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==Introduction==

==Introduction==

Osteomyelitis describes '''inflammation and infection of the medullary cavity, cortex and periosteum of bone'''. This occurs most commonly at the '''metaphyses and epiphyses'''.

Osteomyelitis describes '''inflammation and infection of the medullary cavity, cortex and periosteum of bone'''. This occurs most commonly at the '''metaphyses and epiphyses'''.

It can arise from '''direct penetration of bone''' by microorganisms or by '''haematogenous spread'''. The latter is the most common cause of osteomyelitis in young animals. It can also accompany '''[[Arthritis|septic arthritis]]''', more commonly in foals. Other causes include: '''open fractures and traumatic injuries''', foreign bodies, extension of soft tissue infection etc.

It can arise from '''direct penetration of bone''' by microorganisms or by '''haematogenous spread'''. The latter is the most common cause of osteomyelitis in young animals. It can also accompany '''[[Arthritis|septic arthritis]]''', more commonly in foals. Other causes include: '''open [[fractures]] and traumatic injuries''', foreign bodies, extension of soft tissue infection etc.

Organisms commonly isolated include: ''[[Actinomyces pyogenes]]'', [[Salmonella|''Salmonella'']], [[Escherichia coli|''E.coli'']], [[Klebsiella|''Klebsiella'']], [[:Category:Streptococcus species|''Streptococci'']]

Organisms commonly isolated include: ''[[Actinomyces pyogenes]]'', [[Salmonella|''Salmonella'']], [[Escherichia coli|''E.coli'']], [[Klebsiella|''Klebsiella'']], [[:Category:Streptococcus species|''Streptococci'']].

'''Fungal organisms''' have also been implicated, and diseases, based on geographic distributions, include ''Coccidoides immitis'' (southwestern USA), ''Blastomyces dermatitidis'' (southeastern USA), ''Histoplasma capsulatum'' (central USA), ''Cryptococcus neoformans'' and ''Aspergillus'' (worldwide).

'''Fungal organisms''' have also been implicated, and diseases, based on geographic distributions, include ''Coccidoides immitis'' (southwestern USA), [[Blastomycosis|''Blastomyces dermatitidis'']] (southeastern USA), [[Histoplasma capsulatum var. farciminosum|''Histoplasma capsulatum'']] (central USA), ''[[Cryptococcus neoformans]]'' and ''[[Aspergillus spp.|Aspergillus]]'' (worldwide).

'''Pathogenesis''' involves: [[Bones - Anatomy & Physiology|osteoclastic]] bone resorption stimulated by prostaglandin and cytokines. Blood vessels become occluded and there is tissue necrosis with thickening of cartilage and persistence of infection. The affected area my be surround by fibrous inflammatory tissue.

'''Pathogenesis''' involves: [[Bones - Anatomy & Physiology|osteoclastic]] bone resorption stimulated by prostaglandin and cytokines. Blood vessels become occluded and there is tissue necrosis with thickening of cartilage and persistence of infection. The affected area my be surround by fibrous inflammatory tissue.

'''Risk factors''' include: open fracture and bone contamination, soft tissue trauma, bite and claw wounds, migrating foreign body, orthopaedic surgery and orthopaedic implants, cortical bone allograft and immunodeficiency.

'''Risk factors''' include: open fracture and bone contamination, soft tissue trauma, bite and claw wounds, migrating foreign body, orthopaedic surgery and orthopaedic implants, cortical bone allograft and immunodeficiency.

==Clinical signs==

==Clinical Signs==

Clinical signs may be acute or chronic and can vary widely.

Clinical signs may be acute or chronic and can vary widely.

'''Acute disease''' in small animals presents as a sudden onset ''''systemic illness''' with pyrexia, lethargy, '''limb pain''', and local signs of acute inflammation (heat, swelling, pain, redness, loss of function)

'''Acute disease''' in small animals presents as a sudden onset ''''systemic illness''' with pyrexia, lethargy, '''limb pain''', and local signs of acute inflammation (heat, swelling, pain, redness, loss of function).

'''Chronic cases''' are usually associated with chronic '''draining tracts, non-healing ulcers, pain, secondary muscle atrophy and joint stiffness'''.

'''Chronic cases''' are usually associated with chronic '''draining tracts, non-healing ulcers, pain, secondary muscle atrophy and joint stiffness'''.

'''Prognosis is variable''' and based on the severity and chronicity of the infection and the organism involved.

'''Prognosis is variable''' and based on the severity and chronicity of the infection and the organism involved.

[[Category:Bones - Inflammatory Pathology]]

[[Category:Bones - Inflammatory Pathology]]

[[Category:To Do - Manson]]

[[Category:Musculoskeletal Diseases - Cat]]