Rosh Internal Medicine Boost Practice Exam

For a patient with tearing pain during bowel movements and bright red blood on toilet paper, what is the most likely diagnosis?

1. Anal fissure

2. Anorectal fistula

3. Anorectal ulcer

4. Hemorrhoid

The correct answer is: Anal fissure

The presentation of tearing pain during bowel movements, along with bright red blood on the toilet paper, is most consistent with an anal fissure. An anal fissure is a small tear in the lining of the anus, typically caused by the passage of hard or large stools. The pain is often described as sharp and severe during and following bowel movements, which aligns perfectly with the tearing pain this patient experiences. The bright red blood observed on the toilet paper is due to the injury of the anal mucosa during defecation, which is a common symptom associated with fissures. In contrast, anorectal fistulas are usually associated with chronic drainage and infection, rather than acute pain specifically during bowel movements. Anorectal ulcers would typically present with different symptoms and might not be as acutely painful during the act of defecation as fissures. Hemorrhoids can also cause bright red blood, but the pain associated with them is usually less intense than that of an anal fissure, and bleeding typically occurs from the rectum rather than an acute tear during bowel transit. Thus, the specific combination of tearing pain and bright red blood strongly points to an anal fissure as the most likely diagnosis.