FORT LAUDERDALE, FLA. — Patients presenting with anal pain pose a diagnostic challenge, but a careful, detailed history will lead to the correct diagnosis in 90% of cases, Dana R. Sands, M.D., said at a symposium on pelvic floor disorders sponsored by the Cleveland Clinic Florida.
Ask patients about the quality of their pain, as well as the location, the presence of radiating pain, and the duration of pain, advised Dr. Sands, associate staff surgeon at the Cleveland Clinic Florida, Weston.
Also, associated symptoms—such as changes in bowel habits and bleeding, a history of similar pain, medication use, and information about sexual practices— can help in nailing down a diagnosis.
Among the differential diagnoses are:
▸ Hemorrhoids. Most patients presenting with anal pain have been referred for, or believe they have, hemorrhoids. In some cases hemorrhoids are the cause of the pain, but it is important to keep in mind that only external thrombosing hemorrhoids or prolapsed internal hemorrhoids will cause pain. The pain may be described as acute in onset, short-term, and associated with occasional bright red bleeding and the sensation of a lump around the anal canal, Dr. Sands said.
If the pain is severe, excision can usually be accomplished in the office setting, but prolapsed, irreducible internal hemorrhoids can become gangrenous and pose a surgical emergency.
▸ Anal abscesses. Pain associated with anal abscesses is insidious in onset and is usually associated with fever, swelling, and drainage. Patients may have a history of a previous abscess. Evaluation and treatment is entirely dependent on the location of the abscess, as various spaces around the anal canal can harbor abscesses.
The most common type is a perianal abscess, which can usually be drained easily. Unexplained anal pain is often attributed to internal hemorrhoids or fissures, but may be due to an internal abscess. Such pain warrants examination of the patient under anesthesia, Dr. Sands stressed.
▸ Fissures. Patients with anal fissures describe severe pain, bright red blood from the rectum, and pain for 3-4 hours following a bowel movement. There is no associated fever and usually no drainage. Patients may describe being afraid to move their bowels, and the history may include an episode of diarrhea or constipation. Many patients have had long-term anal pain, indicating chronic fissures.
Patients with fissures are in agony—and are “terribly afraid and extremely anxious” about undergoing an anal examination, Dr. Sands said.
In most cases, the diagnosis can be made by visual inspection of the anal verge with the patient in the prone jackknife position. The digital examination usually cannot be tolerated and can be reserved for after the patient has been treated and the pain is improved or resolved.
▸ Tumors. Pain associated with anal cancer is insidious in onset. Patients do not complain of fever or prolapse, but may describe a recent change in bowel habits. A lesion may be noted on the anal margin, or digital examination may reveal a palpable mass.
Low-lying rectal cancers can also cause anal pain, and may be associated with fecal urgency, bloody stool, swelling, weight loss, and a change in the caliber of the stool. The tumor may be palpable on digital examination; pay careful attention to the posterior midline, which is the location where rectal cancer is most often missed, Dr. Sands noted at the meeting.
Patients with unexplained anal pain and no obvious benign condition who cannot tolerate an office examination should be examined under anesthesia, she said.
▸ Stenosis. This painful condition has a slow onset and can result from overly aggressive anal surgery, such as hemorrhoidectomy. Radiation injury to the anal canal and Crohn's disease also can cause stenosis. The patient complains of painful bowel movements and a change in the caliber of the stool, but not of fever or prolapse.
▸ Infection. Sexually transmitted diseases are a common cause of anal pain. Ulcerations around the anal canal may signal an STD. Ask about potential exposures during the history, examine external genitalia for additional clues to the diagnosis, and follow up with appropriate cultures and biopsies, Dr. Sands advised.
▸ Proctalgia. This is a diagnosis of exclusion in patients presenting with rectal pain and pressure. They describe increased pain after bowel movement, but not of bleeding or fever. They may describe long-term pain.
“I find this is reproducible on palpation of the levator muscles,” said Dr. Sands, noting that patients may also have associated anal hypertonia.
A good endoscopic evaluation is important in these patients, and once organic pathology is ruled out, a diagnosis of proctalgia is appropriate, she said.