Osteomyelitis - Pathophysiologic Processes - Term Paper Example

?Running Head: OSTEOMYELITIS Osteomyelitis Osteomyelitis can be termed as a bone disease caused by infection that is specifically characterized by acute or persistent swelling of the bone and its sub-classification can be done on the basis of pyogenic organisms which provoke the formation of pus. The common symptoms of this disease include fever, irritability, malaise, lethary and swelling. The diagnosis of osteomyelitis is difficult since the clinical symptoms are not very specific. Osteomyelitis is not concentrated in any specific human race. The disease is more likely to strike the males than the females and reaches acute stage during adolescence and in adulthood the ratio falls. Various types of osteomyelitis are there and some are more prone to strike children like hematogenous osteomyelitis while direct trauma and contiguous focus osteomyelitis are more likely to be found in adults (King & Johnson, n.d.). Epidemiological Overview Process Ostermyelitis is a disease associated with bones. It is an infection that affects the bones and which occurs as a result of bacteria or other germs. Fungi can also cause this disease. Bacteria can spread to a bone in various manners. Skin that is suffering from infection can spread bacteria to a bone. Bacteria can also reach the bone from muscles or tendons that are placed near the bone. This disease can also happen under a skin sore. The infection can actually happen in any area of the body and from that area the infection can be carried to the bone by blood. There is another way this infection can start and that is from complications arising from surgery of the bone. The risk of this infection tends to gets more likely if the surgery is done after there is an injury. Infection can also happen from metal rods and plates that are placed in the bone to fix fracture of the bone. In case of children, this disease more often occurs in the long bones of the arms or legs which give strength and provides mobility. Acute hematogenous osteomyelitis can mostly be seen in children. Direct trauma and contiguous focus osteomyelitis affect mostly adults and adolescents. (Osteomyelitis, 2012) Morbidity of the disease can be substantial. The infection can spread in a localized manner to the related soft tissues of joints. The infection can also end up as a chronic infection causing acute pain and can cause disability. The areas of the body that gets extremely infected may have the need to be amputated to stop the spread of the infection to other parts of the body. The infection can also be generalized or sepsis. Figures show that around 10 to 15 percent of patients who have this disease in the bones of their vertebra can develop disorder in the nervous system or frank spinal-cord compression. Recent studies have shown that complications in the vascular system seem to be more common with community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) than it was earlier known. Patients suffering from osteomyelitis generally have low rates of mortality unless there is an associated sepsis. The disease can also be mortal if the patient has a history of a prevalent medical condition (King & Johnson, n.d.). Osteomyelitis in children In children, this disease is more commonly carried by blood and is typically found in long bones like the femur, tibia and humerus. Generally bacteria enter the bones of children through surgical manipulations or penetrating wounds. In case of infants, this disease can spread more as the anatomical resistance power to deflect infection is less in infants. Osteomyelitis is more focal in older children with fever and bacteremia as common symptoms (Kaplan, 2005, pp.787-788). Pathophysiologic Processes Risk Factors The common risk factors for osteomyelitis are diabetis, poor blood supply, injury received in recent past and use of illegal drugs by means of injection. People whose spleen has been removed are also vulnerable to osteomyelitis. (Osteomyelitis, 2012) Diabetis is a disease that is lifelong and happens when the blood sugar level increases in the blood. It is possible to control type 2 diabetis by bringing changes in the lifestyle but there is no way to avoid type 1 diabetes (Diabetes, 2012). Hemodialysis dependence is an isolated risk factor for hematogenous complication that includes osteomyelitis. Research results have proved that hemodialysis-dependent patients have high rates of osteomyelitis complications. In most cases there was