Acute severe ulcerative colitis escalation

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

Acute severe ulcerative colitis is a medical emergency with a surgical endpoint if inflammation cannot be controlled safely. The initial plan is simultaneous rather than sequential: restore physiology, exclude infection, establish mucosal and radiological severity, start effective intravenous corticosteroid, prevent venous thrombosis and introduce the colorectal and stoma teams. Routine broad-spectrum antibiotics are not beneficial for uncomplicated ASUC, although confirmed C difficile infection, perforation or sepsis needs specific antimicrobial treatment.

Time is a treatment variable. Intravenous corticosteroid should not continue indefinitely while nutrition and physiology deteriorate. At day three, stool frequency, blood, CRP and overall condition inform a rescue-or-colectomy discussion. Infliximab and ciclosporin have comparable efficacy in trials, so previous drug exposure, contraindications, albumin, maintenance strategy and local expertise matter. The operation for uncontrolled acute disease is usually subtotal colectomy with end ileostomy and preservation of the rectum; pouch construction is deferred until recovery.

Key points

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.
Review jointly with colorectal surgery from admission and record daily stools, blood, observations, examination, CRP, haemoglobin, albumin, fluid balance and imaging changes.
After at least three days without adequate response, use a defined score and choose intravenous infliximab or ciclosporin rescue with the IBD MDT, while keeping colectomy explicit.
Deterioration, toxic megacolon, perforation or severe haemorrhage demands earlier subtotal colectomy; no response within seven days of rescue is another indication for subtotal colectomy and ileostomy.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Severe inflammatory flare

A major increase in colonic mucosal inflammation may arise during known ulcerative colitis or be the patient’s first presentation.

Superinfection and exposure

C difficile, other enteric infection, treatment interruption and recent medicine exposure can precipitate or mimic acute deterioration and must be sought.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Extensive mucosal injury
Diffuse ulceration causes blood, protein and fluid loss while inflammatory mediators drive fever, tachycardia and a large acute-phase response.
2
Systemic depletion
Frequent stool, reduced intake and protein loss produce dehydration, electrolyte disturbance, anaemia and hypoalbuminaemia that reduce operative reserve.
3
Neuromuscular failure
Inflammation extending into deeper colonic layers can impair motility, causing toxic non-obstructive dilatation, wall ischaemia and eventual perforation.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Entry criteria

Six or more bloody stools per day plus at least one systemic toxicity marker meets Truelove and Witts acute severe criteria.

Early non-response

Persistent stool frequency, visible blood and inflammatory burden after three days of intravenous corticosteroid should prompt rescue-therapy or operative planning.

Toxic dilatation

Distension, worsening pain, systemic toxicity and non-obstructive colonic enlargement suggest toxic megacolon and sharply narrow the window for medical rescue.

Surgical failure state

Perforation, severe haemorrhage, peritonism or physiological deterioration is a complication requiring urgent colectomy assessment rather than another routine drug cycle.

Thrombotic risk

Active severe colitis, immobility, dehydration and corticosteroid exposure combine to increase venous thromboembolism risk despite rectal bleeding.

Red flags requiring action

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.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
FBC, CRP, U&E, liver tests, albumin and magnesiumFirst step
Why
establish severity, losses, organ dysfunction and a baseline for daily response assessment.
Interpretation and limitations
Falling haemoglobin or albumin, persistent CRP, renal impairment and electrolyte loss identify ongoing burden; individual values must be read with stool count and physiology.
02
Stool culture and C difficile assay
Why
detect an infection that may mimic or compound the severe flare.
Interpretation and limitations
Send before escalation when possible; start oral vancomycin when C difficile is detected or strongly suspected while continuing specialist assessment of active colitis.
03
Unprepared flexible sigmoidoscopy with biopsies
Why
confirm severe mucosal activity and obtain tissue for CMV when clinically relevant.
Interpretation and limitations
Deep ulceration supports a high-risk course; use minimal insufflation, and use tissue immunohistochemistry or PCR rather than serum testing alone for colonic CMV.
04
Abdominal radiograph, ultrasound or CT
Why
look for dilatation, perforation, collection and another acute diagnosis.
Interpretation and limitations
CT is preferred when perforation or intra-abdominal collection is suspected; progressive colonic diameter plus toxicity requires urgent surgical reassessment.
05
Day-three response score
Why
combine stool frequency and inflammatory response into a reproducible escalation decision.
Interpretation and limitations
More than eight stools daily, or three to eight with CRP above 45 mg/L, is a classic high-risk signal; use it with the patient’s trajectory and contemporary MDT judgement rather than as an isolated command.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Infectious colitis

C difficile, bacterial dysentery and travel-related pathogens can produce severe bloody diarrhoea and may occur alongside active ulcerative colitis.

