What tests are indicated for a patient who presents with a 5-day history of a painful, swollen, and tender lesion on the foot after stepping on an object, with a central hard area and surrounding redness, but no red streaking?

From the Guidelines

For a patient with a foot injury from stepping on an object 5 days ago, presenting with bleeding, tenderness, a hard central red area, and swelling, I recommend a comprehensive evaluation including a thorough wound examination, X-ray imaging to rule out retained foreign bodies or bone involvement, and basic laboratory tests including complete blood count and C-reactive protein to assess for infection. The patient's symptoms, such as tenderness, swelling, and a hard central red area, are indicative of a potential infection, and the presence of bleeding suggests a possible open wound 1.

Given the patient's presentation, it is essential to assess for infection, as the signs of inflammation, such as redness, warmth, and swelling, are present 1. The wound should be cleaned, debrided if necessary, and cultured if infection is suspected. Tetanus prophylaxis should be administered if the patient's immunization status is not up-to-date. Empiric antibiotic therapy with amoxicillin-clavulanate 875/125 mg twice daily for 7-10 days would be appropriate if infection is present, particularly given the signs of inflammation.

The patient should elevate the foot, apply ice intermittently for 15-20 minutes several times daily to reduce swelling, and take acetaminophen or ibuprofen for pain relief. These recommendations address both diagnostic needs to identify potential foreign bodies or infection and therapeutic interventions to promote healing and prevent complications. The hard central area could indicate either a foreign body or localized inflammatory response, making imaging particularly important in this case. Advanced imaging with MRI, WBC SPECT/CT, or [18 F]FDG PET/CT may be needed to better assess the location, extent, or severity of an infection, especially if the patient has a history of diabetes or other underlying conditions that may affect wound healing 1.

Key considerations in the management of this patient include:

• Thorough wound examination to assess for signs of infection and retained foreign bodies
• X-ray imaging to rule out bone involvement
• Basic laboratory tests, including complete blood count and C-reactive protein, to assess for infection
• Wound cleaning, debridement, and culture if infection is suspected
• Tetanus prophylaxis if the patient's immunization status is not up-to-date
• Empiric antibiotic therapy if infection is present
• Elevation, ice, and pain relief to promote healing and prevent complications.

From the Research

Diagnostic Approach

To determine the appropriate tests for the patient's condition, the following points should be considered:

• The patient reports stepping on something 5 days ago, resulting in bleeding, tenderness, and a hard area with a central red area and swollen area, but no red streaking was noted.
• The presence of pain, necrotic tissue, delayed healing, and wound deterioration can indicate potential chronic wound infection, even in the absence of classic signs of infection 2.
• A culture may be indicated to identify the causative organisms and guide antibiotic therapy when clinical suspicion of an infection exists 3.

Culture Methods

The following culture methods can be considered:

• Quantitative culture of wound tissue is the gold standard, but swab culture is an acceptable alternative option 2.
• The Levine technique is more reliable than the Z-technique for determining microbial load in the wound bed 2.
• Properly performed swab cultures can provide useful data to augment diagnostic and therapeutic decision making 3.

Testing Considerations

Based on the patient's symptoms and the available evidence, the following tests may be considered:

• Swab culture using the Levine method to identify potential wound infection 2, 3.
• Further evaluation to determine the presence of necrotic tissue, delayed healing, or wound deterioration, which can indicate potential chronic wound infection 2.