Osteomyelitis
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Infection of bone by pus-forming bacteria, mainly affecting older children and adults.
Cause
- Any type of bacterium but most commonly aureus, following infection elsewhere in the body
- Risk factor: sickle cell disease (causative agent mostly S. Aureus, Salmonella also common)
Clinical features
Acute osteomyelitis
- Onset is usually over several days
- Fever, usually high but may be absent, especially in neonates
- Pain (usually severe)
- Tenderness and increased “heat” at the site of infection, swelling of the surrounding tissues and joint
- Reduced or complete loss of use of the affected limb
- The patient is usually a child of 4 years or above with reduced immunity, but adults may also be affected
- History of injury may be given, and may be misleading, especially if there is no fever
Chronic osteomyelitis
- May present with pain, erythema, or swelling, sometimes in association with a draining sinus tract
- Deep or extensive ulcers that fail to heal after several weeks of appropriate ulcer care (e.g. in diabetic foot), and non-healing fractures, should raise suspicion of chronic osteomyelitis
Differential diagnosis
- Infection of joints
- Injury (trauma) to a limb, fracture (children)
- Bone cancer (osteosarcoma, around the knee)
- Pyomyositis (bacterial infection of muscle)
- Cellulitis
- Sickle-cell disease (thrombotic crisis)
Investigations
- X-ray shows
- Nothing abnormal in first 1-2 weeks
- Loss of bone density (rarefaction) at about 2 weeks
- May show a thin “white” line on the surface of the infected part of the bone (periosteal reaction)
- Later, may show a piece of dead bone (sequestrum)
- Blood: CBC, ESR, C&S: Type of bacterium may be detected
Management
Patients with suspected osteomyelitis need to be referred to hospital for appropriate management.
Treatment
- Immobilize the limb, splint
- Provide pain and fever relief with paracetamol, or ibuprofen
- Refer URGENTLY to hospital
- Admit and elevate affected limb
- Cloxacillin 500 mg IV every 6 hours for 2 weeks. Continue orally for at least 4 weeks (but up to 3 months)
- Child: 50 mg/kg every 6 hours
- See pyogenic arthritis for other antibiotic treatments
- Osteomyelitis in SCD: see Sickle Cell Disease - Infection Management
- Surgical intervention may be indicated in the following cases:
- Drainage of subperiosteal and soft tissue abscesses, and intramedullary purulence
- Debridement of contiguous foci of infection (which also require antimicrobial therapy)
- Excision of sequestra (i.e. devitalized bone)
- Failure to improve after 48-72 hours of antimicrobial therapy
- Drainage of subperiosteal and soft tissue abscesses, and intramedullary purulence
Chronic osteomyelitis
- Surgery and antibiotics