CLINICAL CASE SCENARIO OF COLITIS
A 28-year-old man comes to the emergency room complaining of 2 days of abdominal pain and diarrhea. He describes his stools as frequent, with 10 to 12 per day, small volume, sometimes with visible blood and mucus, and preceded by a sudden urge to defecate. The abdominal pain is crampy, diffuse, and moderately severe, and it is not relieved with defecation. In the past 6 to 8 months, he has experienced similar episodes of abdominal pain and loose mucoid stools, but the episodes were milder and resolved within 24 to 48 hours. He has no other medical history and takes no medications. He has no recent travel history nor had contact with anyone with similar symptoms. He works as an accountant and does not smoke or drink alcohol. No member of his family has gastrointestinal (GI) problems. On examination, his temperature is 99°F, heart rate 98 bpm, and blood pressure 118/74 mm Hg. He appears uncomfortable, is diaphoretic, and is lying still on the stretcher. His sclerae are anicteric, and his oral mucosa is pink and clear without ulceration. His chest is clear, and his heart rhythm is regular, without murmurs.
His abdomen is soft and mildly distended, with hypoactive bowel sounds and minimal diffuse tenderness but no guarding or rebound tenderness. Laboratory studies are significant for a white blood cell (WBC) count of 15,800/mm3 with 82% polymorphonuclear leukocytes, hemoglobin 10.3 g/dL, and platelet count 754,000/mm3. The HIV (human immunodeficiency virus) assay is negative. Renal function and liver function tests are normal. A plain film radiograph of the abdomen shows a mildly dilated air-filled colon with a 4.5-cm diameter and no pneumoperitoneum or air/fluid levels.
Most likely diagnosis: Colitis, probably ulcerative colitis.
Next step: Admit to the hospital, obtain stool samples to exclude infection, and begin therapy with corticosteroids.
The differential diagnosis for colitis includes ischemic colitis, infectious colitis (C difficile, E coli, Salmonella, Shigella, Campylobacter), radiation colitis, and IBD (Crohn disease vs ulcerative colitis).
Mesenteric ischemia usually is encountered in people older than 50 years with known atherosclerotic vascular disease or other cause of hypoperfusion. The pain usually is acute in onset following a meal and not associated with fevers. With an infectious etiology, patients often have engaged in foreign travel, the symptoms are acute, or the patients recently used antibiotics. Also, family members often have the same symptoms. The IBD is most commonly diagnosed in young patients between the ages of 15 and 25 years. There is a second peak in the incidence of IBD (usually Crohn disease) between the ages of 60 and 70 years. The IBD may present with a low-grade fever. The chronic nature of this patient’s disease (several months) is typical of IBD. Anemia may be present, either due to iron deficiency from chronic GI blood loss, or anemia of chronic disease. Patients with IBD may also report fatigue and weight loss. Ulcerative colitis usually presents with grossly bloody stool, whereas symptoms of Crohn disease are much more variable, mainly chronic abdominal pain, diarrhea, and weight loss. Ulcerative colitis involves only the large bowel, whereas Crohn disease may affect any portion of the GI tract, typically the colon and terminal ileum. Ulcerative colitis always begins in the rectum and proceeds proximally in a continuous pattern; disease is limited to the colon. Crohn disease classically involves the terminal ileum but may occur anywhere in the GI tract from the mouth to the anus. Anal fissures and nonhealing ulcers are often seen in Crohn disease. Additionally, the pattern of Crohn disease is not contiguous in the GI tract; classically, it has a patchy distribution that is often referred to as “skip lesions.” Patients with Crohn may develop strictures caused by fibrosis from repeated inflammation which can lead to bowel obstruction, with crampy abdominal pain and nausea/vomiting. Ulcerative colitis is characterized by diarrhea and typically leads to bowel obstruction. The diagnosis usually is confirmed after colonoscopy with biopsy of the affected segments of bowel and histologic examination. In ulcerative colitis, inflammation will be limited to the mucosa and submucosa, whereas in Crohn disease, the inflammation will be transmural (throughout all layers of the bowel).
The treatment of ulcerative colitis can be complex because the pathophysiology of the disease is incompletely understood. Management is aimed at reducing the inflammation. Most commonly, sulfasalazine and other 5-aminosalicylic acid (ASA) compounds such as mesalamine are used and are available in oral and rectal preparations.
They are used in mid to moderate active disease and to induce remission, and in the maintenance of disease to reduce the frequency of flare-ups. Corticosteroids may be used (po, PR, or IV) to treat patients with moderate to severe disease. Once remission is achieved, the steroids should be tapered over 6 to 8 weeks and then discontinued if possible to minimize their side effects. Immune modulators are used for more severe, refractory disease. Such medications include 6-mercaptopurine, azathioprine, methotrexate, and the tumor necrosis factor (TNF) antibody infliximab. Anti-TNF therapy, such as infliximab, has been an important treatment of patients with Crohn disease who are refractory to steroids, and more recently has shown efficacy in ulcerative colitis. Patients receiving the potent immunomodulator infliximab are at increased risk of infection, including reactivation of latent tuberculosis. Surgery is indicated for complications of ulcerative colitis. Total colectomy is performed in patients with carcinoma, toxic megacolon, perforation, and uncontrollable bleeding. Surgery is curative for ulcerative colitis if symptoms persist despite medical therapy.
Two very important and potentially lifethreatening complications of ulcerative colitis are toxic megacolon and colon cancer. Toxic megacolon occurs when the colon dilates to a diameter more than 6 cm.
It usually is accompanied by fever, leukocytosis, tachycardia, and evidence of serious toxicity, such as hypotension or altered mental status. Therapy is designed to reduce the chance of perforation and includes IV fluids, nasogastric tube placed to suction, and placing the patient npo (nothing by mouth). Additionally, IV antibiotics are given in anticipation of possible perforation, and IV steroids are given to reduce inflammation. The most severe consequence of toxic megacolon is colonic perforation complicated by peritonitis or hemorrhage. Patients with ulcerative colitis have a marked increase in the incidence of colon cancer compared to the general population. The risk of cancer increases over time and is related to disease duration and extent. It is seen both in patients with active disease and in patients whose disease has been in remission. Annual or biennial colonoscopy is advised in patients with ulcerative colitis, beginning 8 years after diagnosis of pancolitis, and random biopsies should be sent for evaluation. If colon cancer or dysplasia is found, a colectomy should be performed
