Disorders of motility, secretion, digestion & absorption, & GI manifestations of systemic disease
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MOTILITY disorder
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Definition:
- Complication of gastroesophageal disease (GERD = malfunction of LES) - Oesophagus inflammation due to stomach acid reflux |
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Mechanism:
- Abnormal lower esophageal sphincter (LES) relaxation → allowing the ascent of stomach acid into the esophagus damaging the lining → inflammation |
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Pathophysiology:
Causes of excessive / prolonged LES relaxation - 1°: Hiatal hernia (✴), foods (coffee, alcohol, chocolate, mint, citrus), drugs (Ca channel blockers, β-agonist, anti-cholinergics) - 2°: scleroderma (autoimmune disorder), delayed gastric emptying |
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Sx & Ssx:
- Barret's esophagus: pre-cancerous lesion - Bright red hematemesis: blood in vomit - Mechanical dysphagia while eating solid foods (swallowing) - HEARTBURN: epigastric / retrosternal burning sensation - Acid regurgitation (water brash), can lead to → chronic cough (especially @ night), asthma, hoarse voice |
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✴ Hiatal hernia
- Type 1: sliding h.h. stomach intermittently slides up through the diaphragm (hiatus) - Type 2: paraoesophagheal h.h. (< common) stomach bulges through hiatus but lies along the esophagus - Mechanism: muscle weakness or ↑ abdominal pressure |
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SECRETION disorder
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Definition:
- Formation of open ulcers in the lining of the stomach, duodenum (upper small intestine), or esophagus - 1° caused by imbalance between factors that protect the mucosal lining & those that promote its erosion |
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Pathophysiology:
- Helicobacter pylori infection: bacterium that colonises in the stomach & weakens the protective mechanisms of the gastric mucosa → > vulnerable to acid & other harmful substances - Acid production: excessive production (1° hydrochloric acid), contributes to development of peptic ulcers - Impaired mucosal defence mechanisms: such as reduced mucus production, diminished blood flow to mucosa, or inadequate bicarbonate secretion, can compromise mucosal defense - NSAIDs: such as aspirin or ibuprofen, can directly irritate gastric mucosa & inhibit the production of protective substances like prostaglandins |
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Mechanism: imbalance between aggressive factors (acid & pepsin) & protective mechanisms leads to erosion & damage to the mucosal lining, eventually → formation of ulcers
- Acid: excessive production / secretion of stomach acid ↑ acidity of gastric contents, can damage mucosal lining - Pepsin: (enzyme that helps breakdown proteins in stomach), when excessive presence, can contribute to mucosal injury - Mucus secretion: reduced mucus production can make the mucosa more susceptible to injury - Bicarbonate secretion: (neutralises stomach acid), insufficient secretion can disrupt mucosal defence mechanisms |
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Sx & Ssx:
- Epigastric pain: in upper abdomen between meals or during the night - Heartburn - Nausea & vomiting: especially if ulcers present in stomach - Loss of appetite or weight loss - GI bleeding: in severe cases |
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Complication of acid peptic disease
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Definition:
- Sudden onset inflammation in the stomach lining - Tends affect a wider area of mucosa |
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Acute gastritis
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Chronic gastritis
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Pathophysiology & mechanisms:
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- Irritants & toxins: consumption can directly damage the gastric mucosa, leading to acute inflammation
- Helicobacter pylori: infection - Immune response: immune system triggers an inflammatory response in gastric mucosa, leading to release of inflammatory mediators (lymphocytes & plasma cells), this inflammation can cause damage to mucosal lining |
- Heliobacter pylori: leads to chronic inflammation of the gastric mucosa
- Autoimmune response: mistakenly attacks the stomach lining cells, causing chronic inflammation - Other factors: prolonged use of NSAIDs, alcohol, bile reflux & certain medical conditions such as Crohn's disease or HIV infection |
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Sx & Ssx:
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- Epigastric pain: typically burning or gnawing
- Nausea & vomiting - Loss of appetite - Bloating or feeling of fullness - Hematemesis: in severe cases |
- Dyspepsia: abdominal discomfort after eating (often w/ early satiety & bloating)
- Loss of appetite or weight loss - Nausea or vomiting - Bloating or fullness - Anemia: vitamin B12 deficiency |
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