Crohn colitis

Skip distribution, ileal disease, deep linear ulceration, granulomas or penetrating complications suggest Crohn disease, although immediate severe-colitis principles remain similar.

Ischaemic colitis

Sudden pain followed by bleeding, vascular risk and segmental watershed injury support ischaemia rather than a typical relapsing inflammatory course.

Drug-induced colitis

Immune checkpoint inhibitors, NSAIDs and other medicines may cause acute colitis; exposure history and biopsy interpretation clarify the mechanism.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01Worked case: steroid non-response at day threeMove from intravenous steroid to a definitive rescue decisionFirst stepDefinitiveA 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.

1Confirm that corticosteroid was delivered as prescribed, infection samples are adequate, thromboprophylaxis was given and no opioid or anticholinergic is impairing colonic motility.
2Repeat 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.
3Present previous advanced-therapy exposure, tuberculosis and hepatitis screening, renal function, cholesterol and magnesium at the joint IBD surgical MDT, and explain infliximab, ciclosporin and subtotal colectomy to the patient.
4Select infliximab 5 mg/kg IV because there is no contraindication and the maintenance plan is suitable; keep the colorectal team engaged and use a documented day-seven limit if rescue fails.
5By day seven stool frequency is three with no visible blood and CRP is 18 mg/L; verify transition to oral steroid taper, scheduled induction doses, maintenance ownership and rapid-access review, rather than recording “better” without objective endpoints.

02Deterioration before day threeDo not wait for the scheduled checkpointEighteen hours after admission, a patient develops increasing distension, generalised guarding, pulse 128/min, blood pressure 88/54 mmHg and lactate 4.1 mmol/L. Radiography shows marked transverse-colon dilatation and erect chest imaging shows free subdiaphragmatic gas.

1Activate the emergency surgical and anaesthetic response, give oxygen as required, obtain large-bore intravenous access, take cultures and cross-match blood, and begin balanced crystalloid resuscitation with frequent reassessment.
2Stop oral intake, opioids, anticholinergics and antimotility drugs; give broad-spectrum intravenous antibiotics because perforation and faecal contamination are now suspected.
3Explain that perforation with shock is not a situation for infliximab or ciclosporin rescue and obtain consent for urgent operative source control and likely stoma.
4Perform subtotal colectomy with end ileostomy and preserve a safely managed rectal stump; avoid pouch construction in the unstable acute setting.
5Verify response through lactate clearance to 1.8 mmol/L, urine output above 0.5 mL/kg/hour, operative source-control findings and postoperative critical-care review, then document later reconstruction choices for recovery.

03Steroid response and safe transitionSecure maintenance after an apparent inpatient successA 55-year-old starts hydrocortisone for ASUC with seven bloody stools daily and CRP 64 mg/L. By day three they have two stools with only trace blood, pulse 76/min, a soft abdomen and CRP 14 mg/L.

1Confirm improvement across physiology, stool chart, haemoglobin and abdominal findings and ensure imaging has not shown new dilatation; one lower CRP alone is insufficient.
2Agree the maintenance therapy based on prior drug exposure and disease history, because an ASUC admission predicts future relapse and colectomy risk even after steroid response.
3Convert intravenous corticosteroid to an explicit oral prednisolone taper when clinically appropriate, usually within seven days, and provide bone and gastric protection when indicated.
4Complete infection-prevention, vaccination, venous-thrombosis and steroid adverse-effect counselling and give the patient direct IBD-team contact for renewed bleeding or rising stool frequency.
5At two-week review they pass two formed non-bloody stools and CRP is 4 mg/L; confirm adherence, taper progress, glucose and blood pressure and book objective disease reassessment instead of discharging indefinitely after symptom control.

Key medicines and prescribing safety4 treatments · regimens, roles and cautions

Provides rapid systemic anti-inflammatory induction while investigation and a time-limited rescue or surgery plan run in parallel.

Hydrocortisone 100 mg powder for injection/infusion

Give 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.

Rescue therapy when immediate colectomy is not required and the patient has a viable continuing maintenance strategy.

Remicade infliximab rescue

For 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.

An alternative to infliximab for corticosteroid-refractory ASUC when contraindications, previous therapy and local calcineurin-inhibitor expertise favour it.