the presence of chronic vascular access. Osteomyelitis complications can also be linked with the direct effect of hemodialysis on host immunity to bacteria infection, including uremia associated phagocyte dysfunction and overload of iron. Refractory osteomyelitis is a chronic form of osteomyelitis and it has been found that refractory osteomyelitis continues or returns even after necessary interventions have been undertaken. It can also persist in cases where acute osteomyelitis could not be cured with existing management techniques. Factors, either systematic or local that influence how diseases respond to treatments are customarily connected with refractory osteomyelitis (Chen et. al, 2008, pp.233-234). Impacts Since osteomyelitis is a disease of the bone, it can affect the remodeling process of bone resulting in bone loss, necrosis of the area affected, and it may also spread to other parts of the body. Its impact is also on multiple biological scales. The infection begins at the intracellular level, after which it affects the tissue and organ level. This disease can also lead to progressive bone destruction, thus affecting bone remodeling which is the cellular-level process (Lio et. al, 2012, pp.163-164). Clinical manifestations The most common symptom of vertebral osteomyelitis is back pain and it happens in the area of infection. In most cases pain happens in lumbar spine followed by thoracic spine and cervical spine. In one third cases, symptoms like loss of senses and weakness are found. Fever is not common since patients tend to take analgesic medications (Zimmerli, 2010). Hematogenous osteomyelitis is more commonly found in children because the growing areas of their long bones are highly vascular and so are more vulnerable to even slightest trauma. Symptoms include “fever and irritability, as well as local erythema, swelling, and tenderness over the involved bone.” (Hatzenbuehler & Pulling, 2011, p.1027) Diagnosis In case of children acute osteomyelitis “is primarily a clinical diagnosis based on the rapid onset and localization of symptoms.” There are some regular symptoms like fever, lethary and irritability. The focus of physical examination must be on common findings that can be identified like erythema, soft tissue swelling or joint effusion, decreased joint range of motion, and tenderness in the bones. In children blood cultures turn to be positive in most cases and so bacterial infection is not easy to detect. Thus diagnosis is difficult for children and in addition they are much more vulnerable to the infection than adults. In case of adults the disease has high recurrence rate and also there may be need for surgery procedures. For these reasons it is better to get advice from an infectious disease subspecialist, orthopedic subspeciaist or plastic surgeon. In osteomyelitis, clinical symptoms are not explicit and so are difficult to detect. Such symptoms include continuous pain, constant drainage of wound or sinus tract, slow healing of wound, malaise and sometimes fever (Hatzenbuehler & Pulling, 2011, p.1028). The ubiquity of Propionibacterium acnes (P.acnes) makes it difficult to identify the bacteria in bone cultures. The first symptom of this infection is continuous pain after surgery or later. But even this is not definite and so cannot always be diagnosed as P. acne infection. One major element needed for the diagnosis is an orthopedic device as the “main virulence factor of P. acnes is its ability to produce biofilm.” (Asseray et.al, 2010, pp.421,424) Cases where the infection is transmittable and there is ulcer, then sterile steel probe will be needed to detect bone. Investigations by laboratory process can be useful but it usually lacks specificity for osteomyelitis. “Leukocytosis and increased erythrocyte sedimentation rate and C-reactive protein levels may be present.” (Hatzenbuehler & Pulling, 2011, p.1029) These can detect inflammations and are elevated in children. The most important requirement for osteomyelitis diagnosis is microbial culture especially positive culture from bone biopsy and histopathology consistent with necrosis. Positive blood cultures when integrated with clinical or radiographic proof of osteomyelitis can decide whether there is a need for bone biopsy. Cultures of wounds that are superficial are not necessary for diagnosis of this disease. Imaging can be useful to decide the type of osteomyelitis and can also detect whether symptoms are caused by any other reasons other than this disease. However, plain