25-year-old man presents to you with an injury to his left foot

The wound should be copiously irrigated and left open to heal by secondary intention.

 

Educational Objective:

Discuss appropriate management of a plantar wound in an immunocompromised patient.

Key Point:

Because of this patient's increased risk of infection, the plantar wound should be cleansed and copiously irrigated.

Explanation:

Placing the patient in the prone position in a well-lit area facilitates proper examination and repair. After administering anesthesia through a local injection or regional block, the wound should be explored for a possible foreign body. Given the risk of a retained sharp foreign body, the examiner should not use his or her finger to explore the wound.

The severity of this wound, the inability to fully explore the wound, and the uncertain mechanism by which the patient was injured heighten the risk of a foreign body. Thus, X-rays are indicated, because they will demonstrate radiopaque objects such as glass, gravel, metal, bone, teeth, or shell fragments. Ultrasonography or computed tomography may assist in the identification of radiolucent objects. Ultrasonography may also be utilized to assist with the removal of a foreign body.

The wound should be left open and not sutured given the increased risk of infection secondary to its plantar location, the severity of tissue destruction, the possibility of a retained foreign body, and impaired host defense.

Most lacerations heal well with simple routine care and without antibiotics. For most wounds, prophylactic antibiotics have not been proven to prevent infection. However, some high-risk cases may benefit from prophylactic treatment, including patients who are immunocompromised (above patient). Or have a possible retained foreign body (above patient), tendon or joint involvement, forefoot injuries (above patient), highly contaminated wounds (water wounds) sustained via puncture, wounds with significant tissue destruction (above patient), or a wound sustained through an athletic shoe. The above patient meets multiple risk categories and should receive empiric prophylactic antibiotics.

For patients with soft tissue injury following water exposure, the following antibiotics are considered reasonable initial empiric therapy:

1. First-generation cephalosporin (cephalexin 500 mg orally four times daily or cefazolin 1 g IV every eight hours) to cover for gram-positive organisms such as Staphylococcus and Streptococcus
a. For patients with immediate hypersensitivity reactions to cephalosporins, clindamycin (300 mg orally four times daily or 600 mg IV every eight hours) is an alternative agent.

 

PLUS

2. Fluoroquinolone such as levofloxacin (750 mg once daily) to cover for hydrophilic pseudomonas species after freshwater exposure

 

PLUS (only if seawater or sewage exposure occurred):

(3a) Seawater exposure: doxycycline (100 mg twice daily) for coverage of Vibrio species

(3b) Exposure to sewage-contaminated water: metronidazole (500 mg four times daily) for anaerobic coverage; not necessary if the regimen includes clindamycin (see point (1) above)

Empiric antibiotic therapy need not include coverage for mycobacterial infection unless acid-fast staining is positive. In such cases, directed therapy should be administered as described below. (See 'Mycobacterial infection' below.)

References:

Baddour LM. Soft tissue infections following water exposure. UpToDate.  https://www.uptodate.com/contents/soft-tissue-infections-following-water-exposure (updated April 30, 2021) (Accessed March 4, 2023)

Necrotizing Soft Tissue Infections: Stevens DL, Bryant AE. Necrotizing soft-tissue infections. N Engl J Med 2017 Dec;377(23): 2253-65 UserId: tbirk