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Overcoming osteomyelitis

 

Authors

  1. Seabolt, Joyce LPN

Abstract

Osteomyelitis is an inflammation of bone tissue that affects approximately 2 in 10,000 people in the United States. Caring for a patient with osteomyelitis can be challenging because the signs and symptoms often mimic other health problems. Find out what you can do to recognize this serious condition and help guide your patient through diagnosis and recovery.

 

Article Content

OSTEOMYELITIS IS AN infectious process in the bone that usually starts in the spongy medullary bone. Osteomyelitis literally means inflammation of the bone and is usually caused by bacteria. The infection that causes osteomyelitis often starts in another part of the body and spreads to the bone through the bloodstream. Affected bone is often vulnerable to infection because of recent trauma, such as a fracture or surgery. Osteomyelitis is most common in children and adults over age 50, affecting men more often than women. It can be acute or chronic.

 

Bone can become infected in one of the following ways:

 

* as an extension of soft-tissue infection from an incision or pressure ulcer

 

* by direct contamination from bone surgery, open fracture, or traumatic injury

 

* via the blood (hematogenous) from other sites of infection (tonsils, boils, teeth, upper respiratory tract).

 

 

Staphylococcus aureus causes between 70% and 80% of osteomyelitis cases. Other frequent causes include Pseudomonas and Escherichia coli. Some infections involve multiple infectious agents.

 

Acute osteomyelitis usually occurs in children as a result of infection with Gram-negative bacteria, and the long bones (tibia, humerus, and femur) are commonly affected. Infection spreads quickly in children. It can damage bones and joints, impairing function, growth, and mobility.

 

Osteomyelitis in adults is most commonly a chronic condition that can last several months to years and lead to bone death. The development of sinus tracts between bone and skin is common in chronic cases. The pelvis and vertebrae are most often affected; about half of the cases of vertebral osteomyelitis are due to S. aureus, and the other half are due to tuberculosis. Chronic osteomyelitis of the spine is dangerous because it can damage the nerves. Sites of chronic osteomyelitis can evolve into skin cancer or gangrene, and possibly lead to limb amputation.

 

Risky business

People who are at high risk for osteomyelitis include those who are poorly nourished, elderly, or obese. Others at risk include those with impaired immune systems; those with chronic illnesses such as diabetes or rheumatoid arthritis; and those receiving long-term corticosteroid therapy or immunosuppressive agents. People with diabetes have an increased risk of getting osteomyelitis for many reasons:

 

* They have impaired circulation, which causes wounds to heal slowly.

 

* If they have neuropathy, an injury may go undetected for a long time.

 

* Impaired vision or impaired mobility can lead to injuries.

 

 

Chronic diseases such as sickle-cell anemia, cancer, hemophilia, rheumatoid arthritis, and HIV also put people at high risk for infections. All these problems can lead to osteomyelitis. Weakness and impaired mobility from these diseases increase the potential for injuries. These patients also have impaired ability to heal after an injury, so their acute osteomyelitis is more likely to evolve into chronic osteomyelitis.

  
Figure. What osteomy... - Click to enlarge in new windowFigure. What osteomyelitis looks like.

Direct contamination

Infectious organisms can enter the bone directly through an open fracture, a traumatic injury such as a gunshot wound, and during surgery. Postoperative surgical wound infections occur within 30 days after surgery. They are classified as incisional (superficial, located above the deep fascia layer) or deep (involving tissue beneath the deep fascia).

 

If the patient received a bone implant, a deep postoperative infection may affect the site within a year. Deep sepsis after arthroplasty may be classified as follows:

 

* Stage 1, acute fulminating: occurring during the first 3 months after orthopedic surgery; frequently associated with hematoma, drainage, or superficial infection

 

* Stage 2, delayed onset: occurring between 4 and 24 months after surgery

 

* Stage 3, late onset: occurring 2 or more years after surgery, usually as a result of hematogenous spread.

 

 

Bone infections are more difficult to wipe out than soft tissue infections because blood vessels don't supply the infected bone to provide access to the body's natural immune response. Penetration by antibiotics is decreased as well, so osteomyelitis may become chronic and affect the patient's quality of life.

 

Before we get to what can be done to treat osteomyelitis, it's time to take a look at the common signs and symptoms.

 

Signs and symptoms

 

Children under the age of 3 are common targets for osteomyelitis because they fall frequently and their immune systems are not yet developed. Instruct parents to monitor a child's injury site (especially fractures and puncture wounds) long after they seem to be healed. Osteomyelitis is one complication they can help prevent.

