Digestive System Overview

Hepatobiliary Tract

• Liver

  • Hepatocytes: Functional cells of the liver.
  • Sinusoids: Specialized capillaries in the liver.
  • Bilirubin: Breakdown product of hemoglobin, processed by the liver.
  • ALT (Alanine Aminotransferase): Enzyme released when hepatocytes are damaged; elevated levels indicate liver injury.
  • AST (Aspartate Aminotransferase): Found in the liver; associated with cellular damage.

• Gall Bladder: Stores and concentrates bile.

• Bile: Digestive fluid produced by the liver, aids in fat digestion.

• Pancreas: Secretes hormones and digestive enzymes necessary for digestion.

  • Hormone Secretion: Insulin and glucagon for blood sugar regulation.
  • Alkaline Fluid Secretion: Neutralizes stomach acid in the small intestine.
  • Amylase: Enzyme that digests carbohydrates.
  • Lipase: Enzyme that digests fats.

Nausea and Vomiting

• Nausea: Subjective feeling of queasiness, often preceding vomiting.
• Vomiting: The act of expelling stomach contents.
  • Causes: Severe pain, drugs, toxins.
  • Mechanism: Increased intra-abdominal pressure pushes contents out.
  • Acid/Base Imbalance: Can lead to metabolic alkalosis due to loss of gastric acid.

Constipation vs. Diarrhea

• Constipation: Difficult or infrequent passage of stool.

  • Acute or Chronic: Can be temporary or long-lasting.
  • Causes: Low fluid intake, dietary factors, medications.
  • Complications: Straining leading to hemorrhoids.
  • Treatment: Stool softeners, disimpaction.

• Diarrhea: Increased frequency or liquidity of stool.

  • Causes: Infection, food intolerance, medications.
  • Complications: Dehydration, electrolyte imbalance.
  • Treatment: Rehydration, medication depending on cause.

Assessment of Vomitus and Stool

• Vomitus Assessment:

  • Hematemesis: Up to upper gastrointestinal bleeding.
  • Yellow Green: Indicates bile present.
  • Deeper Brown: Indicative of lower intestinal content.
  • Recurrent Vomiting: May signal gastric emptying issues.
  • Undigested Food: Suggests gastric emptying problems.

• Stool Assessment:

  • Steatorrhea: "Fatty diarrhea" seen in malabsorption conditions like Celiac disease and Cystic fibrosis.
  • Blood: Differentiation between upper and lower GI bleeding, and occult blood causes.
  • Examples of Stool Color:
  • Coffee brown/darker: Potential bleeding.
  • Bright red (Hematochezia): Lower GI bleeding indicators.
  • Black tarry stools (melena): Upper GI bleeding.
  • Ulcerations possibly causing bleeding in the stomach or esophagus.

Dysphagia

• Definition: Difficulty swallowing.
• Causes:
  • Neurological deficits.
  • Mechanical obstruction.
  • Muscular disorders, tumors.
  • Achalasia: Condition where the lower esophageal sphincter fails to relax, hindering food passage, causing distension.

Hiatal Hernia

• Definition: A portion of the stomach protruding into the thoracic cavity.
  • Types:
  • Sliding Hiatal Hernia
  • Paraesophageal Hiatal Hernia
  • Clinical Manifestations: Indigestion or heartburn (pyrosis), substernal chest pain radiating to shoulder and jaw, worsens when lying flat.

Gastroesophageal Reflux Disease (GERD)

• Definition: Periodic reflux of gastric contents into the distal esophagus.
• Risk Factors: Lifestyle, dietary habits, obesity.
• Clinical Manifestations: Heartburn, regurgitation of food, dysphagia.
• Complications: Esophagitis, Barrett's esophagus, stricture formation.
• Treatment: Lifestyle modification, medications, surgical interventions in severe cases.

Peptic Ulcer Disease

• Definition: Break or ulceration in the protective lining of the gastrointestinal tract (stomach, duodenum).
• Causes: NSAIDs and H. pylori infection.

Gastric and Duodenal Ulcers

• Gastric Ulcer:

  • Symptoms: Anorexia, weight loss, pain after eating.
  • Treatment: Endoscopy for diagnosis, antibiotics if H. pylori is present, medications to reduce gastric acid.

• Duodenal Ulcer:

  • Symptoms: Pain 2-3 hours after eating, relieved with food.
  • Diagnostics: Endoscopy, possible complications include bleeding.

Gastritis

• Definition: Inflammatory disorder of the gastric mucosa.
• Causes: Alcohol, NSAIDs, infections.
• Symptoms: Nausea, vomiting, fullness, lack of appetite.
• Treatment: Bland diet, small frequent meals, avoiding irritants.

Gastrectomy

• Definitions and Complications: Surgical removal of part or all of the stomach.
  • Indicated for severe ulcers, gastric cancer, or weight loss surgeries.
  • Side effects may include dumping syndrome.

Intestinal Obstructions

• Types: Mechanical or Functional.
• Symptoms: Distension, nausea, decreased bowel sounds.
• Risk Factors: Tumors, post-surgical adhesions.
• Diagnostics and Treatment: Imaging, potential surgical intervention, NG tube for decompression.