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| Septic arthritis Classification and external resources |
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| ICD-10 | M00.-M03. |
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| ICD-9 | 711.0 |
| DiseasesDB | 29523 |
| eMedicine | med/3394 orthoped/438 |
| MeSH | D001170 |
Septic arthritis is the invasion of a joint by an infectious agent which produces arthritis. The usual etiology is bacterial, but viral, mycobacterial, and fungal arthritis occur occasionally. Bacteria are carried by the bloodstream from an infectious focus elsewhere, introduced by a skin lesion that penetrates the joint, or by extension from adjacent tissue (e.g. bone or bursae).
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Etiology
Micro-organisms must reach the synovial membrane of a joint. This can happen in any of the following ways:
- dissemination of pathogens via the blood, from abscesses or wound infections,
- dissemination from an acute osteomyelitic focus,
- dissemination from adjacent soft tissue infection,
- entry via penetrating trauma
- entry via iatrogenic means.1
Bacteria that are commonly found to cause septic arthritis are:
- Staphylococcus aureus - the most common cause in adults
- Streptococci - the second most common cause 2
- Haemophilus influenzae - was the most common cause in children but is now uncommon in areas where Haemophilus vaccination is practised3
- Neisseria gonorrhoea - in young adults (although this is now thought rare in western europe 2
- Escherichia coli - in the elderly, IV drug users and the seriously ill
- M. tuberculosis, Salmonella spp. and Brucella spp. - cause septic spinal arthritis 1
In bacterial infection, Pseudomonas aeruginosa has been found to infect joints, especially in children who have sustained a puncture wound. This bacteria also causes endocarditis.4
Indications
Septic arthritis should be suspected when one joint (monoarthritis) is affected and the patient is febrile. In seeding arthritis, several joints can be affected simultaneously; this is especially the case when the infection is caused by staphylococcus or gonococcus bacteria.
Diagnosis is by aspiration (giving a turbid, non-viscous fluid), Gram stain and culture of fluid from the joint, as well as tell-tale signs in laboratory testing (such as a highly elevated neutrophils (approx. 90%), ESR or CRP). A proportion of patients with septic arthritis have little in the way of fever or raised ESR, although the CRP is usually raised 5
Treatment
Therapy is usually with intravenous antibiotics, analgesia and washout/aspiration of the joint to dryness.
Radiologic Findings
Traditionally, the diagnosis of septic arthritis was based on clinical assessment and prompt arthrocentesis. However, the clinical picture may be obscured by multiple confounding factors and a paucity of specific findings especially for the deep joints, ie. the hip or shoulder. Imaging can be used to confirm the diagnosis of septic arthritis and more importantly, imaging findings suggestive of septic arthritis can direct the clinician to a diagnosis that may not have been considered.
Plain film findings of septic arthritis include: joint effusion, soft tissue swelling, periarticular osteoporosis, loss of joint space, marginal and central erosions and bone ankylosis. CT is more sensitive than plain films for the detection of early bone destruction and effusion.
The role of MRI in the diagnosis of septic arthritis has been increasing in recent years in an effort to detect this entity earlier. Findings are usually evident within 24 hours following the onset of infection and include: synovial enhancement, perisynovial edema and joint effusion. Signal abnormalities in the bone marrow can indicate a concomitant osteomyelitis. The sensitivity and specificity of MRI for the detection of septic arthritis has been reported to be 100% and 77% respectively.
See also
References
- ^ a b O'Callaghan C, Axford JS (2004). Medicine, 2nd ed., Oxford: Blackwell Science. ISBN 0-632-05162-0.
- ^ a b Kaandorp CJ, Dinant HJ, van de Laar MA, Moens HJ, Prins AP, Dijkmans BA (Aug 1997). "Incidence and sources of native and prosthetic joint infection: a community based prospective survey". Ann Rheum Dis. 56 (8): 470–5. PMID 9306869.
Weston VC, Jones AC, Bradbury N, Fawthrop F, Doherty M (Apr 1999). "Clinical features and outcome of septic arthritis in a single UK Health District 1982-1991". Ann Rheum Dis. 58 (4): 214–9. PMID 10364899. - ^ Bowerman SG, Green NE, Mencio GA (Aug 1997). "Decline of bone and joint infections attributable to haemophilus influenzae type b". Clin Orthop Relat Res. (341): 128–33. PMID 9269165, http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/media/landingpage.htm?issn=0009-921X&volume=341&spage=128.
Peltola H, Kallio MJ, Unkila-Kallio L (May 1998). "Reduced incidence of septic arthritis in children by Haemophilus influenzae type-b vaccination. Implications for treatment". J Bone Joint Surg Br. 80 (3): 471–3. PMID 9619939, http://www.jbjs.org.uk/cgi/pmidlookup?view=long&pmid=9619939. - ^ Topics in Infectious Diseases Newsletter, August 2001, Pseudomonas aeruginosa.
- ^ Geirsson AJ, Statkevicius S, Víkingsson A (May 2008). "Septic arthritis in Iceland 1990-2002: increasing incidence due to iatrogenic infections". Ann Rheum Dis. 67 (5): 638–43. doi:. PMID 17901088.
- Septic arthritis by William Brinkman, M.D., University of Washington Department of Radiology
- Karchevsky M, Schweitzer ME, Morrison WB, Parellada JA (2004). "MRI findings of septic arthritis and associated osteomyelitis in adults". AJR Am J Roentgenol 182 (1): 119–22. PMID 14684523, http://www.ajronline.org/cgi/pmidlookup?view=long&pmid=14684523.
- Resnick, Donald (1989). Bone and joint imaging. Philadelphia: Saunders, 744-749. ISBN 0721622151.
- Bredella, Miriam A.; Stoller, David W.; Tirman, Phillip F. J. (2004). Diagnostic imaging. Salt Lake City, Utah: Amirsys, 4-99. ISBN 0-7216-2920-2.
- Edwards MS. "Osteomyelitis and Septic Arthritis"
- Septic Arthritis at eMedicine
- Septic Arthritis, Pediatrics at eMedicine
