Slide Presus Osteomielitis [Autosaved]

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Pathophysiology of chronic bacterial osteomyelitis. Why do antibiotics fail so often? J Caimpolini K G Harding Sigit kutniawan 20090310184

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osteomilitis

Transcript of Slide Presus Osteomielitis [Autosaved]

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Pathophysiology of chronic bacterial osteomyelitis. Why do antibiotics fail so

often?J Caimpolini K G Harding

Sigit kutniawan20090310184

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Definition

• Osteomyelitis is an infection of the bone. It can happen in any bone in the body, but it most often affects the long bones (leg and arm), the spine, and foot bones. it can caused by bacterial infection (usually from Staphylococcus) or, more rarely, a fungal infection

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• Acute osteomyelitis occurs with a rapid onset and is usually accompanied by the symptoms of pain, fever, and stiffness. It generally occurs after a break in the skin from injury, trauma, surgery, or skin ulceration from wounds.

• Chronic osteomyelitis is insidious (slow) in onset. It may be the result of a previous infection of osteomyelitis. Despite multiple courses of antibiotics, it may reoccur. Symptoms of chronic osteomyelitis are subtle but may include fever, pain, redness, or discharge at the site of infection.

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Epidemiology

• Approximately 20% of adult cases of osteomyelitis are hematogenous, which is more common in males for unknown reasons.

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Acute bacterial osteomyelitis carried 50 % mortality in the preantibiotic era because of overwhelming sepsis with metatasic abses. Althought antimicrobial drugs have dramatically changed the prognosis of the acut hematogenous form, chronic bacterial osteomielitis remains a challenging medical problem

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• In this review, we analyse the current under-standing of chronic osteomielitis by focussing on how bacteria succeed in overcoming both host defence mechanism and the antibiotic agents

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Micro-organism

• The typical causative agent is S areus, or salmonela epidermidis if associated with an implant. Gram negative bacteria are present in about one third of case

• Chronic osteomyelitis in the diabetic foot is polymicrobial with mixed Gram positive and Gram negative bacteria (aerobes and anaerobes).

• Wound swabs are all too often inaccurate in chronic osteomyelitis: cultures from operative specimens are a more reliable method of planning antibiotic treatment.

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Pathophysiology of bone infectionBacterial contamination

(direct inoculum , Haematogenous)

Bacterial adhesion to bone or implan

infection chronicity

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Patofisiologi Osteomyelitis Hematogenous

• caused by bacteria through the blood

• In the metafisis : blood vessels banked with sharp corners - blood flow slows - bacterial colonization, deposition and thrombus - focus of infection - local necrosis of bone

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Patofisiologi Direct or contiguous inoculation osteomyelitis

• Caused by direct contact between the bone tissue with bacteria

• Common due to open trauma or surgery

• The Manisfestasi is localized on the bone tissue

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• Healthy bone is extremely resistant to infection.• However, once an infection has established, its

eradication by antibiotic treatment is very difficult.• Dead bone and implants are the most common

reasons for failure of conservative treatment. Under those circumstances bacteria cannot be reached by host defence mechanisms or antibiotics.

• The presence of an implant causes exhaustion of local polymorphonuclear cells that become unable to kill phagocytosed bacteria.

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the failure of medical treatment of osteomyelitis

• Chronic osteomyelitis is often a lifelong disease. Late reactivation up to 80 years after the primary episode has been reported.

• Bacteria can also elude host defence mechanisms by hiding intracellularly and by developing a protective slimy coat.

• By acquiring a very slow metabolic rate, bacteria become less sensitive to antibiotics.

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Thank you