the hospital started out as urgency and frequent bowel movements. I would run to the bathroom, sit there for 5 minutes and nothing would come out. This happened all day long for a few days, then the diarrhea hit and it hit hard. I was getting up all night with diarrhea and cramping, sometimes it was just gas. ". In the ER they did a CT w/contrast and said " extensive inflammation of the colon, suggesting diffuse colitis and proctitis) I went to my GI doctor and he was looking back at my colonoscopy results and said word for word "I didn't think it was anything at the time, but your colonoscopy showed inflammation in the ileum, and with your current symptoms it looks like you have Crohns". I was just shocked! No doctor has ever told me that and I've had about 6 colonoscopies in life. I asked him if it's possible that the UC somehow progressed to Crohns and he said it's more likely I've always had both, but the UC was more prominent so that's why my symptoms went along with the UC. He sent me for a blood test and said "sometimes" we can tell which IBD is more prominent with a blood test and adjust my medications accordingly after the results came back.

My question is....Have any of you had this happen to you? Where you had UC and then you were told you had Crohns? Just wondering if it's common for it to progress or not?

There is genetic research which suggests that IBD is a continuum, with UC at one end, Crohn's colitis in the middle, and Crohn's at the other end.

https://www.sciencedaily.com/releases/2015/10/151018223039.htm

That would explain the existence of indeterminate colitis, a form of IBD that cannot be categorised as either Crohn's or UC. Most people with a diagnosis of indeterminate IBD do eventually go on to get a diagnosis of either UC or Crohn's.

https://inflammatoryboweldisease.net/types-of-ibd/indeterminate-colitis/

I had the opposite happen to me. After 15 years of a Crohn's diagnosis, I had my surgeon tell me I didn't have Crohn's. She said my colon biopsies were negative for Crohn's. I asked if it was UC instead - she said no, it was colitis. We argued about it for 5 minutes and she finally checked her notes, which stated that I had "classic Crohn's" of the terminal ileum. Diagnosis restored!

That said, I do have a distant memory of a doctor muttering to himself about the confusingness of my diagnosis and that it wasn't obvious if it was Crohn's or UC - don't remember the exact words. But that was at my first hospital, so a long time ago now. But my official diagnosis has always been Crohn's: I suspect it's the terminal ileum inflammation which nailed it down thus.

Yes. I was dx’ed with mild ulcerative colitis for years and didn’t have many symptoms, didn’t need much treatment, just canasa suppositories to kind of calm the area. Then after about 10 yrs all at once I got the flu and at the same time had a recent root canal form into an abscess (so infection in my body plus heavy antibiotics) -
all of it kind of overwhemed my body and sent me into a full on Crohn’s flare. My GI said that happens where something just “flips the switch”. I at that point had developed several crohn’s markers like a perianal skin tag, mouth ulcers (which went all the way thru my body) and had all the fun stuff, blood and diarrhea 30’times a day, severe urgency to run to the bathroom, abdominal pain and cramping, waking up every hour to run to the bathroom, fever, you name it. My GI dr was on maternity leave then and my primary care Dr insisted I had the flu. He basically said everyone had it and kind of told me to stop complaining. I had no idea what was happening to me and finally one day calling to see if my GI Dr was back got a sympathetic ear of an absolute angel of a receptionist who asked me a couple questions like if I had blood and if I had lost weight (it was up to 40 lbs at that point). She booked me in the next day and another GI dr saw me for my appt, made an appt for a colonoscopy that afternoon (with no prep since none was needed) and when I woke up they told me they were admitting me to the hospital where I stayed for a month on IV steroids and morphine. No one else had listened and I was a severe case at that point so I learned - you know your body better than anyone, including doctors who are only just people (some with less compassion and skill than others). They said there was a test they could do to make it an official diagnosis (??) but after $1000 out of pocket when the insurance refused to cover it my results came back as inconclusive. I have Crohn’s and maybe always did but it didn’t get triggered until that time but they had initially said UC. I hope you are doing ok and find some resolution that puts you on a good treatment plan!! xo

Thanks for the all the responses! It's helps to hear stories from others. It's just shocking when you thought you had one disease for 10 years, then all of a sudden it's something else ! Or now you have 2 diseases. I've always had inflammation in my sigmoid and colon, NEVER anywhere else. Then this year my colonoscopy showed inflammation in the terminal ileum and no where else, so he's now saying I've probably always had both and maybe it was so mild they never found anything. He prescribed me a different medication, but my insurance won't cover it, so I guess we have to go back to the drawing board because the Pentasa doesn't seem to be working too well for me. Thanks again !

Uceris. They just approved the generic though. He wants me to take it for 3 weeks, then go back on the Pentasa.

I'm not a huge fan of my doctor, but I cannot change my insurance until open enrollment next year.