A 40-year-old man comes to the office with pain on defecation. The pain is sharp and severe but subsides within minutes of passing the bowel movement. He often sees spots of bright red blood on the toilet paper. The patient has chronic constipation and has not taken laxatives or increased his fluid intake to compensate. He has no fever, night sweats, diarrhea, or unexpected weight loss. Past medical history is notable for chronic low back pain following a motor vehicle accident, for which he takes a scheduled dose of pain relievers. The patient has smoked a pack of cigarettes daily for the last 20 years but does not use alcohol or illicit drugs. He is married and has no outside sexual contacts. Vital signs are normal. The abdomen is soft and nontender with no hepatosplenomegaly. Rectal examination is likely to show a tear at which of the following locations?

Question

A 40-year-old man comes to the office with pain on defecation.  The pain is sharp and severe but subsides within minutes of passing the bowel movement.  He often sees spots of bright red blood on the toilet paper.  The patient has chronic constipation and has not taken laxatives or increased his fluid intake to compensate.  He has no fever, night sweats, diarrhea, or unexpected weight loss.  Past medical history is notable for chronic low back pain following a motor vehicle accident, for which he takes a scheduled dose of pain relievers.  The patient has smoked a pack of cigarettes daily for the last 20 years but does not use alcohol or illicit drugs.  He is married and has no outside sexual contacts.  Vital signs are normal.  The abdomen is soft and nontender with no hepatosplenomegaly.  Rectal examination is likely to show a tear at which of the following locations?

Quizplus · Accepted Answer

11ec160b_392d_8b6e_9249_5122a9ae63cd_MD0001_00 This patient has sharp pain and bright red rectal bleeding on defecation, suggesting an anal fissure. Anal fissures are due to stretching of the mucosa and are characterized by longitudinal tears in the anal canal distal to the dentate line (Choice B). Spasm of the sphincter can contribute to the pain and create tension across the wound, leading to a chronic fissure. Most fissures are related to chronic constipation with high anal pressures and passage of hard stools. They can also be seen with frequent diarrhea or anal sexual intercourse. In some cases, the pain may be so severe that patients withhold bowel movements, thereby exacerbating the constipation. The majority of fissures, especially those causing prolonged symptoms, occur at the posterior midline of the anal verge. This is likely due to the relatively poor perfusion of the posterior anal canal, which makes its mucosa sensitive to trauma and slows healing times. Anterior midline fissures are less common, but may occur due to mechanical stresses related to the alignment of muscular fibers in the external sphincter (Choice A). (Choice C) Bilateral anal fissures are uncommon. (Choices D and E) Fissures not at the midline are more likely due to unusual causes (eg, inflammatory bowel disease, malignancy, infection) and may warrant more detailed investigation. Educational objective: Anal fissures are longitudinal tears in the mucosa. They are usually due to passage of hard stool in patients with chronic constipation. Most fissures occur at the posterior midline, likely due to decreased blood flow in this area. Fissures in other areas may be due to less common causes. __________ References: Anorectal conditions: anal fissure and anorectal fistula. (http://www.ncbi.nlm.nih.gov/pubmed/24742084)

A 40-Year-Old Man Comes to the Office with Pain on Defecation