Osteomyelitis (Bone Infection)

How bone becomes infected

Common bacteria

• Staphylococcus aureus, including MRSA: the most common cause
• Kingella kingae in children under 4
• Salmonella in people with sickle cell disease
• Pseudomonas after puncture wounds through shoes
• mixed bacteria in diabetic foot infections
• tuberculosis and fungi, less commonly

Types

• acute osteomyelitis: develops over days to weeks
• chronic osteomyelitis: persists for months or years, with dead bone (sequestrum) that bacteria can hide in; may have a draining sinus
• vertebral osteomyelitis: infection of the spine, mostly in adults over 50
• diabetic foot osteomyelitis: from an ulcer reaching bone
• implant-related: around plates, screws or joint replacements

Symptoms

• pain and tenderness over the bone, often worse at night
• swelling, warmth and redness
• fever, chills and feeling unwell (may be absent in chronic or diabetic cases)
• reduced movement of the limb
• children: limping, refusing to walk, not using an arm, irritability
• spine: persistent back or neck pain, often with fever; nerve symptoms if an abscess forms
• diabetic foot: an ulcer that will not heal, exposed bone, a red swollen "sausage" toe; pain may be absent because of nerve damage
• chronic: a draining wound or sinus over the bone

Diagnosis

• blood tests: white cell count, CRP and ESR (inflammation markers), blood cultures
• X-ray: may be normal for the first 10 to 14 days; later shows bone destruction
• MRI: the most sensitive test, showing early bone marrow swelling and abscesses
• CT or bone scan: when MRI is not possible
• probe-to-bone test: in diabetic ulcers, touching bone with a sterile probe strongly suggests osteomyelitis
• bone biopsy: confirms infection and identifies the organism for targeted antibiotics; especially important in chronic and spinal infection

Treatment

Antibiotics

• usually started IV, then often switched to tablets once improving
• total duration typically 4 to 6 weeks; longer for chronic infection or implants
• children with uncomplicated acute osteomyelitis often switch to oral antibiotics early, with shorter total courses
• choice depends on culture results and local resistance patterns (including MRSA)

Surgery

Needed to:

• drain abscesses
• remove dead or infected bone (debridement)
• remove or exchange infected implants
• in diabetic foot osteomyelitis, sometimes remove part of a toe or foot bone
• stabilize the spine or decompress nerves in vertebral infection

Supporting healing

• good blood sugar control in diabetes
• offloading pressure from foot ulcers
• stopping smoking
• nutrition and wound care

Complications

• septic arthritis when infection reaches a nearby joint
• chronic infection and draining sinuses
• growth problems if a child's growth plate is affected
• fractures through weakened bone
• spinal abscess and paralysis
• amputation in severe diabetic foot infection
• rarely, squamous cell carcinoma in long-standing draining sinuses

Prevention

• daily foot checks and prompt treatment of diabetic foot ulcers
• careful wound care for cuts, bites and puncture wounds
• treating skin infections such as cellulitis early
• safe injection practices
• preventing pressure ulcers in people with limited mobility

Frequently asked questions

What are the symptoms of osteomyelitis?

Typical symptoms are pain and tenderness over a bone, swelling, warmth, redness and fever. Children may limp or refuse to use a limb. In people with diabetes, a non-healing foot ulcer may be the only sign. Chronic infection can cause a draining wound.

What causes a bone infection?

Bacteria, most often Staphylococcus aureus, reach the bone through the bloodstream, spread from nearby infections such as diabetic foot ulcers, or enter directly through open fractures, surgery, bites or puncture wounds.

How is osteomyelitis treated?

Treatment involves several weeks of antibiotics, usually 4 to 6 weeks or more, often starting IV. Surgery may be needed to drain pus, remove dead bone or remove infected implants. Treating diabetes, offloading ulcers and stopping smoking help healing.

Can osteomyelitis be cured?

Acute osteomyelitis is usually cured with prompt antibiotics. Chronic osteomyelitis is harder to treat and often needs surgery to remove dead bone plus long antibiotic courses. Infections can recur, sometimes years later.

How is osteomyelitis diagnosed?

Doctors use blood tests for inflammation, X-rays (often normal early), MRI to detect early changes, and sometimes a bone biopsy to confirm infection and identify the bacteria for targeted antibiotics.