 

Signs and symptoms of acute osteomyelitis include:

 

* pain in the affected area

 

* redness, swelling, and warmth over the area of infection

 

* fever

 

* irritability

 

* malaise.

 

 

In children, many of these symptoms may mistakenly be attributed to other causes, such as the flu. Children frequently have scrapes, falls, punctures, and fractures and experience pain, swelling, redness, or drainage after those injuries, and a diagnosis of osteomyelitis can be overlooked.

 

Signs and symptoms of chronic osteomyelitis include:

 

* redness, swelling, and warmth over the area of infection

 

* pain or tenderness in the affected area

 

* drainage from an open wound in the area of infection

 

* fever (in some cases).

 

 

Because bone infections in adults commonly follow an injury or surgery, the symptoms may erroneously be attributed to the injury or surgery and osteomyelitis can be overlooked.

 

Once osteomyelitis is suspected, it's time to perform some tests to make a definitive diagnosis. Here's what you need to know about the current tests available.

 

Testing, testing

Because diagnosing osteomyelitis can be difficult, assessment requires a complete medical history, physical examination, and diagnostic testing. This testing may include blood work, bone biopsy, X-rays, bone scans, computed tomography (CT) scans, and magnetic resonance imaging (MRI).

 

Blood work typically includes a complete blood cell (CBC) count, erythrocyte sedimentation rate (ESR), blood cultures, and C-reactive protein (CRP) level. The CBC count will show an elevated white blood cell count when infection is present. The ESR is almost always elevated in the presence of inflammation. The CRP helps detect inflammation and infection.

 

A bone biopsy is the gold standard for diagnosing osteomyelitis. It will identify the infection and can be performed through surgery (an open biopsy) or by deep needle aspiration.

 

X-rays can detect osteomyelitis only after it has reached an advanced stage, but common findings in chronic osteomyelitis include bone sclerosis and periosteal new bone formation.

 

Bone scans are done after dye has been injected and absorbed by bone tissue. They can detect areas of increased or decreased bone metabolism, even in the early stages of infection.

 

CT scans can show abnormal calcification (the buildup of calcium in body tissues) and ossification (when cartilage is turned into bone).

 

MRIs are most useful to evaluate vertebral lesions and can distinguish between soft tissue infection and bone infection.

 

Treatment options

Once your patient has been diagnosed with osteomyelitis, his treatment will depend on the bacteria involved, the site of infection, and the type of osteomyelitis (acute or chronic). Antibiotic therapy, bed rest and opioid analgesia, nutritional support, and surgery are options; let's take a look at what each can do to help your patient.

 

Intravenous antibiotic therapy is administered after blood cultures or aspiration cultures identify the cause of the infection. Bacterial infections usually require 2 to 6 weeks of antibiotic therapy (unless vertebrae are infected, when treatment lasts 6 to 8 weeks). Fungal infections may require several months of treatment, and chronic infections may require treatment indefinitely.

 

Antibiotic therapy usually begins in the hospital and continues at home, either intravenously (I.V.) or orally. Common antibiotics used include ciprofloxacin (Cipro), nafcillin (Unipen), clindamycin (Cleocin), vancomycin, flucloxacillin (Floxapen), and gentamicin (Genoptic). Remind your patient to take his antibiotics exactly as prescribed and to call his health care provider if any problems occur.

 

Bed rest and opioid analgesia may be indicated to manage pain. Bed rest is especially important when osteomyelitis affects weight-bearing bones (those in the spine, hip, knees, and foot) because standing puts pressure on the infection site.

 

Nutritional support, which includes a high-protein diet unless it's contraindicated, can help aid wound healing.

 

Surgery is considered when:

 

* antibiotic therapy fails

 

* the patient develops neurologic deficits

 

* the bone becomes deformed.

 

 

Surgery may be as simple as draining a bone abscess. Abscesses must be drained because they can impair the blood supply to the affected area and cause bone death (osteonecrosis). Sometimes, the surgery may be as complicated as a spinal reconstruction. It all depends on the infection, the site, the symptoms, and the surgeon. Many surgeries involve bone scraping. Once the infected area is debrided, the bone should regenerate rapidly.

 

If a prosthesis (such as a total knee replacement) is the site of osteomyelitis, it is removed. Sometimes, the empty space is packed with antibiotic-impregnated materials. Other times, a new prosthesis is implanted immediately and I.V. antibiotics are given.

