Snapshot A 23-year-old female presents to the clinic for bloody diarrhea and abdominal pain for the past week. The pain is reported as intermittent, 7/10, and concentrated at the lower left quadrant (LLQ). She denies any rectal pain, trauma, or abnormal ingestions. She endorses subjective fever. A physical examination is unremarkable. A colonoscopy reveals friable rectal mucosa that bleeds easily on contact. Introduction Clinical definition chronic, autoimmune condition that results in the inflammation and ulceration of the colon and rectum characterized by recurring episodes of inflammation limited to the mucosal layer of the colon with treatment, the disease course typically consists of intermittent exacerbations alternating with long periods of complete symptomatic remission commonly involves the rectum and may extend proximally and continuously to involve other parts of the colon Associated conditions extraintestinal manifestations primary sclerosing cholangitis musculoskeletal involvement ankylosing spondylitis arthritis sacroiliitis eye involvement uveitis episcleritis cutaneous involvement erythema nodosum pyoderma gangrenosum venous and arterial thromboembolism autoimmune hemolytic anemia Epidemiology Demographics more common in North American and Europe compared to other regions bimodal distribution in patients aged 15-30 years and > 60 years of age Risk factors positive family history of inflammatory bowel disease (IBD) Ashkenazi Jewish descent smoking may lower risk ETIOLOGY Pathogenesis no direct cause has been identified but is likely due to genetic susceptibility with environmental triggers genetic susceptibility familial aggregation of the disease identification of multiple genetic loci linked to the disease environmental factors diets low in fiber and high in fat have been linked to the disease stress may exacerbate condition interactions of various factors ultimately lead to chronic, immune-mediated inflammation activated innate (e.g., macrophage) and acquired (e.g., T and B cell) immune responses associated with a Th2 cell response loss of tolerance to enteric commensal bacteria Presentation Symptoms diarrhea often with blood and mucus recurrent episodes fatigue tenesmus joint pain abdominal pain Physical exam fever rectal bleeding pallor imaging Abdominal radiograph not required for diagnosis but may be the best initial test for patients presenting with symptoms of colitis may see proximal constipation, mucosal thickening or “thumbprinting” secondary to edema, and colonic dilation Barium enema may be normal in patients with mild disease positive findings include shortening of the colon, loss of haustra (“leadpipe appearance”), narrowing of the luminal caliber, and pseudopolyps Computed tomography (CT) or magnetic resonance imaging (MRI) may demonstrate marked thickening of the bowel wall Colonoscopy with biopsy biopsy is necessary to establish the diagnosis endoscopic findings may include touch friability, erosions, edema, and granularity of the mucosa non-neoplastic pseudopolyps inflammation of the rectum that extends proximally in a continuous and circumferential pattern biopsy features may include crypt abscess inflammatory cells (e.g., eosinophils) within the lamina propria Studies Diagnostic testing diagnostic approach diagnosis is based on clinical presentation (e.g., chronic diarrhea > 4 weeks) and is confirmed via endoscopic biopsy studies stool studies for rule out of other causes of bloody diarrhea complete blood count, albumin, electrolytes, an markers of inflammation for evaluation of disease severity perinuclear antineutrophil cytoplasmic antibody (pANCA) Differential Crohn disease differentiating factors will often present with perianal disease with patchy inflammation on colonoscopy Infectious colitis differentiating factors will present with positive stool and tissue cultures/studies Treatment Management of the disease is dependent on the disease severity and extent of involvement First-line 5-aminosalicylic (5-ASA) drugs (e.g., sulfasalazine or mesalazine) enema is the best initial step corticosteroids (e.g., prednisone) used for acute attacks IV steroids for severe colitis iron supplementation used to management anemia secondary to gradual loss of blood Second-line immunosuppressive agents (e.g., azathioprine) and biological agents (e.g., infliximab or adalimumab) indicated in patients who cannot achieve remission with 5-ASA and corticosteroids Third-line total colectomy curative indicated in the event of exsanguinating hemorrhage, perforation, suspected carcinoma, severe colitis, toxic megacolon, or disease unresponsive to medical management COMPLICATIONS Anemia Bleeding/hemorrhage Perforation Toxic megacolon Colorectal cancer patients should receive initial screening colonoscopy 8 years after pancolitis Osteoporosis Strictures