Bone And Joint Infections

Definition

Bone and joint infections may be caused by bacteria, mycobacteria or fungi. They may spread through the bloodstream into the bone and joints (hematogenous spread) or via entry of the micro-organisms from penetrating injuries or from nearby infected tissue or contaminated open wounds (contiguous spread).

Epidemiology

Bone and joint infections have been reported to occur in 2 out of every 10,000 people. In children, the long bones of arms or legs are often involved. In adults, feet, vertebrae and hips are most commonly affected. It may be acute (sudden onset) or chronic (slow onset).

Risk factors include:

  • Severe open fractures
  • Deep puncture wounds
  • Bone and joint surgery (such as hip and knee replacements)
  • Diabetes
  • Sickle cell disease
  • Rheumatoid arthritis
  • HIV/AIDS
  • Chemotherapy/radiotherapy
  • Organ transplants
  • Dialysis
  • Urinary catheters
  • Presence of central lines
  • Long term use of steroids
  • Intravenous drug use

Common pathogens

Most of the bone and joint infections are caused by Staphylococcus bacteria. Other micro-organisms that may cause these infections include other Gram positive bacteria (Streptococci), Gram negative (Klebsiella, Escherichia coli), Mycobacteria(tuberculosis) and less commonly by fungi (Candida).

Clinical Symptoms

  • Fever and/or chills
  • Irritability or fatigue
  • Pain, tenderness and swelling around the affected area
  • Complications that may occur include bone death (osteonecrosis), bone and joint deformities, restriction movement of the affected joint and impaired growth of affected limbs in children.

Diagnostic Tests

  • Blood tests may reveal increased white blood cell count, raised C Reactive protein (CRP) and increased erythrocyte sedimentation rate (ESR) due to infection and inflammation
  • X-rays may reveal damage to your bone. Changes on plain radiographs may not be visible until the infection has been present for several weeks
  • CT scans and MRIs can produce more detailed images of bones and surrounding tissue
  • A bone biopsy is the gold standard for diagnosing bone and joint infections. Tissue culture can reveal which micro-organism is causing the infection and can help the doctors choose an antibiotic that works well against that micro-organism. Bone biopsy is done with local anaesthetic numbing the area before inserting a long needle into the affected bone.
  • Blood cultures may also reveal the offending organisms if the infection is severe and has entered into the blood stream

Treatment

Treatment focuses on eradicating infection, preventing damage to the bone and joints and preserving as much function as possible. Most bone and joint infections are treated with antibiotics, surgery or both. Antibiotics are usually administered intravenously for 4 – 6 weeks before switching to oral antibiotics. More severe infections may require surgery to stop infection from spreading further. In surgery, the infected area is drained and debrided (where diseased bone and tissue is removed). Surgical removal helps to reduce the load of micro-organisms and this enhances healing.

The prognosis for bone and joint infections are good with early and proper treatment. Sometimes the infection may recur and the infection becomes a chronic condition further weakening the bone.

Prevention

The best way to prevent osteomyelitis and joint infections is to treat any potential infections early. If you get any cuts or scrapes, clean the area completely at once and apply a clean bandage. Check wounds frequently for signs of infection. Acute bone and joint infections can become chronic problems so the sooner you treat such infections, the better chance the chance of full recovery.

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