Incision and Drainage of an Abscess

CHAPTER 20 Incision and Drainage of an Abscess



Daniel J. Derksen


An abscess is a localized infection characterized by a collection of pus surrounded by inflamed tissue. When a sweat gland or hair follicle infection forms an abscess, it is called a furuncle, or boil. If multiple follicles are involved with abscesses, it is referred to as a carbuncle. Paronychia is an abscess that involves the nail. A felon is an abscess in the tuft of soft tissue in the distal phalanx of the finger. A hordeolum is an abscess on the eyelid margin, whereas a chalazion is a chronic abscess of the eyelid itself in the meibomian glands beneath the tarsal plate (see Chapter 65, Chalazion and Hordeolum). Hidradenitis suppurativa is a chronic condition in the axilla and groin with recurrent abscess formation. Pilonidal abscesses are discussed in Chapter 109, Pilonidal Cyst and Abscess: Current Management; perianal abscesses in Chapter 107, Perianal Abscess Incision and Drainage; and Bartholin’s abscesses in Chapter 131, Bartholin’s Cyst and Abscess: Word Catheter Insertion, Marsupialization. For olecranon and prepatellar bursitis, see Chapter 192, Joint and Soft Tissue Aspiration and Injection (Arthrocentesis).


Most often, Staphylococcus aureus is the causative agent in abscesses, but some abscesses are due to Streptococcus species or a combination of microorganisms, including gram-negative and anaerobic bacteria. Perianal abscesses are usually caused by a mix of aerobic and anaerobic enteric organisms. Abscesses can occur in any location, but they are commonly found on the extremities, buttocks, and breast or in hair follicles.


A small abscess may respond to warm compresses or antibiotics and drain spontaneously. As the abscess enlarges, the inflammation, collection of pus, and walling off of the abscess cavity render such conservative treatments ineffectual. The treatment of choice for an abscess is incision and drainage (I&D), and if this treatment is done properly, antibiotics are usually unnecessary. (See precautions for the facial triangle in “Contraindications,” later.) In a nonlactating woman, a breast abscess that is not subareolar is rare. If an abscess occurs away from the areola, it should prompt a biopsy in addition to I&D and raise the clinician’s suspicion of a malignant tumor.


Patients with diabetes, debilitating disease, or compromised immunity should be observed closely after I&D of an abscess. Although usually not necessary, consider a culture obtained by aspiration or swab of the abscess cavity because the abscess may have been caused by unusual organisms in these compromised patients. The infection may also warrant the administration of antibiotics that cover Staphylococcus infection.


If an abscess recurs after incision and drainage, methicillin-resistant S. aureus (MRSA) should be considered, a culture and sensitivity obtained, and the patient treated with appropriate antibiotics based on these results. Community-associated S. aureus is most often sensitive to clindamycin, trimethoprim/sulfamethoxazole, doxycycline, and rifampin. The frequency of MRSA skin and soft tissue infections has increased dramatically, and it is now the most common pathogen for these infections when patients present to the emergency department. Resistance changes rapidly and differs regionally. Initial treatment remains I&D, although some recommend treatment with one or more oral antibiotics based on culture and sensitivity.



Indications


A localized collection of pus that is tender and not spontaneously resolving. If the lesion is not “pointing” and localized, a trial of antibiotics may be indicated. However, antibiotics are usually inadequate once a collection of pus is present.



Contraindications


Small, nonfluctuant facial furuncles without surrounding cellulitis should not be incised or drained if located within the triangle formed by the bridge of the nose and the corners of the mouth. These infections should be treated with antibiotics, with coverage for MRSA, and warm compresses because there is a risk of septic phlebitis with intracranial extension after I&D of a furuncle in this area. However, if the lesion is large and fluctuant, drainage is recommended, regardless of the site. In most instances, drainage alone is adequate, but in this area antibiotics are also recommended.



Equipment



• Local anesthetic (1% to 2% lidocaine), sodium bicarbonate 7.5%, or diphenhydramine (Benadryl) 50 mg/mL

• Syringe with 25- to 30-gauge needle, usually image to 1 inch, because only the skin over the abscess is anesthetized

• Possibly a cryosurgery unit or ethyl chloride for anesthesia (to avoid a needle poke)

• Alcohol or povidone-iodine (Betadine) wipe

• 4 × 4–inch gauze

• No. 11 blade

• Curved hemostats

• Possibly iodoform gauze (image– to image-inch width, and up to 24 inches long depending on abscess size)

• Possibly culture materials

• Bandage scissors

• Dressing of choice


Technique


Protective eyewear should be worn.


1 Prepare the abscess area with povidone-iodine or alcohol.

2 Administer a field block with local anesthetic (see Chapter 8, Peripheral Nerve Blocks and Field Blocks) to allow an adequate incision to be made. Avoid infiltration of the abscess cavity; rather, concentrate on anesthetizing the perimeter of the tissue around the abscess. Local anesthetics usually work poorly in the acidic milieu of an abscess. More anesthetic than usual may be needed to relieve pain. Alternatively, diphenhydramine 10 to 25 mg can be injected into the area for anesthesia. Dilute a 50-mg (1-mL) vial in a syringe with 4 mL of normal saline (Fig. 20-1A and B). Cryocautery can also be used to freeze the roof of the abscess. This can be performed with a nitrous oxide unit, liquid nitrogen, or ethyl chloride. The incision is then made through the cooled skin, which is now anesthetized.

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Figure 20-1 A, Large sebaceous cyst abscess of the back. B, Injecting local anesthetic (2% lidocaine with epinephrine). May augment with field block if desired. C, Incising abscess with no. 11 blade. D, Purulent material is released from the lesion. E, Apply digital pressure to evacuate contents of the infected cyst. F, In the case of sebaceous cyst abscesses, the sac can often be grasped and removed using hemostats. It may be so necrotic in some lesions that it fragments, making removal more difficult. G, In cases where total removal of the cyst sac is uncertain, a reusable dermal curette can be used to scrape the cavity and remove any residual sac. H, Iodoform gauze (image– or image-inch, depending on size of cavity) is used to pack the wound open. Premature closure will lead to recurrence of the abscess. Suturing the wound closed is contraindicated. I, Insert the gauze using pickups without teeth. J, Apply antibiotic ointment over the tail of the iodoform gauze to prevent the outer dressing from sticking to it.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Incision and Drainage of an Abscess

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