Colitis

Disease Description (Causes and Symptoms)

Colitis refers broadly to a condition involving inflammation of the mucosa of the colon (large intestine). Causes vary and include infectious causes (viruses, bacteria, and parasites), inflammatory bowel disease (ulcerative colitis and the colonic form of Crohn’s disease), ischemic colitis, drug-induced colitis (e.g., C. difficile caused by some antibiotics), radiation colitis, and microscopic colitis. Pathophysiologically, mucosal inflammation causes impaired absorption of water and electrolytes and mucosal damage, resulting in diarrhea (sometimes bloody), mucus in the stool, abdominal pain, bowel urgency, fever, nausea and vomiting, weight loss, and other symptoms. Infectious colitis usually improves over a short period, whereas inflammatory bowel disease follows a chronic, relapsing course and requires management of the risks of intestinal perforation, bleeding, and cancer.

Main symptoms: diarrhea (frequent, watery, or bloody), mucus or pus in the stool, abdominal pain (especially in the lower abdomen), changes in bowel habits (frequency and stool characteristics), fever, general fatigue, dehydration, and others.

General risk factors: recent antibiotic use, overseas travel, immunosuppression, smoking (varies by type), dietary factors (high-fat foods, processed meat, etc. are associated with some intestinal diseases and colorectal cancer), obesity, and others.

Treatment Methods

• Diagnosis-based treatment principle: Treatment is determined according to the identified cause (through stool tests, blood tests, endoscopy and biopsy, etc.).

• General treatment (common to all types)

  • Conservative treatment: Fluid and electrolyte replacement, fasting or a low-residue diet, and control of pain and fever. Hospitalization and intravenous fluid therapy may be required in cases of severe diarrhea or dehydration.
  • Symptom management: Antidiarrheal medications may worsen infectious diarrhea and should be used under a doctor’s instructions.

• Infectious colitis

  • Conservative treatment is the basis (most cases recover naturally).
  • Appropriate antibiotics may be used for bacterial infections and infections with specific pathogens (e.g., Salmonella or Campylobacter, depending on the case).
  • Clostridioides difficile infection: Standard medications are oral vancomycin or fidaxomicin (depending on symptoms and severity). Follow a specialist’s guidance in cases of recurrence.

• Inflammatory bowel disease (ulcerative colitis and the colonic form of Crohn’s disease)

  • Mild disease: Oral (or suppository) 5-aminosalicylic acid (such as mesalazine)
  • Moderate to severe disease: Short-term steroids (for induction), or immunomodulators (azathioprine, 6-MP) or biologic agents (anti-TNF agents, vedolizumab, ustekinumab, etc.) for maintenance therapy
  • Surgery (partial resection or total colectomy) may be required in cases of medication-refractory disease or complications (bleeding, perforation, severe stricture, etc.).
  • Long-term follow-up (cancer risk management): Patients with chronic extensive colitis require periodic colonoscopic surveillance.

• Microscopic colitis

  • A locally acting steroid (budesonide) is effective.

• Ischemic colitis

  • Mild cases are treated conservatively (fluid therapy and nutritional support), while severe cases (necrosis or perforation) require surgical treatment.

Precautions (related to treatment): When taking immunosuppressants or biologic agents, the risk of infection increases; pay attention to vaccination (after consulting a doctor) and infection prevention. Use antibiotics only when absolutely necessary. Long-term steroid use requires monitoring for side effects such as osteoporosis, infection, and metabolic abnormalities.

Complications: Dehydration, electrolyte abnormalities, bleeding, intestinal perforation, intestinal stricture or obstruction, toxic megacolon (especially in severe ulcerative colitis), and an increased risk of colorectal cancer due to chronic inflammation (chronic extensive colitis).

Self-care precautions: Drink sufficient fluids; limit irritating foods (fatty foods, spicy foods, caffeine, and alcohol); eat regular meals and adjust fiber intake (according to symptoms and cause); take prescribed medications regularly; and visit a hospital immediately in cases of fever, severe abdominal pain, or persistent bleeding.

Checklist Before an Outpatient Visit (Including Sample Questions)

Items and information to prepare

• A list of currently used medications (including prescription drugs, over-the-counter medications, and health supplements)
• Copies or summaries of previous test results (recent blood tests, colonoscopy results, pathology reports, abdominal CT, etc.)
• Symptom diary: time of onset, number and characteristics of diarrheal stools (watery, mucus, or blood), location and severity of abdominal pain, presence of fever, weight changes, and whether bowel urgency is present
• Recent travel history, dietary history (consumption of unusual foods), history of antibiotic use, allergy history, and chronic diseases (diabetes, heart, liver, kidney disease, etc.)
• Insurance information and identification; bring a guardian if necessary

Questions to check before seeing the doctor (self-assessment)

• When did the diarrhea begin? Is there blood in the stool?
• Are fever, severe abdominal pain, vomiting, or dizziness (symptoms of dehydration) present?
• Have you recently taken antibiotics or been hospitalized?
• Are you undergoing immunosuppressive treatment (steroids, immunosuppressants, or biologic agents)?

What to do during an outpatient visit

• Do not stop your current medications; submit the medication list.
• If a colonoscopy is scheduled, follow the dietary, fasting, and bowel preparation instructions provided by the doctor.
• Visit the emergency room for acute severe symptoms (high fever, low blood pressure, excruciating abdominal pain, or persistent large-volume bleeding).

General Sample Questions to Ask the Doctor

• How will you distinguish the cause of my symptoms (infectious versus chronic inflammatory, etc.)? What additional tests are needed?
• What is the purpose of the medication you plan to prescribe, and what side effects should I expect? What precautions are needed with long-term use?
• How likely is hospitalization or surgery to be necessary? In what situations should I go to the emergency room?
• What lifestyle changes should I make regarding diet, exercise, alcohol consumption, and smoking?
• How often should I undergo long-term follow-up examinations (endoscopy and tests)?

Sample Disease-Specific Questions

• (If inflammatory bowel disease is suspected) How will you confirm whether this is ulcerative colitis or Crohn’s disease? What are the criteria for requiring biologic treatment (such as anti-TNF agents)?
• (If infectious colitis is suspected) Which organisms will be checked in the stool test? Are antibiotics absolutely necessary, or is conservative treatment sufficient?
• (If C. difficile is suspected) Which test will confirm the diagnosis? How does treatment differ between a first infection and a recurrence?

(If necessary, determine the additional testing and treatment plan in consultation with a specialist. The information above is general information; follow the healthcare professional’s evaluation for individual diagnosis and treatment.)