Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 8 Sept 2026Clinical review pending
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Escalate deterioration immediately
New distension, increasing tenderness or peritonism, hypotension, rising lactate, major haemorrhage or radiological dilatation during ASUC suggests toxic megacolon, perforation or failing medical treatment.
Action: Call senior colorectal surgery and gastroenterology immediately, resuscitate, repeat blood gas and cross-sectional or plain imaging as appropriate, stop drugs that impair motility, give sepsis treatment when indicated, and proceed to urgent subtotal colectomy with end ileostomy when perforation, uncontrolled bleeding or deterioration makes further rescue unsafe.
Synopsis
Treat acute severe ulcerative colitis as a time-defined emergency: confirm severity, exclude infection and complications, deliver intravenous corticosteroid and thromboprophylaxis, measure response at day three, and progress without delay to rescue therapy or subtotal colectomy.
ASUC is at least six bloody stools daily plus tachycardia above 90/min, fever above 37.8°C, haemoglobin below 105 g/L or ESR above 30 mm/hour; admit every adult who meets it.
On admission obtain FBC, CRP, renal and liver profile including albumin, magnesium, stool culture and C difficile testing, limited flexible sigmoidoscopy and abdominal imaging.
Give hydrocortisone 100 mg IV every six hours, administering each injection over 1–10 minutes, plus pharmacological VTE prophylaxis unless contraindicated; routine antibiotics do not treat uncomplicated ASUC.
Key red flags
Pulse or vasopressor requirement rising despite fluid resuscitation, oliguria, altered consciousness or increasing lactate indicates physiological failure and overrides a planned later review.
Progressive abdominal distension, guarding, rebound, silent abdomen or free intraperitoneal gas requires immediate operative assessment.
Continued frequent bloody stool with CRP remaining high after three days of intravenous corticosteroid is a failure signal requiring rescue or surgical decision.
Severe haemorrhage with ongoing transfusion requirement is an indication to abandon prolonged medical escalation and secure definitive control.
Investigation priorities
01
FBC, CRP, U&E, liver tests, albumin and magnesiumFirst step
establish severity, losses, organ dysfunction and a baseline for daily response assessment.
Management branches
Worked case: steroid non-response at day threeMove from intravenous steroid to a definitive rescue decision
A 41-year-old is admitted with nine bloody stools daily, pulse 108/min, haemoglobin 101 g/L, CRP 78 mg/L and no peritonism. Stool culture and C difficile assay are negative; limited sigmoidoscopy shows deep ulceration. After 72 hours of hydrocortisone 100 mg IV every six hours, they still pass eight bloody stools and CRP is 71 mg/L.
Confirm that corticosteroid was delivered as prescribed, infection samples are adequate, thromboprophylaxis was given and no opioid or anticholinergic is impairing colonic motility.
Repeat abdominal examination and imaging, haemoglobin, CRP, albumin, electrolytes and lactate; absence of dilatation, perforation and shock permits a rescue discussion but does not justify more unreviewed steroid.
Key medicines
Hydrocortisone 100 mg powder for injection/infusionGive 100 mg intravenously every 6 hours for ASUC, with each reconstituted injection administered over 1–10 minutes. Formally assess response after at least 3 days and switch responders to an oral plan, usually within 7 days; do not extend an ineffective course beyond 7–10 days.Contraindications include untreated systemic fungal infection and live vaccine at immunosuppressive doses. Monitor infection, glucose, blood pressure, mental state, sodium, potassium and fluid balance. Check CYP3A4 inducers/inhibitors, potassium-depleting drugs and warfarin; ciclosporin coadministration can increase convulsion and toxicity risk.
Remicade infliximab rescueFor selected corticosteroid-refractory ASUC, give 5 mg/kg by IV infusion at week 0 and, when continued, at weeks 2 and 6. Administer the initial infusion over 2 hours and observe for at least 1–2 hours afterwards with anaphylaxis equipment available; any intensified schedule requires specialist MDT agreement.Do not give with tuberculosis, another severe infection such as sepsis or abscess, or NYHA class III/IV heart failure. Complete infection screening including TB and hepatitis B, stop further dosing for serious infection or sepsis, and interrupt the infusion immediately for an acute serious reaction; deterioration still requires surgery.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 8 Sept 2026; clinical approval remains outstanding.