GI PACKET 6

Ulcerative Colitis (UC)

• Definition & Disease Overview:

  • A disease of the colon causing inflammation and ulceration.

  • Involves the rectum and proceeds proximally through the colon (sigmoid, descending, and transverse colon).

  • May extend all the way around to the distal ileum, though this is uncommon.

  • Does not usually spread to the small intestine.

  • Characterized by alternating active and inactive periods.

• Demographics & Epidemiological Data:

  • Peak Age Range of Onset: Observed in two distinct age brackets: $20-30\text{ years of age}$ and $50-70\text{ years of age}$.

  • Affected Populations: More common in Caucasians and specific Jewish populations.

• Etiology & Proposed Causes:

  • The precise etiology is unknown, with no single definitive cause identified.

  • Possible Causes & Unproven Theories:

    • Overactive immune system response.

    • Genetic factors.

    • Environmental factors: Oral contraceptives, high-fat diet, chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs), and chronic use of antibiotics (abx).

    • Infectious triggers (microbial origin).

• Clinical Manifestations & Symptoms:

  • Diarrhea accompanied by blood or pus (indicating active infection/inflammation).

  • Abdominal pain.

  • Rectal urgency (a rapid, immediate imperative to defecate).

  • Weight loss.

  • Fever.

• Diagnostic Evaluation:

  • History: Detailed medical and family history (Hx).

  • Physical Examination (PE): Comprehensive physical assessment.

  • Endoscopic Examination: Flexible sigmoidoscopy or colonoscopy with tissue biopsy as needed.

  • Laboratory Work: Evaluates for signs of anemia, active infection, or systemic inflammation.

• Therapeutic Interventions & Treatment:

  • Mild Symptoms: Over-the-counter (OTC) antidiarrheals such as Imodium.

  • Pharmacological Options:

    1. Steroids (e.g., Prednisone): Targets active inflammation; intended for intermittent, short-term use due to the risk of bone density loss with long-term administration.

    2. Aminosalicylates (e.g., Azulfidine): Taken daily to prevent flare-ups and maintain disease control.

    3. Immunomodulators (e.g., Methotrexate, Azothiaprine): Interfere directly with DNA synthesis in immune system cells.

    4. Biologics / TNF Inhibitors: Target tumor necrosis factor (TNF), a protein produced by the immune system, neutralizing TNF to reduce inflammation.

  • Surgical Interventions: Surgical excision of bowel tissue may be necessary, which may require placement of a colostomy bag.

• Complications:

  • Colon Cancer: Elevated risk in patients with long-standing disease spanning $> 10\text{ years}$.

  • Toxic Megacolon: Severe condition where inflammation extends across all layers of the colon wall; can lead to severe dilation and paralysis of the bowel, potentially proceeding to intestinal perforation and sepsis.

Crohn's Disease (Regional Enteritis)

• Definition & Disease Overview:

  • A chronic inflammatory condition that occurs most commonly in the distal ileum.

  • Can occasionally occur in the colon (referred to as Crohn's disease of the colon).

  • Capable of affecting any segment of the gastrointestinal tract, including the stomach and esophagus.

  • Fluctuates between active and inactive disease periods.

• Demographics & Epidemiological Data:

  • Peak Age Range of Onset: Observed in two age brackets: $15-30\text{ years of age}$ and $50-70\text{ years of age}$.

  • Affected Populations: More common in Caucasians and specific Jewish populations.

• Etiology:

  • Unknown etiology; shares the same four unproven causal theories as Ulcerative Colitis (immune hyperresponsiveness, genetic traits, environmental exposure, and microbial infection).

• Clinical Manifestations & Symptoms:

  • Diarrhea.

  • Crampy abdominal pain.

  • Weight loss.

  • Gastrointestinal bleeding (sometimes present).

  • Fever (may be present).

• Complications:

  • Colon Cancer: Increased risk, though the overall risk is not as high as that seen in Ulcerative Colitis.

  • Fistulas: Abnormal connections or tracts; an inflamed bowel wall breaks open and connects to adjacent mucosal structures or internal organs.

  • Strictures: Tightening or structural irregularities in the bowel wall, leading to abnormal narrowing of the passage.

  • Abscesses: Localized collections of infection/pus secondary to deep inflammatory penetration.

• Diagnostic Evaluation:

  • History & Physical: Medical history (Hx) and physical examination (PE).

  • Endoscopy: Colonoscopy with biopsy.

  • Laboratory Tests:

    • ASCA Antibody Test: Measures anti-saccharomyces cerevisiae antibody, which is frequently present in the blood of individuals with Crohn's disease.

    • Complete Blood Count (CBC): Evaluates for evidence of systemic infection or anemia.

• Therapeutic Interventions & Treatment:

  • Primary Treatment Goal: Reduce gut tissue inflammation.

  • Pharmacological & Procedural Interventions:

    1. Steroids.

    2. Aminosalicylates.

    3. Immunomodulators.

    4. Biologics.

    5. Anti-diarrheals (e.g., Imodium).

    6. Surgical excision if medically necessary.

    7. Fecal Microbiota Transplant (FMT): Transfers processed stool from a healthy donor into the patient's gastrointestinal tract to restore healthy gut bacteria.

Key Differences Between Ulcerative Colitis and Crohn's Disease

• Anatomical Location:

  • Ulcerative Colitis: Confined strictly to the colon, though it may occasionally extend to affect the distal ileum.

  • Crohn's Disease: Typically affects the distal ileum, but can also involve the colon, stomach, and esophagus.

• Pattern and Depth of Inflammation:

  • Ulcerative Colitis: Limited usually to the superficial layers of the bowel wall; inflammation is continuous, diffuse, and uniform throughout the involved segment.

  • Crohn's Disease: Involves both deep (transmural) and superficial layers of the bowel wall; inflammation is discontinuous, presenting as non-continual skip lesions where areas of abnormal tissue are interspersed with normal tissue.