4 Inflammatory Bowel Disease

What IBD is

Inflammatory bowel disease (IBD) is a group of chronic immune-mediated disorders, chiefly Crohn’s disease and ulcerative colitis. Both can have periods of active symptoms, called flares, and periods of remission. Treatment aims to control inflammation, achieve and maintain remission, prevent complications, and support nutrition and quality of life.

Irritable bowel syndrome is different from IBD: it does not cause the intestinal inflammation and tissue damage associated with IBD.

How Crohn’s disease and UC differ

The diseases have typical but not absolute patterns. Symptoms and complications can overlap, so these patterns should not be used alone to diagnose an individual.

• Crohn’s disease: Can affect any part of the gastrointestinal tract, from mouth to anus, and often involves the terminal ileum and colon. Inflammation may occur in patchy areas called skip lesions and may extend through the full thickness of the bowel wall. Common symptoms include diarrhea, abdominal pain, and weight loss; blood may occur, especially with colonic disease. Complications include strictures and obstruction, fistulas, abscesses, fissures, and malabsorption.

• Ulcerative colitis (UC): Affects the colon only, usually beginning in the rectum and extending continuously toward the proximal colon, without normal segments between affected areas. It primarily affects the inner lining of the colon. Common symptoms include bloody diarrhea, urgency, rectal bleeding, cramping, and tenesmus—the feeling of needing to pass stool when the bowel is empty. Complications include severe bleeding, toxic megacolon, perforation, and increased colorectal cancer risk with longstanding colonic inflammation.

Assessment and diagnosis may involve stool and blood tests, endoscopy with biopsies, and imaging. Infection should be considered when symptoms worsen.

Assessing and managing a flare

A flare is a return or worsening of symptoms, but worsening diarrhea or pain should not automatically be assumed to reflect active IBD. Infection, including Clostridioides difficile, medication effects, and Crohn’s-related narrowing or obstruction can produce similar symptoms. Notify the treating team and follow the ordered evaluation plan.

Track stool frequency and appearance, blood, urgency, abdominal pain, nausea or vomiting, oral intake, urine output, weight, temperature, and vital signs. Assess hydration and signs of blood loss or anemia, such as dizziness, pallor, tachycardia, or weakness. Review ordered laboratory and stool-test results.

Promptly report increasing abdominal distension, severe or worsening pain, guarding, fever, persistent vomiting, heavy bleeding, markedly reduced urine output, or inability to pass stool or gas. During an acute severe flare, follow orders for fluids, laboratory monitoring, stool testing, imaging or endoscopy, nutrition support, and medication. Hospitalized patients may need additional complication-prevention measures, such as prescribed venous-thromboembolism prophylaxis when it is not contraindicated.

Recognizing urgent complications

Some flare symptoms can signal urgent complications and need prompt assessment.

• Possible obstruction: Cramping pain, abdominal distension, vomiting, and reduced passage of stool or gas warrant urgent assessment. Keep the patient NPO if ordered, do not give laxatives or antidiarrheal medicine unless specifically directed, and promptly notify the clinician. New cramping with distension and repeated vomiting in a patient with Crohn’s disease should prompt notification of the clinician and preparation to follow an obstruction evaluation plan—not reassurance or unsupervised food or antidiarrheal treatment.

• Possible toxic megacolon or perforation: Severe colitis with distension, fever, tachycardia, or worsening abdominal tenderness is an emergency; escalate care immediately. Antidiarrheal drugs and opioids may worsen bowel dilation or mask deterioration, so administer them only under an appropriate order and clinical plan.

• Dehydration or major bleeding: Report these promptly and monitor vital signs, intake and output, and laboratory results as directed. Severe abdominal pain, ongoing vomiting, high fever, heavy bleeding, or dehydration may require emergency care.

Medication choices and safety

Medication selection depends on disease type, location, severity, prior response, and patient-specific risks. Therapies may induce remission, maintain it, or do both.

• 5-aminosalicylates (5-ASAs): Commonly used for mild-to-moderate UC. They are not effective maintenance therapy for Crohn’s disease in current ACG guidance.

• Corticosteroids: May be prescribed short term to induce control of a flare, but are not maintenance therapy because prolonged use can cause serious adverse effects. Do not stop a prolonged course abruptly; follow the prescribed taper. For UC, corticosteroids should not be used to maintain remission.

• Immunomodulators and advanced therapies: Options include thiopurines, biologic medicines, and targeted small-molecule drugs. They require individualized monitoring. Before certain immunosuppressive therapies, clinicians may screen for infections such as tuberculosis and hepatitis B and review vaccination status. Follow medication-specific instructions for blood tests, liver monitoring, and infection precautions.

Report fever or other possible infection symptoms while taking immune-suppressing medication. Discuss new prescriptions, over-the-counter medicines, supplements, and vaccines with the care team. NSAIDs such as ibuprofen or naproxen may aggravate symptoms for some people. Do not start, stop, or increase IBD medicines independently.

Ongoing care and patient education

Take maintenance medicines as prescribed, even when symptoms improve. Remission does not mean the disease is cured. Contact the IBD team early about new or worsening symptoms, missed doses, or medication concerns, and discuss any proposed treatment changes with the team rather than stopping medicine or taking it only when symptoms return.

Maintain fluids, especially during diarrhea, and choose a balanced diet as tolerated. There is no single diet that suits everyone or cures IBD. A food and symptom record may help identify personal triggers. Ask about a registered dietitian if there is weight loss, restricted intake, or concern about malnutrition or deficiencies; Crohn’s disease and bowel surgery can affect nutrient absorption.

Ask the clinician which vaccines are appropriate, especially before starting immune-suppressing therapy. Some live vaccines may be unsuitable during significant immunosuppression; do not change vaccines or medication without clinical advice. Avoid smoking because it worsens Crohn’s disease outcomes. Ask the care team before using NSAIDs or antidiarrheal medicines.

Keep recommended follow-up appointments and colonoscopy surveillance. Surveillance timing depends on disease extent, duration, and individual risk. Report persistent fatigue, unexplained weight loss, or ongoing blood in stool. Discuss pregnancy plans, emotional health, work or school accommodations, and support resources with the care team.