imaging cannot expose abnormalities unless two weeks have passed after the infection. Imaging can usually detect non-specific periosteal reaction and osteolysis (Hatzenbuehler & Pulling, 2011, p.1029). There is case example of misjudgement because of difficulty of diagnosis. A woman of 66 years was initially diagnosed with calcaneal psteomyelitis of her right heel. The cause was presumed as penetration of foreign body. In the first stage of treatment she was given antibiotics intravenously but it failed. When there was noticeable fluctuation, surgery was done to drain her right heel. But even after the surgery the condition of her right heel did not improve and same thing happened on her left side. Only then panniculitis was diagnosed and after proper treatment she recovered fully (Marmor et.al, 2009). Patients with spinal cord injury should be tested for vertebral osteomyelitis, especially if infection even after being treated does not duly respond. For this purpose “culture should be attained, with prompt antibiotic treatment and surgical intervention, if indicated, to prevent severe morbidity and mortality.” (Hsiao & Liang, 2011, 1022) Clinical course Osteomyelitis has two clinical forms which are acute and chronic. Acute osteomyelitis is infection at early stage and generally affects the body system. Chronic osteomyelitis is continuation of the infection after the passage of acute phase. The signs of the disease can exacerbate during any stage of the disease. Since there is no perfect treatment method, so there is remission of the disease even after it gets healed. So, healing does not mean the disease is getting cured (Newton & Nunamaker, 1985, Ch.37). Prevention Prevention is very important in osteomyelitis since there is no permanent cure. All wounds especially which has a bone underneath should be promptly treated. Soft tissue trauma during fracture repair should be minimized by surgery. The vascularity of bone fragment must be protected by leaving muscles attached to bones undisturbed. All foreign objects like metallic implants and suture materials that are used for wound treatment should be used carefully. Avascular bone fragments should be removed unless they are necessary for fracture that has been reconstructed (Scott & McLaughlin, 2006, p.41). Management of the disease Medical and pharmacotherapeutic management Organisms that contribute towards osteomylitis are Staphylococcus aureus, coagulase-negative staphylococci, Pesudomonas aeruginosa, streptococci, Bartonella henselae and Candida albicans. The bacteria that is most common cause of this disease is S aureus. Infections caused by these bacteria are not easy to treat because of the bacteria’s ability to survive in the osteocytes and its resistant power against antimicrobial therapies. It is recommended that pharmacologic or surgical treatments can be applied to prevent bone necrosis. If the disease is caused by methicillin-resistant S aureus, then the standard treatment is implementation of intravenous vancomycin therapy for 4 to 6 weeks. However, the duration of this kind of treatment is long and there is also the risk of toxicity associated with the treatment. For this reason very often the health care professionals find it difficult to decide the right kind of monitoring processes. Although there is no perfect method for finding out the vancomycin concentrations in the bone, the range of vancomycin bone concentrations usually range from 15% to 35% of serum concentrations. “To achieve local concentrations 4 to 5 times the minimum inhibitory concentration of the causative organism, it is critical to achieve serum concentrations reflective of adequate bone penetration and killing ability against the affecting organism(s).” (Malloy & Davis, 2009, pp.499-500) Because the vancomycin killing is concentration independent, so the dosage and the frequency are also matters of consideration. Vancomycin dosing depends on the actual weight of the body and is not concerned with the type of infection. Even though there is not enough data available in obese patients, still the initial doses are based on the actual weight of the body. The subsequent doses need to be adjusted according to the response of the patient, concentrations of serum and clinical judgement. Intervals between initial dosing are normally 12 hours to target serum concentrations 4 to 5 times greater than the minimum bacterial inhibitory concentration. The concentration-independent killing of vancomycin has encouraged some