View source for Osteomyelitis

{{Infobox Disease |
  Name           = Osteomyelitis |
  Image          = Osteomyelitis in cancer.jpg|
  Caption        = Osteomyelitis in cancer. <br> <small> [http://www.peir.net Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology] </small>|
  ICD10          = {{ICD10|M|86||m|86}} |
  ICD9           = {{ICD9|730}} |
  ICDO           = |
  OMIM           = |
  DiseasesDB     = 9367 |
  MedlinePlus    = 000437 |
  eMedicineSubj  = ped |
  eMedicineTopic = 1677 |
  MeshName       = Osteomyelitis |
  MeshNumber     = C01.539.160.495 |
}}
{{Search infobox}}
{{CMG}}

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'''Osteomyelitis''' is an [[infection]] of [[bone]] or bone marrow, usually caused by [[pyogenic]] [[bacterium|bacteria]] or mycobacteria. It can be usefully subclassifed on the basis of the causative organism, the route, duration and anatomic location of the infection.

==Presentation==
Generally microorganisms may be disseminated to bone hematogenously (''i.e.'', via the blood stream), spread contiguously to bone from local areas of infection, such as [[cellulitis]], or be introduced by penetrating [[Physical trauma|trauma]] including [[iatrogenic]] causes such as joint replacements, internal fixation of fractures or root-canalled teeth. [[Leukocyte]]s then enter the infected area, and in their attempt to [[phagocyte|engulf]] the infectious organisms, release enzymes that lyse bone. [[Pus]] spreads into the bone's blood vessels, impairing the flow, and areas of devitalized infected bone, known as ''sequestra'', form the basis of a chronic infection. Often, the body will try to create new bone around the area of necrosis. The resulting new bone is often called an [[involucrum]]. 

On [[histology|histologic]] examination, these areas of necrotic bone are the basis for distinguishing between ''acute osteomyelitis'' and ''chronic osteomyelitis''. Osteomyelitis is an infective process which encompasses all of the bone (osseous) components, including the bone marrow. When it is chronic it can lead to bone sclerosis and deformity. 

Because of the particulars of their blood supply, the [[tibia]], the [[femur]], the [[humerus]], the [[vertebra]], the maxilla and the mandibular bodies are especially susceptible to osteomyelitis. [http://www.emedicine.com/emerg/topic349.htm]

==Etiology==
Newborns (younger than 4 mo): S aureus, Enterobacter species, and group A and B Streptococcus species
Children (aged 4 mo to 4 y): S aureus, group A Streptococcus species, Haemophilus influenzae, and Enterobacter species
Children, adolescents (aged 4 y to adult): S aureus (80%), group A Streptococcus species, H influenzae, and Enterobacter species
Adult: S aureus and occasionally Enterobacter or Streptococcus species

In children, the long bones are usually affected. In adults, the vertebrae and the pelvis are most commonly affected.

Acute osteomyelitis almost invariably occurs in children. When adults are affected, it may be because of compromised host resistance due to debilitation, intravenous drug abuse, infectious root-canalled teeth, other disease or drugs (e.g. [[immunosuppressive]] therapy).

==Treatment==
Osteomyelitis often requires prolonged [[antibiotic]] therapy. IV antibiotics are generally used to combat the infection, with a course lasting a matter of weeks or months. A PICC line or [[central venous catheter]] is often placed for this purpose.  Osteomyelitis also may require surgical [[debridement]].  Severe cases may lead to the loss of a limb. Initial first line antibiotic choice is determined by the patient's history and regional differences in common infective organisms.

American artist Thomas Eakins in 1875 depicted a surgical procedure for osteomyelitis in a famous oil painting titled "The Gross Clinic," now part of Jefferson Medical College.

Prior to the widespread availability and use of antibiotics, blow fly larvae were sometimes deliberately introduced to the wounds to feed on the infected material, effectively scouring clean.[http://www.ejbjs.org/cgi/content/abstract/13/3/438]

==Causes==
The vast predominance of hematogenously seeded osteomyelitis is caused by ''[[Staphylococcus aureus]]''. ''[[Escherichia coli]]'', ''Salmonella paratyphi'', and ''[[streptococcus|streptococci]]'' are other common [[pathogen]]s. In some subpopulations, including intravenous drug users and [[splenectomy|splenectomized]] patients, [[Gram negative]] bacteria, including enteric bacilli, are significant pathogens.

''Staphylococcus aureus'' is also one of the most common organisms seen in osteomyelitis seeded from areas of contiguous infection, but here Gram negative organisms and anaerobes are somewhat more common, and mixed infections may be seen.

Systemic mycotic, or fungal infections may cause osteomyelitis. The two most common are Blastomyces dermatitidis and [[Coccidioides immitis]].

In osteomyelitis involving the vertebral bodies, about half the cases are due to ''Staphylococcus aureus'', and the other half are due to [[tuberculosis]] (spread hematogenously from the [[lung]]s). Tubercular osteomyelitis of the spine was so common before the initiation of effective antitubercular therapy that it acquired a special name, ''[[Pott's disease]]'', by which it is sometimes still known. The most frequent cause is from infection of an incision from surgery.

==Complete Differential Diagnosis of Associated Conditions==
*[[Bacteroides]]
*Decubitus
*Diabetic angiopathy
*[[E.Coli]]
*Gastrointestinal infection
*[[Klebsiella]]
*[[Otitis]]
*[[Pneumonia]]
*[[Pseudomonas]]
*[[Serratia]]
*[[Sinusitis]]
*Skin infection
*[[Staphylococcus aureus]]
*[[Staphylococcus epidermidis]]
*[[Streptococcus pyogenes]]
*[[Streptococcus pneumoniae]]
*[[Tonsilitis]]
*[[Urinary tract infection]]
*[[Vasculitis]] <ref>Sailer, Christian, Wasner, Susanne. Differential Diagnosis Pocket. Hermosa Beach, CA: Borm Bruckmeir Publishing LLC, 2002:77 ISBN 1591032016</ref> <ref>Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:68 ISBN 140510368X</ref>

==Diagnostic Findings==

[http://www.radswiki.net Images courtesy of RadsWiki]

'''Extensive calcaneal osteomyelitis. Note soft tissue ulceration and [[cellulitis]]'''

<gallery>
Image:Osteomyelitis MRI 001.jpg|T1
Image:Osteomyelitis MRI 002.jpg|STIR
Image:Osteomyelitis MRI 003.jpg|T1 
Image:Osteomyelitis MRI 004.jpg|STIR
Image:Osteomyelitis MRI 005.jpg|T1 fat sat contrast
Image:Osteomyelitis MRI 006.jpg|T1 fat sat contrast
</gallery>

==Osteomyelitis and Chondritis of Vertebrae==

<youtube v=KTfOwYS1ykY/>

==See also==
*[[Brodie abscess]]

==References==
{{Reflist}}

==Additional Resources==
* {{MerckManual|5|54|b}}
* {{Chorus|00298}}

{{Diseases of the musculoskeletal system and connective tissue}}
[[Category:Orthopedics]]
[[Category:Bacterial diseases]]
[[Category:Skeletal disorders]]

{{SIB}}

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