Mock Online Case: November 2015

History:

A 41 year old diabetic male presents to your ER on October 31st with a painful perianal area.

You walk into the room to find a clearly uncomfortable man laying prone on the exam table. He says that he began having pain 3 days ago and was prescribed “penicillin or something” by his primary doctor, but it hasn’t been helping. He came in today because he felt feverish. He had similar pain in this area years ago and at that time had “something” drained. No bloody stools, hematuria or abdominal pain with this episode.

Exam: VS: T: 99.5 HR: 98 BP: 123/87 RR 18 Sat 96% Physical exam reveals an indurated, red and tender indurated mass 4cm from the anal verge. It is draining scant greenish yellow pus. No surrounding erythema or warmth. Digital rectal exam reveals bogginess and “chandelier sign” tenderness internally.

DDx: Perirectal abscess, perianal abscess, fistula, hemorrhoid, fissure.

You perform a superficial soft tissue US using the vascular probe and see evidence of deep tracts. CT later confirms fistula formation with tracking into the perirectal space.

Butt Pus Pearls:

• Perianal abscesses are the most common and are visible along the tissues adjacent to the anus.
• Perirectal abscesses involve the deeper tissues and are higher risk for complications. 
• About 50% of anorectal abscesses will form fistulas over time.
• Etiology: 80% form from infection of the cryptoglandular tissue of the perianal region. Less common, but still prevalent causes are Crohn’s (20%), HIV, radiation proctitis, malignancies and TB.
• If you can see the abscess externally, you can drain it.
• Do a digital rectal exam. Inability to tolerate the exam or bogginess or induration on exam = advanced imaging such as CT pelvis with IV contrast to rule out deep tissue abscess/process.

How To Best I & D:

• Pinpoint injection of anesthetic followed by using an 18G finder needle/11 blade scalpel to allow draining to begin. After drainage has started, it will be more comfortable for them/easier for you to further anesthetize with a field block and enlarge the incision.
• Use an elliptical or cruciate incision > 1cm to prevent closing an recurrence.
• Although the initial thought is to be as far from the sphincter as possible, the closer you incise to the sphincter the better (as long as you don’t injure the sphincter!). Remember, 50% of these will go on to become fistulas. The closer the incision to the anus, the shorter the fistula tract.

Antibiotics?

• Like other simple abscesses in uncomplicated patients, they don’t need antibiotics. Consider antibiotics if the patient has cellulitis, diabetes, immunocompromised or systemic symptoms.
• If antibiotics are going to be used, cover gram negatives and anaerobes with Cipro/Flagyl.

Case continued… A small elliptical incision was made after injection with lidocaine with epinephrine and the area was deloculated. Patient was sent home with a course of ciprofloxacin and metronidazole given his history of DM2 and systemic symptoms. He will follow up in the next 2 days for a wound check and evaluation by the colorectal surgery service. Questions:

1. The best type of incision to drain a perianal abscess is: a. Single straight b. Elliptical or cruciate incision > 1cm in length c. Single straight with packing material d. Needle aspiration e. By crossing the streams 2. True or False: Digital rectal exam is not useful in differentiating types of anorectal infections. 3. Uncomplicated perianal abscesses do not require antibiotics. Antibiotics should be considered in which of the following patients with perianal abscess? a. cellulitis b. diabetes c. immunocompromised d. systemic symptoms e. all of the above 4. True or False: 50% of anorectal abscess go on to become fistulas over time. 5. The most common cause of anorectal abscesses is: a. Crohn’s b. Infection of the cryptoglandular tissue c. HIV d. TB e. Proton packs 6. Bonus Question: Which of the following ghosts does NOT appears in the Ghostbusters movies? a. Slimer b. The Scoleri Brothers c. Nearly Headless Nick d. Gozer e. Stay Puft Marshmallow Man

From Emergency Medicine Reviews and Perspectives , September 2015 Podcast “Anorectal Infections”, by Paul Jhun MD and Kyle Cologne MD