physicians to examine the effects of continuous infusion regimens, more because the most standard dose, 1 g every 12 hours, often produces subtherapeutic trough concentrations. It is believed that continuous infusions can maximise the concentrations of serums while reducing the total dose of drug in an effort to minimize toxicity. Emergence of glycopeptide-intermediate staphylococcal species can be prevented by maximizing drug concentrations above the minimum inhibitory concentration. The timing and frequency of concentration monitoring needs to be carefully considered especially for the standard osteomyelitis infections whose treatment continues for 4 to 6 weeks. It is recommended that trough concentrations be obtained at steady rate before the next dose, usually between the fourth and fifth dose. It is required to repeat monitoring till the needed concentration is achieved and after that frequency may be lowered. Weekly trough concentrations may be applied to patients getting long-term vancomycin therapy for osteomyelitis. Also it is needed to monitor function of the kidney through serum creatinine just before beginning the therapy and also at regular intervals during the therapy. As the treatment progresses and the patient gets stabilized, monitoring can be done less frequently. In case of pediatric patients, monitoring recommendations are not very clear. Some medical centers support monitoring in particular types of patients like “neonates, children with burns or malignancies, children with renal insufficiency, children receiving concurrent nephrotoxic medications, and children receiving higher daily doses of vancomycin.” (Malloy & Davis, 2009, pp.500-501) In the case of other pediatric patients, the recommendation is to draw trough concentration 1 to 2 days into therapy for the purpose of minimizing the need for subsequent monitoring and also to evaluate the presence of underdosing. With the use of vancomycin as the only kind of treatment, it is possible to reduce the risk of nephrotoxicity and ototoxicity in patients suffering from osteomyelitis. However, monitoring of trough concentration is necessary at regular basis to ensure that troughts of 15 to 20 mcg/mL are achieved for adequate bone penetration and to assess clearance of drug. Treatment that needs to be done for long-term in osteomyelitis patients, monitoring should be done at a steady rate initially, then weekly after dose adjustments, and later on periodically depending on the patient’s recovery and function of kidney (Malloy & Davis, 2009, p.502). Surgery For some osteomyelitis patients, surgery is needed and the procedures for surgery include – 1) draining the infected area, to remove pus or fluid, 2) debridement which means removal of infected bone or tissue, 3) correcting improper flow of blood to the bone by replacing the damaged bone with any graft of bone or muscle from any other part of the body, and 4) to remove any foreign objects like pins or screws that were used formerly to set the bone (Osteomyelitis, n.d.). Non- pharmacotherapeutic management Herbs are generally used to strengthen the systems of the body. Herbs can be taken as dried extracts, glycerites or tinctures (not recommended for patients with alcohol history). Although there are no specific drugs for osteomyelitic treatment, however some types of herbs can enhance the immune system of the body to fight infection by cleaning the blood. Some such herbs are garlic, Echinacea, Goldenseal, Astragalus, Eleuthero and Barberry (Osteomyelitis, n.d.). Future research Since there is no proper treatment of osteomyelitis and even after healing it can recur, it is absolutely necessary that future research must focus on various aspects of this disease. Research should be done to know whether the need of radionuclide scintigraphy for evaluation of multifocal osteomyelitis can be ensured by using the technique of whole-body magnetic resonance (MR) imaging. It is also important to understand whether MR with gadolinium can impart more information than ultrasound in the assessment of septic arthritis. Further research should be done to know whether results from plain film imaging, MR or ultrasound can predict possibility of success of medical treatment or whether the results can provide early triage to surgical treatment. Research should also be done to assess the contribution of PET-CT in the evaluation of acute osteomyelitis (Medina et.al, 2009, pp.256-257). Osteoblasts which are special kinds of cells developed from mesenchymal