What Is Osteomyelitis
Bone infections and diseases are fairly common cause of visit to medical office since moderate to severe bone conditions significantly impairs a person’s ability to perform normal daily tasks. Osteomyelitis refers to infection of bones as a result of introduction of infectious organisms to inner bone substance. These type of infection are rare but can be very serious and even life threatening if not managed in earlier stages. According to the statistics, almost infections of osteomyelitis are reported each year in United States.
What are the causes of infection and what increases your risk of developing chronic osteomyelitis?
Injury, trauma or open wounds are the most common etiologic agents that are quite often implicated in the pathogens of osteomyelitis. The nature and severity of Infection and treatment protocols are dependent on the nature of microorganism involved. Most common agent is staph aureus (mostly because of direct invasion or transfer from abraded skin since S. aureus is a normal commensal of skin).
According to the data presented by S.H. Sheehy (1), S. Aureus is responsible for almost 2/3 of all the reported chronic cases of osteomyelitis. Other commonly implicated microorganisms are anaerobes (the organisms that do not require oxygen for growth are referred to as anerobes), gram negative bacilli and coagulase negative staphylococci. Sheehy also suggested that in addition to 32% of S. aureus infections, almost 29% infections are polymicrobial (caused by multiple organisms) and almost 28% infections are culture –negative (no organism on initial investigation).
In only a small number of cases, the infection may also be caused by a fungal agent. The overall prevalence of osteomyelitis is not very high (2 out of 10,000) but the total duration or severity of infection significantly varies. Both children and elderly can be a victim of this chronic, long lasting infection.
Risk factors associated with chronic osteomyelitis
There are a few risk factors that increases the risk of developing chronic infection and risk of complications, these are
- Long standing and uncontrolled diabetes mellitus is one of the most significant risk factors for the development of chronic osteomyelitis. According to a recent study, approximately 30 to 40% of all the diabetics develop a mild to moderate injury (as a result of puncture wound to the feet or legs) that may worsen to culminate in full blown chronic osteomyelitis.
- Inherited blood disorders like sickle cell anemia is also responsible for at least 15 to 25% of all the cases of chronic osteomyelitis. According to a latest research, at least one in every 200 patients of sickle cell anemia develops chronic osteomyelitis each year.
- Chronic or long standing degenerative or autoimmune bone conditions like rheumatoid arthritis.
- Intravenous drug abuse or long history of alcoholism.
- Any other chronic disease or infection that affects immunity like HIV or AIDS infection or prolonged use of steroids.
- If you have history of peripheral artery disease or any other vascular disorder, you are also at higher risk of developing a chronic infection.
- Statistics suggest that more cases of chronic osteomyelitis are reported in males than females.
- A prior history of injury, infection or surgery to bone also increases the risk of invasion of pathogenic agents.
What are the common sign and symptoms of osteomyelitis?
Most cases of osteomyelitis are acute in children (lasting for less than 3- 4 weeks). You should suspect chronic osteomyelitis if your lesions are not healing or are getting worse. Healthcare providers suggest that the only classic feature that differentiates acute osteomyelitis from chronic osteomyelitis is the “duration of infection”.
Following sign and symptoms suggest chronic osteomyelitis:
- Fever more than 102.0 degree Fahrenheit for more than 2 weeks.
- Irritability, agitation and fatigue without any physical activity.
- Nausea and changes in the normal digestion due to high serum concentration of inflammatory mediators.
- Tenderness and moderate to severe swelling at or around the affected bones.
- Limited range of motion due to stiffness and tenderness of joints.
- Moderate to severe bone pain in the involved limb.
- Due to swelling, pain and edema, the affected area of skin may appear deformed.
What are the complications of chronic osteomyelitis?
Generally, the overall prognosis of chronic osteomyelitis is good especially if the infection is diagnosed in the early stages and treatment is initiated with appropriate antibiotic. In most cases, the infection resolves within 4 to 8 weeks with appropriate antibiotic and leaves no residual deformity or complication. However, with delay in diagnosis or treatment or both, the risk of complications increases like:
- Recurrent infections.
- Permanent damage to bone matrix leading to disability requiring surgical debridement or tissue grafting.
- In long standing untreated infection (especially chronic osteomyelitis), the ongoing process of inflammation increases the risk of malignant transformation of squamous cells. Research conducted by Krisner (6) confirmed the metastatic transformation and suggested that the management of such a lesion is amputation of the involved limb as a life saving procedure.
