The Role of Serial Radiographs in Diagnosing Diabetic Foot Bone Osteomyelitis

Background and Objective

Diagnosing diabetes-related foot osteomyelitis is sometimes a challenge for clinicians since it may occur without local or systemic signs of infection. Thus, the primary purpose of this article was to evaluate the role of progressive radiographic changes in diagnosing diabetic foot osteomyelitis.

Materials and Methods

A retrospective review of databases of our Institution was performed to identify all long-standing diabetic foot patients who underwent two radiographic examinations spaced no more than five weeks apart and a subsequent magnetic resonance (MR) examination from November 2015 to November 2020. A total of 46 patients (32 men, 14 women; mean age, 57.3 years) were identified.

Results

serial radiographs showed 89% sensitivity, 38% specificity, 80% diagnostic accuracy, 87% positive predictive value (PPV), 43% negative predictive value (NPV) to diagnose osteomyelitis (P value < 0,05). Bone destruction was the most reliable radiographic sign with 89% sensitivity, 88% specificity, 89% diagnostic accuracy, 97% PPV, 64% NPV (P value < 0,05).

Conclusion

Progressive bony changes detected by serial radiographs are a useful tool to diagnose diabetic foot osteomyelitis.

Microbiology and Antimicrobial Therapy for Diabetic Foot Infections

In addition to being the prime factor associated with amputation, diabetic foot infections (DFIs) are associated with major morbidity, increasing mortality, and reduced quality of life. The choice of appropriate antibiotics is very important in order to reduce treatment failure, antimicrobial resistance, adverse events, and costs. We reviewed articles on microbiology and antimicrobial therapy and discuss antibiotic selection in Korean patients with DFIs. Similar to Western countries, Staphylococcus aureus is the most common pathogen, with Streptococcus, Enterococcus, Enterobacteriaceae and Pseudomonas also prevalent in Korea. It is recommended that antibiotics are not prescribed for clinically uninfected wounds and that empirical antibiotics be selected based on the clinical features, disease severity, and local antimicrobial resistance patterns. Narrow-spectrum oral antibiotics can be administered for mild infections and broad-spectrum parenteral antibiotics should be administered for some moderate and severe infections. In cases with risk factors for methicillin-resistant S. aureus or Pseudomonas, empirical antibiotics to cover each pathogen should be considered. The Health Insurance Review and Assessment Service standards should also be considered when choosing empirical antibiotics. In Korea, nationwide studies need to be conducted and DFI guidelines should be developed.

Antibiotic Resistance in Diabetic Foot Soft Tissue Infections: A Series From Greece

Diabetic foot infections are a common and serious problem for all health systems worldwide. The aim of this study was to examine the resistance to antibiotics of microorganisms isolated from infected soft tissues of diabetic foot ulcers, using tissue cultures. We included 113 consecutive patients (70 men, 43 women) with a mean age of 66.4 ± 11.2 years and a mean diabetes duration of 14.4 ± 7.6 years presenting with diabetic foot soft tissue infections. Generally, no high antibiotic resistance was observed. Piperacillin-tazobactam exhibited the lowest resistance in Pseudomonas, as well as in the other Gram-negative pathogens. In methicillin-resistant Staphylococcus aureus isolates, there was no resistance to anti-Staphylococcus agents. Of note, clindamycin, erythromycin, and amoxycillin/clavulanic acid exhibited high resistance in Gram-positive cocci. These results suggest that antibiotic resistance in infected diabetic foot ulcers in our area is not high and they are anticipated to prove potentially useful in the initial choice of antibiotic regimen.

Efficacy of a New Heparan Sulfate Mimetic Dressing in the Healing of Foot and Lower Extremity Ulcerations in Type 2 Diabetes: A Case Series

A novel heparan sulfate glycosaminoglycan mimetic product for local application to promote wound healing (CACIPLIQ) has recently become available. It is a biophysical therapeutic product comprising a polysaccharide as an innovative biomaterial to accomplish mechanical tissue engineering and skin regeneration in the site of ulceration. We present a series of 12 patients with type 2 diabetes (4 men and 8 women; age 53-87 years; diabetes duration 8-25 years) having chronic resistance to therapy for foot and lower extremity ulcerations. CACIPLIQ was locally applied twice per week after careful debridement. Complete ulcer healing was accomplished in all patients after a mean treatment duration of 4.92 months (range = 2-12 months). The product was very well tolerated. In conclusion, these results, although preliminary, are encouraging and suggest adequate efficacy and safety of the new product in difficult-to-heal foot and lower extremity ulcerations in type 2 diabetes.

A Proposed New Classification of Skin and Soft Tissue Infections Modeled on the Subset of Diabetic Foot Infection

Schemes for classifying skin and soft tissue infections (SSTIs) pose limitations for clinicians and regulatory agencies. Diabetic foot infections (DFIs) are a subset of SSTIs. We developed and are proposing a classification to harmonize current schemes for SSTIs and DFIs. Existing schemes for classifying SSTIs are limited in both their usefulness to clinicians and to regulatory agencies. The guidelines on SSTI from the Infectious Diseases Society of America (IDSA) and the guidance from the US Food and Drug Administration do not adequately address many types of wound infections. However, guidelines developed by the IDSA for DFIs provide a classification scheme that has been validated and widely used. Diabetic foot infections are similar to SSTIs in pathophysiology, microbiology, and treatment and can be seen as a subset of SSTI. Thus, based on the documents noted above, and our review of the literature, we have developed a proposed classification scheme for SSTI that harmonizes well with the DFI classification. We believe this new scheme will assist clinicians in classifying most wound infections and potentially aid regulatory agencies in testing and approving new antimicrobials for these infections.

