AIM LEARNING CYCLE | FINAL YEAR MBBS | GIT MODULE
Student Memory Support — Topic 7
Lower GI Bleeding, Inflammatory Bowel Disease & Colorectal Cancer
Rapid KMU-focused revision and clinical memory reinforcement
1. High-Yield Flashcards
Tap each question to reveal the answer.
What does hematochezia mean?
Passage of fresh or maroon blood per rectum.
Which finding makes lower GI bleeding an emergency?
Shock or ongoing major hemorrhage requiring immediate resuscitation.
What can CT angiography identify during active bleeding?
Contrast extravasation that localizes a bleeding vessel.
Which investigation confirms colorectal cancer?
Colonoscopy with biopsy and histological examination.
Which IBD has continuous inflammation beginning at the rectum?
Ulcerative colitis.
Why do fistulas and strictures occur in Crohn’s disease?
Transmural inflammation can penetrate or scar the intestinal wall.
What is first-line treatment for mild ulcerative proctitis?
Rectal mesalazine suppositories.
What treatment is favored for mild left-sided UC?
Combined oral and rectal mesalazine.
What is the role of corticosteroids in IBD?
Induce remission in flares; not long-term maintenance.
What is first-line anti-inflammatory treatment for acute severe UC?
Inpatient intravenous corticosteroids.
Which Crohn’s location may respond to controlled-release budesonide?
Mild-to-moderate active ileocecal disease.
What monitoring matters during azathioprine therapy?
Regular complete blood count and liver function tests.
What takes priority for a Crohn’s intra-abdominal abscess?
Antibiotics as indicated and drainage/source control.
Why may a fibrotic Crohn’s stricture require intervention?
Established fibrosis does not reverse with anti-inflammatory drugs.
Which imaging is key for local rectal cancer staging?
Pelvic MRI for invasion and mesorectal margin risk.
What is the usual treatment principle for stage III colon cancer?
Surgical resection plus appropriate adjuvant chemotherapy.
2. Mnemonics
Lower GI bleeding: first decisions
SAFE
S — Stability and vital signs; A — Assess bleeding and anemia; F — Find source with appropriate tests; E — Establish hemostasis and reassess.
Ulcerative colitis escalation
M-S-R
M — Mesalazine for suitable mild disease; S — Steroids to induce remission in active flares; R — Rescue treatment or surgery when severe disease fails treatment.
Colorectal cancer workup
B-S-P
B — Biopsy to establish diagnosis; S — Stage with CT and pelvic MRI for rectal tumors; P — Plan stage-directed treatment with the multidisciplinary team.
3. Memory Tables
Ulcerative colitis versus Crohn’s disease
| Feature | Ulcerative colitis | Crohn’s disease |
|---|---|---|
| Distribution | Continuous colonic disease from rectum | Skip lesions; may involve ileum |
| Inflammatory depth | Predominantly mucosal | Transmural |
| Typical symptoms | Bloody diarrhea, urgency | Pain, diarrhea, weight loss |
| Complication clue | Acute severe colitis, toxic megacolon | Stricture, fistula, abscess |
| After surgery | Proctocolectomy can cure intestinal UC | Recurrence remains possible |
Colon versus rectal cancer planning
| Point | Colon cancer | Rectal cancer |
|---|---|---|
| Definitive diagnosis | Colonoscopy + biopsy | Endoscopic biopsy |
| Key staging | CT chest/abdomen/pelvis | CT plus pelvic MRI |
| Stage III approach | Resection + adjuvant chemotherapy | Often neoadjuvant treatment then surgery |
| Surgery principle | Segmental oncologic colectomy | Resection depends on level and sphincter involvement |
4. Rapid Revision Points — Last-Minute Revision
- Hematochezia with shock requires immediate stabilization; stool color cannot exclude a brisk upper GI source.
- Bleeding with weight loss, persistent altered bowel habit or iron-deficiency anemia warrants colorectal investigation.
- Colonoscopy identifies lesions and permits biopsy; CT angiography localizes significant ongoing active bleeding.
- Infective colitis must be excluded before attributing a new bloody-diarrhea episode to IBD.
- Ulcerative colitis is continuous and mucosal; Crohn’s disease is segmental and transmural.
- Mesalazine is central to mild UC therapy but is not a core treatment for Crohn’s disease.
- Steroids induce remission; azathioprine is delayed-onset maintenance therapy requiring CBC and LFT checks.
- Acute severe UC requires admission, IV steroids, thromboprophylaxis when appropriate, and early response assessment.
- Crohn’s abscess needs source control; fixed fibrotic obstruction often needs endoscopic or surgical treatment.
- Colorectal cancer requires biopsy confirmation and TNM staging; CEA is useful for follow-up, not primary diagnosis.
5. Clinical Memory Hooks
Painless large-volume hematochezia in an older adult → Consider diverticular or vascular bleeding; assess hemodynamic stability
Bloody diarrhea + urgency + tenesmus → Think distal mucosal inflammation in ulcerative colitis
Crohn’s disease + fever + focal abdominal collection → Suspect abscess; drain/control infection before escalating immunosuppression
Right-sided colon mass + microcytic anemia → Chronic occult blood loss can produce iron deficiency
6. Starred High-Yield Exam Points
- ⭐ Unstable lower GI hemorrhage → resuscitate first; CT angiography may localize persistent active bleeding.
- ⭐ Mild ulcerative proctitis → rectal mesalazine; left-sided UC → oral plus rectal mesalazine.
- ⭐ Acute severe UC → IV corticosteroids and reassessment around day 3 for rescue therapy or colectomy.
- ⭐ Toxic megacolon with perforation → immediate surgical assessment and emergency intervention.
- ⭐ Crohn’s disease → transmural inflammation leads to fistulas and fibrotic strictures; surgery is not curative.
- ⭐ Long-standing colonic IBD → colorectal dysplasia/cancer risk → risk-adapted surveillance colonoscopy.
- ⭐ Rectal cancer → pelvic MRI for local staging; stage III colon cancer commonly needs adjuvant chemotherapy.