Chapter 30

Constipation

  • Overview: Most people experience constipation at some point. Key causes include:
    • Functional disorders: E.g., Irritable Bowel Syndrome (IBS)
    • Neurological disorders: E.g., Multiple Sclerosis, spinal cord injury
    • Metabolic disorders: E.g., Hypothyroidism
    • Medications: E.g., Opioids affecting GI motility
    • Inadequate fiber intake

Inflammatory Bowel Disease (IBD)

  • Definition: Encompasses disorders like Crohn's disease and ulcerative colitis.

  • Similarities:

    • Both chronic, incurable with periods of remission (asymptomatic) and exacerbation (symptomatic).
    • Common GI symptoms: Abdominal pain, malabsorption leading to nutritional deficiencies, anemia due to blood loss and vitamin deficiencies, weight loss, nausea, vomiting, diarrhea, dehydration.

  • Nutritional deficiencies:

    • Vitamin B12: Needed for blood formation.
    • Vitamin K: Needed for clotting.
    • Anemia more common in ulcerative colitis.
    • Symptoms like arthritis and uveitis may occur in both but their exact relationship is unclear.
Differences Between Crohn’s Disease and Ulcerative Colitis

  • Crohn’s Disease:

    • Affects any part of the GI tract (mouth to anus).
    • Involves entire thickness of the intestinal wall with "skip lesions" (healthy segments amidst affected segments).
    • Characteristic "cobblestone" appearance due to inflammation.
    • Complications: Can lead to toxic megacolon due to severe inflammation causing obstruction.

  • Ulcerative Colitis:

    • Affects only the large intestine, specifically mucosa and submucosa.
    • Continuous inflammation starting from the rectum.
    • Pseudopolyps are formed.
    • More common to have blood in stool; frequent stools (often >20/day).
    • Fluid loss can be significant (500 to 2000 mL per day).
Visual Summary of Differences:
  • Crohn's Disease: Skip lesions, cobblestoning, thickened walls.
  • Ulcerative Colitis: Continuous inflammation, pseudopolyps.

Large Bowel Obstruction

  • Classification: Mechanical (physical blockage) vs. Non-mechanical (impaired motility).
  • Mechanical Obstruction Examples:
    • Tumors
    • Volvulus: Twisting of bowel leading to obstruction.
    • Intussusception: Bowel section telescopes into itself.
  • Pathophysiology:
    • Blockage leads to distension proximal to the obstruction, stimulating peristalsis, but ineffective due to obstruction.
    • Increased pressure can lead to ischemia, perforation, and peritonitis.
  • Symptoms: Colicky abdominal pain, distension, rigidity of abdomen, complete obstruction leads to no bowel movements/bowel sounds.

Appendicitis

  • Description: Inflammation of the appendix.
  • Symptoms:
    • Pain starting at the umbilicus and moving to the right lower quadrant (McBurney’s point).
    • Rebound tenderness and Rovsing's sign (pain in right lower quadrant when pressing left).
    • Positive psoas and obturator signs indicate inflammation.
  • Complications: Rupture can lead to peritonitis.

Irritable Bowel Syndrome (IBS)

  • Important Distinction: IBS differs from IBD; no inflammation, no structural abnormalities visible.
  • Symptoms: Abdominal pain, altered bowel activity, anxiety, bloating, relieved by bowel movement.
    • Commonly linked to stress.

Diverticular Disease

  • Terminology:
    • Diverticulum (singular pouch), Diverticula (multiple pouches), Diverticulosis (presence of diverticula), Diverticulitis (inflammation of diverticula).
  • Pathophysiology:
    • Inflammation can occur when intestinal content blocks a diverticulum.
    • Low fiber diet increases risk.
  • Symptoms: Abdominal pain (can mimic appendicitis), fever, nausea, altered bowel habits, possibly occult blood in stools.

Volvulus

  • Definition: Twisting of the intestines causing a knot preventing stool passage.
  • Risk Factors: Can be congenital in neonates; in adults typically occurs in the sigmoid colon.
  • Symptoms: Vomiting, abdominal pain/tenderness, shock (if rupture occurs).