Osteomyelitis

A pyogenic bone infection, osteomyelitis may be chronic or acute. It commonly results from a combination of local trauma - usually quite trivial but resulting in hematoma formation - and an acute infection originating elsewhere in the body. Although osteomyelitis often remains localized, it can spread through the bone to the marrow, cortex, and periosteum.

Acute osteomyelitis is usually a blood-borne disease, which most often affects rapidly growing children. Chronic osteomyelitis (rare) is characterized by multiple draining sinus tracts and metastatic lesions.

Osteomyelitis occurs more often in children than in adults - and particularly in boys-usually as a complication of an acute localized infection. The most common sites in children are the lower end of the femur and the upper end of the tibia, humerus, and radius. In adults, the most common sites are the pelvis and vertebrae, generally the result of contamination associated with surgery or trauma.

The incidence of both chronic and acute osteomyelitis is declining, except in drug abusers. With prompt treatment, the prognosis for acute osteomyelitis is very good; for chronic osteomyelitis, which is more prevalent in adults, the prognosis is still poor.

Causes

Bones are infected by blood-borne micro-organisms. In most cases, the micro-organisms are bacteria such as Staphylococcus aureus, but fungi can also cause osteomyelitis. Some of the conditions and events that can lead to osteomyelitis include:

• Bacteria introduced during bone surgery.
• Bacteria introduced by trauma to bone.
• Infection of bone fractures.
• Infection of prosthetic implants (such as an artificial hip joint).
• Infections elsewhere in the body that reach the bones via the bloodstream.
• A primary infection of the blood (septicaemia).

Signs and symptoms

Symptoms of osteomyelitis vary, depending on the cause and if it is a rapid or slow onset of infection. The following are the most common symptoms of osteomyelitis. However, each individual may experience symptoms differently. Symptoms may include:

• fever (the fever may be high when osteomyelitis occurs as the result of a blood infection)
• pain and tenderness in the affected area
• irritability
• feeling ill
• swelling of the affected area
• redness in the affected area
• warmth in the affected area
• difficulty moving joints near affected area
• difficulty bearing weight or walking
• a new limp
• a stiff back (with vertebral involvement)

The symptoms of osteomyelitis may resemble other medical conditions or problems. Always consult your physician for a diagnosis.

Diagnosis

Patient history, physical examination, and the following laboratory tests help to confirm osteomyelitis:

• White blood cell count shows leukocytosis.
• Erythrocyte sedimentation rate and Creactive protein (CRP) are elevated; however CRP appears to be a better diagnostic tool
• Blood cultures identify the causative organism.

X-rays may not show bone involvement until the disease has been active for some time, usually 2 to 3 weeks. Bone scans can detect early infection. Diagnosis must rule out poliomyelitis, rheumatic fever, myositis, and bone fractures.

Treatment

Treatment varies for acute and chronic osteomyelitis.

Acute osteomyelitis

Acute osteomyelitis should be treated before a definitive diagnosis. Treatment includes:

• administration of large doses of I. V. antibiotics (usually a penicillinase-resistant penicillin, such as nafcillin or oxacillin, or a cephalosporin) after blood cultures are taken
• early surgical drainage to relieve pressure buildup and sequestrum formation .
• immobilization of the affected bone by plaster cast, traction, or bed rest
• supportive measures, such as administration of analgesics and I. V. fluids.

If an abscess forms, treatment includes incision and drainage, followed by a culture of the drainage. Antibiotic therapy to control infection may include administration of systemic antibiotics; intracavitary instillation of antibiotics through closed-system continuous irrigation with low intermittent suction; limited irrigation with blood drainage system with suction (Hemovac); or local application of packed, wet, antibiotic-soaked dressings.

Chronic osteomyelitis

In chronic osteomyelitis, surgery is usually required to remove dead bone (sequestrectomy) and to promote drainage (saucerization). The prognosis is poor even after surgery. Patients are often in great pain and require prolonged hospitalization. Resistant chronic osteomyelitis in an arm or leg may necessitate amputation.

Some facilities also use hyperbaric oxygen to increase the activity of naturally occurring leukocytes.

Free tissue transfers and local muscle flaps are also used to fill in dead space and increase blood supply.

Alternative treatment

General recommendations for the treatment of infections include increasing vitamin supplements, such as vitamins A and C. Liquid garlic extract is sometimes suggested. Guided imagery can help induce relaxation and improve pain, both of which are considered to improve healing. Herbs such as echinacea ( Echinacea spp.), goldenseal ( Hydrastis canadensis ), Siberian ginseng ( Eleutherococcus senticosus ), and myrrh ( Commiphora molmol ) are all suggested for infections. Juice therapists recommend drinking combinations of carrot, celery, beet, and cantaloupe juices. A variety of homeopathic remedies may be helpful, especially those used to counter inflammation.

Prevention

Prompt and complete treatment of infections is helpful. High-risk people should see a health care provider promptly if they have signs of an infection anywhere in the body.