 

Unless there is nerve damage, surgery isn't recommended for patients with spinal osteomyelitis.

 

Other approaches for treating osteomyelitis include:

 

* splinting and cast immobilization to prevent further trauma or to help the bone and joint heal (usually used in children)

 

* two different types of external fixators: static fixators hold bones in place; dynamic fixators adjust to compress, angle, or lengthen bones

 

* free tissue transfers, in which tissue (with its blood supply) is attached to new vessels in the wound

 

* bone grafts to replace infected bone cells with healthy bone (usually from the patient's pelvis)

 

* hyperbaric oxygen therapy, along with antibiotics, to inhibit the growth of anaerobic organisms

 

* amputation when a new prosthesis will function better than the chronically infected limb.

 

 

Chronic osteomyelitis resists treatment, especially if multiple microbes or a fungus are the cause. Chronic types usually require a combination of antibiotics and surgery.

 

Caring for your patient

Caring for a patient with osteomyelitis includes managing immediate problems and making sure his ongoing treatment is safe and effective. Your goals should be to:

 

* control the patient's pain with prescribed analgesics and nonpharmacologic techniques

 

* monitor his response to antibiotic therapy

 

* observe the patient's I.V. site for signs of complications

 

* monitor the area of infection and neurovascular status (if an extremity is involved)

 

* apply gentle range-of-motion exercises to the joints above and below the affected site

 

* unless contraindicated, provide nutritional support in the form of a high-protein diet

 

* teach your patient how to take prescribed antibiotics and how to recognize possible adverse reactions. See Teaching facts for more information.

 

 

It can be prevented

Because osteomyelitis is a preventable disease, inform all your patients, especially those with risk factors, about the causes of osteomyelitis and how preventive measures can help (see An ounce of prevention). Educated patients may succeed in preventing or minimizing the pain that accompanies osteomyelitis.

 

Teaching facts

Patients with osteomyelitis need to take care of themselves to improve their chances of fighting infection. Teach your patients to:

 

* Eat a variety of fruits and vegetables, which can provide the body with the nutritional support it needs to fight infection and stay healthy.

 

* Stop smoking. Smoking slows blood flow to the hands and feet, making it more difficult for the body to fight infection. Provide your patient with smoking cessation materials if he needs help.

 

* Continue antibiotic treatment as prescribed. Advise him to call his health care provider to report any adverse effects before discontinuing the drug on his own. The success of antibiotic treatment depends on following the complete regimen.

 

 

An ounce of prevention

When patients have an increased risk of infection, educate them about ways to prevent infections and help prevent osteomyelitis. If they do get cuts and scrapes, the American Association of Orthopaedic Surgeons recommends these simple steps to prevent infections in skin wounds:

 

* First, control the bleeding, then clean the wound with soap and water.

 

* Keep all foreign matter out of the wound but don't try to remove matter embedded in the wound.

 

* Use sterile materials for the first dressing.

 

* See your primary care provider for a final, definitive cleaning of the wound.

 

  

Figure. Normal bone.... - Click to enlarge in new windowFigure. Normal bone.

Selected references

 

American Academy of Orthopaedic Surgeons. Infections. http://orthoinfo.aaos.org/topic.cfm?topic=A00197. Accessed December 10, 2007.

 

Cierny III G. Guest editorial. http://www.osteomyelitis.com Accessed January 1, 2007.

 

The Cleveland Clinic. Osteomyelitis. http://www.clevelandclinic.org/health/health-info/docs/2700/2702.asp?index=9495. Accessed January 17, 2007.

 

The Mayo Clinic. Osteomyelitis. http://www.mayoclinic.com/health/osteomyelitis/DS00759. Accessed November 29, 2006.

 

The Merck Manual of Geriatrics. Osteomyelitis. http://www.merck.com/mrkshared/mmg/sec7/ch50/ch50a.jsp. Accessed February 11, 2007.

 

National Institutes of Health. Malignant otitis externa. http://www.nlm.nih.gov/medlineplus/ency/article/000672.htm. Accessed February 17, 2007.

 

Sheff EK. Solving the mystery of osteomyelitis. Nursing2005. 35(7):32hn1-32hn3, July 2005.

 

Smeltzer SC, et al. Brunner and Suddarth's Textbook of Medical-Surgical Nursing, 11th edition. Philadelphia, Pa., Lippincott Williams & Wilkins, 2007.