Common Disorders of the Large Intestine

Common Disorders of the Large Intestine

Overview of Common Disorders
  • Constipation: Defined as infrequent bowel movements or difficulty in passing stools.
  • Inflammatory Bowel Disease (IBD)
    • Types: Crohn's Disease and Ulcerative Colitis.
    • Characteristics: Chronic, incurable with periods of remission and exacerbation.
    • Symptoms: Include abdominal pain, malabsorption, nutritional deficiencies, anemia, weight loss, nausea, vomiting, diarrhea, dehydration.
    • Extraintestinal Complications: May lead to arthritis, cheilitis, uveitis, and various dermatological problems.
Causes of Constipation
  • Functional Disorders: Impaired bowel function.
  • Neurological Disorders: Multiple Sclerosis (MS), spinal cord injuries.
  • Metabolic Disorders: Hypothyroidism.
  • Medications: Opioids and others.
  • Inadequate Fiber Intake: Lack of dietary fiber can lead to constipation.

Inflammatory Bowel Disease (IBD)

Crohn's Disease
  • Affected Areas: Can impact any part of the gastrointestinal (GI) tract from mouth to anus.
  • Wall Layer Involvement: Affects the entire thickness of the intestinal wall.
  • Lesions: Characterized by skip lesions (sections of healthy bowel between diseased areas).
  • Signs: Cobblestoning, obstruction, toxic megacolon.
Ulcerative Colitis
  • Affected Areas: Primarily affects only the large intestine.
  • Wall Layer Involvement: Only affects mucosa and submucosa layers.
  • Lesion Pattern: Continuous inflammation from rectum upwards.
  • Signs: Presence of pseudopolyps, bleeding, frequent stools.

Large Bowel Obstruction (LBO)

Types of Obstruction
  • Mechanical: Physical blockage preventing normal bowel movement.
  • Nonmechanical: Impaired peristalsis leading to obstruction.
Description of Obstruction
  • Can be partial or complete, acute or chronic, reversible or irreversible.
    • Pathophysiology:
    • Obstruction → Distention proximal to obstruction → Stimulates peristalsis
    • Results in increased pressure that leads to decreased absorption and blood flow → Ischemia or infarction and potential perforation.
Signs and Symptoms of LBO
  • Abdominal pain: Varies based on obstruction type.
  • Distention and Rigidity: Especially in complete obstruction.
  • Bowel Movements:
    • Complete: No bowel movements, absent bowel sounds.
    • Partial: Gas and some solid movements possible; diarrhea may occur, high-pitched bowel sounds detected.

Appendicitis

  • Definition: Inflammation of the appendix.
  • Signs and Symptoms:
    • Pain starting at the umbilicus and radiating to the right lower quadrant (RLQ) at McBurney's point.
    • Rebound tenderness and abdominal guarding.
    • Positive Psoas & Obturator signs especially relevant for diagnosis.
    • Other associated signs: Abdominal distention, fever.
  • Complications: Can lead to rupture of the appendix.

Irritable Bowel Syndrome (IBS)

  • Symptoms: Chronic abdominal pain and altered bowel habits, lasting at least 6 months.
  • No structural abnormalities: Diagnosis relies on symptomatology.
  • Additional Symptoms: Anxiety, flatulence, mucous in stools, nausea, abdominal distention.
  • Connection to Stress: Flare-ups often relate to stress factors.

Diverticular Disease

  • Definitions:
    • Diverticulum: Single pouch formed in weak areas of the colon.
    • Diverticula: Multiple pouches in similar weak spots.
    • Diverticulosis: Presence of diverticula without inflammation.
    • Diverticulitis: Inflammation or infection of diverticula.
  • Pathophysiology: Contents can block diverticula leading to irritation/infection and potential narrowing of bowel lumen.
  • Risk Factors: Low fiber diet.
  • Signs and Symptoms:
    • Abdominal pain (LLQ or RLQ).
    • Symptoms may vary based on severity and location: fever, nausea, changes in bowel habits (constipation or diarrhea), potential occult blood in stool.

Volvulus

  • Description: Twisting of the large intestine.
  • Population Affected: Common neonatal congenital abnormality; in adults, primarily affects the sigmoid colon.
  • Consequences: Bowel obstruction and possible ischemia leading to perforation/necrosis.
  • Symptoms: Vomiting, abdominal pain, tenderness, signs of shock.