What is Osteomyelitis?
Osteomyelitis is a severe infection of bone, bone marrow and surrounding soft tissue that requires immediate treatment. The disease may be either acute or chronic, and acute cases may become chronic or recurrent if treatment is delayed or unsuccessful. Early recognition and initiation of antibiotic therapy is critical in preventing complications.
In acute osteomyelitis, bacteria lodge in bones where circulation is sluggish. The bacteria then multiply and cause destruction of the bone. The destruction is the result of the body's response to the infection, which creates pus and increased pressure in the bone. Finally, there is decreased circulation and bone death (necrosis).
As the disease progresses, areas of bone may become isolated by the infection and lack of circulation, forming islands or segments of necrotic bone that remain infected (sequestra). These areas become a source of recurrent episodes of acute infection and possible draining wounds (sinus tracts). The infection can also spread to other areas of the body. This pattern of recurring infection or failure of the bone to heal is chronic osteomyelitis. When areas of the bone die, circulation through the bone stops and treatment is very difficult. Systemic drugs may not be effective at this point and surgery is necessary.
The most common organisms that cause osteomyelitis are bacteria, but the infection may also be from tuberculosis and fungal organisms. The organism enters the bone either directly through the blood stream (hematogenous), through the open wound in open fractures, or, rarely, from soft tissue infections near the bone (contiguous focus). When the infection spreads through the bloodstream (hematogenous), the primary area of infection may be the respiratory tract, gastrointestinal tract, skin, or urinary tract. In adults, the target bone is primarily the spine and is more commonly found in those over age 50. In direct infection, the organism is introduced into the bone during surgery, from a compound or open fracture, from a contaminated wound over exposed bone, or from a foreign object penetrating the skin and bone. Hardware or prosthetic implants may carry infection into a bone, and may also become infected later and are an area where bacteria multiply rapidly (focus for infection). Because the metal is not affected by circulating blood, antibiotics may not have any effect on the infection. Infection may spread from soft tissue injury (contiguous focus) resulting from trauma, pressure ulcers or burns. The bone itself is not injured initially, but the infection spreads through the layers of soft tissues around it.
How is it diagnosed?
Osteomyelitis signs and symptoms
- Fever. Sometimes this is the only symptom.
- Pain, swelling, redness, warmth and tenderness in the area over the infected bone, especially when moving a nearby joint. Nearby joints, especially the knee, may also be red, warm and swollen.
- If a child is too young to talk, signs of pain are reluctance to move an arm or leg or refusal to walk or limping or screaming when the limb is touched or moved.
- Pus drainage through a skin abscess, without fever or severe pain (chronic osteomyelitis only).
- General ill feeling.
History: In adults with acute onset of osteomyelitis, the main complaint is bone pain, with or without redness of the area. In acute cases, individuals may report loss of appetite, fatigue, and fever. Adults may not appear as ill as children with acute osteomyelitis, which can be confusing. There may be a history of recent trauma or surgery, infection of other organs, such as the lungs or bladder.
Individuals with chronic osteomyelitis will have a history of an acute episode if it was recognized initially, and often have a recurrence of drainage, pain and swelling. They may also have systemic complaints of fever, loss of appetite and fatigue. These individuals may have an underlying immune system disease, or peripheral vascular disease. Individuals must be questioned about IV drug abuse.
Physical exam will reveal local pain and tenderness, perhaps redness over the area (erythema), draining wounds or chronic skin ulcers. Fever, signs of dehydration, general malaise or other signs of sepsis may be evident.
Tests: Laboratory tests include complete blood count (CBC), blood and wound cultures with gram stain, ESR. Other studies include needle aspiration, open bone biopsy Doppler studies in cases of peripheral vascular disease, x-rays, bone scan (most specific is gallium), CT scan and MRI scan.
How is Osteomyelitis treated?
Because early treatment is critical, antibiotic therapy is usually started immediately, before test results are known. The IV therapy continues for four to six weeks and may be followed with oral treatment for several months.
Wound care may include debridement and frequent dressing changes.
Surgery may be required to obtain a culture specimen and to relieve pressure in the bone, which provides pain relief and prevents pressure necrosis of additional bone (surgical decompression).
If a prosthetic implant or hardware is suspected to be the cause, the implants will be removed, and the infection treated before reinsertion. In chronic osteomyelitis, surgical removal of the sequestra and surrounding tissue is followed with antibiotic therapy. In severe cases, amputation may be necessary. Dehydration, protein deficiency and anemia caused by draining wounds require nutritional supplementation. Individual education is very important to insure compliance with long-term therapy. Home care services are necessary for IV medication administration, wound care and education.
Rest in bed until 2 to 3 weeks after symptoms disappear. Resume your normal activities gradually.
No special diet. Eat a nutritionally balanced diet. Take vitamin and mineral supplements if needed.
What might complicate it?
Soft tissue abscess formation, septic arthritis, spreading of a localized infection, paraplegia and meningitis (from infections of the spine), chronic drainage, pathological fracture, and amputation could all result from acute or chronic osteomyelitis.
Acute episodes have a good prognosis, although complications can occur in as many as 25% of cases. Delayed or inadequate treatment may lead to chronic osteomyelitis, which may be inactive for several years, with a flare-up as late as 20 to 30 years later. Chronic cases often have a poor outcome.
Acute septic arthritis, rheumatic fever, cellulitis, tumor, compression fracture of spine, chronic skin ulcer (decubitus), and arthritis of spine are other possibilities.
Infectious disease specialist, orthopedic surgeon, nutritionist, home health care specialist, occupation therapist, and physiatrist.
Seek Medical Attention
- You or your child has symptoms of osteomyelitis.
- The following occur during treatment:
- An abscess forms over the infected bone, or drainage from an existing abscess increases.
- Pain becomes intolerable.
Last updated 19 December 2011