What are the treatment options for chronic osteomyelitis?
The treatment of chronic osteomyelitis is dependent on the early identification of the lesion. Healthcare providers usually use a multidimensional approach (due to generic presentation and deep seated lesions) to identify and manage the issues. This includes blood tests, radiological testing and bone biopsies to determine the type of infections.
Mader (2) explained in his report published in peer review journal that the success of therapy depends on various factors (like initiating appropriate antibiotic therapy with or without surgical debridement of the wound). Before choosing antibiotic therapy, certain evaluating factors are very important including:
- The type of infection.
- The nature and biological properties of infecting organism.
- The results of the culture sensitivity.
- Salient host factors like co-existing diseases (like diabetes mellitus, hypertension and ischemic heart disease) and possible drug interactions.
The important antibiotics that are usually employed in the management of chronic osteomyelitis (2) are sulfamethoxazole, metronidazole, vancomycin, trimethoprim, clindamycin, fluoroquinolones, penicillins, refampin, aminoglycosides, β-lactamase inhibitors, cephalosporins, other β-lactams (aztreonam and imipenem). Investigational agents including teicoplanin, oxazolidinones and quinupristin or dalfopristin may also be administered.
The approximate duration of antibiotic therapy is 6 weeks but the overall duration can be modified according to the severity of infection and various other factors. Besides pharmacological options, other treatment modalities are employed in more serious or advanced infectious stages. If the infection is not responsive to antibiotics or is progressing, it is recommended to opt for surgical debridement under anesthesia to remove the infected tissue.
Sometimes, amputation is needed in case of a very bad wound that is refractory to resection and antibiotics. According to research data presented by Anthony (4), chronic recurrent osteomyelitis can be managed by surgical debridement and coverage by muscle flap. The use of muscle flap (under best possible surgical environment) can serve as a one step effective treatment that only decreases the requirement of antibiotics and resulting side effects. Anthony concluded:
“Muscle flaps covered with skin grafts provide durable coverage while allowing subsequent ancillary procedures (i.e. bone grafts) to be performed under the flaps”
Anthony also reported an overall success rate of 96% in managing the chronic and recurrent bone infections by this procedure.
How can you prevent chronic osteomyelitis?
A few preventive options can decrease your risk of developing chronic infection.
- Keep your wound clean and dry.
- In case of any moderate to severe injury or cut involving muscles or deep tissues, use sterilized techniques immediately to wash and secure the wound.
- Take optimal cautions to maintain your blood sugar levels in control.
- Optimal and early treatment of acute osteomyelitis decreases the chances of developing chronic infection.
- Maintain a high quality nutritious and balanced diet to maintain high immunity levels to fight infection causing pathogens.
- If you consume immuno-suppressant medications for any reason (for asthma management or any chronic viral condition), speak to your healthcare provider regarding risks and alternative options.
- Work together closely with your healthcare provider to know the causes and work accordingly to shorten the period of misery and pain.
1. Sheehy, S. H., Atkins, B. A., Bejon, P., Byren, I., Wyllie, D., Athanasou, N. A., … & McNally, M. A. (2010). The microbiology of chronic osteomyelitis: prevalence of resistance to common empirical anti-microbial regimens. Journal of Infection, 60(5), 338-343.
2. Mader, J. T., Shirtliff, M. E., Bergquist, S. C., & Calhoun, J. (1999). Antimicrobial treatment of chronic osteomyelitis. Clinical orthopaedics and related research, 360, 47-65.
3. Sia, I.G., Baebari, E.F. “Infection and Musculoskeletal Conditions: Osteomyelitis.” Best Pract Res Clin Rheumatol 20 (2006): 1065-1081
4. Anthony, J. P., Mathes, S. J., & Alpert, B. S. (1991). The muscle flap in the treatment of chronic lower extremity osteomyelitis: results in patients over 5 years after treatment. Plastic and reconstructive surgery, 88(2), 311-318.
5. Waldvogel, F. A., Medoff, G., & Swartz, M. N. (1970). Osteomyelitis: a review of clinical features, therapeutic considerations and unusual aspects. 3. Osteomyelitis associated with vascular insufficiency. The New England journal of medicine, 282(6), 316.
6. Kirsner, R. S., Spencer, J., Falanga, V., Garland, L. E., & Kerdel, F. A. (1996). Squamous cell carcinoma arising in osteomyelitis and chronic wounds. Dermatologic surgery, 22(12), 1015-1018.