A 40-year-old man comes to the office due to anal discharge and pruritus. The patient had an episode of severe anal pain several months ago, which resolved spontaneously after 2 days. Since then, he has had an intermittent, foul-smelling discharge on his undergarments and occasional pain during defecation. The patient has had no abdominal pain, diarrhea, or blood in the stool. He has no prior medical conditions and takes no medications. Vital signs are within normal limits. Physical examination shows a soft and nontender abdomen. The perianal skin appears inflamed. There is an indurated pustule-like lesion close to the anal verge. Digital rectal examination reveals mild tenderness but no mass. Which of the following is the most appropriate next step in management of this patient?

Question

A 40-year-old man comes to the office due to anal discharge and pruritus.  The patient had an episode of severe anal pain several months ago, which resolved spontaneously after 2 days.  Since then, he has had an intermittent, foul-smelling discharge on his undergarments and occasional pain during defecation.  The patient has had no abdominal pain, diarrhea, or blood in the stool.  He has no prior medical conditions and takes no medications.  Vital signs are within normal limits.  Physical examination shows a soft and nontender abdomen.  The perianal skin appears inflamed.  There is an indurated pustule-like lesion close to the anal verge.  Digital rectal examination reveals mild tenderness but no mass.  Which of the following is the most appropriate next step in management of this patient?

Quizplus · Accepted Answer

11ec25c8_d2e0_afbd_bc81_b169f00b6832_MD0003_00 This patient with an inflamed perianal lesion associated with pain on defecation and chronic discharge has an anorectal fistula (fistula in ano). Anorectal fistulas are most often due to rupture of a perianal abscess with formation of a residual sinus tract. They may also occur as a complication of Crohn disease, radiation proctitis, atypical infections (eg, lymphogranuloma venereum), or trauma. Examination of an anorectal fistula often reveals an external terminus and an indurated tract leading to the rectum. An internal terminus can sometimes be identified on anoscopy or by cautiously passing a probe through the fistula from the external opening. The diagnosis is often apparent on clinical grounds, but endoscopic sonography, MRI, or fistulogram can be used in complex cases to assess the extent of fistula formation. Management of an anorectal fistula requires surgical intervention (eg, fistulotomy). Fistulas can often be assessed more fully (eg, exploration with a soft probe) while patients are under anesthesia at the time of surgery to delineate the extent of the fistula. The entirety of the fistula must be addressed because residual fistula tracts can lead to persistent symptoms and fecal incontinence. (Choice A) Anorectal manometry can provide information regarding anorectal neurologic dysfunction (eg, decreased relaxation of puborectalis and anal sphincter) and is indicated for evaluation of chronic constipation and fecal incontinence. Patients with anorectal fistula can have leakage of stool, but neurologic function is typically normal. (Choice B) Flexible sigmoidoscopy is occasionally needed to identify the internal fistula opening if it is not apparent on anoscopy. However, colonoscopy is typically only necessary for complex, recurrent, or atypical fistulas or fistulas associated with inflammatory bowel disease. (Choice C) Some perianal fistulas associated with Crohn disease can be managed with antibiotics and medical treatment of the underlying inflammatory bowel disease. For fistulas arising from a perianal abscess, nonsurgical treatment has a high failure rate. (Choice D) Stool test for ova and parasites is typically performed in the evaluation of diarrhea. The most common organisms detected include Giardia intestinalis and Cryptosporidium species. This patient has no diarrhea (or abdominal pain or blood in the stool) and is unlikely to have an intestinal infection. Educational objective: Anorectal fistulas are most often due to rupture of a perianal abscess with formation of a persistent sinus tract. Symptoms include pain with defecation and chronic discharge. Management requires surgical intervention. 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 Due to Anal