Inflammatory Bowel Disease Overview

Inflammatory Bowel Disease (IBD)

• IBD encompasses Crohn's disease and ulcerative colitis (UC), both chronic disorders with unpredictable exacerbations.
• Symptoms of both Crohn's and UC include diarrhea, weight loss, abdominal pain, fever, and fatigue. Key differences exist.

Crohn's Disease

• Common symptoms include diarrhea and cramping abdominal pain.
• Small intestine involvement contributes to weight loss due to malabsorption.
• Rectal bleeding is less common than in UC.
• Inflammation can cause pseudopolyps.

Ulcerative Colitis (UC)

• Predominant symptoms are bloody diarrhea and abdominal pain.
• Pain ranges from mild cramping to severe, constant pain (with complications).
• Stool characteristics vary by severity: mild disease shows small amounts of blood; moderate disease increases stool output (up to 10/day), bleeding, and systemic symptoms; severe disease features bloody, mucus-filled stools multiple times a day, significant weight loss, fever, anemia, tachycardia, and dehydration.
• Water and electrolyte loss from diarrhea are common.

Complications of IBD

• GI Tract Complications: Hemorrhage, strictures, perforation, abscesses, fistulas, Clostridium difficile infection (CDI), and toxic megacolon (more common in UC). Toxic megacolon poses risk of perforation and necessitates emergency colectomy. Perineal abscesses and fistulas are more common in Crohn's.
• Increased Cancer Risk: IBD patients face an increased risk of colorectal cancer (CRC), particularly small intestine cancer in Crohn's disease.
• Systemic Complications: IBD can lead to other conditions such as multiple sclerosis, ankylosing spondylitis, malabsorption, liver disease (primarily primary sclerosing cholangitis), and osteoporosis. Inflammatory activity in the bowel can be a link, improving with remission. Routine liver function tests are crucial for monitoring primary sclerosing cholangitis. Bone density scans are important for IBD patients.

Diagnostic Studies

• Clinical Assessment: Ruling out other diseases with similar symptoms, determining Crohn's from UC is crucial. Early Crohn's symptoms can mimic IBS.
• Diagnostic Tests: Complete Blood Count (CBC) typically reveals iron deficiency anemia due to blood loss. High White Blood Cell (WBC) count suggests potential toxic megacolon or perforation. Reduced serum electrolytes (sodium, potassium, chloride, bicarbonate, magnesium) indicate fluid and electrolyte loss from diarrhea and vomiting. Hypoalbuminemia (low albumin) is indicative of severe disease and poor nutrition/protein loss. Elevated erythrocyte sedimentation rate, C-reactive protein, and WBC reflect inflammation. Stool examination checks for blood, pus, and mucus. Stool cultures detect infection.
• Imaging: Double-contrast barium enema, small bowel series, transabdominal ultrasound, CT, and MRI aid diagnosis.
• Endoscopy: Colonoscopy examines the entire colon and sometimes the distal ileum. Inflammation, ulcers, pseudopolyps, and strictures are visually assessed, enabling biopsy for a definitive diagnosis. Capsule endoscopy may be needed for small intestine Crohn's disease.