Flares & ER
If you have ulcerative colitis and your flare has crossed into territory that feels genuinely dangerous, you may be facing something called acute severe ulcerative colitis, or ASUC. This is a medical emergency that affects roughly 15-25% of UC patients at some point during their disease course. Knowing what happens once you arrive at the hospital can make a frightening situation a little more manageable.
How Doctors Diagnose ASUC
Gastroenterologists use a set of criteria developed by researchers Truelove and Witts to determine whether a UC flare qualifies as acute severe. The threshold is six or more bloody bowel movements per day combined with at least one sign of systemic illness: a heart rate above 90 beats per minute, a temperature above 37.8 degrees Celsius, hemoglobin below 10.5 g/dL, or an elevated erythrocyte sedimentation rate above 30 mm/h. If you meet these criteria, you will be admitted to the hospital. This is not a gray area. ASUC requires inpatient treatment with close monitoring by both a gastroenterology team and a colorectal surgeon.
Day 1: Admission and Starting IV Steroids
Once admitted, your medical team will run blood work and imaging to assess disease severity and rule out infections like C. difficile, which can mimic or worsen a severe flare. You will likely have a plain abdominal X-ray to check for complications like toxic megacolon, a dangerous dilation of the colon.
The first-line treatment is intravenous corticosteroids, typically methylprednisolone at 60 mg per day. Higher doses have not been shown to work better. Your team will also likely stop any oral mesalamine you have been taking, as it has not been shown to help during ASUC and may occasionally make things worse. You will receive IV fluids, and your team will monitor your stool frequency, blood counts, and inflammatory markers daily. Venous thromboembolism prevention with subcutaneous heparin is standard, since severe UC significantly raises clot risk.
Day 3: The Decision Point
Day 3 of IV steroids is a well-established checkpoint. Your doctors will assess whether the steroids are working by looking at your stool frequency and C-reactive protein level. The Oxford criteria, developed by Travis and colleagues, found that patients still passing more than eight stools per day on day 3, or passing three to eight stools with a CRP above 45 mg/L, had a high likelihood of needing further treatment escalation.
About one-third of ASUC patients do not respond to IV steroids. If you are in that group, your gastroenterologist will discuss rescue therapy options with you. This is not a failure on your part. Steroid-refractory disease is a recognized and common pattern that your medical team is prepared for.
Rescue Therapy: What Comes Next
If steroids have not brought your flare under control by day 3 to 5, rescue therapy is the next step. The two most established options are infliximab and cyclosporine. Both have been studied in randomized trials and are supported by clinical guidelines.
Infliximab is a biologic medication given as an IV infusion. Many gastroenterologists prefer it because of its established long-term maintenance data and relative ease of use. Cyclosporine is a calcineurin inhibitor given as a continuous IV infusion, with blood levels monitored closely. The two medications are generally considered comparable in short-term effectiveness, though infliximab tends to have better long-term outcomes. Tofacitinib, a JAK inhibitor taken orally, is also emerging as a potential rescue option due to its rapid onset of action.
Your medical team will choose the best option based on your medication history, any prior biologic exposure, and your individual risk factors.
When Surgery Becomes Part of the Conversation
Surgery is discussed early in an ASUC admission, and that is a good thing. Having a colorectal surgeon involved from the start is standard practice recommended by guidelines, and early involvement leads to better outcomes if surgery becomes necessary.
If rescue therapy has not produced a meaningful response within about seven days, colectomy becomes the recommended path. Approximately 30% of patients hospitalized with ASUC ultimately require surgery. Delaying surgery when medical therapy is failing increases the risk of postoperative complications, so timely decision-making matters. The standard procedure is a subtotal colectomy with an ileostomy, which removes the diseased colon while preserving the option for reconstructive surgery later.
Colectomy is a significant operation, but it is also a definitive treatment. Many patients describe profound relief after years of poorly controlled disease.
What You Can Do to Prepare
If you have UC, especially if you have experienced severe flares before, having a plan for an ASUC emergency is worth considering. Know which hospital near you has a gastroenterology team experienced in managing ASUC. Keep an updated medication list accessible. And if you track your symptoms with an app like Aidy, bring that data with you. Your symptom history helps the inpatient team understand your baseline and how this flare compares to previous ones, which directly informs treatment decisions.
ASUC is a serious medical event, but it follows a structured treatment protocol. Understanding that protocol can help you participate in your own care and ask informed questions at each stage.