Summary
Highlights
Ulcerative colitis (UC) is a chronic inflammatory bowel disease that affects the large intestine (colon), always involving the rectum and spreading proximally. The cause is unknown but is believed to involve an immune response to enteric bacteria. Smokers have a decreased risk/symptoms, unlike Crohn's disease. It has a higher incidence in Jewish populations. The main symptom is bloody diarrhea.
Common symptoms include bloody diarrhea (often sudden onset, high frequency, small volume), which may contain mucus or pus. Nocturnal diarrhea is also common and can cause significant blood loss. Abdominal pain is less likely than in Crohn's disease. Urgency and tenesmus (sensation of incomplete evacuation) due to rectal inflammation are frequent.
Anemia (iron deficiency, microcytic) can occur due to blood loss, leading to fatigue, pallor, and shortness of breath. Fatigue and malaise are also common due to chronic inflammation. There are interesting extra-intestinal manifestations of UC like erythema nodosum that affects approximately 10% of patients with ulcerative colitis.
UC can present with extra-intestinal manifestations including skin findings like erythema nodosum and pyoderma gangrenosum (less common than in Crohn's). Other possible findings are fever, weight loss (due to loss of appetite), episcleritis, uveitis, ankylosing spondylitis, arthritis and sacroilitis.
Long-term complications include primary sclerosing cholangitis (inflammation and narrowing of the biliary tract) and a significantly increased risk of colorectal cancer. Toxic megacolon (enlargement and distension of the colon) is another potential complication, presenting with acute abdominal pain, bloody diarrhea, fever and increased mortality risk.