precursors are contributors towards creation of new bones. Modern mouse genetic studies have been successful in recognizing various kinds of osteoblasts, however, together these bone cells are the last option for resistance power of host to prevent bacterial presence and biofilm formation in bone. To help in resistance power, “osteoblastic cells express an array of immunostimulatory molecules that are triggered by their Toll-like receptors (TLR) following litigation by bacterial factors.” After these receptors are initiated by bacterial ligands, the osteoblasts yield “antimicrobial peptides, chemokines, inflammatory cytokines, co-stimulatory molecules and MHC II”. (Lorenzo et.al, 2010, p.374) All these minimize bone infection by bacteria. With the production of MHC II it is implied that osteoblasts would internalize bacteria during infection. Earlier investigation has confirmed that S aureus which is the most common cause of osteomyelitis is internalized by osteoblasts. The role of osteoblasts in the immune system is needed to be studied further. Thus future research must concentrate on “the mechanisms by which bacteria infect ostoblasts in vivo and how bone formation is inhibited in acute osteomyelicin.” (Lorenzo et.al, 2010, p.374) Conclusion Since there is no definite and proper diagnosis method for osteomyelitis, so a large section of population faces the risk of infections in the lower extremities. People who suffer from diabetes are the ones who are most prone towards this disease and so it is imperative that osteomyelitis can be clearly comprehended with precise definitions by the physicians of diabetic patients. Although surgical debridement is generally not recommended for diabetic foot osteomyelitis, it is still not possible to predict which type of medical therapy will be perfectly suitable for patients suffering from osteomyelitis (Greenhagen & Crim, 2010, p.138). Proper and regular monitoring can keep the disease in control. Osteomyelitis is still a disease which requires intense research since many times it is either wrongly diagnosed resulting in wrong treatment or it is detected at much later stage when treatment becomes even more difficult. References Asseray, N. et al. (2010) Improving diagnostic criteria for Propionibacterium acnes osteomyelitis: A retrospective analysis. Scandinavian Journal of Infectious Diseases, 42, 421-425 Chen, C.Y et. al. (2008). Adjuvant Hyperbaric Oxygen Therapy in the Treatment of Hemodialysis Patients with Chronic Osteomyelitis. Renal Failure, 30(2), 233-237 Diabetes, (2012) NCBI, retrieved on November 9, 2012 from: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0002194/ Greenhagen, R. & B.E. Crim (2010) Osteomyelitis in the Diabetic Foot. Podiatry Management Hatzenbuehler, J. & T.J. Pulling (2011). Diagnosis and Management of Osteomyelitis. American Family Physician, 84(9), 1027-1032 Hsiao, M.Y. & H.W. Liang (2011) Delayed diagnosis of vertebral osteomyelitis in a paraplegic patient. Spinal Cord, 49, 1020-1022 Kaplan, S.L. (2005). Osteomyelitis in Children. Infect Dis Clin N Am, 19, 787-797 King, R.W. & D. Johnson (n.d.), Osteomyelitis in Emergency Medicine, medscape, retrieved on November 9, 2012 from: http://emedicine.medscape.com/article/785020-overview#showall Lio, P., Merelli, E. & N. Paoletti (2012) Disease processes as hybrid dynamical systems. EPTCS, 92, 152-166 Lorenzo, J., Horowitz, M., Choi, Y. & H. Takayanagi (2010). Osteoimmunology: Interactions of the Immune and Skeletal Systems. USA: Academic Press Malloy, K.M. & G.A. Davis (2009) Summary of ASHP/IDSA/SIDP Vancomycin Monitoring Recommendations: A Focus on Osteomyelitis, Orthopedics, 32(7), 499-502 Marmor, M., Haim, A., Drexler, M. & T. Pritsch (2009) Bilateral heel panniculitis presenting as calcaneal osteomyelitis, Orthopedics, 32(1), 59 Medina, L.S., Applegate, K.E. & C.C. Blackmore (2009). Evidence-Based Imaging in Pediatrics: Improving the Quality of Imaging in Patient Care. Springer Newton, C.D. & D.M. Nunamaker (1985). Small Animal Orthopaedics. Lippincott Williams & Wilkins Osteomyelitis, (2012) NCBI, retrieved on November 9, 2012 from: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001473/ Osteomyelitis, (n.d.) UMM, retrieved on November 10, 2012 from: http://www.umm.edu/altmed/articles/osteomyelitis-000119.htm Scott, H.W. & R. McLaughlin (2006). Feline Orthopaedics. Barcelona: Manson Publishing Zimmerli, W. (2010) Clinical practice. Vertebral osteomyelitis. New England Journal of Medicine, 362(11), 1022-1029 Read More