A 66-year-old man presents to the clinic with a 6-week history of bloody stools. He describes the blood as bright red wisps that float on the surface of the stool. He has no pain with bowel movements but notes on occasion he may strain. He does not endorse fatigue, fever, constipation, diarrhea, nausea, vomiting, abdominal pain, weight loss, or dyspnea. His last colonoscopy was 3 years prior to presentation and was benign. He has a medical history significant for hypertension that is well-controlled with lisinopril. He had an uncomplicated appendectomy when he was 23 years old. He has no family history of gastrointestinal malignancy. His temperature is 98.6°F (37.0°C), blood pressure is 140/90 mmHg, pulse is 76/min, and respirations are 16/min. On physical exam, the patient's abdomen is soft, non-distended, and non-tender with normal bowel sounds and without organomegaly or masses. The anus is patent without fissures, hemorrhoids, or skin tags. Which of the following is the most appropriate next step in management?
Increase fiber in diet
Colonoscopy
Observation
Sigmoidoscopy
Colonoscopy
This patient is presenting with painless bright red blood per rectum. Because he is over 50 years old and having rectal bleeding, he should be evaluated for malignancy with a colonoscopy.

Bright red blood per rectum has a broad differential diagnosis including anal fissures, hemorrhoids, angiodysplasia, inflammatory bowel disease, diverticular bleed, infection, polyps, and colon cancer. However, as patients age, their risk for malignancy increases significantly. Therefore, stable patients older than 50 years of age with rectal bleeding, regardless of their symptoms or family history, should receive a colonoscopy to rule out malignancy. Patients younger than 50 with warning signs of colon cancer (abnormal bowel habits, weight loss, family history of colon cancer, iron deficiency anemia) should also be evaluated with a colonoscopy. Often, colonoscopy is performed routinely at the age of 50 or 10 years prior to the age of presentation for malignancy in family members (whichever is sooner). Of note, even if there is an apparent cause for a lower GI bleed in patients 50 or older (such as hemorrhoids) colonoscopy is still indicated to rule out malignancy.

Barry et al. note the guidelines for colon cancer screening. They note the different age cutoffs. The USPSTF recommends screening for colorectal cancer in all adults aged 50-75 years.

Incorrect Answers:
Answer B: Computerized tomography scan of the abdomen and pelvis is incorrect because colonoscopy is the gold standard for diagnosis of suspected colon cancer. A CT scan may detect larger masses and a CTA may be performed if there is active bleeding and concern for an arterial source of bleeding that can be intervened upon.

Answer C: Increasing fiber in the diet may help patients with constipation or hemorrhoidal bleeding. Constipation presents with straining to have bowel movements and hard stools. However, because of this patient's age, he needs a colonoscopy to rule out malignancy.

Answer D: Observation is not appropriate at this patient's age. Patients greater than 50 years old with bright red blood per rectum should receive a colonoscopy to rule out malignancy despite any recent negative colonoscopy results.

Answer E: Sigmoidoscopy is less preferred to colonoscopy, as a smaller portion of the colon would be visualized, and colonic polyps or malignancies may be missed. For this reason, it is not the preferred study in this patient.

Bullet Summary:
Patients with bright red bleeding per rectum over 50 years old or with warning signs of colonic malignancy (weight loss, abnormal bowel habits, positive family history, or anemia) should receive a colonoscopy.