| Osteomyelitis (Bone Infection) |
| Counselor, Osteomyelitis is a difficult-to-treat infection of bone and bone marrow. It is progressive and results in inflammatory destruction of the bone. Bacterial osteomyelitis causes substantial morbidity despite continued progress toward understanding its pathophysiology and optimal management. The approach to osteomyelitis depends upon the route by which bacteria gained access to bone, bacterial virulence, local and systemic host immune factors, and patient age. While imaging studies and nonspecific blood tests may suggest the diagnosis, an invasive technique is generally required to identify the causative pathogens. A high index of suspicion must be maintained in order to promptly diagnose this serious condition. We value all your comments, so, if you have a suggestion for a newsletter subject but haven't submitted it yet, or if you have already submitted one but think of another, please take a minute to let us know by clicking on your "Reply" button and dropping us a note. To learn more about AMFS, Inc., the organization run by Physicians and Attorneys that provides medical experts and case review services nationwide, and has produced the following informational newsletter to aid you in understanding complex medical issues, please click here - www.medicalexperts.com. |
|
| 
Pathophysiology: The two primary categories of acute osteomyelitis are hematogenous osteomyelitis and contiguous osteomyelitis. Hematogenous osteomyelitis is an infection caused by bacterial seeding from the blood from a remote source. This condition occurs primarily in children. The most common site is the rapidly growing and highly vascular metaphysis of growing bones. The apparent slowing or sludging of blood flow as the vessels make sharp angles at the distal metaphysis predisposes the vessels to thrombosis and the bone itself to localized necrosis and bacterial seeding. This condition generally has a slow clinical development and insidious onset. Contiguous osteomyelitis is an infection in the bone secondary to the inoculation of organisms from direct trauma, spread from a contiguous focus of infection, or sepsis after a surgical procedure. Clinical manifestations of direct inoculation osteomyelitis are more localized than those of hematogenous osteomyelitis and tend to involve multiple organisms. Disease states known to predispose patients to osteomyelitis include diabetes mellitus, sickle cell disease, acquired immune deficiency syndrome (AIDS), IV drug abuse, alcoholism, chronic steroid use, immunosuppression, and chronic joint disease. In addition the presence of a prosthetic orthopedic device is an independent risk factor as is any recent orthopedic surgery or open fracture. A single pathogenic organism is almost always recovered from the bone. The most common bone isolates are Staphylococcus species, the most common gram-negative organism is Pseudomonas aeruginosa, and the most common anaerobes are Peptostreptococcus species. However, in immunocompromised patients, other organisms, including fungi and mycobacteria, also must be considered. |
|
|
|
| Frequency: The overall prevalence of acute osteomyelitis is 1 case per 5,000. The prevalence of osteomyelitis after foot puncture may be as high as 16% (30-40% in patients with diabetes). Lower extremity osteomyelitis accounts for 90% of osteomyelitis cases and is much more common than upper extremity osteomyelitis, which accounts for 10% of extremity cases. |
|
|
|
| Clinical: The clinical presentation and location of osteomyelitis differ in infants, children, and adults. Symptoms are often vague and indistinguishable from other more mundane conditions. Fever, localized pain, swelling, redness, increased warmth, irritability, and lethargy are often progressive when associated with hematogenous osteomyelitis. The infection of contiguous osteomyelitis usually manifests within 1 month after inoculation of the organisms from trauma, surgery, or a soft tissue infection. Affected patients typically present with low-grade fever, pain, and drainage. |
|
|
|
| 
