Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Gastritis

Gastritis, an inflammation of the gastric mucosa, may be acute or chronic. Acute gastritis produces mucosal reddening, edema, hemorrhage, and erosion; this benign, self-limiting disease is usually a response to local irritants. Chronic gastritis is common among elderly persons and those with pernicious anemia. It's characterized by progressive cell atrophy and commonly occurs as chronic atrophic gastritis (inflammation of all stomach mucosal layers and reduced numbers of chief and parietal cells). Acute or chronic gastritis can occur at any age.

Causes

Acute gastritis

·   Habitually ingested irritants, such as hot peppers, alcohol

·   Drugs, such as aspirin, other nonsteroidal anti-inflammatory agents, cytotoxic agents, caffeine, corticosteroids, antimetabolites, phenylbutazone

·   Poisons, such as DDT, ammonia, mercury, carbon tetrachloride, corrosive substances

·   Bacterial endotoxins, such as staphylococci, Escherichia coli, salmonella

·   Physiological stress, such as surgery, head trauma, renal failure, hepatic failure, or respiratory failure

Chronic gastritis

·   Helicobacter pylori infection

·   Pernicious anemia

·   Peptic ulcer disease

·   Renal disease

·   Diabetes mellitus

Pathophysiology

Gastritis is an inflammation of the lining of the stomach. In acute gastritis, the protective mucosal layer is altered. Acid secretion produces mucosal reddening, edema, and superficial surface erosion. In chronic gastritis, progressive thinning and degeneration of gastric mucosa occur. In either form, as mucus membranes become more eroded, gastric juices, containing pepsin and acid, come into contact with the erosion and an ulcer forms.

Pernicious anemia is often associated with atrophic gastritis, a chronic inflammation of the stomach resulting from degeneration of the gastric mucosa. In pernicious anemia, the stomach can no longer secrete intrinsic factor, which is needed for vitamin B12 absorption.

Signs and symptoms

·   Epigastric discomfort

·   Indigestion, cramping

·   Anorexia

·   Nausea, hematemesis, and vomiting

·   Coffee-ground emesis or melena if GI bleeding present

·   Grimacing

·   Restlessness

·   Pallor

·   Tachycardia

·   Hypotension

·   Abdominal distention, tenderness, and guarding

·   Normoactive to hyperactive bowel sounds

Diagnostic test results

·   Occult blood tests reveal blood in vomitus or stools (or both) if the patient has gastric bleeding.

·   Complete blood count shows decreased hemoglobin level and hematocrit.

·   Urea breath test is positive for H. pylori.

·   Upper GI endoscopy reveals gastritis when endoscopy is performed within 24 hours of bleeding.

·   Biopsy reveals inflammatory process.

Treatment

·   Elimination of the cause

·   Bland diet

·   Antacids, histamine antagonists, proton pump inhibitors

·   Prostaglandins

·   Vitamin B12

·   Antibiotics

·   Blood replacement

·   Iced saline lavage, possibly with norepinephrine

·   Angiography with vasopressin

·   Surgery—vagotomy, pyloroplasty, partial or total gastrectomy

Clinical Tip

Simply avoiding aspirin and spicy foods may relieve gastritis.

P.179

ACUTE GASTRITIS

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