Intravenous ciclosporin rescue

BSG supports 2 mg/kg/day by continuous IV infusion for up to 7 days as specialist off-label ASUC rescue, with a prespecified oral bridge and maintenance plan. The current South East London Joint Medicines Formulary is one UK regional example confirming the off-label indication, 2 mg/kg over 24 hours and adjustment to blood concentration and response, but it is not prescribing authority outside its member organisations. Do not start at another site until gastroenterology and pharmacy have identified its current named ASUC monograph defining product, compounding, infusion equipment, concentration target and sampling, renal/BP/electrolyte stop rules, and oral bridge. The transplant-labelled Sandimmun SmPC 2–6-hour infusion instructions do not validate a 24-hour ASUC schedule.

Before treatment correct magnesium and review renal function, potassium, cholesterol, blood pressure, infection and malignancy. Observe continuously for at least the first 30 minutes and frequently thereafter for polyoxyl-castor-oil anaphylactoid reactions, with adrenaline and oxygen available. Monitor creatinine, BP, electrolytes and whole-blood concentration under the verified protocol. Do not combine with St John’s wort, bosentan, dabigatran etexilate or aliskiren: these combinations are contraindicated. Separately review strong CYP3A4/P-gp inhibitors or inducers, nephrotoxins and potassium-raising drugs for avoidance, dose adjustment and concentration monitoring as appropriate.

Reduces inpatient VTE risk from severe active colitis, dehydration, immobility and corticosteroid treatment.

Clexane enoxaparin thromboprophylaxis

For an acutely ill adult medical inpatient with severe mobility restriction, give Clexane 4,000 IU (40 mg)/0.4 mL subcutaneously once daily for 6–14 days. If creatinine clearance is 15–30 mL/min use 2,000 IU (20 mg) SC once daily; below 15 mL/min it is not recommended outside the haemodialysis indication. Reassess duration, mobility and bleeding risk rather than extending the medical licence beyond 14 days automatically.

Contraindications include active clinically significant bleeding and immune-mediated HIT within 100 days or circulating HIT antibodies. Check platelet count, renal function, weight, concurrent haemostasis-altering drugs and neuraxial timing; visible colitis bleeding alone does not routinely justify withholding prophylaxis.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Toxic megacolon

Systemic toxicity with non-obstructive colonic dilatation creates imminent risks of ischaemia, perforation, bacterial translocation and shock.

Massive haemorrhage

Diffuse friable ulcerated mucosa can cause ongoing blood loss that overwhelms resuscitation and requires urgent colectomy.

Venous thromboembolism

Inflammation, dehydration, immobility and corticosteroid exposure together increase deep-vein thrombosis and pulmonary embolism risk during admission.

Delayed operative morbidity

Prolonged ineffective medical treatment permits malnutrition, anaemia and physiological deterioration, increasing the hazard of subsequent emergency surgery.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Chart every stool and visible blood over each 24-hour period and pair this with pulse, temperature, blood pressure, fluid balance and at least daily abdominal examination.
Trend haemoglobin, CRP, albumin, renal function, potassium and magnesium; repeat lactate and imaging promptly if physiology or abdominal findings worsen.
Hold a documented day-three review of steroid response with gastroenterology and colorectal surgery, including the selected rescue, contraindications, operative threshold and patient preference.
During rescue treatment monitor drug-specific infection and organ toxicity while retaining daily assessment for toxic dilatation, haemorrhage and perforation.
Before discharge record the oral steroid taper, maintenance regimen, laboratory ownership, thrombosis advice, rapid-access contact and date of objective reassessment.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Admission starts two clocks

The corticosteroid response clock and surgical planning clock begin together; introducing surgery only after rescue fails creates avoidable delay.

Rectal blood does not prevent prophylaxis

BSG advises anticoagulant thromboprophylaxis in ASUC because it does not precipitate or exacerbate colonic bleeding in usual practice.

Rescue choices are contextual

Infliximab and ciclosporin have comparable trial efficacy, so contraindications, previous therapy, maintenance feasibility and local expertise determine selection.

Day three is active

A high-risk day-three score should lead to an actual rescue or operative decision, not merely a note to observe again tomorrow.

Pouch formation waits

The urgent operation removes the colon and creates an end ileostomy while preserving the rectum; restorative pouch surgery follows recovery and counselling.

11Common pitfallsFrequent interpretation and management errors.

01
Delaying stool samples until after immunosuppressive escalation can obscure an infection that changes isolation and treatment.
02
Withholding all thromboprophylaxis because stools contain blood overlooks the high VTE risk and the guideline’s explicit recommendation.
03
Continuing intravenous hydrocortisone past day three without a recorded response decision allows anaemia, hypoalbuminaemia and operative risk to accumulate.
04
Giving rescue therapy despite peritonism, perforation, uncontrolled haemorrhage or shock delays definitive source control.
05
Building an ileal pouch during the unstable acute colectomy increases pelvic complication risk and removes a staged recovery choice.

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