Case 1: Differential Diagnosis

Good choice! Given the inflammatory features (blood in stool, urgency, nocturnal bowel movements, rectal pain) of his chronic diarrhea IBD should be considered. He falls within the range of second peak in the distribution of age of onset of UC. Chronic bloody diarrhea with urgency and tenesmus, is a classic presentation of UC. The recent cessation of tobacco use may have triggered a flare in disease activity.

Good choice! Given the inflammatory features (blood in stool, urgency, nocturnal bowel movements, rectal pain) of his chronic diarrhea IBD should be considered. CD often presents with non bloody diarrhea, abdominal pain, cramping, weight loss, and may also have symptoms of perianal involvement. However Crohn’s colitis may present as bloody diarrhea.

Should be lower on the differential given that his rectal bleeding is associated with increased bowel frequency, urgency and nocturnal bowel movements. Try again!

Should be lower on the differential. While this is a common cause of chronic diarrhea in the elderly, his features of blood in stool and rectal pain make this diagnosis less likely. Try again!

Should be lower on the differential. While this can be a cause of bloody diarrhea, it is more likely to have an acute presentation. Try again!

Should be lower on the differential. Given that he is elderly, with a history of tobacco abuse and associated cardiovascular disease, he has multiple risk factors for ischemia. However ischemic colitis would have a more acute presentation. Try again!

Should be lower on the differential. Given that he is elderly, with a history of tobacco abuse and associated cardiovascular disease, he has multiple risk factors for ischemia. However chronic mesenteric ischemia is more often associated with abdominal pain. Try again!

Good choice! Given his recent exposure to fluoroquinolone antibiotics C. difficile infection is on the differential. While it is usually associated with acute diarrhea, more severe or long-standing infection may cause colonic mucosal damage leading to blood in stool.

Should be lower on the differential. While the patient has significant travel history within the last 6 months, and has chronic diarrhea, giardial infection is less likely to cause blood in stool. Try again!

Good choice! In a patient with positive travel history and chronic diarrhea with blood in stool, amoebic colitis is on the differential.

Good choice! About 5-20% of patients who receive pelvic radiation therapy for prostate cancer develop chronic radiation proctopathy, 3-6 months after. Changes can include rectal inflammation and angioectasias that lead to bleeding per rectum. However increased bowel frequency and nocturnal bowel movements are not frequently seen with radiation proctopathy.

Good choice! New onset change in bowel habits, with blood in stool, in an elderly patient with a history of tobacco abuse, should raise the concern for rectal or colonic malignancy.

Good choice! Patients with chronic heavy NSAID intake can develop intestinal ulcers, leading to diarrhea and blood in stool. Exact amount and duration of intake is often under-reported by patients and should be clarified.