Upper GI

Chapter 33: Therapy of Gastrointestinal Disorders

33.1 Process of Digestion

  • Phases of Digestion:

    • Cephalic Phase:

      • Triggered by sight, smell, taste, or thought of food; stimulates gastric juice release.

    • Gastric Phase:

      • Stomach distension leads to increased gastric juices.

    • Intestinal Phase:

      • Presence of fats and acids inhibits gastric juice secretion.

33.2 Digestive Enzymes and Gastric Secretions

  • Gastric Secretions Include:

    • Mucous Cells:

      • Secrete mucus to protect stomach lining.

    • Parietal Cells:

      • Secrete hydrochloric acid (HCl).

    • Chief Cells:

      • Secrete pepsinogen, which is activated to pepsin to digest proteins.

    • G Cells:

      • Secrete gastrin, stimulating acid secretion from parietal cells.

33.3 Peptic Ulcer Disease Causes and Symptoms

  • Causes of Peptic Ulcers:

    • Helicobacter pylori infection.

    • Long-term use of NSAIDs (non-steroidal anti-inflammatory drugs).

    • Conditions of hyperacidity and hyperchlorhydria.

  • Symptoms Include:

    • Periodic pain, nausea, vomiting, loss of appetite, and heartburn.

33.4 Gastroesophageal Reflux Disease (GERD)

  • Main Symptom:

    • Heartburn resulting from regurgitation of digestive juices into the esophagus.

  • Cause:

    • Inappropriate constriction of the lower esophageal sphincter.

33.5 Management of Gastrointestinal Disorders

  • Antibiotic Treatment for H. pylori:

    • Combination of at least two antibiotics and bismuth salts, often dual or triple therapy.

  • Anti-ulcer Drug Therapy:

    • Reduces gastric acidity and enhances mucosal barrier defenses.

33.6 GERD Drug Therapy and Lifestyle Modifications

  • GERD Drug Therapy:

    • Suppresses acid production, prevents erosion, and provides symptomatic relief.

  • Lifestyle Modifications:

    • Stop smoking, avoid caffeine and alcohol, lose weight, and elevate the head of the bed.

33.7 Antisecretory Drugs for Acid Suppression

  • H2 Receptor Antagonists:

    • Reduce acid secretion by blocking histamine from activating H2 receptors.

    • Indications include benign gastric ulcers, duodenal ulcers, and GERD.

  • Proton Pump Inhibitors (PPIs):

    • Examples (e.g., Omeprazole) effective for H. pylori, gastric ulcers, and GERD.

  • Prostaglandins:

    • Used primarily for NSAID-induced gastric ulcers and administered orally multiple times a day.

33.8 Acid Neutralization with Antacids

  • Antacids:

    • Indications include hyperacidity, upset stomach, heartburn, and GERD.

    • Mechanism: React with HCl to form water and salts, administered orally.

33.9 Barrier Enhancers: Sucralfate

  • Mechanism of Action:

    • Forms a protective barrier over damaged mucosa by binding proteins from damaged cells.

  • Indications:

    • Short-term treatment of duodenal ulcers.

33.10 Prokinetic Drugs for GERD

  • Metoclopramide:

    • Stimulates contraction of the lower esophageal sphincter, treats meal-induced heartburn and chemotherapy-induced vomiting.

33.11 Management of Emesis

  • Vomiting (Emesis):

    • A natural defense mechanism; may indicate disease or organ dysfunction.

    • Common causes include flu, pregnancy, motion sickness, and certain drugs.

  • Control Centers:

    • Vomiting Center (VC) and Chemoreceptor Trigger Zone (CTZ) are key areas regulating vomiting.