Final · Week 13 · BIO 280 Pathophysiology
M13 · Gastrointestinal Disorders
From mouth to colon: reflux, ulcers, obstruction and the two inflammatory bowel diseases that get confused.
▸M13Gastrointestinal DisordersWeek 13
💡 The one idea
The gut is a tube with a protective lining and a one-way valve system. Almost every disorder here is acid where it should not be, a blockage, or inflammation of the wall.
Where the pain is, and what it does after eating, usually names the diagnosis.
👄 Mouth to esophagus
- GERD — a lax lower esophageal sphincter lets acid back up. Heartburn worse lying flat or after meals, regurgitation, sour taste, chronic cough, hoarseness. Aggravated by caffeine, alcohol, chocolate, fat, peppermint, nicotine, and large late meals.
- Barrett esophagus — chronic acid causes metaplasia of the lining. It is pre-malignant and needs surveillance.
- Hiatal hernia — stomach pushes up through the diaphragm; worsens reflux.
- Achalasia — the sphincter fails to relax; food sticks. Dysphagia to solids and liquids from the start.
- Esophageal varices — dilated veins from portal hypertension. Painless, catastrophic bleeding.
Progressive dysphagia to solids first, then liquids, with weight loss, suggests an obstructing tumor rather than a motility problem. That direction matters.
🚨 Peptic ulcer disease — gastric vs duodenal
| Gastric ulcer | Duodenal ulcer | |
|---|---|---|
| Pain vs food | Worse with eating — 30–60 min after | Better with eating, then returns 2–3 h later; wakes them at night |
| Weight | Loss — eating hurts | Gain or stable |
| Acid | Normal or low; the defense has failed | High |
| Malignant? | Can be | Rarely |
H. pylori and NSAIDs are the two big causes. H. pylori weakens the mucus barrier; NSAIDs block the prostaglandins that maintain it. Both let acid reach the wall.
Sudden severe abdominal pain with a rigid, board-like abdomen means perforation. Coffee-ground vomit or melaena means bleeding. Both are surgical emergencies.
🪥 Crohn vs ulcerative colitis
| Crohn disease | Ulcerative colitis | |
|---|---|---|
| Where | Mouth to anus, anywhere — usually terminal ileum | Colon and rectum only, continuous from the rectum up |
| Pattern | Skip lesions — patchy | Continuous, no gaps |
| Depth | Full thickness — hence fistulas, strictures, abscesses | Mucosa and submucosa only |
| Stool | Diarrhea, often without visible blood; steatorrhoea | Bloody diarrhea with mucus, urgency, tenesmus |
| Nutrition | Malabsorption — B12, iron, fat | Less affected |
| Big risk | Obstruction, fistula | Toxic megacolon; higher colon cancer risk |
Crohn is patchy, deep and anywhere. UC is continuous, shallow and colon only.
⭐ Lower GI — obstruction and the acute abdomen
| Small bowel obstruction | Large bowel obstruction | |
|---|---|---|
| Vomiting | Early and profuse | Late, may be faeculent |
| Distension | Less | Marked |
| Pain | Cramping, frequent waves | Cramping, less frequent |
| Commonest cause | Adhesions, hernia | Tumor, volvulus, diverticular disease |
- Appendicitis — periumbilical pain migrating to the right lower quadrant (McBurney point), rebound tenderness, anorexia, low fever.
- Diverticulitis — left lower quadrant pain, fever, altered bowel habit. Diverticulosis is the pouches; diverticulitis is when they inflame.
- Peritonitis — rigid abdomen, rebound tenderness, absent bowel sounds, shallow breathing, lying still.
- C. difficile — follows antibiotics; profuse watery diarrhea. Contact precautions and soap-and-water handwashing — alcohol gel does not kill the spores.
A patient with abdominal pain who is lying completely still has peritoneal irritation. One who is writhing and cannot get comfortable has colic — obstruction or a stone. That difference is diagnostic.
🎯 Module quiz
Questions for this module.
Nothing here yet — drop it in when you have it