Diarrhea: Clinical Medicine Lecture

Introduction

• Video part of clinical medicine section.
• Focus on acute and chronic diarrhea.
• Encouragement to engage with the content and access additional resources (notes, quizzes, exam prep) on the Ninja Nerd website.

Acute Diarrhea

Definition

• Acute Diarrhea: More than three loose stools per day for less than two weeks.
• Chronic Diarrhea: More than three loose stools per day for more than two weeks.

Types of Acute Diarrhea

Non-inflammatory (Secretory) Diarrhea

• Characteristics:
  • High-volume, watery stools.
  • Involves the small bowel (ilium, jejunum, duodenum).
  • No direct mucosal damage.
  • Pathogens release enterotoxins that cause secretion of sodium, potassium, chloride, and water.
• Common Pathogens:
  • Staphylococcus aureus (often linked with food left out, e.g., mayonnaise in picnics).
  • Bacillus cereus (associated with reheated rice).
  • Enterotoxigenic E. coli (causes traveler’s diarrhea).
  • Vibrio cholerae (causes rice-water stools).
• Features:
  • No fecal white blood cells, no fecal calprotectin, and no blood in stool.

Inflammatory Diarrhea

• Characteristics:
  • Bloody, mucoid stools.
  • Involves the colon (descending colon, transverse colon).
  • Direct mucosal damage leads to inflammation.
  • Presence of fecal white blood cells, fecal calprotectin, and blood.
• Common Pathogens:
  • Salmonella, Shigella, Campylobacter, Enterohemorrhagic E. coli (EHEC), C. difficile.
  • Entamoeba histolytica (invasive amoeba).

Chronic Diarrhea

Types

• Secretory Diarrhea:

  • Hormone-related (e.g., VIPoma, gastrinoma, carcinoid syndrome).
  • Stimulant laxatives (e.g., Senna, docusate).

• Osmotic Diarrhea:

  • Malabsorption (e.g., celiac disease, exocrine pancreatic insufficiency, tropical sprue).
  • Osmotic laxatives (e.g., lactulose, polyethylene glycol).

• Inflammatory Diarrhea:

  • Features bloody, mucoid stools due to inflammatory bowel disease (e.g., Crohn’s disease, ulcerative colitis).
  • Chronic infections (e.g., CMV).

Complications of Acute Diarrhea

• Hypovolemia: Due to loss of fluids and electrolytes.
• Metabolic Acidosis: Loss of bicarbonate.
• Hemolytic Uremic Syndrome (HUS): Associated with EHEC and Shigella.
• Toxic Megacolon: Particularly with C. difficile infection.

Diagnostics

• Acute Diarrhea:

  • Assess complications with CBC, BMP.
  • Stool analysis if risk factors present.
  • Identify type: inflammatory vs. non-inflammatory.

• Chronic Diarrhea:

  • Assess fecal white blood cells, calprotectin, occult blood.
  • Stool osmolar gap to differentiate secretory from osmotic diarrhea.
  • Identify hormonal causes or stimulant laxatives if secretory.
  • Identify malabsorption or osmotic agents if osmotic.

Treatment

Acute Diarrhea

• Supportive Care: Focus on hydration.
• Antibiotics: Only in specific cases (severe colitis, immunocompromised).
• Avoid Loperamide: In infectious diarrhea, especially with EHEC or Shigella.
• Bismuth Subsalicylate: Can be considered.

Chronic Diarrhea

• Identify and Treat Underlying Cause: Hormonal, malabsorption, inflammatory.
• Anti-Diarrheal Agents: Use cautiously.

Conclusion

• Understanding types and causes of diarrhea is crucial for management.
• Emphasis on diagnostic approach and complications.
• Thank you for engaging with the lecture. Further resources available on the Ninja Nerd website.

These notes provide a high-level overview of the lecture content focused on diarrhea, covering key points, types, complications, diagnostics, and treatment strategies in both acute and chronic scenarios.