Osteomyelitis occurs in patients with diabetes and it refers to the inflammation and infection of the bone and at times, the bone marrow. In the absence of appropriate treatment it can lead to limb amputation. Therefore, the diagnosis, treatment and therapy are crucial for controlling damage due to osteomyelitis. Patient with poor management of blood sugar and a patient suffering from diabetes for many years is more likely to suffer from foot disease. Diabetic foot is also associated with development of peripheral neuropathy. The high levels of blood glucose make diabetes patients more susceptible to infections.
A probe to bone test that employs a blunt ended metallic probe is used to investigate the site of the ulcer. Laboratory tests that are required to assess a case of osteomyelitis due to infection include erythrocyte sedimentation rate, WBC count, and C-reactive proteins. Markers that point to healing include Hb1Ac, hemoglobin, albumin, blood urea and levels of creatinine. These tests are usually followed by plain radiography to assess osteomyelitis. If evidence points at osteopenia, cortical erosions, periosteal thickening and formation of new bone then osteomyelitis cn be confirmed in the patient. The only drawback of plain radiography is that detection is possible only after 30-50% bone loss has occured. Magnetic resonance imaging can confirm osteomyelitis as early as 2-3 days after infection.
Treatment usually involves antibiotic therapy and Staphylococcus aureus infection is common in foot ulcers. The efficacy of systemic antibiotic therapy alone may not be sufficient to treat the infection because foot ulcers are commonly associated with biofilm formation by one or more causative organism/s that acts as a barrier and prevents the action of antibiotic on the wound site. Surgery for removal of the infected tissue is often more effective and is usually followed by antibiotic therapy to treat residual infection. The duration of the antibiotic therapy depends on the extent of residual infection.
The surgery aims at removal of the bone of the affected digit. A second surgery may be required if the removal of infected tissue and bone is incomplete. Bone biopsy should be done for sensitivity. The selection of the antibiotic based on the test is likely to be effective in treating the infection rather than giving antibiotics empirically. In the case of the patient of this study the distal phalanx is affected with the ulcer. Weight bearing is still possible in the foot of a patient even after removal of an osteomyelitic digit.
Studies and clinical trials with high local concentrations of antibiotics applied through polymethylmethacrylate (PMMA) beads impregnated with antibiotics have yielded good control of osteomyelitis by successfully treating infections in diabetics rather than use of systemic antibiotic therapy. (Roeder, et al., 2000). The use of PMMA beads makes a second surgery necessary for removal of beads. The use of vancomycin impregnated biodegradable beads has been assessed and has been found to be beneficial in the treatment of osteomyelitis (Liu, et al., 2002).
Therefore a combination of antibiotic therapy and surgery is more suited to the treatment of osteomyelitis. Although complete treatment of infections with systemic antibiotics has been reported (Acharya, et al., 2013).
Acharya, S., Soliman, M., Egun, A. & Rajbhandari, S., 2013. Conservative management of diabetic foot osteomyelitis. Diabetes Research and Clinical Practice, 01(3), pp. e18-20.
Liu, S., Wen-Neng Ueng, S., Lin, S. & Chan, E., 2002. In vivo release of vancomycin from biodegradable beads.. Journal of BiomedicalMaterial Research, 63(6), pp. 807-13.
Malhotra, R., Chan, S.-Y. C. & Nather, A., 2014. Osteomyelitis in the diabetic foot. Diabetic Foot and Ankle, 5(10.3402/dfa.v5.24445.).
Roeder, B., Van Gils, C. & Maling, S., 2000. Antibiotic beads in the treatment of diabetic pedal osteomyelitis.. The Journal of Foot and Ankle Surgery, 39(2), pp. 124-30.