Lab and Imaging Studies: Routine laboratory test findings are usually nonspecific. These include CBC count, erythrocyte sedimentation rate (ESR), C- reactive protein (CRP), renal and hepatic profile, and bone profile. These studies although widely employed are often abnormal but can be associated with many other conditions. Plain radiographs may be used to make the diagnosis, help in interpreting and choosing other studies, and allow one to exclude other conditions (eg, gas in the soft tissues). In uncomplicated acute infection, the triad of soft tissue swelling, bone destruction, and periosteal reaction is fairly specific for osteomyelitis and is sufficient to warrant a course of therapy. However, early in the condition, plain films are often inaccurate. This is in part due to the 2-3 weeks required for bone changes to be evident on plain films. CT scan is used to evaluate an area in which focal findings are present on examination and plain films findings are negative. The CT scan (with and without contrast) is very accurate for detecting cortical destruction, intraosseous gas, periosteal reaction, and soft tissue extension. MRI is an alternative to CT scan and is especially useful in evaluating a patient for osteomyelitis in the vertebrae and in the infected foot. Multiple different nuclear medicine imaging procedures are available to evaluate for osteomyelitis, including bone scan, indium-labeled leukocyte scan, and bone marrow scan. In most settings these are the tests most commonly used to make the diagnosis. The 3-phase technetium bone scan is the test of choice in evaluating for acute osteomyelitis if the plain film findings are normal. In this situation, it has an estimated sensitivity and specificity of almost 95% and findings generally are positive in 2-3 days of infection. The standard for the diagnosis of osteomyelitis is open bone biopsy with histopathologic examination and cultures. Needle biopsy is commonly used to obtain bone for histopathologic analysis. However, the incidence of sampling error is not negligible, with the sensitivity and specificity of this technique being 87% and 93%, respectively. If the clinical suspicion is strong and blood culture results and the needle biopsy findings are negative, the needle biopsy should be repeated or an open biopsy should be performed. |
|
|
|
| Treatment: Successful management of osteomyelitis requires aggressive pursuit of the diagnosis and early antimicrobial and surgical therapy. If acute osteomyelitis is not treated optimally, the risk is high of developing chronic osteomyelitis, which is significantly less amenable to treatment. Once the etiologic organism is identified, the antibiotic regimen should be based upon susceptibility patterns. The patient should be treated for 6 weeks with appropriate intravenous antimicrobial therapy. Surgical management of contiguous osteomyelitis can be very challenging. The principles of treating any infection are equally applicable to the treatment of infection in bone. These include adequate drainage, extensive debridement of all necrotic tissue, obliteration of dead spaces, stabilization, adequate soft tissue coverage, and restoration of an effective blood supply. Recurrence of osteomyelitis has been reported in 3-40% of patients. Chronic osteomyelitis is very serious and more difficult to treat than acute osteomyelitis. Disability is more common and is often permanent. |
|
|
|
| 
Medical/Legal Concerns: Most cases resulting in litigation involve a delay in diagnosis when associated with a recent orthopedic procedure. Unless the physician maintains a high index of suspicion, the condition will not be diagnosed and treated in a timely manner. There is a direct correlation between delay and bone/tissue damage. Physicians often prescribe oral antibiotics early on, but these medications are ineffective in the treatment of early osteomyelitis. If the diagnosis is considered, the physician must order the necessary studies to rule it in or out, and must then treat accordingly with intravenous antibiotics and possibly surgical debridement. |
|
|
|
|
Since 1990 and through 100,000+ nationwide cases, AMFS, Inc. (American Medical Forensic Specialists) has been providing plaintiff and defense attorneys in-house case evaluations as well as access to a carefully screened, nationwide panel of more than 7,500 board-certified medical experts practicing in all specialties and regions of the country. With just a single phone call, you reach an in-house staff physician who will assist you in clarifying the medical issues present in your case, identifying the medical specialties involved and interviewing prospective experts from our panel for your case. Whether you need a physician to review your case, testify as an expert, perform an IME, or perform any other task in the medical-legal field, in any region of the country, AMFS can help. As always, our mission is to provide counsel with the most efficient way to retain quality experts in a timely, cost effective manner. Call Today to Speak with an AMFS Staff Physician at NO Charge. Or use this handy form to submit a case for a Quick Review. Thank you for your time,
Attorney & Physician Advisory Board
CALL TOLL FREE: 1-800-275-8903 |
|