Antibiotherapy with and without bone debridement in diabetic foot osteomyelitis: A retrospective cohort study

BACKGROUND AND OBJECTIVE

The treatment of diabetic foot osteomyelitis (DFO) is a controversial issue, with disagreement regarding whether the best treatment is surgical or conservative. The purpose of this study was to compare the outcome of patients with DFO who were treated with antibiotherapy alone and those who underwent concurrent minor amputation.

METHODS

Hospital records of patients who were diagnosed as having DFO within a 2-year study period were retrospectively reviewed. Patients were divided into two groups: those who received antibiotherapy alone and those who underwent concurrent minor amputation. Groups were compared in terms of duration in hospitalization, antibiotherapy, and wound healing.

RESULTS

Thirty seven patients were included in the study. These comprised patients who received antibiotherapy alone (ABG, n=15) and patients who underwent concurrent minor amputation (AB-MAG, n=22). Hospitalization duration was 37.2 (± 16.2) days in ABG and 52.8 (± 40.2) days in AB-MAG (p = 0.166). Mean duration of antibiotherapy was 45.0 (± 21.7) days in ABG and 47.7 (± 19) days in AB-MAG (p = 0.689). Wound healing duration was 265.2 (± 132.7) days in ABG and 222.6 (± 85.9) days in AB-MAG (p = 0.243). None of the outcome measures were significantly different between ABG and AB-MAG.

CONCLUSIONS

Our results have shown similar outcomes for both patient groups who received antibiotherapy alone and who underwent concurrent minor amputations. Considering the small sample sizes in this study, it is important to confirm these results on a larger scale.

Diagnosis and management of infection in the diabetic foot

Foot infections are common in persons with diabetes mellitus. Most diabetic foot infections occur in a foot ulcer, which serves as a point of entry for pathogens. Unchecked, infection can spread contiguously to involve underlying tissues, including bone. A diabetic foot infection is often the pivotal event leading to lower extremity amputation, which account for about 60% of all amputations in developed countries. Given the crucial role infections play in the cascade toward amputation, all clinicians who see diabetic patients should have at least a basic understanding of how to diagnose and treat this problem.

Diagnosing diabetic foot osteomyelitis in patients without signs of soft tissue infection by coupling hybrid 67Ga SPECT/CT with bedside percutaneous bone puncture

OBJECTIVE

Successful treatment of osteomyelitis is more likely with accurate diagnosis and identification of the causative pathogens. This typically requires obtaining a specimen of bone, usually by image-guided biopsy. We sought to develop a simpler bedside method for definitively diagnosing osteomyelitis.

RESEARCH DESIGN AND METHODS

Over 2 years, we enrolled consecutive patients presenting to our diabetic foot clinic with a foot ulcer and clinically suspected osteomyelitis but without soft tissue infection. Each underwent hybrid (67)Ga single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) imaging; those with a positive scan underwent bedside percutaneous bone puncture. Patients with a positive bone culture received culture-guided antibiotic therapy. Patients with negative (67)Ga SPECT/CT imaging or with positive imaging but negative bone culture were not treated with antibiotics. All patients were followed up for ≥ 1 year.

RESULTS

Among 55 patients who underwent (67)Ga SPECT/CT imaging, 13 had negative results and all of their foot ulcers resolved without antibiotic therapy. Among 42 with positive imaging, 2 were excluded (for recent antibiotic therapy) and 40 had bone punctures (3 punctured twice): 19 had negative results, 3 of which were likely false negatives, and 24 had positive results (all gram-positive cocci). At follow-up, 3 patients had died, 3 had undergone amputation, and 47 had no evidence of foot infection. The sensitivity and specificity of this combined method were 88.0 and 93.6%, respectively, and the positive and negative predictive values were 91.7 and 90.7%, respectively.

CONCLUSIONS

Coupling of (67)Ga SPECT/CT imaging and bedside percutaneous bone puncture appears to be accurate and safe for diagnosing diabetic foot osteomyelitis in patients without signs of soft tissue infection, obviating the need for antibiotic treatment in 55% of suspected cases.

Expert opinion on the management of infections in the diabetic foot

This update of the International Working Group on the Diabetic Foot incorporates some information from a related review of diabetic foot osteomyelitis (DFO) and a systematic review of the management of infection of the diabetic foot. The pathophysiology of these infections is now well understood, and there is a validated system for classifying the severity of infections based on their clinical findings. Diagnosing osteomyelitis remains difficult, but several recent publications have clarified the role of clinical, laboratory and imaging tests. Magnetic resonance imaging has emerged as the most accurate means of diagnosing bone infection, but bone biopsy for culture and histopathology remains the criterion standard. Determining the organisms responsible for a diabetic foot infection via culture of appropriately collected tissue specimens enables clinicians to make optimal antibiotic choices based on culture and sensitivity results. In addition to culture-directed antibiotic therapy, most infections require some surgical intervention, ranging from minor debridement to major resection, amputation or revascularization. Clinicians must also provide proper wound care to ensure healing of the wound. Various adjunctive therapies may benefit some patients, but the data supporting them are weak. If properly treated, most diabetic foot infections can be cured. Providers practising in developing countries, and their patients, face especially challenging situations.